Apparatus for measuring a dose delivered through a radiation sensitive film under exposure to ionizing radiation

Abstract

The invention relates to a device for measuring a dose delivered through a radiation sensitive film under exposure to ionizing radiation, a system comprising such a device, and a use of such a device. More specifically, the device comprises a reflective film, at least one light source, a radiation sensitive film, and an optical sensor system comprising a 2D array of one or more photoresistive and / or semiconducting cells. The invention further relates to a system comprising the aforementioned device, a readout integrated circuit unit connected to the optical sensor system of the device, and a processing unit connected to the readout integrated circuit. The invention further relates to a use of the aforementioned device.

Description

Technical Field

[0001] The present invention relates to an apparatus for measuring the dose delivered through a radiation-sensitive membrane under exposure to ionizing radiation, a system including such an apparatus, and the use of such an apparatus or system.

[0002] More specifically, the device includes: a reflective film; at least one light source; a radiation-sensitive film; and an optical sensor system comprising a 2D array of one or more photoresistor units and / or semiconductor units. The invention also relates to a system comprising: the aforementioned device; a readout integrated circuit unit of the optical sensor system connected to the device; and a processing unit connected to the readout integrated circuit. The invention further relates to the use of the aforementioned device or system. Background Technology

[0003] In the medical, chemical, or safety fields, irradiation refers to the process by which an object is exposed to radiation. Most commonly, the term "radiation" refers to ionizing radiation. Ionizing radiation is produced by various sources, which can be natural, such as cosmic rays or terrestrial radiation, or artificial, such as radiation for medical or industrial purposes. Among the different types of ionizing radiation, some have health effects, which can be categorized as deterministic effects by killing cells or stochastic effects by forming somatic cell mutations or other processes that may lead to the development of cancer.

[0004] The effects of ionizing radiation depend on the type of radiation emitted, as well as the delivered and absorbed doses. The term "absorbed dose" describes the amount of radiation absorbed by an object or person. The unit of absorbed dose is the gray (Gy). Absorbed dose refers to the energy of ionizing radiation deposited locally per unit mass in an absorbing medium. The dose can be delivered at a high dose rate or a low dose rate (e.g., through multiple fractionated doses).

[0005] Precise assessment of the dose of ionizing radiation delivered to a location is fundamental in many technical fields. For example, in radiation therapy, a specific dose must be delivered to a specific area of ​​the patient. It is expected from the equipment used that the precisely specified dose is delivered correctly to the target location at the anticipated rate. Measuring or monitoring ionizing radiation is an important aspect of radiation protection and radiation therapy, allowing for the determination of appropriate equipment for radiation protection or the effective operation of devices based on dose and circumstances.

[0006] Traditionally, radiochromic films, such as GAFchromic™ films, have been considered fundamental two-dimensional passive detectors in the field of dosing verification. Due to their high spatial resolution, low energy dependence, and near-water equivalent, they are widely used for quality assurance measurements and therapy validation (Devic, S. Radiochromic film dosimetry: Past, present and future. Phys. Med. 2011, 27, 122–134). Upon exposure to ionizing radiation, a polymerization reaction occurs within the active layer of the radiochromic film, resulting in a change in the film's optical density, i.e., a change in the film's color, which can be correlated with the dose delivered within the film without the need for additional chemical post-treatment.

[0007] However, these standard methods for quantifying optical density are based on image scanning and require post-processing after irradiation. In fact, it is recommended that there be at least 24 hours between irradiation and film scanning (Niroomand-Rad, A.; Blackwell, CR; Courtey, BM; Gall, KP; Galvin, JM; McLaughlin, WL et al. Radiochromic film dosimetry: Recommendations of AAPM Radiation Therapy Committee Task Group 55. Med. Phys. 1998, 25, 2093–2115).

[0008] Therefore, there is a considerable time delay in assessing the delivered dose. In practice, the delivered dose is calculated using an analytical model implemented in the treatment planning system of radiation therapy software, but this has not been validated experimentally in real time. The analytical time delay of the radiochromic membrane renders it an impractical tool for real-time and in-situ daily dose assessment, assuming that optical density is considered the only parameter relevant to the delivered dose.

[0009] Therefore, there is a need for a device that can measure the dose delivered to a specific location in real time and in situ. Summary of the Invention

[0010] Therefore, the present invention discloses an apparatus for measuring the dose delivered through a radiation-sensitive membrane under exposure to ionizing radiation, the apparatus comprising: - A reflective film having an inner surface opposite to the outer surface, the inner surface being adapted to reflect light; - At least one light source, which is arranged to emit at least one light beam toward the inner surface of the reflective film; - A radiation-sensitive film having a first side and an opposite second side, the first side of the radiation-sensitive film facing the inner side of the reflective film; - An optical sensor system having a first surface facing a second surface of a radiation-sensitive film, the first surface being adapted to receive a light beam from at least one light source after reflection from an inner surface of a reflective film, the second surface being opposite to the first surface. The first surface of the optical sensor system includes a 2-D array of one or more photoresistor units and / or semiconductor units, and one or more photoresistor units and / or semiconductor units are fixed to a support layer. In this array, the reflective film, the radiation-sensitive film, and the 2-D array of photoresistor units and / or semiconductor units are substantially parallel, and In this case, at least one light source is not located between the inner surface of the reflective film and the first surface of the radiation-sensitive film.

[0011] This device allows for real-time in-situ measurement of doses delivered to a specific location.

[0012] The term "radiation-sensitive film" should be understood as a film containing materials whose structure and / or optical properties change in response to irradiation.

[0013] The phrase "a 2-D array of one or more photoresistor units and / or semiconductor units" should be understood as a plurality of photoresistor units and / or semiconductor units arranged in a matrix or grid, thus side-by-side and forming an optical sensor surface substantially parallel to the radiation-sensitive film. The photoresistor units and / or semiconductor units in the 2-D array are adapted to receive light reflected by the reflective film and passing through the radiation-sensitive film.

[0014] Optical sensor systems utilize photoresistor units and / or semiconductor units that generate changes in current or resistance in response to light striking them. These units are used in a variety of fields to capture and record spatial, spectral, and / or temporal optical features. A 2D array of photoresistors or semiconductor units can correspond to a mosaic of closely spaced detector elements that convert incident electromagnetic radiation into electrical signals. The term "photoresistor unit" in an optical sensor system should be understood as a passive component whose resistance decreases as light is received on its sensitive surface. "Photoresistor unit" can also be understood as a photoresistor comprising a semiconductor substrate. The term "semiconductor unit" in an optical sensor system can be understood as a semiconductor with high resistance or a semiconductor doped to have high resistance, which is modulated when light strikes the semiconductor unit or photodiode.

[0015] Regarding the phrase "wherein the 2-D array of the reflective film, the radiation-sensitive film, and the photoresistor units and / or semiconductor units are substantially parallel," it should be understood that each of the 2-D arrays of the reflective film, the radiation-sensitive film, and the photoresistor units and / or semiconductor units can correspond to a plane, and each of these planes is substantially parallel to each other. Where the 2-D array of the reflective film, the radiation-sensitive film, and the photoresistor units and / or semiconductor units is curved or has any particular shape, it should be understood that the surface of each of the 2-D arrays of the reflective film, the radiation-sensitive film, and the photoresistor units and / or semiconductor units corresponds to a surface that is parallel to each other, meaning that each of these surfaces has a point located at a fixed normal distance from the other surfaces.

[0016] Regarding the phrase "wherein at least one light source is not located between the inner surface of the reflective film and the first surface of the radiation-sensitive film," it should be understood that at least one light source is arranged around a volume formed between the inner surface of the reflective film and the first surface of the radiation-sensitive film. This position of at least one light source prevents ionizing radiation from passing through it, thus potentially affecting the light source and / or causing it to be attenuated, deflected, or reflected, which could lead to erroneous measurements. In fact, the light source should be placed outside the radiation field. Furthermore, this position prevents the formation of any shadows on the radiation-sensitive film, or prevents scattering of radiation sources impacting the device due to reflection of the light beam from the reflective surface of the reflective film between the light source and the radiation-sensitive film.

[0017] This device allows for real-time reading of the dose delivered to the radiation-sensitive membrane when it is irradiated by ionizing radiation.

[0018] Advantageously, the support layer for the reflective film, radiation-sensitive film, and optical sensor system is flexible. Utilizing such flexible elements, the device can be bent or folded to fit the shape of an object with complementary forms. For example, a device including such a flexible reflective film, radiation-sensitive film, and optical sensor system can be bent to conform to the shape of the human body.

[0019] Advantageously, the photoresistor unit and / or semiconductor unit are embedded in one or more flexible printed circuits.

[0020] Since the optical sensor system includes one or more photoresistor units and / or semiconductor units, the device can be bent because the photoresistor units and / or semiconductor units can be displaced independently of each other when combined with a flexible support layer or when the photoresistor units and / or semiconductor units are embedded in one or more flexible printed circuits.

[0021] Advantageously, the device is encapsulated in a polymer. Preferably, the polymer is water-equivalent. For example, the polymer consists of or contains polymethylsiloxane (PDMS), polyester, polyimide, or nylon. Preferably, the polymer is a transparent, ultrathin polymer with a thickness of less than or equal to 200 nm. This encapsulation allows for protection of the device and keeps its components together when they are manipulated.

[0022] Advantageously, at least one light source comprises one or more LEDs and / or one or more lasers. Preferably, at least one light source is a low-power light source, for example, at least one light source is a low-power light source with a luminous efficiency of at least 100 lumens per watt, or even more preferably, at least one light source is a low-power light source with a luminous efficiency of at least 200 lumens per watt. Preferably, at least one light source comprises at least one green light source. Even more preferably, at least one light source consists of green light sources. Green light sources allow for higher efficiency in the detection of light passing through the radiation-sensitive membrane by the optical sensor system.

[0023] Advantageously, the radiation-sensitive membrane comprises a polymer, for example, a polyester or a polymer with dyes, such as crystalline polyacetylene, particularly butadiyne, which is a polymer whose structure and / or optical properties change in response to irradiation, for example by changing color upon exposure to ionizing radiation.

[0024] Advantageously, the radiation-sensitive membrane is a radiochromic membrane. A radiochromic membrane can refer to a radiochromic dosimeter, which is typically used in liquid, gel, and pellet form, and is used as a membrane in this invention.

[0025] Exposure to ionizing radiation causes a polymerization reaction within the active layer of a radiochromic film, resulting in an irreversible change in the film's optical density—a change in its color—which may be related to the dose delivered within the film without requiring additional chemical post-treatment. Radiochromic films typically comprise an active layer between two layers containing a labeling dye whose darkness increases with increasing absorbed dose. Gafchromic™ films are an example of radiation-sensitive films, such as Gafchromic... TM EBT3 membrane is composed of polydiacetylene material containing a yellow-labeled dye.

[0026] Advantageously, the radiation-sensitive membrane is made of polycarbonate. Polycarbonate membranes can be used, for example, in nuclear applications, for example, to produce a fading effect due to ultraviolet C (UVC) exposure.

[0027] Advantageously, the device includes at least one light guide. "Light guide" should be understood as a transparent material such as glass or plastic that can transmit an emitted light beam from at least one light source to a reflective film via internal reflection. Alternatively, "light guide" should be understood as a light guide tube comprising a rigid or flexible plastic tube, such as an optical fiber. The light guide focuses the light beam emitted from at least one light source and uniformly disperses it on the reflective film in a desired shape to obtain uniform reflection on the radiation-sensitive film. Therefore, at least one such light guide allows for improved uniform reflection and diffusion of light on the radiation-sensitive film, and thus allows for better measurement of light passing through the radiation-sensitive film and received by the optical sensor system. Preferably, at least one such light guide is located between at least one light source and the reflective film, but not between the inner surface of the reflective film and the first surface of the radiation-sensitive film.

[0028] Advantageously, the reflective film is a metallized microfilm or a polymer film coated with a metal (such as aluminum) layer. This metallized microfilm allows for efficient reflection of light from at least one light source of the device. Preferably, the metallized microfilm is a metallized BoPET film, i.e., a biaxially oriented terephthalate film, such as Mylar™.

[0029] Advantageously, the reflective film has a thickness of less than 100 μm, preferably less than 20 μm. Even more preferably, such a reflective film has a thickness of less than or equal to 1 μm, with a preferred thickness of 0.5 μm to 1 μm. This thickness of the reflective film allows ionizing radiation to pass through without being disturbed, deflected, reflected, or reduced, and thus allows for the measurement of the delivered dose emitted by the radiation generating device without providing such a device. In certain embodiments, the reflective film can be obtained using physical vapor deposition, which allows for reflective films of, for example, 10 nm to 1 μm in thickness.

[0030] The present invention also discloses a system including one of the aforementioned devices, the system comprising: a readout integrated circuit unit connected to the optical sensor system of the device via a first connection; and a processing unit connected to the readout integrated circuit via a second connection.

[0031] The readout circuit relays electrical signals from each detector element or pixel (e.g., a photoresistor and / or semiconductor unit according to the invention) to an output, such as, but not limited to, an output amplifier. For example, the readout circuit can measure voltage changes when a light source emits at least one beam of light, and these voltage changes are transmitted to a processing unit. In particular, the readout circuit allows connection to any type of processing unit to transmit information to a user.

[0032] The term "processing unit" should be understood as any element capable of receiving information from a readout circuit and managing such information by converting, interpreting, calculating, or displaying it. A processing unit can correspond to a computer, a remote control system, a mobile phone, or any similar device.

[0033] Advantageously, the second connection between the readout integrated circuit and the processing unit includes at least one micro-antenna for communicating with the processing unit. Preferably, the second connection is a wireless connection and corresponds to, for example, a Bluetooth or Wi-Fi connection.

[0034] Advantageously, the second connection between the readout integrated circuit and the processing unit is a radio frequency identification (RFID) tag.

[0035] Advantageously, the processing unit controls the remote system.

[0036] The present invention also discloses the use of the aforementioned apparatus or system for measuring the dose delivered through a radiation-sensitive membrane under exposure to ionizing radiation.

[0037] The invention has been described according to different advantageous features, which can all be combined with each other. Attached Figure Description

[0038] The invention will be better understood through the following description of several exemplary embodiments and their accompanying drawings, and its various features and advantages will become apparent, wherein: - Figure 1 The apparatus of the present invention is shown; - Figure 2 The system of the present invention, including the apparatus of the present invention, is shown; - Figure 3 A 2-D diagram showing the pixel distribution corresponding to the detection of light by a 2-D array of photoresistors and / or semiconductor units of the device of the present invention is displayed. Detailed Implementation

[0039] In this specification, the invention will be described by way of examples relating to different devices and related systems of the invention.

[0040] The device of the present invention allows for the measurement of dose delivered through a radiation-sensitive membrane while exposed to ionizing radiation. In particular, the device allows for real-time, in-situ measurement of the dose delivered to a specific location. The device includes a reflective membrane having an inner surface opposite to the outer surface, the inner surface being adapted to reflect light.

[0041] The inner surface of the reflective film corresponds to the surface facing the interior of the device, while the outer surface faces the exterior of the device. While the inner surface is adapted to reflect light, the outer surface is preferably adapted to prevent any light from entering the interior of the device, while allowing ionizing radiation to pass through the reflective film. Specifically, a light beam emitted by a light source is directed toward the inner surface of the reflective film and reflected inside the device. When using the device, preferably, this light beam is uniform and constant. Also preferably, after reflection on the reflective film, the light is focused onto a radiation-sensitive film and further focused onto a 2-D array of photoresistors and / or semiconductor cells.

[0042] Those skilled in the art will understand that the number of light sources directly depends on the size and surface of the radiation-sensitive membrane that receives light from the light sources. The size and surface of the radiation-sensitive membrane depend on the surface that should be covered by the device of the present invention for measuring the delivered dose.

[0043] Preferably, the outer surface of the reflective film prevents any light from passing through it. More preferably, the reflective film does not alter the ionizing radiation passing through it, for example, it does not reflect, reduce, interfere with, or deflect any ionizing radiation passing through it.

[0044] A light beam emitted from at least one light source is directed toward the inner surface of the reflective film, and the light source is not located between the inner surface of the reflective film and the first surface of the radiation-sensitive film. Therefore, the light beam is directed toward the reflective film.

[0045] The light beam passes through the radiation-sensitive membrane after reflection. Depending on the structure and / or optical properties of the radiation-sensitive membrane, the beam will pass through it differently, as these properties may vary depending on the ionizing radiation emitted by the radiation impacting the device. Typically, the thickness of the radiation-sensitive membrane is between 100 μm and 300 μm; however, a preferred thickness is less than 150 μm, and even more preferably, a thickness less than or equal to 100 μm.

[0046] In some embodiments, the radiation-sensitive film is a radiochromic film. A radiochromic film includes at least an active layer containing a dye that changes color upon exposure to ionizing radiation. For example, a radiation-sensitive film is a radiochromic film, such as the GAFCHROMIC™ MD-55 film, which includes, for example, a 25 μm transparent polyester sandwiched between two adhesive films, for example, 25 μm thick; the transparent polyester and adhesive films sandwiched between two active layers, for example, 16 μm thick; and the transparent polyester, adhesive films, and active layers again sandwiched between two transparent polyester films, for example, 67 μm thick. The GAFCHROMIC™ MD-55 film has a net density of 0.90 at 25 Gy and a net density of 1.75 at 50 Gy, the net density being the density change due to the absorbed radiation dose. Radiation-sensitive films can also be radiochromic films, such as GAFCHROMIC™ HD-810, which has an active layer of about 6.5 μm sandwiched between a 0.75 μm surface layer and, for example, a transparent polyester of about 97 μm. The GAFCHROMIC™ MD-55 film has a net density of 0.30 at 100 Gy and a net density of 1.15 at 500 Gy. GAFCHROMIC™ EBT3 films can also be used, which include an active layer of about 28 μm sandwiched between, for example, two transparent polyesters of about 125 μm.

[0047] Depending on the optimal dose range of this type of radiochromic membrane and the expected dose of ionizing radiation passing through the radiochromic membrane or the dose specified in radiation therapy, other radiochromic membranes, such as GAFCHROMIC™ DM-1260, GAFCHROMIC™ MD-55-2, and GAFCHROMIC™ FWT-60, may be used.

[0048] Specifically, GAFCHROMIC™ EBTs, such as EBT, EBT-XD, EBT2, and EBT3, are used. GAFCHROMIC™ EBT3 is designed for a dosage range of 0.2 Gy to 10 Gy and comprises an active layer of approximately 28 µm containing a yellow-labeled dye, sandwiched between two matte polyester substrates of approximately 125 µm each, the matte polyester substrates containing silica particles embedded in their surfaces. GAFCHROMIC™ EBT2 comprises an active layer of approximately 28 µm, with a smooth polyester layer of approximately 175 µm on one side and an acrylic adhesive layer of approximately 20 µm on the other side. The opposite side of the acrylic adhesive layer faces the approximately 50 µm matte polyester substrate.

[0049] The light beam that can pass through should be received by an optical sensor system comprising a 2-D array of one or more photoresistor units and / or semiconductor units. These 2-D arrays of one or more photoresistor units and / or semiconductor units have a pixel-type distribution that allows for the creation of a 2D dose map. In fact, the size of each unit can preferably be less than or equal to 20 mm, and even more preferably less than or equal to 700 μm. The smaller the photoresistor and / or semiconductor units, the more accurate the dose map. Therefore, the 2D dose map of the pixel can be determined based on the intensity of the light received by each unit in the unit, wherein each pixel can be correlated with the intensity of light received corresponding to the delivered dose of ionizing radiation.

[0050] Such a 2-D array of one or more photoresistor units and / or semiconductor units can be called a multi-array system. Such a system allows for the creation of custom patterns using photolithography. This material and microfabrication technique allows for the creation of tailored microstructures with any desired spatial resolution. Furthermore, the semiconductor material of the semiconductor units can be doped to change resistivity characteristics and thus select the radiation-sensitive range. For example, in the case of silicon semiconductors commonly used in microtechnology, silicon-on-insulator (SOI) can be used to obtain a thinner final result. Device silicon can be, for example, <100> The wafer is an n-type phosphorus-doped material with a nominal resistivity greater than 3.5 kΩ·cm and a nominal thickness of 10 ± 0.5 μm and 20 ± 0.5 μm. The wafer can be patterned to have a desired layout and to produce well-defined pixels corresponding to each photoresistor unit and / or semiconductor unit through diffusion or implantation.

[0051] For example, a ring-shaped cylindrical engraving can be fabricated centered on a pixel of a "unit lattice," and then, depending on the substrate type, doped with N+ or P+ to achieve the desired resistance range. These pixels can be distributed in a multi-channel array with a spacing of 25 µm to 200 µm and stacked laterally to cover an area of ​​several centimeters. A similar procedure can be followed for a standard 300 µm wafer. At the end of the procedure, the substrate can be thinned by chemical etching or reactive ionization processes to obtain a sufficiently thin film-like device to avoid ionizing radiation scattering, for example, within a patient's body (when the device of the present invention is attached to the skin). The semiconductor can be Si, Ge, SiC, CdTe, CdS, CdZnTe, GaAs, B4C, etc.

[0052] When using semiconductor cells that include semiconductor wafers such as silicon on insulator (SOI) wafers, the SOI support wafer can be removed to have a semiconductor cell layer with a thickness of 2 μm to 50 μm.

[0053] Even without removing the typically rigid support wafer, if the semiconductor unit is small enough, or separated or cut into sufficiently small pieces, it can be embedded in the support layer of an optical sensor system to follow any bends in the device, which in this case is also a bend in the optical sensor system.

[0054] For example, a 2D array of photoresistors or semiconductor cells can include cells ranging in size from 0.2 mm to 20 cm. Semiconductor cells from optical sensor systems, such as commercially available photodiodes, can be used, but other photodiodes can also be used. For example, semiconductors of photodiodes, such as CdSe, CdS, CdTe, InSb, InP, PbS, PbSe, Ge, Is, GaAs, etc., can be used to create patterns using a mask, thereby maximizing spatial resolution to cover any area. High-resistivity semiconductors, such as CdS, are preferred, but other semiconductors can be doped to obtain high resistance.

[0055] Preferably, the device is calibrated before use. Calibration means that a reference light or baseline value is received by the optical sensor system and established before the radiation-sensitive membrane receives any ionizing radiation. Light is emitted from at least one light source toward the reflective membrane such that the light is reflected to the first surface of the optical sensor system after passing through the radiation-sensitive membrane, which has not previously received any ionizing radiation. This reference light or baseline value allows the delivery dose to be determined based on the difference between the light passing through the radiation-sensitive membrane before and after being irradiated by ionizing radiation, rather than based on a single value of the light received by the optical sensor system. This calibration also allows for the consideration of any defects in any component of the device, as the reference light received by the optical sensor system allows for a relative determination rather than a raw determination.

[0056] Of particular importance is that during the calibration of the device, the light emitted by at least one light source remains the only light source, which is then received by the optical sensor system after being reflected by the reflective film and passing through the radiation-sensitive film.

[0057] The device of this invention is not limited to classically known radiochromic films. In fact, films irradiated with ionizing radiation can also exhibit color changes compared to other polymers, regardless of whether the intensity is low or high. This is due to the inevitable chemical reactions following irradiation that alter the structure and optical properties of these materials. Irradiation generates primary and secondary free radicals in polymer-based materials, which initiate C / C bond transformations, double bond formation, and crosslinking. Clough RL et al., Polymer Degradation and Stability 49 (1995) 305-313; Nouh SA, Radiation Protection Dosimetry, Vol. 183, Issue 4, June 2019, pp. 450–4592 These effects alter the optical properties of the polymer and depend on the type of radiation.

[0058] Similarly, the device according to the invention, which allows for in-situ and real-time measurement of the delivered dose, selects both the polymer and the material based on ionizing radiation, which can produce permanent or annealable color centers in a radiochromic film.

[0059] In radiation therapy, the device can be placed between the patient's body and a radiation-generating device that emits ionizing radiation. The ionizing radiation emitted by the radiation-generating device affects a radiation-sensitive membrane, which alters the transmittance of a light beam emitted by at least one light source after reflection on the reflective membrane. The amount of light passing through the radiation-sensitive membrane after ionizing radiation is emitted by the radiation-generating device should differ from the amount of light passing through the radiation-sensitive membrane before emission. In addition to the amount, the device of the present invention particularly allows for the determination of one or more locations where the radiation-sensitive membrane has been irradiated and the determination of the dose delivered at these locations.

[0060] In a particular embodiment, the device may include an adhesive layer comprising an inner surface and an adhesive surface. The inner surface is attached to the device, while the adhesive surface is positioned wherever ionizing radiation is to be measured. This adhesive layer allows the device to be positioned such that it requires no additional maintenance in any way. For example, the adhesive layer may be at least partially attached to the outer surface 14b of an optical sensor system via its inner surface. The adhesive layer may also be partially attached to a readout integrated circuit unit via its inner surface. The adhesive layer may be attached to the polymer encapsulating the device via its inner surface. Such a device including an adhesive layer can be considered a patch.

[0061] In any embodiment of the invention, the device includes an opening that allows access to the radiation-sensitive membrane for replacement. This opening allows the device to be reused by replacing only the radiation-sensitive membrane. In embodiments where the device is encapsulated in a polymer, the polymer includes an opening that allows for replacement of the radiation-sensitive membrane or separation of the polymer from the remainder of the device.

[0062] Alternatively, the device can be incorporated into any wound care product or any existing patch.

[0063] In certain implementations, the device can be a portable device. It can be incorporated into a bracelet or any other portable device.

[0064] Preferably, there is no space between the radiation-sensitive film and the optical sensor system.

[0065] Figure 1An apparatus of the present invention is shown, comprising: a reflective film 11 having an inner surface 11a opposite to an outer surface 11b, the inner surface being adapted to reflect light; two light sources 12 arranged to emit at least one light beam toward the inner surface 11a of the reflective film; a radiation-sensitive film 13 having a first surface 13a and an opposite second surface 13b, the first surface of the radiation-sensitive film facing the inner surface 11a of the reflective film; and an optical sensor system 14 having a first surface 14a facing the second surface 13b of the radiation-sensitive film 13, the first surface of the optical sensor system being adapted to receive light beams reflected from the inner surface 11a of the reflective film 11 by at least one light source 12, the second surface 14b being opposite to the first surface 14a. The first surface 14a of the optical sensor system 14 includes a 2-D array of one or more photoresistor units and / or semiconductor units fixed to a support layer. The 2-D array of the reflective film 11, the radiation-sensitive film 13, and the photoresistor unit and / or semiconductor unit is substantially parallel, and the two light sources 12 are not located between the inner surface 11a of the reflective film 11 and the first surface 13a of the radiation-sensitive film 13.

[0066] Figure 2 The system 20 of the present invention, including the device 10 of the present invention, is shown. The system 20 includes: a readout integrated circuit unit 22 connected to the optical sensor system 14 of the device 10 via a first connection 21; and a processing unit 24 connected to the readout integrated circuit 22 via a second connection 23.

[0067] The first connection 21 can be any known type of connection between the photoresistor and / or semiconductor detector unit and the readout circuit. The second connection 23 can be any known wired connection or any known wireless connection capable of transmitting electrical signals obtained from each photoresistor and / or semiconductor detector unit.

[0068] Processing unit 24 can be any element capable of receiving any information, such as electrical signals, from readout circuit 22 and managing such information by transforming, interpreting, calculating, or displaying it. Processing unit 24 can correspond to a computer, remote control system, mobile phone, or any similar electronic device. Such a processing unit may include applications or software installed via standard wired, wireless, or Bluetooth connections.

[0069] For radiation therapy applications of the present invention, the transmission of such information can be confidential if it relates to personal medical data. In this case, appropriate means for transmitting information obtained by the apparatus of the present invention should be used in accordance with regulations such as the EU Regulation on the protection of personal data (EU 2016 / 679, GDPR) or any other national regulations.

[0070] The second connection 23 between the readout integrated circuit 22 and the processing unit 24 may include at least one micro-antenna communicating with the processing unit 24. Preferably, the second connection 23 is a wireless connection and corresponds to, for example, a Bluetooth or Wi-Fi connection. Alternatively, the second connection between the readout integrated circuit 22 and the processing unit 24 may include an RFID tag.

[0071] The system may include an integrated micro-antenna for transmitting output signals from the device 10 attached to the patient's body to an external radiation therapy control room. Multiple radio frequency antennas may be assembled with the device or system of the present invention and transmit the cumulative dose in each 2-D array pixel immediately in real time.

[0072] If RFID tags are used, the system 20 of this invention can transmit serial numbers to a fixed RFID reader, such as a device that can wirelessly communicate with an antenna when the device is irradiated. Each RFID tag can have an identification number associated with a user or patient. Similarly, in accordance with regulations such as the EU Personal Data Protection Regulation (EU 2016 / 679, GDPR) or any other national regulation (where applicable), a far-field communication (FFC) system can be used to allow clinicians to collect information from the control room during radiation therapy. The wireless readout circuit unit can transmit voltage in the form of a digital output. When received by the processing unit, this voltage can be converted into a cumulative dose according to the calibration curve contained in each batch of radiation-sensitive membranes.

[0073] Figure 3 A 2-D diagram 30 showing a pixel distribution of 10*10 pixels is shown, which corresponds to the detection of light by a 2-D array of photoresistors and / or semiconductor units in the device of the present invention. Figure 3 The 2-D map can correspond to the graphical user interface transmitted to the user by the processing unit. This 2-D dose map is indicated by different colors or different shades of gray based on the intensity of light received by different photoresistors and / or semiconductor units, which is related to the delivered dose of ionizing radiation. Figure 3 Corresponding to the example, many different pixel distributions can be used, not limited to a 10x10 pixel distribution. In contrast, a pixel distribution following a specific pattern can be used for a specific application, depending on the surface the device of the present invention should cover. A higher number of pixels can provide more detailed information about the delivered dose.

[0074] according to Figure 3 In the 2D diagram, pixel 4 is blank and corresponds to the following pixel: this pixel has received light with an intensity equal to the reference light or baseline value and therefore corresponding to the region of the radiation-sensitive film that does not block light from passing through it. Therefore, this region of the radiation-sensitive film has not been altered by ionizing radiation. From such a pixel 4, it can be concluded that no ionizing radiation passes through this region and the delivered dose to this region is negligible.

[0075] according to Figure 3 In the 2D diagram, pixel 3 is light gray and corresponds to a pixel that has received light with an intensity slightly lower than the reference light or baseline value, and therefore corresponds to a region of the radiation-sensitive film that slightly blocks light from passing through it. Thus, this region of the radiation-sensitive film is only slightly altered by ionizing radiation. From such a pixel 3, it can be concluded that a first amount of ionizing radiation has passed through this region and that the delivered dose in this region is superior to the delivered dose in the region of pixel 4. For example, this does not limit the invention; the dose delivered according to pixel 3 could be 0.1 Gy.

[0076] according to Figure 3 In the 2D diagram, pixels 2 and 1 are gray and dark gray, respectively, and correspond to pixels that have received light with an intensity lower than the reference light or baseline value, and therefore corresponding to the region of the radiation-sensitive film that prevents light from passing through it. Thus, this region of the radiation-sensitive film has been altered by ionizing radiation. From such pixels 2 and 1, it can be concluded that a second and a third amount of ionizing radiation have passed through this region, and that the delivered dose in these regions is superior to the delivered dose in the regions of pixels 3 and 4. For example, this does not limit the invention; the delivered dose according to pixel 2 could be 0.2 Gy, and the delivered dose according to pixel 1 could be 1 Gy. Other dose gradients between pixels can be used.

[0077] This invention also relates to a graphical user interface (GUI) that acquires and stores data on all voltages of a 2-D array of photoresistors and / or semiconductor cells via an FFC, thereby generating a 2-D dose map with a visual dosimetry indicator. The photoresistor voltages can be scored in two consecutive steps: before irradiation (Vi) and after irradiation (Vf). Vi corresponds to a reference or baseline value for each pixel or region corresponding to the photoresistor or semiconductor cell. Vf Vi uses the corresponding calibration curve to indicate the final change in voltage in the photoresistor or semiconductor unit for each pixel or region, and the results are plotted in a user-friendly GUI.

[0078] The devices and systems of the present invention can be applied in various technical fields related to the monitoring of ionizing radiation. Therefore, such devices and systems can be used in radiation therapy or nuclear applications, such as radiation protection. However, these devices can also be used as everyday devices for monitoring ionizing radiation in any environment.

[0079] The device or system of the present invention can be miniaturized, wearable, low-cost, and placed on human skin. It can be a skin patch for radiation exposure using a commercial gafchromic™ membrane or any other radiation-sensitive membrane manufactured for this application, employing colorimetric chemical reagents. Such devices and systems allow the user to be provided with information in real time about the dose delivered to the skin based on a specific exposure. The device and system of the present invention can be disposable.

[0080] The apparatus and system of the present invention enable the fulfillment of the need for a device that allows for real-time in-situ measurement of doses delivered to a specific location (e.g., delivered to a patient during radiation therapy), whereas conventional detection systems require a delay in measuring doses delivered by scanning a radiation-sensitive membrane.

[0081] The examples given above are provided to illustrate embodiments of the invention. They do not in any way limit the scope of the invention as defined by the appended claims.

Claims

1. A wearable device (10) for measuring the dose delivered through a radiation-sensitive membrane (13) under exposure to ionizing radiation, the wearable device comprising: - A reflective film (11) having an inner surface (11a) opposite to an outer surface (11b) and adapted to reflect light; - At least one light source (12), said at least one light source being arranged to emit at least one light beam toward the inner surface (11a) of the reflective film; - A radiation-sensitive film (13) having a first side (13a) and an opposite second side (13b), the first side of the radiation-sensitive film facing the inner side (11a) of the reflective film. - An optical sensor system (14) having a first surface (14a) facing a second surface (13b) of the radiation-sensitive film (13), and the first surface of the optical sensor system being adapted to receive a light beam from the at least one light source (12) after reflection from the inner surface (11a) of the reflective film (11), the optical sensor system having a second surface (14b) opposite to the first surface (14a). The first surface (14a) of the optical sensor system (14) includes a 2-D array of one or more photoresistor units and / or semiconductor units, which are fixed to a support layer. The 2D array of the reflective film (11), the radiation-sensitive film (13), and the photoresistor unit and / or semiconductor unit is substantially parallel, and Wherein, the at least one light source (12) is not located between the inner surface (11a) of the reflective film (11) and the first surface (13a) of the radiation-sensitive film (13).

2. The wearable device (10) according to claim 1, wherein, The support layer of the reflective film (11), the radiation-sensitive film (13), and the optical sensor system (14) is flexible.

3. The wearable device (10) according to any one of claims 1 or 2, wherein, The wearable device (10) is encapsulated in a polymer.

4. The wearable device (10) according to any one of claims 1 or 2, wherein, The at least one light source includes one or more LEDs and / or one or more lasers.

5. The wearable device (10) according to any one of claims 1 or 2, wherein, The radiation-sensitive film (13) is a radiation-sensitive film.

6. The wearable device (10) according to any one of claims 1 or 2, wherein, The radiation-sensitive membrane (13) is made of polycarbonate.

7. The wearable device (10) according to any one of claims 1 or 2, wherein, The wearable device includes at least one light guide.

8. The wearable device (10) according to any one of claims 1 or 2, wherein, The reflective film (11) is a metallized microfilm or a polymer film coated with a metal layer.

9. The wearable device (10) according to any one of claims 1 or 2, wherein, The reflective film (11) has a thickness of less than 100 μm.

10. A system (20) for measuring a dose delivered through a radiation-sensitive membrane (13) under exposure to ionizing radiation, the system comprising a wearable device (10) according to any one of claims 1 to 9, the system comprising: A readout integrated circuit unit (22) is connected to the optical sensor system (14) of the wearable device (10) via a first connection (21); and a processing unit (24) is connected to the readout integrated circuit unit (22) via a second connection (23).

11. The system (20) according to claim 10, wherein, The second connection (23) between the readout integrated circuit unit (22) and the processing unit (24) includes at least one micro-antenna (25) communicating with the processing unit (24).

12. The system (20) according to claim 10, wherein, The second connection (23) between the readout integrated circuit unit (22) and the processing unit (24) is an RFID tag.

13. The system (20) according to any one of claims 10 to 12, wherein, The processing unit (24) is a remote control system.

14. Use of a wearable device (10) according to any one of claims 1 to 9 or a system (20) according to any one of claims 10 to 13 for measuring a dose delivered through a radiation-sensitive membrane (13) under exposure to ionizing radiation.

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