Stereotactic radiosurgery apparatus

Abstract

A radiotherapy apparatus is provided which is designed to deliver coplanar and non-coplanar radiation treatment beams. The apparatus comprises: i) a mount; ii) a treatment head comprising a radiation source; and iii) a treatment dual arm system comprising a first treatment arm having first and second ends, wherein the first end is rotatably connected to the mount, and a second treatment arm having a joint end and a treatment end, wherein the joint end is rotatably mounted onto the second end of the first treatment arm and the treatment head is mounted on the treatment end of the second treatment arm, wherein the first and second treatment arms rotate 360° about first and second axes, respectively. The radiotherapy apparatus is useful to deliver unique treatment paths to a patient while in a stationary treatment position.

Description

[0001] STEREOTACTIC RADIOSURGERY APPARATUS

[0002] Field of Invention

[0003] [1] This invention generally relates to the field of radiotherapy. In particular, a radiotherapy apparatus is provided, designed for delivering radiotherapy treatments including, but not limited to, high-dose, high-precision modalities such as stereotactic radiosurgery (SRS), fractionated stereotactic radiosurgery (FSRT), stereotactic body radiation therapy (SBRT) and stereotactic ablative radiotherapy (SABR). The apparatus is designed to enable dynamic treatments with spherical geometry including coplanar and non-coplanar beam arrangements without requiring patient repositioning during a treatment session.

[0004] Background of the Invention

[0005] [2] Radiation therapy for cancer treatments uses high doses of radiation to eradicate or shrink tumors. Radiation therapy uses radiation beams of various energies, usually in the form of x- rays, gamma rays, electrons, protons or heavy ions, to kill cancer cells.

[0006] [3] Current radiation therapy uses radiation beams that are designed to enter the body from multiple angles. Each beam delivers a fraction of the total prescribed dose, with all beams converging at the tumor site to deliver a high cumulative dose to the target. Meanwhile, the lower dose of each individual beam minimizes radiation exposure to surrounding healthy tissues and helps to spare critical structures. Several treatment techniques utilize such multi-angle beam arrangements. When all beams lie within a single plane, typically perpendicular to the patient’s longitudinal axis, they are referred to as coplanar beams. In contrast, beams entering from directions outside this plane are referred to as non-coplanar beams.

[0007] [4] While conventional radiation therapy typically delivers small doses over many sessions (e.g., 25-30 fractions), stereotactic radiosurgery (SRS) is a specialized modality designed to deliver a very high dose with exceptional precision to a small, well-defined target, often in a single session. Originally developed for small, isolated brain tumors (commonly called brain radiosurgery), SRS has proven highly effective and is now used for multiple brain tumors (five or more) and larger or more complex targets. When the total dose is divided into several smaller sessions (typically three to five), the technique is referred to as fractionated stereotactic radiosurgery (FSRS) or fractionated stereotactic radiotherapy (FSRT), though “SRS” is often used broadly to encompass all such approaches. Advances in clinical practice have shifted the management of brain metastases from whole-brain irradiation toward these targeted stereotactic methods, improving tumor control, minimizing neurocognitive side effects, and enhancing quality of life. The same principles of high dose, high precision, and low fractionation have been successfully applied to extracranial tumors such as those in the lung, liver, or spine, known as stereotactic body radiotherapy (SBRT) or stereotactic ablative radiotherapy (SABR). Collectively, these methods are often referred to as stereotactic radiotherapy (SRT) and now represent a substantial portion of modern radiotherapy practice. A key feature of these techniques is the use of multi-directional, three-dimensional beam arrangements, in which multiple radiation beams are directed toward the target from different angles to achieve a high therapeutic dose at the tumor while minimizing exposure to surrounding healthy tissues and critical organs. SRT and FSRT, in particular, rely heavily on non-coplanar beam geometries, where beams are delivered from various planes rather than a single flat plane. This configuration distributes the entry dose more evenly and reduces radiation to normal tissue, which is essential for safe and effective stereotactic delivery. These treatments necessitate radiotherapy systems configured for high-accuracy, efficient non- coplanar beam delivery to enable effective and patient-tolerable therapy.

[0008] [5] Radiotherapy systems employing gamma radiation (mainly using cobalt-60 sources), include the Leksell Gamma Knife™ system by Elekta, which is widely regarded as the gold standard for intracranial SRS. Such systems use large numbers of cobalt-60 sources (e.g. 192 or 201) to produce fixed gamma radiation beams that converge precisely at the target area, delivering a high dose of radiation with extreme precision. They work well for small, well-defined brain tumors. However, these systems have certain disadvantages when treating multiple or large tumors. One significant limitation is the long treatment time. Treating one tumor can take up to an hour, and patients may have to lay in a rigid, uncomfortable position for several hours during a single treatment session. This can be particularly challenging and uncomfortable for patients who must remain still during the entire procedure. Treating multiple tumors may take several hours and often requires multiple sessions, making the process less efficient and more taxing for patients. Additionally, the use of circular beam collimation with cones in this technology restricts its ability to effectively conform the dose to multiple tumors and larger tumors with complex shapes. Further, these machines, including the Leksell Gamma Knife are limited to treating exclusively the brain. [6] The CyberKnife™ is a robotic radiosurgery system that delivers high doses of radiation with high precision using a flexible, robotic arm to target tumors from many angles. However, CyberKnife uses fixed beams, which can limit its efficiency compared to techniques like Volumetric Modulated Arc Therapy (VMAT). Fixed beams require longer treatment times as the system repositions for each beam delivery, and it cannot continuously modulate the intensity and shape of the radiation dose as effectively as VMAT. This makes CyberKnife less suitable for treating larger tumors or multiple lesions in a time- efficient manner. In addition, the CyberKnife lacks an integrated volumetric imaging solution for patient positioning and anatomical verification, relying instead on external or third-party imaging systems.

[0009] [7] Linear accelerators (LINACs) are the most widely used and versatile radiotherapy systems, typically configured in a C-arm design to deliver high-energy X-ray or electron beams for a broad range of cancer treatments. They are increasingly used in SRS and are the most convenient for multiple and large tumors. The advantage of using LINACs with Volumetric Modulated Arc Therapy (VMAT) is that VMAT allows for continuous delivery of radiation while the machine rotates around the patient, modulating the intensity and shape of the beam in real-time. This results in shorter treatment times and conformal dose distributions, thereby improving overall efficiency. However, similar to Gamma Knife and CyberKnife, LINACs need to use non-coplanar radiation beams that irradiate tumors from various planes to achieve acceptable dose distributions. Due to their rigid geometry and single rotation axis, LINACs require the patient to be rotated multiple times during treatment to achieve limited non-coplanar beam configurations. This repositioning increases the likelihood of patient movement, leading to potential inaccuracies and necessitating additional verifications of the treatment couch position and patient alignment. These extra verifications and frequent realignments can significantly extend treatment times, increase patient discomfort, and require additional resources, such as advanced patient tracking systems. Maintaining the high precision needed for SRS becomes challenging, as frequent patient movement can result in errors in radiation delivery. This is one of the reasons many neurosurgeons are hesitant to refer their patients for LINAC-based SRS treatments. Furthermore, even with patient rotation, conventional LINAC systems offer only limited beam geometry options, constraining the flexibility of non-coplanar treatment delivery.

[0010] [8] The ZAP-X™ is a LINAC-based system specifically designed for brain radiosurgery, utilizing a gyroscopic design to deliver radiation from multiple angles, closely resembling the treatment geometry of the Gamma Knife. Despite its innovative approach, the ZAP-X has several limitations, including its use of cone-shaped collimation static beam delivery which restricts flexibility in beam shaping, may extend treatment times and limit beam modulation. This system is unable to treat tumors outside the brain.

[0011] [9] There currently exists technology which can deliver targeted radiation therapy using the above techniques at varying degrees of freedom. For example, Canadian patent no.2935418 discloses a method of irradiating a target site in a patient comprising directing a beam of radiation from an external source of radiation at a target in the patient from numerous directions in a broad solid angle by longitudinally rotating the external source of radiation around a central axis and simultaneously or sequentially, in either order, latitudinally rotating the external source of radiation.

[0012]

[0010] However, existing technologies lack the rotational degrees of freedom needed to enable fully flexible non-coplanar radiotherapy with dynamic beam delivery (such as VMAT) while allowing the patient to remain stationary during treatment of either cranial or extracranial targets. Accordingly, there is a need for a radiotherapy system that overcomes one or more of these limitations and integrates imaging for precise patient positioning and anatomical verification.

[0013] Summary of the Invention

[0014]

[0011] A novel radiotherapy apparatus has now been developed which provides dynamic treatments with complete spherical geometry including coplanar and non-coplanar treatments without requiring patient repositioning during a treatment session.

[0015]

[0012] In one aspect, a radiotherapy apparatus is provided comprising a base, a treatment head comprising a radiation source; and a dual treatment arm system comprising first and second treatment arms. The first treatment arm has first and second ends, wherein the first end is rotatably mounted to the base and permits the first treatment arm to rotate 360° around a first axis. The second treatment arm has a first end rotatably connected to the second end of the first treatment arm and permits the second treatment arm to rotate 360° around a second axis. A second end of the second treatment arm is secured to the treatment head.

[0016]

[0013] In an embodiment, the radiotherapy apparatus may further comprise an imaging system. For example, the imaging system may comprise an imaging arm extending from the base, an imaging head comprising an imaging source, and a detector arm extending from the base and comprising a detector panel adapted to receive signals emitted by the imaging source within the imaging head. The imaging arm and the detector arm may be rotatably mounted on the base.

[0017]

[0014] In a further aspect, a method of delivering radiation to a patient is provided. The method comprises administering radiation to a patient situated in a treatment position, wherein said radiation is administered to the patient via a treatment head of a radiotherapy apparatus, the position of the treatment head being controlled by at least two rotatable arms of the radiotherapy apparatus. The angle of rotation of each rotatable arm may be the same or different; however, collectively, the total angle of rotation of all of the rotatable arms is at least 180° allowing for full spherical motion of the treatment head.

[0018]

[0015] These and other aspects of the invention are described herein by reference to the following drawings.

[0019] Brief Descriptions of the Drawings

[0020]

[0016] Figure 1 shows a radiotherapy apparatus comprising a dual treatment arm system in accordance with an embodiment of the invention in A) operation, and B) in a resting nested position.

[0021]

[0017] Figure 2 shows embodiments of a radiotherapy apparatus comprising: A) arc-shaped treatment arms in resting nested position; B) 90°-90° treatment arms in an extended position which clear the treatment couch; C) 90°-90° treatment arms in an extended position which do not clear the treatment couch; D) treatment arms of different lengths which are 90°-60° arms; and E) treatment arms of equal lengths which are 60°-60° arms.

[0022]

[0018] Figure 3 shows an embodiment of a floor mounted radiotherapy apparatus comprising a three treatment arm configuration.

[0023]

[0019] Figure 4 shows a radiotherapy apparatus with an imaging system comprising independently rotatable imaging and detector arms in accordance with an embodiment of the invention.

[0024]

[0020] Figure 5 shows a radiotherapy apparatus with an imaging system wherein treatment, imaging and detector arms are retracted into a nested configuration in accordance with an embodiment.

[0021] Figure 6 shows a radiotherapy apparatus with an imaging system comprising 180° fixed imaging and detector arms in accordance with an embodiment of the invention.

[0025]

[0022] Figure 7 shows a front perspective view of a wall-mounted radiotherapy apparatus with an imaging system wherein the treatment arms and imaging system each comprise a dual-arm system in an embodiment.

[0026]

[0023] Figure 8 shows a rear perspective view of a floor-mounted radiotherapy apparatus with an imaging system wherein the treatment arms and imaging system each comprise a dual-arm system in an embodiment.

[0027]

[0024] Figure 9 shows a front perspective view of the radiotherapy apparatus of Fig. 7 wherein the treatment and imaging arms are in a fully retracted position with A) all arms on the top side of the mount; and B) the treatment and imaging arms are on the top side of the mount, while the detector arms are below the mount.

[0028]

[0025] Figure 10 shows a front perspective view of A) the radiotherapy apparatus of Fig. 9A and B) the radiotherapy apparatus of Fig 9B, with the imaging arms retracted and the treatment arms and head extended.

[0029]

[0026] Figure 11 shows a front perspective view of a radiotherapy apparatus in an embodiment in which the imaging radiation source is secured at the joint of the second treatment arm, and the detector arm rotates independently of the treatment arm.

[0030]

[0027] Figure 12 shows a front perspective view of a radiotherapy apparatus of Fig. 11 with the imaging and treatment arms in a fully retracted position.

[0031]

[0028] Figure 13A shows a front perspective view of a radiotherapy apparatus of Fig. 11 in a kV imaging configuration utilizing the imaging radiation source.

[0032]

[0029] Figure 13B shows a front perspective view of a radiotherapy apparatus of Fig. 11 in an MV imaging configuration utilizing the treatment head radiation source for imaging.

[0033]

[0030] Figure 14 shows a front perspective view of a radiotherapy apparatus in an embodiment in which the radiation source and detector panel for the imaging system are on opposite ends of a single 180° C-arm, i.e. the detector arm and first treatment arm are fixed at 180° from one another.

[0034]

[0031] Figure 15 shows a front perspective view of sites of rotation in a radiotherapy apparatus via rotation motors M1-M6 in an embodiment such as shown in Fig. 7.

[0035]

[0032] Figure 16 illustrates mounting of the radiotherapy apparatus on: A) the floor; B) the wall; C) the ceiling; and D) a stand.

[0036]

[0033] Figure 17 is a schematic illustrating the operation of an apparatus in accordance with an embodiment of the invention.

[0037]

[0034] Figure 18 shows a radiation delivery embodiment for delivery of radiation A) in a wedgelike pattern to the head of a patient B) with four distinct delivery paths using a radiotherapy apparatus in accordance with an embodiment of the invention.

[0038]

[0035] Figure 19 shows a radiation delivery embodiment for delivery of radiation A) in a pie-like pattern to the head of a patient B) with four distinct delivery paths using a radiotherapy apparatus in accordance with an embodiment of the invention.

[0039]

[0036] Figure 20 shows a radiation delivery embodiment for delivery of radiation A) to the head of a patient B) with three distinct 360° concentric delivery paths using a radiotherapy apparatus in accordance with an embodiment of the invention.

[0040]

[0037] Figure 21 shows a radiation delivery embodiment for delivery of radiation A) to the head of a patient B) with a non-linear wave delivery path based on simultaneous rotation of first and second treatment arms using a radiotherapy apparatus in accordance with an embodiment of the invention.

[0041]

[0038] Figure 22 shows a radiation delivery embodiment with three distinct radiation delivery paths for delivery of radiation to the body of a patient using a radiotherapy apparatus in accordance with an embodiment of the invention.

[0042]

[0039] Figure 23 is a schematic of cranial treatment and / or imaging of a patient A) in supine position and B) sitting at an angle using an apparatus in accordance with an embodiment of the invention.

[0040] Figure 24 is a schematic of extra-cranial treatment of a patient A) in supine position and B) sitting at an angle using an apparatus in accordance with an embodiment of the invention.

[0043]

[0041] Figure 25 is a schematic of extra-cranial treatment patterns of a patient in supine position including: A) three arcs at three different angles along the longitudinal axis; and B)... three arcs at three different angles along the transverse (left-right) axis.

[0044] Detailed Description of the Invention

[0045]

[0042] A radiotherapy apparatus (10) is provided designed to deliver radiation to a given target volume or group of volumes at an isocenter from every possible direction with a complete spherical geometry in an embodiment of the invention. This includes coplanar and non-coplanar radiation treatment beams. For clarity, coplanar treatments involve the delivery of radiation from a single plane that is transverse to the patient and perpendicular to the patient’s longitudinal (vertical) axis, whereas non-coplanar treatments deliver radiation from additional planes and directions that deviate from this transverse plane.

[0046]

[0043] The radiotherapy apparatus (10) comprises a base or mount (12), a treatment head (40) which contains a treatment radiation source, and a dual treatment arm system comprising a first arc-shaped treatment arm (20) and a second arc-shaped treatment arm (30) as shown in Figure 1. The dual treatment arm system (20, 30) is rotatably connected to the mount (12) which is adapted to be fixed to a support as further described herein.

[0047]

[0044] A first end (22) of the first arc-shaped treatment arm (20) is rotatably connected to the mount (12) at a first joint (J1) such that the first arc-shaped treatment arm (20) rotates 360° latitudinally about a first axis (A1), as seen in Figure 1. A first end (32) of the second arc-shaped treatment arm (30) is rotatably connected at a second joint (J2) to a second end (24) of the first arc-shaped treatment arm (20), such that the second arc-shaped treatment arm (30) rotates 360° latitudinally about a second axis (A2) which is perpendicular to the first axis (A1), as seen in Figure 1. As will be appreciated by one of skill in the art, rotation about J1 and J2 may be modified in some embodiments, for example, to result in longitudinal rotation of one or both of the treatment arms relative to A1 and / or A2. In general, modifications for the rotation of the treatment arms can result in rotation in any direction in 4pi (spherical) geometry.

[0045] The treatment head (40) is secured to a second end (34) of the second arc-shaped treatment arm (30) and is oriented such that radiation emitted from the treatment head (40) is directed along a third axis (A3) perpendicular to A2 at an isocenter (100). The “mechanical isocenter” is the point in space relative to the apparatus (10) about which the components of the apparatus rotate forming a total spherical path or a sphere. The radiation isocenter is the point where radiation beams from the treatment head (40) converge from all directions (full sphere). These two isocenters are generally aligned and share the same coordinates. The treatment center is positioned at this shared isocenter, typically aligning with the center of the tumor or group of tumors being targeted for treatment.

[0048]

[0046] The treatment head (40) may be mounted in a fixed position at the end of the second treatment arm (30) or may be rotatably mounted to the second end (34) of the second treatment arm (30) at a third joint (J3) to permit the treatment head (40) to rotate 360° around a third axis (A3). The rotational mobility of the first and second treatment arms (20,30) enables the treatment head (40) to rotate 360° both latitudinally and longitudinally about the isocenter (100) and allows for the delivery of radiation treatment beams from any position along a sphere about the isocenter (100), resulting in the ability to administer radiation in both coplanar and non- coplanar treatment paths. Coplanar treatment paths are defined as those that are within a single plane perpendicular to axis A1 , which runs vertically through the patient in the superior-inferior direction, from head to foot. Non-coplanar treatment paths refer to any radiation beam paths that deviate from this plane, originating from angles outside of the plane perpendicular to axis A1.

[0049]

[0047] In one embodiment, the treatment arms are sized and shaped to permit nesting of the second treatment arm (30) against or under the first treatment arm (20). This allows the radiotherapy apparatus (10) to assume a retracted position as shown in Figure 1 B in which the second treatment arm (30) retracts so that it nests under the first treatment arm (20) in a concentric manner. While arc-shaped arms are preferred, it will be understood by a person skilled in the art that the arms of the dual arm system may assume other shapes, including arms that assume different curvatures, angles or combinations thereof, such that they retain their ability to rotate spherically about their respective axes, i.e. unhindered by their shape, and to deliver treatment beams at any angle latitudinally or longitudinally along coplanar and non- coplanar paths. Such other shapes may also permit nesting of the treatment arms.

[0048] The treatment head (40) comprises any suitable source of radiation for use to treat a patient. In an embodiment, the radiation source is an x-ray source. The present apparatus may comprise a treatment head (40) adapted to deliver x-ray radiation with energy in the megavoltage (MV) range, for example, from about 1-6 MV. Alternatively, the treatment head may provide x- ray radiation energies in the kilovoltage (kV) range.

[0050]

[0049] Preferably, the x-ray source comprises an x-ray generation and collimation system in the form of a linear accelerator (LINAC). The linear accelerator uses microwaves to create an electromagnetic field that accelerates electrons to high speeds along a waveguide system. The x-ray generation system includes a target for electron creation (e.g. an electron gun), an electron acceleration system (e.g., a magnetron and a waveguide), a target for x-ray generation (e.g. heavy metal such as tungsten), and a dose-monitoring ion chamber. The electrons are accelerated in the wave guide and strike the x-ray target, generating X-rays through the bremsstrahlung effect. The collimation system generally includes a fixed primary collimator, which initially shapes and restricts the X-ray beam to a broad rectangular field. It may also include a multi-leaf collimator (MLC), composed of thin, heavy metal leaves that offer more precise beam shaping to customize the size and shape of the radiation beam around the treatment volume and to protect surrounding tissues. A third collimator may be used to minimize radiation leakage between the MLC leaves. The MLC system generally rotates 360° around axis (A3). While a LINAC can generate x-rays with a wide range of energies, for use in the present apparatus, a LINAC preferably delivers radiation within a range that permits the use of compact parts, for example, an energy of up to about 6 megavolts (MV). This energy range is the most clinically used and only requires a compact magnetron for microwave generation and a relatively short waveguide of about 60 cm - 70 cm for electron acceleration.

[0051]

[0050] In another embodiment, the apparatus may be equipped with removable SRS cones mounted at the distal end of the treatment head (40). The SRS cones are heavy-metal cylindrical collimators, typically made of tungsten or a tungsten-alloy, that shape the radiation beam into fixed circular fields. These cones produce highly collimated, sharply defined beams with steep dose gradients and minimal radiation leakage, suitable for stereotactic radiosurgery applications.

[0052]

[0051] The apparatus (10) may, in one embodiment, utilize Volumetric Modulated Arc Therapy (VMAT). VMAT is an advanced radiation therapy technique in which the linear accelerator continuously delivers radiation while rotating around the patient (about the isocenter) and dynamically adjusts the beam's intensity and shape using the multi-leaf collimator (MLC) system. Compared to other options in which a delivery machine must be static during beam delivery, VMAT delivery allows for highly conformal treatment plans, enabling effective dose distribution and reduced treatment times. In another embodiment, the apparatus (10) may employ conformal arcs. Similar to VMAT, radiation is continuously delivered as the treatment head (40) rotates along one or more arcs around the patient. However, in this case, only the beam shape is modulated using the MLCs, while the beam intensity remains constant.

[0053]

[0052] In another embodiment, the LINAC utilizes electron radiation, either alone or together with x-ray radiation (i.e. alternating between electron and x-ray radiation). Electron beam radiation therapy (EBRT) is a type of external radiation therapy that uses high-energy electrons to target and destroy cancer cells.

[0054]

[0053] In other embodiments, the treatment head (40) comprises a radioactive source, such as gamma radiation using, for example, 60Cobalt isotope.

[0055]

[0054] The present radiotherapy apparatus (10) with rotatable treatment arms (20, 30) advantageously provides advanced treatment options with at least two rotational degrees of freedom (e.g. about A1 and A2) to provide full spherical coverage. This allows radiation to be delivered from any direction within a spherical geometry toward the isocenter (100), offering treatment paths that are not achievable with current radiotherapy devices. For example, the provision of 360° rotational first and second treatment arms, i.e. that can rotate 360°, also referred to as spherical rotation, provides two degrees of freedom and allows for treatment including coplanar and non-coplanar treatment paths such as arc-shaped beam patterns of varying angles for cranial and extra-cranial treatments. Wave-like treatment is also possible. Three or more degrees of freedom, provided by introduction of a rotational treatment head (40) and / or rotational collimation system within the treatment head, permits more options for shaping the radiation dose around tumors while sparing normal tissue.

[0056]

[0055] Radiation treatment using the present apparatus (10) may be delivered either through arcs, where radiation is administered while one or more of the rotational components are moving, including one or more of the treatment arms (20, 30), treatment head (40) or MLC or collimation system are moving, or through a static beam, where the treatment arms (20, 30) remain stationary during beam delivery. The treatment paths available with simultaneous movement of both treatment arms include wave-like paths and arcs in any direction and angle.

[0057]

[0056] The treatment arms (20, 30) may be the same length or different lengths. Treatment arms of the same length having an arc-shape are able to achieve spherical coverage as above described if together the angles of their arc shapes comprise at least 180°, also referred to as 90-90 arms (Fig. 2B). The term “arc-shape” as used herein refers to the arc of a circle. However, in practice, certain angles of such arms will be restricted to prevent collisions with the patient or the treatment couch. An example of the limitations of the 90-90 arm configuration is shown in Fig. 2C. To address this, in the development of a treatment plan, permissible geometries will be calculated and non-permissible geometries will be excluded to prevent collisions with the patient or couch. These calculations may utilize patient positioning data and anatomical volume information derived from the patient’s CT simulation images.

[0058]

[0057] In another embodiment, collision risk may be mitigated by altering the length of one or both treatment arms. For example, either or both of the treatment arms may be shortened. As shown in Fig. 2D, the second treatment arm (30) only is shortened to create a 60-degree angle, resulting in a 90°-60° configuration of the treatment arms. Both treatment arms (20, 30) may be shortened as shown in Fig. 2E to achieve a 60°-60° configuration. However, shortening of one or both treatment arms will result in treatment arm angles that are unable to achieve full spherical coverage around the isocenter (100). Thus, the apparatus may be modified to include one or more additional rotatable arms to increase the degrees of freedom achieved by the apparatus and to permit the treatment arms to attain spherical coverage. The additional arm may be added as a third treatment arm (35) rotatably connected to the second treatment arm at joint 3 (J3), to form a triple treatment arm system in which the treatment head (40) is connected to the terminal end of the third treatment arm at a fourth joint (J4) as shown in Fig. 3. Alternatively, rotation about a support arm mounting the apparatus (10) to the floor or ceiling as shown in Figure 16, and described in more detail herein, may provide the additional degrees of freedom.

[0059]

[0058] As one of skill in the art will appreciate, the treatment arms (20, 30) will be sized and positioned on the apparatus (10) to enable effective use in radiotherapy. Specifically, the distance of the mount (12) to the isocenter, and the distance of the treatment head (40) to the isocenter (100) is selected so as to avoid collision with the treatment couch and / or patient for a given treatment path. In this regard, the treatment head (40) may be adjustably connected to its treatment arm (30) to allow adjustment of its position to permit flexibility with different treatment paths and patients. This distance may also be controlled by adjusting the treatment couch. In an embodiment, a distance of the treatment head (40) to the isocenter (100) of about 400-500 mm, e.g. 450 mm, and a distance of about 1500-1700 mm, e.g. 1600 mm, from the mount (12) to the isocenter (100) have been determined to be suitable distances. As one of skill in the art will appreciate, these distances are exemplary and modifications within a reasonable range, would also be expected to be suitable. For example, the term “about” may be understood to refer to variance from a given value of either greater or less than 10%.

[0060]

[0059] The radiotherapy apparatus (10) may additionally comprise an imaging system, which may be referred to as ‘on-board imaging’ (OBI). The inclusion of an imaging system enhances treatment precision by confirming that the patient's position and anatomy align with the reference images from the planning phase. An imaging system for use combined with the present radiotherapy apparatus (10) comprises an imaging arm (50) comprising an imaging x-ray source (56), and detector arm (60) comprising a detector panel (66) as shown in Fig. 4 in a treatment / image configuration, and in Fig. 5 in a nested configuration in an exemplary embodiment.

[0061]

[0060] The imaging arm (50) has a first end (52) rotatably connected to the mount (12) at joint

[0062] (JI B), such that the imaging arm (50) rotates 360° about the joint (J1 B) and axis 1 (A1). An imaging x-ray source (56) is positioned at a second end (54) of the imaging arm (50). The imaging x-ray source (56) preferably uses x-rays in the kV range to produce an image of the target, e.g. tumor or patient anatomy within the treatment volume. The imaging system may be used to acquire static X-ray images or volumetric cone-beam computed tomography (CBCT) images just before treatment, enabling verification of the patient’s positioning and ensuring the anatomy matches the reference images from a previously prepared treatment plan. Additionally, the imaging system may be used to facilitate real-time tracking during treatment to detect any patient movement or positional changes that may occur during radiation delivery to permit patient adjustment.

[0063]

[0061] The detector arm (60) has a first end (62) rotatably connected to the mount (12) at joint

[0064] (JIC) such that the detector arm (60) can rotate 360° about J1C and axis 1 (A1). In this embodiment, the rotatable connection of the first treatment arm (20) on the mount (12) is said to be at joint (J1A), wherein J1A, J1 B and J1C are adjacently positioned on mount (12). Each of the first treatment arm (20), the imaging arm (50) and the detector arm (60) are independently rotatable about their respective joints, J1A, J1 B and J1C. A detector panel (66) is positioned at a second end (64) of the detector arm (60) and absorbs radiation emitted from the imaging radiation source (56). The imaging arm (50) and the detector arm (60) are designed to permit radiation emitted by the imaging radiation source (56) to pass through the isocenter (100) and to be received by the detector panel (66).

[0065]

[0062] The detector panel (66) may comprise any suitable detector that converts the x-ray signal from the imaging radiation source (56) into electronic signals for imaging. A digital x-ray detector generally comprises a scintillator layer, photodiode array, and readout electronics. The scintillator layer transforms x-rays into visible light once they have passed through the patient. The photodiode array then converts the light into an electrical signal, which is read out by a thin- film transistor array and converted into a digital image for use to determine patient positioning, image verification and potentially plan adaptation or creation. The detector utilized will preferably correspond with the radiation source used, for example, a LINAC detector will be used with a LINAC radiation source, and a CBCT detector is used with a CBCT radiation source. Preferably, the detector panel (66) is connected to a monitor or other means to receive signal from the detector panel and reproduce and display the signal captured by the detector panel as an image.

[0066]

[0063] As depicted in the embodiment of Figure 6, the imaging arm (50) and detector arm (60) form a single arm joined at a centre (112) which is rotatably connected to mount (12) and are, thus, in a fixed position relative to one another such that the imaging x-ray source (56) and the detector panel (66) consistently face one another (separated by 180°). Shown is the retracted positioning of the imaging system and treatment arms (20, 30).

[0067]

[0064] In another embodiment, the imaging arm and the detector arm (50, 60) are both provided as a dual arm system rotatably connected to the mount (12) to permit 360° rotation about the joints at their first ends, 52 and 62, respectively, as shown in Fig. 7 and 8. Thus, the imaging arm comprises a primary imaging arm (50a) and a secondary imaging arm (70). The secondary imaging arm (70) has a first end (72) rotatably secured to a second end (54a) of the primary imaging arm (50a) at a joint (J5), such that the secondary imaging arm (70) rotates 360° about the joint (J5). The secondary imaging arm (70) has a second end (74) at which is located the imaging radiation source (56). The detector arm (60) comprises a primary detector arm (60a) and a secondary detector arm (80). The secondary detector arm (80) has a first end (82) which is rotatably secured at a joint (J6) to the second end (64a) of the primary detector arm (60a), such that the secondary detector arm (80) rotates 360° about the joint (J6). The secondary detector arm (80) has a second end (84) at which is located the detector panel (66) which is adapted to received radiation emitted from the radiation source (56). The dual imaging arm (50a / 70) and dual detector arm (60a / 80) are designed to permit radiation emitted by the imaging radiation source (56) to pass through the isocenter (100) and to be received by the detector panel (66).

[0068]

[0065] As set out above with respect to the treatment arms, the shape and size of the imaging and detector arms of the imaging system, whether they comprise single or dual arm systems, is not particularly restricted as long as they retain the ability to rotate spherically around the isocentre (100). In this regard, it is further noted that the arrangement / configuration of the imaging and / or detector arms will be such that they do not affect the use and movement of the treatment arms, for example, in terms of the degrees of freedom thereof.

[0069]

[0066] As shown in Figures 5 and 9, treatment, imaging and detector arms may be retractable in a manner which permits nesting thereof. Fig. 5 illustrates nesting of imaging and detector arms (50, 60) which are single arms with a dual treatment arm system. Fig. 5 shows nesting of the imaging arm (50) under the detector arm (60); however, the detector arm (60) and the imaging arm (50) may be reversed such that the detector arm (60) nests under the imaging arm (50). The retracted arms as shown are resting on a top side of the mount (12); however, as the arms are rotatable about the mount, the resting position may be on the under side of the mount, or a combination thereof. Fig. 9 illustrates nesting when the imaging and detector arms are each dual arm systems. In particular, Fig. 9A shows that the secondary arm of each dual arm system folds so as to lie against and under (on an inner side of) the first or primary arm, while Fig 9B shows nesting in which the secondary detector arm (80) lies against and above (on an outer side of) the primary detector arm (60a). In addition, the dual treatment arms when retracted, nest under the imaging arm or dual imaging arm system, which in turn nests under the detector arm or dual detector arm system. More specifically, in the embodiment shown, for the treatment arms, the second arc-shaped treatment arm (30) is retractable so that it nests under and is concentric with the first arc-shaped treatment arm (20). The first treatment arm (20) retracts such that it nests under and is concentric with the secondary imaging arm (70), which retracts and nests in a concentric manner with the imaging arm (50a). The imaging arm (50a) retracts and nests in a concentric manner with the secondary detector arm (80), which retracts and nests in a concentric manner with the detector arm (60a) as shown in Fig. 9A. However, in another embodiment, as in Fig. 9B, to provide a more compact arrangement, at least one of the dual treatment, imaging or detector arm systems may rest in a position on the under side of the mount (12), while the other dual arm systems assume a resting position on the top side of the mount (12).

[0070]

[0067] As shown in Figure 10, the imaging and detector arms (50a / 70, 60a / 80) may be retracted while the treatment arms (20, 30) are extended to deliver radiation to a target site via the treatment head (40). The apparatus of Fig. 10A corresponds to that of Fig. 9A, while the apparatus of Fig. 10B corresponds to that of Fig. 9B. The apparatus may assume this configuration once imaging is completed.

[0071]

[0068] In another embodiment, as shown in Figure 11 , the imaging radiation source (56) is mounted to the inside of the first end (32) of the second treatment arm (30) at the joint (J2), to provide a compact alternative. In this embodiment, the position of the imaging radiation source (56) is adjustable via movement of the first treatment arm (20) to target the isocenter (100). The imaging radiation source (56) is rotatable in a circular path around the isocenter (100). Both the imaging radiation source (56) and the treatment head (40) emit radiation that share the same isocenter (100). As a result, in this embodiment, the apparatus (10) comprises treatment arms (20) and (30) and a detector arm (60) comprising detector panel (66). The detector arm (60) is rotatable about the mount (12) such that it may be positioned to receive radiation from the imaging radiation source (56) or the treatment head (40) that passes through the target site. The retracted position of this embodiment is shown in Fig. 12.

[0072]

[0069] An advantage of the present radiotherapy apparatus (10) is the ability to utilize either the imaging radiation source (56) or the treatment radiation source in the treatment head (40) for imaging due to the independent rotational movement of the treatment, imaging and detector arms. This enables imaging in both the kV (kilovoltage) and MV (megavoltage) ranges as illustrated in Fig. 13A / B using the device of Fig. 11.

[0073]

[0070] Fig. 13A shows the kV imaging configuration in which the detector arm (60) is positioned to detect radiation emitted from the imaging radiation source (56). In this orientation, the imaging radiation source (56) and the detector panel (66) are aligned 180° from one another along axis 2 (A2) to capture kV images. 2D images in the kV range are obtained when the system is in a fixed position, i.e. the imaging radiation source (56) and the detector panel (66) are fixed. Alternatively, 3D or volumetric images are obtained when the system operates as a cone beam CT in which images are acquired when the detector panel (66) and the imaging radiation source (56) are fixed at 180° from one another and rotate 360° in this fixed position about the isocenter (100).

[0074]

[0071] Fig. 13B shows the MV imaging configuration in which the detector panel (66) is positioned to detect radiation emitted from the treatment head (40). In this orientation, the treatment head (40) and the detector panel (66) are aligned 180° from one another. The treatment head (40) emits radiation in the MV range which passes through the isocenter (100) and is then detected by the detector panel (66) on the detector arm (60). When the detector panel (66) and the treatment head (40) are fixed in position aligned 180° from one another, 2D images in the MV range are obtained. Alternatively, when the detector panel (66) and the treatment head (40) are in a fixed position aligned 180° from one another and rotated 360° in this fixed position about the isocenter (100), 3D or volumetric images are obtained.

[0075]

[0072] In another embodiment, as shown in Figure 14, the detector arm (60) and the first treatment arm (20) are secured to the mount (12) but are fixed at 180° from one another. Thus, during rotation about axis 1 (A1; main axis), the detector arm (60) and the first treatment arm (20) remain at 180° from one another. The imaging radiation source (56) is secured to the inside of the first end (32) of the second treatment arm (30), such that the imaging radiation source (56) is directed toward the isocenter (100) and remains opposite to the detector panel (66) at all times, including during imaging. While this embodiment is limited to kV imaging, it advantageously provides a compact option that does not require a separate imaging arm. This allows the patient to be situated lower (i.e. closer to the ground).

[0076]

[0073] MV imaging using the treatment radiation can be performed during treatment delivery, which is beneficial for motion management (motion tracking), quality assurance, and dose verification. However, in the apparatus configuration shown in Fig. 11, images can only be acquired for coplanar beam arrangements, meaning when the radiation beam is perpendicular to A1 axis (running from the patient's head to feet). MV images at other angles (including non- coplanar) can be obtained with the apparatus configuration shown in Fig. 7, i.e. with dual treatment and detector arm systems. Similarly, kV imaging using the imaging radiation source (56) can also be performed before or during treatment delivery. In the apparatus configurations shown in Fig. 11 and 14, these images are limited to coplanar beam arrangements, but the advantage is that they can be acquired regardless of the treatment arm's position and configuration. kV images at other angles can be obtained with the apparatus configuration shown in Fig. 7.

[0077]

[0074] In embodiments, the imaging system may comprise a detector panel (66) that is adapted for movement. For example, the detector panel (66) may be adapted for translational motion perpendicular to axis A1. Perpendicular movement of both the detector panel (66) and the imaging radiation source (56) along axis A2 is appropriate for kV imaging, for example, along A2 as shown in Fig. 13A. For MV imaging, perpendicular movement along axis A3 is appropriate, as shown in Fig. 13B.

[0078]

[0075] The provision of a radiotherapy apparatus (10) comprising an imaging system as described is advantageous in that imaging and therapy are provided by a single apparatus, although the imaging capability operates independently from the treatment system, without interfering with the treatment. The design of the imaging and detector arms permits capture of both planar and non-coplanar images, i.e. images that are not limited to 90 degrees from the axis (A1). Further, embodiments of the present radiotherapy device support both MV and kV imaging.

[0079]

[0076] The present apparatus may also be used in combination with a remote imaging system that is not integrated within the apparatus. In this regard, imaging by a computed tomography (CT) imaging system, a magnetic resonance imaging (MRI) system, or a positron emission tomography (PET) / computed tomography (CT) imaging system may be utilized.

[0080]

[0077] The radiotherapy apparatus (10) may be mounted onto a support such as a platform. The support to which the mount (12) is attached may be fixed to the floor, or may be fixed on a vertical wall, on the ceiling or on another supporting stand-alone structure as shown in Fig. 16. The support may be fixed in position or may be adapted to rotate to permit rotation of the radiotherapy apparatus (10) in order to achieve additional degrees of freedom.

[0081]

[0078] In one example, as shown in Fig. 8, a support (98) is provided comprising a platform (90). The platform (90) may be secured to a stable support structure such as the floor. For compact embodiments of the present apparatus, such as is shown in Figs. 6 or 14 with a low energy treatment head, the platform may be secured to the base of an appropriate mobile unit that provides sufficient support to accommodate the weight and precision requirements of the apparatus. The platform (90), whether mounted on the floor, ceiling or wall, may incorporate a mechanism that allows movement (e.g. horizontally and / or vertically), with a range of about 15 cm. This additional mobility would enable the apparatus to shift to different isocenter locations aligning with different treatment volumes, allowing for the treatment of various areas or groups of tumors without the need to reposition the patient.

[0082]

[0079] The support (98) shown in Fig. 8 additionally comprises a mounting arm (92) having first (94) and second (96) ends. The mounting arm (92) is secured to the platform (90) at its first end (94). The second end (96) of the mounting arm (92) is secured to the mount (12) at its distal end (16). In embodiments, the platform (90) may be rotatably mounted on the floor or other base or, alternatively, the mounting arm (92) is rotatably connected at its first end (94) to the platform (90), to permit rotation of the apparatus. As one of skill in the art will appreciate, if the platform (90) or the mounting arm (92) of support (98) are adapted to rotate, the support (98) may also incorporate a mechanism to lock the support in place once rotated into a desired position.

[0083]

[0080] The components of the radiation apparatus (10) such as the dual treatment arm system, imaging arm (50), the detector arm (60), treatment head (40) and radiation sources, and the motors which drive these systems (see Fig. 15), are powered by one or more power sources. For clarity, the motors drive the following systems: M1 drives rotation of the first treatment arm (20). Additional motors at mount 12, e.g. M1a, M 1b and M1c, may be present to separately drive rotation of the first treatment arm, the primary imaging arm and the primary detector arm. M2 drives rotation of the second treatment arm (30); M3 drives rotation of the treatment head (40); M4 drives rotation of the collimation system within the treatment head (40); M5 drives rotation of the imaging arm (50); and M6 drives rotation of the detector arm (60).

[0084]

[0081] The power source(s) may be situated in any appropriate position relative to the component or motor to be powered, for example, within mount (12) of the radiotherapy apparatus, on or within a mounting platform or the power source may be more remotely situated with a power or control panel that is mounted elsewhere, for example, on a wall or other remote support structure. Mechanisms for programming and / or controlling movement of components of the radiotherapy apparatus may be situated with the power source(s) or may be situated separately therefrom for convenience. In addition, one or more of the motors may be remotely positioned from the component of the apparatus which the motor operates. Power is supplied to the components of radiotherapy apparatus (10) by any suitable connection. In preferred embodiments, power is supplied through appropriately gauged wires that run internally through the dual arm system, imaging and detector arms, treatment head and any other component which requires power. Slip rings may be used to supply power where components of the radiotherapy apparatus rotate, such as the treatment arms, imaging arm, detector arm, platform, and treatment head.

[0085]

[0082] The source of power is controlled by a control panel. The source(s) of power and control panel may be incorporated within the apparatus or may be external to the radiotherapy apparatus. Together the radiotherapy apparatus, the source(s) of power and the control panel form a radiotherapy system. The control panel regulates power from the source of power to the components of the radiotherapy apparatus that require power. The control panel may be powered by the power source or a second source of power.

[0086]

[0083] As one of skill in the art will appreciate, the system incorporating the present apparatus may also comprise a cooling unit, including a tank, which may reside in a stand supporting the apparatus, or may be situated remotely. Cooling hoses that circulate coolant / water from the cooling unit through the system run internally through any stand supporting the apparatus, the mount and into the various treatment, imaging and detector arms, as required.

[0087]

[0084] A flowchart generally illustrating the present apparatus (10) within a system is shown in Fig. 17. The system comprises a modulator (110) with a high voltage power supply and primary power distribution which converts incoming 3-phase electrical power into AC electrical power for use in the treatment unit, as well as a pulse forming network (PFN) which generates and regulates high-voltage DC pulses used by the magnetron to produce radio-frequency (RF) waves in the linear accelerator. The modulator components may be housed in a power box (100). The system will also comprise a cooling system to manage water cooling for the power supplies, X-ray target, and high-current steering coils around the waveguide. The cooling unit may be located within a stand supporting the apparatus (10) or within the wall or other unit when the apparatus is wall or ceiling mounted. The drive for the treatment, imaging and detector arms, namely the mechanical system (120) that provides rotation motion control to the mechanical arms, and the KV generator, which provides high-voltage power for X-ray generation in the imaging system and includes feedback and monitoring for the system, may also be located within a stand supporting the apparatus or other unit as appropriate.

[0085] Also shown in Fig. 17 is an exemplary layout of an x-ray generation and collimation system (130) within the treatment head (40) of an apparatus (10) according to the invention. An electron gun injects electrons into an electron acceleration system (e.g. comprising a magnetron and a waveguide). The magnetron converts high-voltage pulses from the modulator and generates high-frequency microwave radiation, providing the RF energy needed to accelerate electrons in the waveguide. The waveguide (linear accelerator) is a vacuum-sealed structure that uses RF electromagnetic waves to accelerate electrons to near-light speed. An AFC (Automated Frequency Control) System monitors and controls the microwave frequency, which is coupled to the waveguide. As the waveguide heats up, the output of the RF driver is adjusted to maintain constant energy output. A vacuum system generates and monitors the high vacuum within the waveguide (linear accelerator). The accelerated electron beam strikes a tungsten target, causing rapid deceleration and the emission of high-energy photons (X-rays). The primary collimator, made of a dense material, such as tungsten, shapes and limits the initial size of the radiation beam emerging from the X-ray target, ensuring the beam is properly aligned and directed toward the treatment area. The ion chamber monitors radiation dose and helps steer the beam by measuring ionizing radiation to ensure precise dose delivery and beam alignment. The MLC (multi-leaf collimator) comprises tungsten leaves that precisely shape the radiation beam to target specific treatment areas while protecting healthy tissue. Additional collimation or radiation shielding can be used or added to reduce radiation leakage and transmission.

[0088]

[0086] The treatment process is monitored in a control room (140) via a control console comprising a central interface used by an operator to manage and monitor the process. It allows control over machine parameters such as beam energy, dose, and patient positioning. The control room also includes a treatment workstation comprising a computer system where treatment plans are reviewed and controlled. It integrates patient data, treatment parameters, and imaging to ensure accurate and personalized therapy delivery. An imaging workstation processes and displays imaging data provided by the imaging system for patient positioning and treatment verification.

[0089]

[0087] The present radiotherapy apparatus is used in the treatment of a patient following appropriate imaging and treatment planning. Patient imaging, for example, using diagnostic platforms such as MRI or PET, are used to identify tumors and / or cancers to be treated. CT simulation images may then be used to design a treatment plan, including determining treatment parameters, such as the number and strength of beams, required arcs and their angles. On the day of treatment, the patient is brought to the treatment room and positioned on a treatment platform which is any platform suitable to support a patient during treatment such as a standard treatment couch or robotic couch, or an upright seat with adjustable seating angles. If appropriate, the patient may also be treated in a standing position. The patient is aligned with the treatment isocenter using markers, tattoos or any surface imaging technology. Verification imaging is then conducted to obtain images to be compared with the previously obtained reference images. Verification imaging may be conducted using the present radiotherapy apparatus if it comprises an imaging system. As previously noted, imaging may be conducted by CBCT or static imaging using the kV source static imaging, or by CBCT or static imaging using the treatment radiation source (MV source). Following comparison of the verification and reference images, the patient’s position may require adjustment prior to commencing treatment.

[0090]

[0088] Once verification is complete, the imaging arms of the radiotherapy apparatus are retracted, if used. Surface imaging with cameras and 3D technology can be used to monitor patients in real time during treatment, tracking movement to ensure they remain in the correct, verified position. Administration of the treatment plan via the radiotherapy apparatus will generally be automated. Algorithms defining various treatment plans may be included in a computer system in communication with the radiotherapy device, or may be programmed into the computer system following imaging, once details of the desired treatment plan are determined.

[0091]

[0089] Once the radiotherapy apparatus is activated, the treatment arms (20, 30) are powered to move into position according to the selected algorithm to administer a selected treatment path. As noted above, the treatment path may require certain components to be static while other components continue to move along a path by rotation, in latitudinal or longitudinal movements. The treatment head (40) will generally be optimally aligned with the isocenter to continuously administer an appropriate dose of radiation along the treatment pathway, through the precise movements of the first and second treatment arms (20, 30) (the base could also potentially rotate in the floor- or ceiling- mounted configurations). Treatment parameters such as intensity of the radiation beam, MLC shape and rotation speed may be varied during treatment delivery (VMAT treatments) or prior to activation of the treatment plan (conformal arc or fixed beam treatments). Pulsed delivery of radiation may also be administered. The radiotherapy apparatus is not limited to linear coplanar or non-coplanar treatment pathways but may also administer complex treatment configurations and radiation beam geometry not possible with present radiotherapy apparatuses, including but not limited to, wave therapy, and treatment variations such as spiral, cone-shaped and curve treatments. The entire treatment is delivered without requiring movement of the patient between different beams or arcs. If necessary, the imaging arms can be (or remain) extended to obtain additional images (either MV or kV, depending on the setup and need) during treatment. This workflow ensures precise patient positioning and effective treatment delivery while minimizing the need for patient repositioning during the procedure.

[0092]

[0090] While the present apparatus provides treatment options not available with other radiotherapy devices without requiring movement of the patient, the present apparatus may additionally be utilized for treatments in which the patient is moved. This permits the ability to conduct a helical treatment pattern similar to that achieved by the Tomotherapy™ system which is useful to treat cancers such as lung cancer, head and neck tumors, breast cancer, and prostate cancer.

[0093]

[0091] Thus, in another aspect of the invention, a method of delivering radiation to a patient is provided. The method comprises administering radiation to a patient situated in a treatment position, wherein the radiation is administered to the patient via a treatment head of a radiotherapy apparatus. The position of the treatment head is controlled by at least a pair of rotatable treatment arms of the radiotherapy apparatus which are designed to achieve spherical rotation of the treatment head. A first treatment arm is rotatable about a mount to which it is secured, and a second treatment arm is rotatably mounted to the first treatment arm. An additional treatment arm may be rotatably mounted to the second treatment arm. The angle of rotation of each rotatable arm may be the same or different; however, in one embodiment, the total angle of rotation of all the rotatable arms is at least 180°. This rotational flexibility provides for two or more degrees of freedom along coplanar and non-coplanar treatment paths, permitting cranial treatment as well as extra-cranial treatments, including treatment around a patient, treatment from the side of a patient or targeting a difficult to access site on a patient, while retaining the patient stationary during treatment

[0094]

[0092] In the present method, radiation is administered to a patient situated in a stationary treatment position. Radiation is administered from a radiation source with a treatment head in a radiotherapy apparatus. The treatment head is adapted to be rotatable 360° latitudinally and longitudinally about a treatment isocentre. In order to achieve 360° rotation latitudinally and longitudinally about the treatment isocentre, the treatment head is mounted in one embodiment onto a dual treatment arm system comprising a first arm rotatably connected to a mounting base, and a second arm rotatably mounted to the first arm, wherein the first arm is rotatable 360° about a first axis that passes through the isocentre, and the second arm is rotatable 360° about a second axis that passes through the isocentre and which is perpendicular to the first axis. To achieve full spherical treatment, the angle of rotation of each of the treatment arms is 90°. Lesser angles of rotation may be utilized, however, in order to achieve full spherical treatment, additional treatment arms may be utilized to achieve a total angle of rotation of 180°.

[0095]

[0093] Exemplary treatment plans are exemplified in the embodiments described in the following specific examples which are not to be construed as limiting. The treatment plans have been conducted with an apparatus comprising a treatment arm as shown in Fig. 1.

[0096] Example 1 - Arc Treatment Path - Configuration 1

[0097]

[0094] Use of the present radiotherapy apparatus permits the administration of arc patterns useful to treat cranial tumors. A treatment path is illustrated in Figure 18A / B and comprises four delivery arcs. Arc 1 is coplanar, while arcs 2, 3 and 4 are non-coplanar.

[0098]

[0095] To achieve arc 1, the first arc-shaped arm (20) powered by motor 1 (01) rotates 360° about axis 1 (A1) while the second arc-shaped arm (30) powered by motor 2 (02) is fixed at either 90° or 270° relative to the first arm (20).

[0099]

[0096] To achieve arc 2, the first arc-shaped treatment arm (20; 01) rotates 180° ( from 270° to 90°) about axis 1 (A1) while the second arc-shaped treatment arm (30, 02) rotates about axis 2 (A2) from 90° to 45° relative to the first arm (20) during the first 90° rotation of the first arc-shaped arm (20; 01) and rotates from 45° to 90° relative to the first arm (20) during the second 90° rotation of the first arc-shaped arm (20; 01).

[0100]

[0097] To achieve arc 3, the first arc-shaped arm (20; 01) is fixed at 90° or 270° about axis 1 (A1) while the second arc-shaped arm (30, 02) rotates 180° about axis 2 (A2).

[0101]

[0098] To achieve arc 4, the first arc-shaped arm (20; 01) rotates 180° about axis 1 (A1) while the second arc-shaped arm (30, 02) rotates about axis 2 (A2) from 270° to 315° (45° range) relative to the first arm (20) during the first 90° rotation of the first arc-shaped arm (20; 01) and rotates from 315° to 270° (45° range) during the second 90° rotation of the first arc-shaped arm (20; 01).

[0102]

[0099] With the present radiotherapy apparatus, this treatment is possible without rotating the patient, i.e. the patient is in a fixed position for all four arcs. This has not been done with other devices, and movement of the patient is required to achieve this treatment.

[0103] Example 2 - Arc Treatment = Configuration 2

[0104]

[0100] Use of the present radiotherapy apparatus permits the administration of a pie-shaped pattern useful to treat cranial tumors. The treatment path is illustrated in Figure 19A / B and comprises four non-coplanar delivery arcs.

[0105]

[0101] To achieve arc 1, the first arc-shaped arm (20; 01) is fixed at either 90° or 270° to axis 1 (A1) while the second arc-shaped arm (30, 02) rotates 180° relative to the first arm (20) about axis 2 (A2). To achieve arc 2, the first arc-shaped arm (20; 01) is fixed at 225° to axis 1 (A1) while the second arc-shaped arm (30, 02) rotates 180° about axis 2 (A2). To achieve arc 3, the first arc-shaped arm (20; 01) is fixed at 0° or 180° to axis 1 (A1) while the second arc-shaped arm (30, 02) rotates 180° about axis 2 (A2). To achieve arc 4, the first arc-shaped arm (20; 01) is fixed at 135° to axis 1 (A1) while the second arc-shaped arm (30, 02) rotates 180° about axis 2 (A2).

[0106] Example 3 - Concentric Circular Treatment Path

[0107]

[0102] Use of the present radiotherapy apparatus permits the administration of a concentric conical treatment path pattern useful to treat cranial tumors. The treatment path is illustrated in Figure 20A / B and comprises one coplanar arc (arc 1) ans several non-coplanar cone-shaped delivery arcs centered at the isocenter (100).

[0108]

[0103] To achieve arc 1, the first arc-shaped arm (20; 01) rotates 360° about axis 1 (A1) while the second arc-shaped arm (30, 02) is fixed at 270° relative to the first arm (20).

[0109]

[0104] To achieve arc 2, the first arc-shaped arm (20; 01) rotates 360° about axis 1 (A1) while the second arc-shaped arm (30, 02) is fixed at 290° relative to the first arm (20).

[0110]

[0105] To achieve arc 3, the first arc-shaped arm (20; 01) rotates 360° about axis 1 (A1) while the second arc-shaped arm (30, 02) is fixed at 310° relative to the first arm (20).

[0111] Example 4 - Wave Treatment Path

[0106] Use of the present radiotherapy apparatus permits the administration of a wave pattern useful to treat cranial and / or extra-cranial tumors. The treatment path is illustrated in Figure 21A / B and comprises a dynamic non-coplanar wave arc produced by the simultaneous rotation of treatment arms (20; 30) at angle rotations, 01 and 02, about their respective axes.

[0112]

[0107] In such embodiments, the first arc-shaped arm (20; 01) is continuously moving about axis 1 (e.g. at selected angles between 0°-360°), while the second arc-shaped arm (30, 02) is simultaneously moving at selected angles between 0°-360° about axis 2.

[0113]

[0108] The benefit of the dynamic wave delivery is that it can be used to run a continuous treatment path while avoiding irradiation of critical, radio-sensitive tissues or structures of the patient. Delivery of dynamic wave treatment is not possible using other devices without rotating a patient during irradiation, i.e. while the radiation beam is in operation.

[0114] Example 5

[0115]

[0109] Use of the present radiotherapy apparatus permits the administration of a non-coplanar arc pattern useful to treat areas such as the chest or pelvis. The treatment path as illustrated in Figure 22 shows a treatment path comprising three partial arcs.

[0116]

[0110] To achieve arc 1 , the first arc-shaped arm (20; 01) rotates 360° fully or partially about axis 1 while the second arc-shaped arm (30, 02) is fixed at 90° to axis 2._To achieve arc 2, the first arc-shaped arm (20; 01) rotates 360° fully or partially about axis 1 while the second arcshaped arm (30, 02) is fixed at 70° to axis 2._To achieve arc 3, the first arc-shaped arm (20; 01) rotates 360° fully or partially about axis 1 while the second arc-shaped arm (30, 02) is fixed at 110° to axis 2. _ As one of skill in the art will appreciate, there are other treatment path configurations that may be employed, for example, arcs going from the head to foot direction that are not shown here.

[0117]

[0111] This non-coplanar treatment has many dosimetric advantages including: (1) avoidance of beam paths and entrance doses through critical organs, thereby preventing or minimizing damage thereto, and (2) producing steeper dose gradients with a more rapid fall-off around the target, reducing radiation exposure to surrounding normal tissues. In addition, as with other treatments, this treatment is applied using the present radiotherapy apparatus while the patient is maintained in a stationary position. Other devices cannot deliver this treatment without moving the patient. Example 6

[0118]

[0112] The use of an embodiment of the present radiotherapy apparatus as shown in Fig. 11 for cranial treatment and / or imaging of a patient is shown in Fig. 23. Fig. 23A illustrates use of the apparatus for cranial imaging (kV imaging) or treatment when the patient is lying flat on a treatment couch. Fig. 23B illustrates cranial imaging (MV imaging) or treatment via the treatment head when the patient is sitting at an angle.

[0119] Example 7

[0120]

[0113] The use of the embodiment of the present radiotherapy apparatus of Fig. 11 may also be used for extra-cranial treatment of a patient is shown in Fig. 24. The treatment head is positioned to target an extra-cranial target in a patient A) lying down (supine or prone), or B) sitting at an angle. The apparatus may also be used to for extra-cranial imaging, either MV imaging using radiation emitted by the treatment head, or kV imaging (as shown) using radiation emitted by the imaging radiation source.

[0121] Example 8

[0122]

[0114] Similar to intracranial applications, the present radiotherapy apparatus enables extracranial treatments using multiple non-coplanar arcs oriented in any direction permitted by patient and couch geometry (i.e. , without causing collision between the treatment head and the patient or couch). Representative treatment trajectories are shown in Figure 25A, illustrating arcs aligned with the patient’s longitudinal axis, and in Figure 25B, illustrating arcs aligned with the transverse axis.

Claims

CLAIMS1. A radiotherapy apparatus comprising: i) a mount; ii) a treatment head comprising a radiation source; and iii) a treatment dual arm system comprising a first treatment arm having first and second ends, wherein the first end is rotatably connected to the mount, and a second treatment arm having a joint end and a treatment end, wherein the joint end is rotatably mounted onto the second end of the first treatment arm and the treatment head is mounted on the treatment end of the second treatment arm, wherein the first and second treatment arms rotate 360° about first and second axes, respectively.

2. The radiotherapy apparatus of claim 1 , wherein the treatment head comprises an x-ray generation system and an x-ray-collimation system.

3. The radiotherapy apparatus of claim 1 , wherein the treatment head comprises a linear accelerator (LINAC).

4. The radiotherapy apparatus of any one of claims 1-3, wherein the treatment head is rotatably mounted on the treatment end of the second treatment arm.

5. The radiotherapy apparatus of any one of claims 1-4, wherein the first and second treatment arms comprise an arc shape.

6. The radiotherapy apparatus of any one of claims 1-5, wherein the treatment arms each have an angle of rotation that together is at least 180°.

7. The radiotherapy apparatus of any one of claims 1-6, wherein the first and second treatment arms are retractable into a nested position in which the second treatment arm is nested against the first treatment arm.

8. The radiotherapy apparatus of any one of claims 1-7, comprising an imaging system, said imaging system comprising an imaging arm mounted to and extending from the mount which comprises a terminal imaging source, and a detector arm connected to and extending from the mount which comprises a terminal detector adapted to receive signals emitted by the imaging source.

9. The radiotherapy apparatus of claim 8, wherein the imaging arm and the detector arm are rotatably mounted on the mount.

10. The radiotherapy apparatus of claim 8, wherein the imaging arm and the detector arm each comprise a primary and a secondary arm each having first and second ends, wherein the first end of each primary arm is independently rotatably mounted onto the mount, and the first ends of the imaging and detector secondary arms are rotatably mounted to the second ends of the primary imaging and detector arms, respectively.

11. The radiotherapy apparatus of claim 9, wherein the imaging arm and detector arm are independently connected to the mount.

12. The radiotherapy apparatus of claim 11, wherein the imaging arm and detector arms are retractable into a nested position with the treatment arms such that each of the treatment, imaging and detector arms are in alignment.

13. The radiotherapy apparatus of claim 9, wherein the imaging arm and detector arm are rotatably connected to the mount in a fixed position such that the imaging source and detector are at 180° to one another.

14. The radiotherapy apparatus of claim 1 , comprising an imaging source mounted at the joint end of the second treatment arm, and a detector arm rotatably connected to and extending from the mount which comprises a terminal detector adapted to receive signals emitted by the imaging source.

15. The radiotherapy apparatus of claim 11, wherein the imaging and detector arms are arcshaped.

16. The radiotherapy apparatus of claim 8, comprising one or more motors to drive rotation of the first and second treatment arms, and optionally the treatment head, the imaging arm and the detector arm.

17. The radiotherapy apparatus of claim 16, adapted for connection to a power source to power the one or more motors, or comprising a power source.

18. A method of delivering radiation to a patient comprising administering radiation to a patient situated in a stationary treatment position, wherein the radiation is administered using a radiotherapy apparatus as defined in claim 1.

19. A method of delivering radiation to a patient comprising administering radiation to a patient situated in a stationary treatment position, wherein the radiation is administered via a treatment head of a radiotherapy apparatus, wherein the treatment head is rotatable 360° latitudinally and longitudinally about an isocentre.

20. The method of claim 19, wherein the treatment head is mounted to a dual treatment arm system comprising a first treatment arm rotatably connected to a mount, and a second treatment arm rotatably mounted to the first treatment arm, wherein the first treatment arm is rotatable 360° about a first axis that passes through the isocentre, and the second treatment arm is rotatable 360° about a second axis that passes through the isocentre and which is perpendicular to the first axis.

21. The method of claim 20, wherein the treatment arms each have an angle of rotation which together is at least 180°.

22. A radiotherapy system comprising a radiotherapy apparatus as defined in any one of claims 1- 17, one or more power sources and a control panel that regulates power from the source of power to motors that drive movement of components of the radiotherapy apparatus.

Images