165 results about "Multi leaf collimator" patented technology

A method of continuous real-time monitoring and positioning of multi-leaf collimators during on and off radiation exposure conditions of radiation therapy to account for target motion relative to a radiation beam is provided. A prediction algorithm estimates future positions of a target relative to the radiation source. Target geometry and orientation are determined relative to the radiation source. Target, treatment plan, and leaf width data, and temporal interpolations of radiation doses are sent to the controller. Coordinates having an origin at an isocenter of the isocentric plane establish initial aperture end positions of the leaves that is provided to the controller, where motors to position the MLC midpoint aperture ends according to the position and target information. Each aperture end intersects a single point of a convolution of the target and the isocenter of the isocentric plane. Radiation source hold-conditions are provided according to predetermined undesirable operational and/or treatment states.

Methods and systems of operating a support structure and beam shaping mechanism in a manner that compensates for motion patterns exhibited by a patient, promotes comfort of the patient, and optimizes accuracy of delivery of radiotherapy to a targeted location within the patient. The support structure can be a treatment table or couch and the beam shaping mechanism can be a multi-leaf collimator (MLC), and/or an MLC-bank/-carriage. The control system can utilize algorithms for predicting tumor motion and loading condition on the table/couch during radiation therapy.

Various embodiments of the present invention provide methods and systems for deterministic calculation of radiation doses, delivered to specified volumes within human tissues and organs, and specified areas within other organisms, by external and internal radiation sources. Embodiments of the present invention provide for creating and optimizing computational mesh structures for deterministic radiation transport methods. In general these approaches seek to both improve solution accuracy and computational efficiency. Embodiments of the present invention provide methods for planning radiation treatments using deterministic methods. The methods of the present invention may also be applied for dose calculations, dose verification, and dose reconstruction for many different forms of radiotherapy treatments, including: conventional beam therapies, intensity modulated radiation therapy (“IMRT”), proton, electron and other charged particle beam therapies, targeted radionuclide therapies, brachytherapy, stereotactic radiosurgery (“SRS”), Tomotherapy®; and other radiotherapy delivery modes. The methods may also be applied to radiation-dose calculations based on radiation sources that include linear accelerators, various delivery devices, field shaping components, such as jaws, blocks, flattening filters, and multi-leaf collimators, and to many other radiation-related problems, including radiation shielding, detector design and characterization; thermal or infrared radiation, optical tomography, photon migration, and other problems.

The invention is intended to shorten a positioning time required for forming an irradiation area with high accuracy using a number of leaf plates, and to reduce physical and mental burdens imposed on patients. A multi-leaf collimator comprises leaf plate driving body each including a plurality of movable leaf plates and provided respectively on one side and the other side, the plurality of leaf plates of the leaf plate driver on one side and the plurality of leaf plates of the leaf plate driver on the other side being disposed in an opposing relation to form an irradiation field of a radiation beam between the opposing leaf plates. Each of the leaf plate driving body includes a motor provided in common to the plurality of leaf plates. Driving force of the motor can be transmitted to the plurality of leaf plates at the same time through a pinion gear, upper and lower air cylinders, and upper and lower guides. Also, the driving force can be cut off selectively for each leaf plate.

A multi-leaf collimator with electromagnetically actuated leaves. The multi-leaf collimator includes a plurality of leaves, a leaf guide configured to support the plurality of leaves, and a plurality of magnets. Each leaf includes a blocking portion that is radio opaque, a drive portion connected to the blocking portion, and a coil embedded in the drive portion. The coil is operatively connected to an electrical current source to generate a first magnetic field. The first magnetic field interacts with the magnetic field generated by the magnet to thereby move the leave to a desired state. The leaves have the capability of moving at speeds of 50 cm/s up to and higher than 1 m/s.

A method is disclosed for controlling the delivery of radiation therapy to a tumor of a patient from one or more beams of ionizing radiation, to conform to a prescribed dosage of radiation for each of predetermined plural respectively shaped portions of the tumor according to the shape and other characteristics of the tumor. A radiation beam is selectively generated from different directions with respect to travel of the beam along a plurality of spatial paths including oscillating and arcuate movements. Parameters of the beam are calculated from conditions of distribution of a target dose, and the cross-section of the beam is adjusted so as to deliver the prescribed dosage of radiation to each of the respectively shaped portions of the tumor on which the beam impinges. The cross-section of the beam is constantly adjusted according to a predetermined area of the tumor which is to receive radiation therapy, and adjusted cross-sections of the beam are moved along selected individual ones of the spatial paths at least one time. Also, movements of the beam along individual spatial paths are split according to the plural portions of the tumor which are to receive different radiation doses. Travel of the beam is controlled along the selected individual paths so as to deliver radiation therapy within the prescribed dosage to each of the plural portions of the tumor in a minimum amount of time. In one embodiment, a micro multi-leaf collimator is placed between the beam and the tumor, and the collimator leaves are adjusted to change the cross-section of the beam impinging on a specified portion of the tumor according to the shape of the specified portion.

A method and system for providing intensity modulated radiation therapy to a moving target is disclosed. According to a preferred embodiment of the invention, a treatment plan for providing radiotherapy using a multi-leaf collimator (“MLC”) comprises a plurality of sub-plans, each of which is optimized for a different phase of target movement. Movements of the treatment target are tracked in real time, and the choice of which sub-plan to implement is made in real time based on the tracked position of the target. Each of the sub-plans is preferably formulated to minimize interplay effects between target movements and MLC leaf movements, consistent with other planning goals. In addition, the sub-plans preferably include a predicted region corresponding to the next anticipated position of the target, in order to facilitate the transition to the next position.

Described herein are multi-leaf collimators that comprise leaf drive mechanisms. The leaf drive mechanisms can be used in binary multi-leaf collimators used in emission-guided radiation therapy. One variation of a multi-leaf collimator comprises a pneumatics-based leaf drive mechanism. Another variation of a multi-leaf collimator comprises a spring-based leaf drive mechanism having a spring resonator.

In a method for sequentially generating segment fields for use in delivering intensity modulated radiotherapy an input continuous intensity map is generated. A segment field is generated directly from the input intensity map. A residual continuous intensity map is generated that is based on the respective photon fluence contributions from the input intensity map and a fractionally intensity map corresponding to the segment field. These steps are repeated for a number of iterations to generate a like number of additional segment fields and residual maps derived therefrom. In each iteration, the residual map generated in the previous iteration is used as the input intensity map.

A charged particle beam reduces treatment time in the uniform scanning or in the conformal layer stacking irradiation. In the uniform scanning, an optimum charged particle beam scan path for uniformly irradiating a collimator aperture area is calculated. In the conformal layer stacking irradiation, an optimum charged particle beam scan path for uniformly irradiating a multi-leaf collimator aperture area of each layer for each of the layers obtained by partitioning the target volume is calculated. Alternatively, a minimum irradiation field size that covers the multi-leaf collimator aperture area of each layer is calculated, and a scan path corresponding to the irradiation field size, prestored in a memory of a particle therapy control apparatus, is selected. The charged particle beam scan path is optimally changed in the lateral directions in conformity with the collimator aperture area in the uniform scanning or in each layer in the conformal layer stacking irradiation.

A radiation therapy apparatus has a multi-leaf collimator device, a driving gear, a torque wire and a driving unit. The multi-leaf collimator device has a pair of collimator components which respectively comprise a plurality of leaves arranged close to one another such that the leaves face one another across an irradiation axis, and configured to set a desired irradiation field by individually moving the leaves. The driving gear is engaged with a gear tooth of the each leaf, respectively. The torque wire is connected to a shaft center of the driving gear, respectively. The driving unit is configured to drive the driving gears through the torque wire.

Embodiments of the present invention provide a multi-leaf collimator with a plurality of leaves and at least one motor for each leaf. The motor for each leaf has a lateral width which is equal to or narrower than the corresponding leaf, and in this way the motors can be arranged within the lateral extent of the leaf. A cut-out section in the leaf allows the motor to lie at least partially within the depth of the leaf, and in this way the drive mechanism and the multi-leaf collimator as a whole are made extremely compact. This in turn allows the leaves to be deeper than would otherwise be the case, increasing their efficacy in blocking radiation.

The invention relates to a leaf (1) for a multi-leaf collimator (2) for delimiting a high-energy beam (3, 3′, 3″) of an irradiation device, in particular for conformational radiation therapy. According to the invention, the multi-leaf collimator (2) comprises a plurality of opposing leaves (1), which can be brought into the beam path (3, 3′, 3″) by means of drives (4), in such a way that the contour (5) of said path can be shaped in accordance with the volume to be irradiated. The need for beam-absorbent material (7) is reduced, as the leaf (1) essentially only comprises a beam-absorbent material (7) of an appropriate thickness (8) in a region (6) that is brought into the path (3, 3′, 3″) of the high-energy beam (3) during the course of all possible positional displacements (9). The invention also relates to a corresponding multi-leaf collimator (2), a device (22) for delimiting beams, and an irradiation device.

The invention discloses a method for establishing a measurement data-based simple and convenient irradiation source model of a medical linear accelerator. The method is characterized by comprising the following steps of: supposing that an irradiation source of the medical linear accelerator is on the part of the bottommost end of an MLC (Multi-leaf Collimator); measuring a flux pattern of data inversion from the accelerator through adjustment; and realizing simulation of the irradiation source of the medical linear accelerator by using a method of combining weight of outgoing particles and flux strength by combining the position of the outgaining particles with the flux distribution. Dose distribution in a template is obtained by using geometric description of a particle transport model of classic monte carlo program EGSnrc and a model of DOSXYZnrc. The method is established based on measurement data of the medical linear accelerator, so that the dependence of the conventional full accelerator simulation on the technical detail of the structure of the accelerator and heavy calculation task brought by need of sectional re-simulation in each modification process of the simulation parameter are avoided. The model can be used as an irradiation source model for an accurate monte carlo dosage calculation tool in a human body and can also be used for providing a source model for a dosage verification tool in a treatment planning system and an analytical dosage calculation tool of a treatment scheme optimization algorithm.