WO2012168527A1 - Real-time evaluation of neutron doses in patients undergoing radiotherapy treatment and detector for carrying out the process - Google Patents
Real-time evaluation of neutron doses in patients undergoing radiotherapy treatment and detector for carrying out the process Download PDFInfo
- Publication number
- WO2012168527A1 WO2012168527A1 PCT/ES2012/070420 ES2012070420W WO2012168527A1 WO 2012168527 A1 WO2012168527 A1 WO 2012168527A1 ES 2012070420 W ES2012070420 W ES 2012070420W WO 2012168527 A1 WO2012168527 A1 WO 2012168527A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- neutron
- doses
- treatment
- dummy
- detector
- Prior art date
Links
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
- A61N5/00—Radiation therapy
- A61N5/10—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy
- A61N5/1048—Monitoring, verifying, controlling systems and methods
- A61N5/1071—Monitoring, verifying, controlling systems and methods for verifying the dose delivered by the treatment plan
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
- A61N5/00—Radiation therapy
- A61N5/10—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy
- A61N2005/1085—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy characterised by the type of particles applied to the patient
- A61N2005/109—Neutrons
Definitions
- the present invention relates to the radiotherapy methodology, in particular to methods for evaluating the radiation doses of a patient during treatment.
- Radiation therapy represents one of the most useful tools available to cure cancer, along with surgery and chemotherapy.
- the emission of neutrons occurs essentially in high Z materials (W, Pb, Fe, Cu, etc.) in the accelerator head components (white, flattener filter, jaws, collimators, deflection magnet, shielding, etc. ) by electronuclear (e, e ', n) and photonuclear ( ⁇ , n) reaction as a result of the presence of photons in the beam with greater energy than the photonuclear reaction threshold.
- the method and device of the invention allows an estimate of equivalent doses of neutrons in organs of a patient and the associated risk of induction of secondary cancers by neutrons in photon radiotherapy.
- the detector used does not cause interference with patients and can easily be used in daily practice.
- the procedure is simple and universal. Consequently, equivalent doses of neutrons in organs of patients undergoing radiotherapy treatments can be estimated at any facility, based on the readings of the digital device and using the developed model, without any additional radiation measurement.
- the procedure for calculating equivalent doses follows the steps of: a. place an anthropomorphic dummy in front of a radiation device, the manikin being provided with passive neutron dosimeters in predetermined locations,
- the device comprises a plurality of memory cells that have a dielectric layer of borophosphosilicate glass (BPSG) in the chip arrangement adapted for each memory to store a logical level that changes due to the interaction of a thermal neutron.
- BPSG borophosphosilicate glass
- Figures 2a and 2b.- show the positions of the detectors with respect to a model of the organs.
- Figure 3.- is a graph that shows the calculations to determine a correction factor for the bunker size (treatment room).
- the detector of the invention is really a plurality of detectors corresponding to each memory cell of a digital semiconductor device.
- Each memory cell stores a logical level (bit) that can change due to the interaction of a particle with the materials of the semiconductor component, producing sufficient ionization from subsequent processes. This process is known as the effect of a single event (SEE, "Single Event Effecf).
- the detector consists of a plurality of chips, for example 128 with a total memory of 64 MiB.
- Memory components are selected to have a dielectric layer of borophosphosilicate glass (BPSG) in the chip arrangement so that they are sensitive to thermal neutrons.
- BPSG borophosphosilicate glass
- devices showing BPSG in close proximity to the silicon substrate should be considered.
- the mechanism responsible is the capture of neutrons from the 10 B isotope that constitutes 20% of the natural boron. Boron is commonly used in semiconductors as a dopant of the type p and silicon implant species, and also in the composition of the dielectric layer of borophosphosilicate glass (BPSG) (2-8% by weight).
- the effective section of 10 B neutron capture behaves like 1 / v, where v represents the speed of the neutrons. Therefore, it is not necessary to consider fast neutrons.
- the detector is placed inside the radiotherapy room and is controlled with a computer through a serial connection. Before each irradiation, the memory content is adjusted to a fixed pattern. After that, the memory content is read and the amount of SEE is calculated.
- the digital device is located near the main axis of rotation of the accelerator (gantry in English) in front of the linear accelerator, usually near the wall of the room. In this way, it does not interfere with radiotherapy treatments and is independent of the angle with the main axis of rotation.
- the system shows that the number of events has repeatability (relative standard deviation) of approximately 2% for irradiations of 1000 monitor units (UM at 15 MV with a field of (10 ⁇ 10) cm 2 ).
- the device is basically insensitive to photons while the memory size and operation produces a neutron sensitivity of the system sufficient to measure the intensity of neutron production of the accelerator through 1000-2000 UM shots with low statistical uncertainty that guarantees linearity and Reliable operation
- An anthropomorphic dummy (figure 1) allows to acquire a set of measurements that resemble the dose in the patient.
- the best choice of material low density wood for the lungs and polyethylene for the rest of the body
- other dummies made of nylon, injecting urea into polyethylene, real tissues and organs from pigs, etc.
- elements such as nitrogen or the proportion of hydrogen with respect to human tissues.
- Sixteen strategic locations in the dummy are chosen to perform neutron creep measurements with dosimeters of passive neutrons, which allow for the evaluation of equivalent dose values at those points, located at varying depths.
- a suitable cavity is constructed for passive detectors at each location.
- the evaluation of neutron dose equivalents at all specified points allows estimating the equivalent doses of neutrons in all the patient's relevant organs or tissues, selected for radioprotection: brain, thyroid, breast, lungs, esophagus, stomach, liver , gallbladder, colon (ascending, descending, transverse and sigmoid), ovaries, testicles, as well as bones and red bone marrow. Since there is no direct correspondence of the locations of the measurements with each organ position, the equivalent doses in the organs are obtained through the interpolation of the readings of the nearest data points, taking into account Cristy's model -Eckermann in which the organs and the positions of the centroids thereof are defined.
- a simple geometric model for the dummy allows an estimate by Monte Cario of the neutron spectrum.
- the measurement points within the dummy are strategically distributed to make It is possible to deduct the dose at any point and, consequently, to accurately assign doses to specific organs. This allows doses to be evaluated even in organs that are not on the actual list, mentioned above, but may be of interest in the future.
- a minituarized version of a passive neutron dosimeter based on UAB-PADC (poly allyl diglycol carbonate) is used to determine the neutron dose equivalents at the 16 points specified in the dummy ( Figures 2a and 2b).
- Dosimeters based on UAB-PADC are sensitive to both rapid and thermal neutrons, and the neutron field to which they are exposed within the dummy includes all thermal, epidermal and rapid components.
- a calibration factor (C) can be calculated with respect to the reference detector.
- the Bonner multisphere or sphere spectrometer (BSS) is the most used for radiation protection purposes, due to advantageous features such as the wide range of energy (from the thermal range, about 25meV to GeV), the wide variety of active or passive thermal sensors that allow sensitivity to be adapted to the specific workplace, good photon discrimination and simple signal management.
- the most delicate part of BSS-based spectrometry is the deployment process.
- the response matrix of the passive UAB-BSS system was calculated using a Monte Cario simulation for a wide range of neutron energies (from thermal to 20 MeV).
- the calculated response functions were adjusted to the experimental calibration results, and good concordance was found when a calibration factor of 0.974 ⁇ 0.028 was applied to the calculated data.
- the FRUIT code has been used for deployment, in order to obtain the distribution of neutron creep energy from the detector readings in the center of the Bonner spheres and from the evaluated response matrix.
- ICRP 103 provides a nominal risk coefficient (RN).
- the risk per organ can be calculated using the general expression
- C is the calibration factor
- B is the correction factor for the room size (bunker size)
- S is the number of treatment sessions
- RN is the nominal risk as in the previous table
- DE is the equivalent of calculated dose.
- the total risk (RT) of acquiring a second malignant tumor due to neutrons is the sum of the risk of each organ:
Abstract
Process and detector for calculating the equivalent neutron doses in organs of a patient and the associated risk of inducing secondary cancers by means of neutrons in radiotherapy with photons. The calculation is carried out by associating doses in detectors placed at different positions in an anthropomorphic dummy and the events with a single effect in a semiconductor device placed in the treatment room. The method allows a simple and universal process for estimating the risk of secondary cancer from the real-time readings of an electronic device.
Description
EVALUACIÓN EN TIEMPO REAL DE DOSIS DE NEUTRONES EN PACIENTES EN TRATAMIENTO CON RADIOTERAPIA Y DETECTOR PARA LLEVAR A REAL-TIME EVALUATION OF NEUTRON DOSE IN PATIENTS IN TREATMENT WITH RADIOTHERAPY AND DETECTOR TO BRING
CABO EL PROCEDIMIENTO I FIT THE PROCEDURE
DESCRIPCIÓN DESCRIPTION
CAMPO DE LA INVENCIÓN FIELD OF THE INVENTION
La presente invención se refiere a la metodología de la radioterapia, en particular a métodos para evaluar las dosis de radiación de un paciente durante el tratamiento. The present invention relates to the radiotherapy methodology, in particular to methods for evaluating the radiation doses of a patient during treatment.
ESTADO DE LA TÉCNICA STATE OF THE TECHNIQUE
La radioterapia representa una de las herramientas más útiles disponibles para curar el cáncer, junto con la cirugía y la quimioterapia. Radiation therapy represents one of the most useful tools available to cure cancer, along with surgery and chemotherapy.
En muchos de los procedimientos de terapia con radiación, la dosis periférica no deseada se debe a fotones y neutrones. Aunque las dosis de fotones se han estudiado en profundidad, la contaminación con neutrones de haces de fotones de alta energía todavía es objeto de investigación y discusión. In many of the radiation therapy procedures, the unwanted peripheral dose is due to photons and neutrons. Although photon doses have been studied in depth, contamination with neutrons of high-energy photon beams is still under investigation and discussion.
La emisión de neutrones se produce esencialmente en materiales de alta Z (W, Pb, Fe, Cu, etc.) en los componentes de cabezal de acelerador (blanco, filtro de aplanador, mordazas, colimadores, imán de desviación, blindaje, etc.) mediante reacción electronuclear (e, e', n) y fotonuclear (γ, n) como consecuencia de la presencia de fotones en el haz con mayor energía que el umbral de reacción fotonuclear. The emission of neutrons occurs essentially in high Z materials (W, Pb, Fe, Cu, etc.) in the accelerator head components (white, flattener filter, jaws, collimators, deflection magnet, shielding, etc. ) by electronuclear (e, e ', n) and photonuclear (γ, n) reaction as a result of the presence of photons in the beam with greater energy than the photonuclear reaction threshold.
La medición de la fluencia de neutrones dentro de una sala de radioterapia es una tarea difícil. Por tanto, no resulta fácil cuantificar la producción de neutrones en radioterapia: los detectores pasivos (es decir, activación de oro, TLD, detectores de trazas, etc.) requieren un tiempo considerable para el procesamiento, el análisis y la evaluación, mientras que para los contadores activos (es decir, centelleadores de BF3, 3He, 6Lil), la acumulación y saturación de la señal debido a la radiación pulsada de los aceleradores médicos dificulta la separación de la contribución de neutrones inmersos en un campo de fotones pulsado de elevada fluencia. Por tanto, el riesgo radiológico asociado con los neutrones producidos durante el tratamiento no se evalúa habitualmente cuando se elige la mejor estrategia que implica la
menor cantidad de riesgo para el paciente. Por tanto, existe una necesidad de nuevos métodos de determinación de las dosis equivalentes de neutrones recibidas en órganos relevantes en tiempo real. Measuring neutron creep within a radiotherapy room is a difficult task. Therefore, it is not easy to quantify neutron production in radiotherapy: passive detectors (i.e. gold activation, TLD, trace detectors, etc.) require considerable time for processing, analysis and evaluation, while for active counters (i.e. BF 3 , 3 He, 6 Lil scintillators), the accumulation and saturation of the signal due to pulsed radiation from medical accelerators makes it difficult to separate the contribution of neutrons immersed in a photon field high flow pulsed. Therefore, the radiological risk associated with the neutrons produced during treatment is not usually evaluated when the best strategy that involves Less risk to the patient. Therefore, there is a need for new methods of determining equivalent doses of neutrons received in relevant organs in real time.
RESUMEN DE LA INVENCIÓN SUMMARY OF THE INVENTION
El procedimiento y dispositivo de la invención permite una estimación de las dosis equivalentes de neutrones en órganos de un paciente y el riesgo asociado de inducción de cánceres secundarios mediante neutrones en radioterapia con fotones. El detector usado no provoca interferencia con los pacientes y puede usarse fácilmente en la práctica diaria. A pesar de la complejidad del problema, el procedimiento es sencillo y universal. En consecuencia, las dosis equivalentes de neutrones en órganos de pacientes que se someten a tratamientos con radioterapia pueden estimarse en cualquier instalación, a partir de las lecturas del dispositivo digital y usando el modelo desarrollado, sin ninguna medición adicional de la radiación. El procedimiento para calcular las dosis equivalentes sigue las etapas de: a. colocar un maniquí antropomorfo enfrente de un dispositivo de radiación, estando dotado el maniquí de dosímetros de neutrones pasivos en ubicaciones predeterminadas, The method and device of the invention allows an estimate of equivalent doses of neutrons in organs of a patient and the associated risk of induction of secondary cancers by neutrons in photon radiotherapy. The detector used does not cause interference with patients and can easily be used in daily practice. Despite the complexity of the problem, the procedure is simple and universal. Consequently, equivalent doses of neutrons in organs of patients undergoing radiotherapy treatments can be estimated at any facility, based on the readings of the digital device and using the developed model, without any additional radiation measurement. The procedure for calculating equivalent doses follows the steps of: a. place an anthropomorphic dummy in front of a radiation device, the manikin being provided with passive neutron dosimeters in predetermined locations,
b. calcular las dosis en los detectores teniendo en cuenta la distribución de energía de fluencia de neutrones mediante una simulación de Monte Cario, b. calculate the doses in the detectors taking into account the distribution of neutron creep energy by means of a Monte Cario simulation,
c. interpolar las dosis usando el modelo de Christy-Eckermann a las posiciones reales de los órganos. C. Interpolate the doses using the Christy-Eckermann model to the actual positions of the organs.
El dispositivo comprende una pluralidad de celdas de memoria que tienen una capa dieléctrica de vidrio de borofosfosilicato (BPSG) en la disposición del chip adaptadas para que cada memoria almacene un nivel lógico que cambia debido a la interacción de un neutrón térmico. The device comprises a plurality of memory cells that have a dielectric layer of borophosphosilicate glass (BPSG) in the chip arrangement adapted for each memory to store a logical level that changes due to the interaction of a thermal neutron.
Pueden encontrarse ventajas adicionales de la invención en las reivindicaciones dependientes. Additional advantages of the invention can be found in the dependent claims.
BREVE DESCRIPCIÓN DE LOS DIBUJOS BRIEF DESCRIPTION OF THE DRAWINGS
Para completar la descripción y con el fin de proporcionar una mejor comprensión de la invención, se proporciona un conjunto de dibujos. Dichos dibujos ilustran una realización preferida de la invención, que no debe interpretarse como restrictiva del alcance de la invención sino tan sólo como un ejemplo de cómo puede llevarse a cabo la invención. Los dibujos comprenden las siguientes figuras:
Figura 1 .- es un modelo de un maniquí antropomorfo usado en la medida y cálculo de la dosis de neutrones To complete the description and in order to provide a better understanding of the invention, a set of drawings is provided. Such drawings illustrate a preferred embodiment of the invention, which should not be construed as restrictive of the scope of the invention but only as an example of how the invention can be carried out. The drawings comprise the following figures: Figure 1 .- is a model of an anthropomorphic dummy used in the measurement and calculation of the neutron dose
Figuras 2a y 2b.- muestran las posiciones de los detectores con respecto a un modelo de los órganos. Figures 2a and 2b.- show the positions of the detectors with respect to a model of the organs.
Figura 3.- es un gráfico que muestra los cálculos para determinar un factor de corrección para el tamaño de búnker (sala de tratamiento). Figure 3.- is a graph that shows the calculations to determine a correction factor for the bunker size (treatment room).
DESCRIPCIÓN DE LA INVENCIÓN DESCRIPTION OF THE INVENTION
El detector de la invención es realmente una pluralidad de detectores que corresponden a cada celda de memoria de un dispositivo semiconductor digital. Cada celda de la memoria almacena un nivel lógico (bit) que puede cambiar debido a la interacción de una partícula con los materiales del componente semiconductor, produciendo suficiente ionización a partir de los procesos posteriores. Este proceso se conoce como efecto de un único evento (SEE, "Single Event Effecf). The detector of the invention is really a plurality of detectors corresponding to each memory cell of a digital semiconductor device. Each memory cell stores a logical level (bit) that can change due to the interaction of a particle with the materials of the semiconductor component, producing sufficient ionization from subsequent processes. This process is known as the effect of a single event (SEE, "Single Event Effecf).
El detector consiste en una pluralidad de chips, por ejemplo 128 con una memoria total de 64 MiB. Los componentes de memoria se seleccionan para que tengan una capa dieléctrica de vidrio de borofosfosilicato (BPSG) en la disposición del chip de manera que sean sensibles a neutrones térmicos. Preferiblemente, deben considerarse dispositivos que muestran BPSG en proximidad estrecha al sustrato de silicio. El mecanismo responsable es la captura de neutrones a partir del isótopo 10B que constituye el 20% del boro natural. El boro se usa comúnmente en semiconductores como dopante de tipo p y especie de implante en silicio, y también en la composición de la capa dieléctrica de vidrio de borofosfosilicato (BPSG) (2-8% en peso). La sección eficaz de la captura de neutrones de 10B se comporta como 1/v, donde v representa la velocidad de los neutrones. Por tanto, no es necesario considerar neutrones rápidos. The detector consists of a plurality of chips, for example 128 with a total memory of 64 MiB. Memory components are selected to have a dielectric layer of borophosphosilicate glass (BPSG) in the chip arrangement so that they are sensitive to thermal neutrons. Preferably, devices showing BPSG in close proximity to the silicon substrate should be considered. The mechanism responsible is the capture of neutrons from the 10 B isotope that constitutes 20% of the natural boron. Boron is commonly used in semiconductors as a dopant of the type p and silicon implant species, and also in the composition of the dielectric layer of borophosphosilicate glass (BPSG) (2-8% by weight). The effective section of 10 B neutron capture behaves like 1 / v, where v represents the speed of the neutrons. Therefore, it is not necessary to consider fast neutrons.
El detector se coloca dentro de la sala de radioterapia y se controla con un ordenador a través de una conexión en serie. Antes de cada irradiación, se ajusta el contenido de la memoria a un patrón fijado. Después de eso, se lee el contenido de la memoria y se calcula la cantidad de SEE. El dispositivo digital se ubica próximo al eje de giro principal del acelerador (gantry en inglés) enfrente del acelerador lineal, normalmente cerca de la pared de la sala. De este modo, no interfiere con los tratamientos de radioterapia y resulta independiente del ángulo con el eje de giro principal. El sistema muestra que el número de eventos tiene una repetibilidad
(desviación estándar relativa) de aproximadamente el 2% para irradiaciones de 1000 unidades monitor (UM a 15 MV con un campo de (10 χ 10) cm2). También presenta una excelente linealidad, ya que las lecturas promedio presentan una desviación relativa a partir de una regresión lineal con UM del acelerador lineal menor del 1 %. El dispositivo es básicamente insensible a los fotones mientras que el tamaño de memoria y funcionamiento produce una sensibilidad a neutrones del sistema suficiente para medir la intensidad de producción de neutrones del acelerador mediante disparos de 1000-2000 UM con baja incertidumbre estadística que garantiza la linealidad y el funcionamiento fiable. The detector is placed inside the radiotherapy room and is controlled with a computer through a serial connection. Before each irradiation, the memory content is adjusted to a fixed pattern. After that, the memory content is read and the amount of SEE is calculated. The digital device is located near the main axis of rotation of the accelerator (gantry in English) in front of the linear accelerator, usually near the wall of the room. In this way, it does not interfere with radiotherapy treatments and is independent of the angle with the main axis of rotation. The system shows that the number of events has repeatability (relative standard deviation) of approximately 2% for irradiations of 1000 monitor units (UM at 15 MV with a field of (10 χ 10) cm 2 ). It also has excellent linearity, since the average readings have a relative deviation from a linear regression with a linear accelerator UM of less than 1%. The device is basically insensitive to photons while the memory size and operation produces a neutron sensitivity of the system sufficient to measure the intensity of neutron production of the accelerator through 1000-2000 UM shots with low statistical uncertainty that guarantees linearity and Reliable operation
Un maniquí antropomórfico (figura 1 ) permite adquirir un conjunto de mediciones que se asemejan a la dosis en el paciente. La mejor elección del material (madera de baja densidad para los pulmones y polietileno para el resto del cuerpo) se basa en los ensayos llevados a cabo con otros maniquíes (construidos en nylon, inyectando urea al polietileno, tejidos y órganos reales procedente de porcino, etc.) para conocer la repercusión de elementos, tales como el nitrógeno o la proporción de hidrógeno respecto a los tejidos humanos. Se eligen dieciséis ubicaciones estratégicas en el maniquí para realizar las mediciones de la fluencia de neutrones con dosímetros de neutrones pasivos, que permiten evaluar los valores equivalentes de dosis en esos puntos, ubicados a profundidades variables. Se construye una cavidad adecuada para los detectores pasivos en cada ubicación. An anthropomorphic dummy (figure 1) allows to acquire a set of measurements that resemble the dose in the patient. The best choice of material (low density wood for the lungs and polyethylene for the rest of the body) is based on tests carried out with other dummies (made of nylon, injecting urea into polyethylene, real tissues and organs from pigs, etc.) to know the impact of elements, such as nitrogen or the proportion of hydrogen with respect to human tissues. Sixteen strategic locations in the dummy are chosen to perform neutron creep measurements with dosimeters of passive neutrons, which allow for the evaluation of equivalent dose values at those points, located at varying depths. A suitable cavity is constructed for passive detectors at each location.
La evaluación de los equivalentes de dosis de neutrones en todos los puntos especificados permite estimar las dosis equivalentes de neutrones en todos los órganos o tejidos de relevancia del paciente, seleccionados para su radioprotección: cerebro, tiroides, mamas, pulmones, esófago, estómago, hígado, vesícula biliar, colon (ascendente, descendente, transversal y sigmoide), ovarios, testículos, así como huesos y médula ósea roja. Puesto que no hay una correspondencia directa de las ubicaciones de las mediciones con cada posición de órgano, se obtienen las dosis equivalentes en los órganos a través de la interpolación de las lecturas de los puntos de datos más cercanos, teniendo en cuenta el modelo de Cristy-Eckermann en el que se definen los órganos y las posiciones de los centroides de los mismos. The evaluation of neutron dose equivalents at all specified points allows estimating the equivalent doses of neutrons in all the patient's relevant organs or tissues, selected for radioprotection: brain, thyroid, breast, lungs, esophagus, stomach, liver , gallbladder, colon (ascending, descending, transverse and sigmoid), ovaries, testicles, as well as bones and red bone marrow. Since there is no direct correspondence of the locations of the measurements with each organ position, the equivalent doses in the organs are obtained through the interpolation of the readings of the nearest data points, taking into account Cristy's model -Eckermann in which the organs and the positions of the centroids thereof are defined.
Un modelo geométrico sencillo para el maniquí permite una estimación mediante Monte Cario del espectro de neutrones. Además, los puntos de mediciones dentro del maniquí están estratégicamente distribuidos para hacer
posible deducir la dosis en cualquier punto y, en consecuencia, para asignar de manera precisa dosis a órganos específicos. Esto permite evaluar dosis incluso en órganos que no están en la lista real, mencionada anteriormente, pero pueden ser de interés en el futuro. A simple geometric model for the dummy allows an estimate by Monte Cario of the neutron spectrum. In addition, the measurement points within the dummy are strategically distributed to make It is possible to deduct the dose at any point and, consequently, to accurately assign doses to specific organs. This allows doses to be evaluated even in organs that are not on the actual list, mentioned above, but may be of interest in the future.
Se usa una versión minituarizada de un dosímetro pasivo de neutrones basado en UAB-PADC (poli allil diglicol carbonato) para determinar los equivalentes de dosis de neutrones en los 16 puntos especificados en el maniquí (figuras 2a y 2b). Los dosímetros basados en UAB-PADC son sensibles tanto a neutrones rápidos como térmicos, y el campo de neutrones al que se exponen dentro del maniquí incluyen todas las componentes térmica, epitérmica y rápida. A minituarized version of a passive neutron dosimeter based on UAB-PADC (poly allyl diglycol carbonate) is used to determine the neutron dose equivalents at the 16 points specified in the dummy (Figures 2a and 2b). Dosimeters based on UAB-PADC are sensitive to both rapid and thermal neutrons, and the neutron field to which they are exposed within the dummy includes all thermal, epidermal and rapid components.
Puede calcularse un factor de calibración (C) con respecto al detector de referencia. Entre las muchas técnicas de espectrometría de neutrones disponibles, el espectrómetro de multiesferas o esferas de Bonner (BSS) es el más usado para los fines de protección contra la radiación, debido a características ventajosas como el amplio intervalo de energía (desde el rango térmico, unos 25meV hasta GeV), la gran variedad de sensores térmicos activos o pasivos que permiten adaptar la sensibilidad al lugar de trabajo específico, la buena discriminación de fotones y la gestión sencilla de señales. La parte más delicada de la espectrometría basada en BSS es el proceso de despliegue. Se calculó la matriz de respuesta del sistema UAB-BSS pasivo mediante una simulación de Monte Cario para un amplio intervalo de energías de neutrones (desde térmicos hasta 20 MeV). Se ajustaron las funciones de respuesta calculadas a los resultados de calibración experimentales, y se encontró una buena concordancia cuando se aplicaba un factor de calibración de 0,974 ± 0,028 a los datos calculados. Se ha usado el código FRUIT para el despliegue, con el fin de obtener la distribución de energía de la fluencia de neutrones a partir de las lecturas de los detectores en el centro de las esferas de Bonner y a partir de la matriz de respuesta evaluada. A calibration factor (C) can be calculated with respect to the reference detector. Among the many neutron spectrometry techniques available, the Bonner multisphere or sphere spectrometer (BSS) is the most used for radiation protection purposes, due to advantageous features such as the wide range of energy (from the thermal range, about 25meV to GeV), the wide variety of active or passive thermal sensors that allow sensitivity to be adapted to the specific workplace, good photon discrimination and simple signal management. The most delicate part of BSS-based spectrometry is the deployment process. The response matrix of the passive UAB-BSS system was calculated using a Monte Cario simulation for a wide range of neutron energies (from thermal to 20 MeV). The calculated response functions were adjusted to the experimental calibration results, and good concordance was found when a calibration factor of 0.974 ± 0.028 was applied to the calculated data. The FRUIT code has been used for deployment, in order to obtain the distribution of neutron creep energy from the detector readings in the center of the Bonner spheres and from the evaluated response matrix.
También se realizaron cálculos experimentales con el fin de estudiar la influencia del tamaño de la sala de tratamiento (figura 3). El factor de tamaño de búnker (B) se ha calculado como:
Experimental calculations were also performed in order to study the influence of the size of the treatment room (Figure 3). The bunker size factor (B) has been calculated as:
siendo P1 = 0,396 ± 0,027m2, P2 = 37,3 ± 1 ,1 m2, F la fluencia de neutrones térmicos normalizada y s la superficie del suelo de la sala (m2), excluyendo el
laberinto. where P1 = 0.396 ± 0.027m 2 , P2 = 37.3 ± 1, 1 m 2 , F the normalized thermal neutron creep and s the floor surface of the room (m 2 ), excluding labyrinth.
Se calcularon las dosis equivalentes para dos tipos de tratamientos, cabeza y resto del cuerpo (abdomen), y se muestran en esta tabla: Equivalent doses were calculated for two types of treatments, head and rest of the body (abdomen), and are shown in this table:
El conocimiento de las dosis equivalentes hace posible estimar el riesgo de desarrollo de un cáncer secundario tras un tratamiento con radiación con un acelerador lineal, siguiendo algunas directrices como las propuestas por la Comisión Internacional de Protección contra la Radiación, (ICRP-103) o el Consejo Nacional de Investigación de los EE.UU. (BEIR VII). Como ejemplo, la siguiente tabla de la ICRP 103 proporciona un coeficiente de riesgo nominal (RN).
The knowledge of the equivalent doses makes it possible to estimate the risk of development of a secondary cancer after radiation treatment with a linear accelerator, following some guidelines such as those proposed by the International Commission for Radiation Protection, (ICRP-103) or National Research Council of the USA (BEIR VII). As an example, the following table of ICRP 103 provides a nominal risk coefficient (RN).
El riesgo por órgano puede calcularse mediante la expresión general
The risk per organ can be calculated using the general expression
en la que E es el número de eventos de efecto único
in which E is the number of single effect events
del detector, C es el factor de calibración, B es el factor de corrección para el tamaño de la sala (tamaño de búnker), S es el número de sesiones de tratamiento, RN es el riesgo nominal como en la tabla anterior y DE es el equivalente de dosis calculado. of the detector, C is the calibration factor, B is the correction factor for the room size (bunker size), S is the number of treatment sessions, RN is the nominal risk as in the previous table and DE is the equivalent of calculated dose.
El riesgo total (RT) de adquirir un segundo tumor maligno debido a los neutrones es la suma del riesgo de cada órgano: The total risk (RT) of acquiring a second malignant tumor due to neutrons is the sum of the risk of each organ:
Claims
1 . Procedimiento de cálculo de dosis equivalentes de neutrones que un órgano de un paciente recibiría durante el tratamiento con radiación con un acelerador lineal, que comprende las etapas de: one . Procedure for calculating equivalent doses of neutrons that an organ of a patient would receive during radiation treatment with a linear accelerator, comprising the steps of:
a. colocar un maniquí antropomórfico enfrente de un dispositivo de radiación, estando dotado el maniquí de dosímetros de neutrones pasivos en ubicaciones predeterminadas, to. place an anthropomorphic dummy in front of a radiation device, the dummy being provided with passive neutron dosimeters at predetermined locations,
b. calcular las dosis en los detectores teniendo en cuenta la distribución de energía de fluencia de neutrones mediante una simulación de Monte Cario, c. interpolar las dosis usando el modelo de Christy-Eckermann a las posiciones reales de los órganos. b. calculate the doses in the detectors taking into account the distribution of neutron fluence energy using a simulation of Monte Cario, c. Interpolate the doses using the Christy-Eckermann model to the actual positions of the organs.
2. Procedimiento según la reivindicación 1 , caracterizado porque el maniquí está hecho de polietileno y madera. 2. Method according to claim 1, characterized in that the dummy is made of polyethylene and wood.
3. Procedimiento de evaluación del riesgo de adquirir un segundo tumor maligno tras un tratamiento con radioterapia debido a la radiación de neutrones, en el que la evaluación se realiza mediante la fórmula 
en la que E es un número de efectos de un único evento en un dispositivo semiconductor, C es un factor de calibración, B es un factor de corrección debido al tamaño de búnker facilitado por la fórmula 
siendo P1 = 0,396 ± 0,027m2, P2 = 37,3 ± 1 ,1 m2, F la fluencia de neutrones térmicos normalizada y s la superficie del suelo de la sala, RN es un coeficiente de riesgo normalizado, S es el número de sesiones de tratamiento, en la que DE es una dosis equivalente por evento en un órgano determinado calculada según las reivindicaciones 1 -2. 3. Procedure for assessing the risk of acquiring a second malignant tumor after radiotherapy treatment due to neutron radiation, in which the evaluation is carried out using the formula in which E is a number of effects of a single event in a semiconductor device, C is a calibration factor, B is a correction factor due to the bunker size provided by the formula where P1 = 0.396 ± 0.027m 2 , P2 = 37.3 ± 1, 1 m 2 , F the normalized thermal neutron creep and s the floor surface of the room, RN is a normalized risk coefficient, S is the number of treatment sessions, wherein DE is an equivalent dose per event in a given organ calculated according to claims 1-2.
4. Procedimiento según la reivindicación 3, caracterizado porque el tratamiento es un tratamiento en el abdomen o un tratamiento en la cabeza y las dosis equivalentes para cada órgano son: 
4. Method according to claim 3, characterized in that the treatment is a treatment in the abdomen or a treatment in the head and the equivalent doses for each organ are:
5. Dispositivo semiconductor digital especialmente adaptado para usarse en el método según la reivindicación 3, que comprende una pluralidad de celdas de memoria que comprenden a su vez una capa dieléctrica de vidrio de borofosfosilicato (BPSG) en la disposición del chip adaptadas para que cada memoria almacene un nivel lógico que cambia debido a la interacción de un neutrón térmico (E). 5. A digital semiconductor device specially adapted for use in the method according to claim 3, comprising a plurality of memory cells which in turn comprise a dielectric layer of borophosphosilicate glass (BPSG) in the chip arrangement adapted to make each memory store a logical level that changes due to the interaction of a thermal neutron (E).
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| ES201130932A ES2537720B1 (en) | 2011-06-06 | 2011-06-06 | REAL-TIME EVALUATION OF NEUTRON DOSE IN PATIENTS IN TREATMENT WITH RADIOTHERAPY AND DETECTOR TO CARRY OUT THE PROCEDURE |
| ESP201130932 | 2011-06-06 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2012168527A1 true WO2012168527A1 (en) | 2012-12-13 |
Family
ID=47295534
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/ES2012/070420 WO2012168527A1 (en) | 2011-06-06 | 2012-06-06 | Real-time evaluation of neutron doses in patients undergoing radiotherapy treatment and detector for carrying out the process |
Country Status (2)
| Country | Link |
|---|---|
| ES (1) | ES2537720B1 (en) |
| WO (1) | WO2012168527A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109173081A (en) * | 2018-09-10 | 2019-01-11 | 东莞东阳光高能医疗设备有限公司 | Line appraisal procedure, device, equipment and the storage medium of boron neutron capture therapy |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5341292A (en) * | 1992-06-04 | 1994-08-23 | New England Medical Center Hospitals, Inc. | Monte Carlo based treatment planning for neutron capture therapy |
| WO2001045556A1 (en) * | 1999-12-21 | 2001-06-28 | Bechtel Bwxt Idaho, Llc | Monte carlo simulation of neutron transport for use in radiotherapy |
| US20100258732A1 (en) * | 2006-09-20 | 2010-10-14 | Faustino Gomez Rodriguez | Neutron dosimetry for radiotherapy |
-
2011
- 2011-06-06 ES ES201130932A patent/ES2537720B1/en not_active Expired - Fee Related
-
2012
- 2012-06-06 WO PCT/ES2012/070420 patent/WO2012168527A1/en active Application Filing
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5341292A (en) * | 1992-06-04 | 1994-08-23 | New England Medical Center Hospitals, Inc. | Monte Carlo based treatment planning for neutron capture therapy |
| WO2001045556A1 (en) * | 1999-12-21 | 2001-06-28 | Bechtel Bwxt Idaho, Llc | Monte carlo simulation of neutron transport for use in radiotherapy |
| US20100258732A1 (en) * | 2006-09-20 | 2010-10-14 | Faustino Gomez Rodriguez | Neutron dosimetry for radiotherapy |
Non-Patent Citations (11)
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109173081A (en) * | 2018-09-10 | 2019-01-11 | 东莞东阳光高能医疗设备有限公司 | Line appraisal procedure, device, equipment and the storage medium of boron neutron capture therapy |
| CN109173081B (en) * | 2018-09-10 | 2020-12-22 | 东莞东阳光高能医疗设备有限公司 | Beam evaluation method, device and equipment for boron neutron capture therapy and storage medium |
Also Published As
| Publication number | Publication date |
|---|---|
| ES2537720A1 (en) | 2015-06-11 |
| ES2537720B1 (en) | 2017-01-05 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Domingo et al. | Neutron spectrometry and determination of neutron ambient dose equivalents in different LINAC radiotherapy rooms | |
| Qi et al. | Real-time in vivo dosimetry with MOSFET detectors in serial tomotherapy for head and neck cancer patients | |
| Cherpak et al. | Evaluation of a novel 4D in vivo dosimetry system | |
| Alhujaili et al. | Quality assurance of Cyberknife robotic stereotactic radiosurgery using an angularly independent silicon detector | |
| Xu et al. | Real‐time tumor tracking using implanted positron emission markers: Concept and simulation study | |
| Rowbottom et al. | Characteristics and performance of a micro‐MOSFET: an “imageable” dosimeter for image‐guided radiotherapy | |
| Nikoofar et al. | High-dose-rate 192Ir brachytherapy dose verification: A phantom study | |
| Toossi et al. | Evaluation of dose calculations accuracy of a commercial treatment planning system for the head and neck region in radiotherapy | |
| Rivera-Montalvo | Radiation therapy dosimetry system | |
| Gasparian et al. | Demonstrating the use of optically stimulated luminescence dosimeters (OSLDs) for measurement of staff radiation exposure in interventional fluoroscopy and helmet output factors in radiosurgery | |
| Wagner et al. | In vivo alanine/electron spin resonance (ESR) dosimetry in radiotherapy of prostate cancer: a feasibility study | |
| Kinhikar et al. | Dosimetric evaluation of a new OneDose MOSFET for Ir-192 energy | |
| Persson et al. | Experience of using MOSFET detectors for dose verification measurements in an end-to-end 192Ir brachytherapy quality assurance system | |
| Kinhikar et al. | Clinical application of a OneDose™ MOSFET for skin dose measurements during internal mammary chain irradiation with high dose rate brachytherapy in carcinoma of the breast | |
| ES2537720B1 (en) | REAL-TIME EVALUATION OF NEUTRON DOSE IN PATIENTS IN TREATMENT WITH RADIOTHERAPY AND DETECTOR TO CARRY OUT THE PROCEDURE | |
| AL-Shareef et al. | Implementation of in-vivo diode dosimetry for intensity modulated radiotherapy as routine patients' quality assurance | |
| Pike | A dosimetric characterization of an electronic brachytherapy source in terms of absorbed dose to water | |
| Bueno et al. | On the suitability of ultrathin detectors for absorbed dose assessment in the presence of high‐density heterogeneities | |
| Krishnamoorthy et al. | A proof-of-concept study of an in-situ partial-ring time-of-flight PET scanner for proton beam verification | |
| Oliveira et al. | Treatment verification and in vivo dosimetry for total body irradiation using thermoluminescent and semiconductor detectors | |
| Lohrabian et al. | Dosimetric characterization of a new 192Ir pulse dose rate brachytherapy source with the Monte Carlo simulation and thermoluminescent dosimeter | |
| Moafi et al. | Analysis of TLD-100 calibration and Correction factor in different field sizes under low dose conditions irradiated with two systems: Gamma knife 4C and Theratron 780-C | |
| Schaeken et al. | Experimental determination of the energy response of alanine pellets in the high dose rate 192Ir spectrum | |
| Bollinger et al. | Clinical considerations and dosimeters for in vivo dosimetry | |
| Tung et al. | In vivo dose verification for photon treatments of head and neck carcinomas using MOSFET dosimeters |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 12796295 Country of ref document: EP Kind code of ref document: A1 |
|
| NENP | Non-entry into the national phase |
Ref country code: DE |
|
| 122 | Ep: pct application non-entry in european phase |
Ref document number: 12796295 Country of ref document: EP Kind code of ref document: A1 |