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EP-4230259-B1 - BORON NEUTRON CAPTURE THERAPY SYSTEM AND TREATMENT PLAN GENERATION METHOD THEREFOR

EP4230259B1EP 4230259 B1EP4230259 B1EP 4230259B1EP-4230259-B1

Inventors

  • TENG, Yi-chiao
  • CHEN, JIANG

Dates

Publication Date
20260506
Application Date
20210923

Claims (10)

  1. A boron neutron capture therapy, BNCT, system, wherein the BNCT system comprises: a neutron beam irradiation device generating a treatment neutron beam during irradiation treatment and irradiating the treatment neutron beam to an irradiated body who has ingested a boron-containing drug, to form an irradiated site; a treatment plan module performing dose simulation and calculation and generating treatment plans according to medical imaging data of the irradiated site and parameters of the treatment neutron beam generated by the neutron beam irradiation device, the medical imaging data of the irradiated site comprising tissue-related information and boron concentration-related information; and a control module retrieving a respective one of the treatment plans corresponding to the irradiated body from the treatment plan module, and controlling the neutron beam irradiation device to perform irradiation treatment on the irradiated body according to the treatment plans; wherein the treatment plan module establishes a corresponding three-dimensional, 3D, voxel prosthesis tissue model with tissue type data according to the tissue-related information, and gives boron concentration data of each voxel unit in the 3D voxel prosthesis tissue model according to the boron concentration-related information; wherein the boron concentration-related information comprises a body weight of the irradiated body, Body Weight, a drug injection dose, Injection Dose, a drug activity measure time, Measure Time, a radiography time, Scan Time, a radionuclide half time, Half Time, and an image lattice intensity, Image Pixel Intensity pixel , the treatment plan module calculates a boron concentration of each voxel unit in the 3D voxel prosthesis tissue model according to the boron concentration-related information, the treatment plan module gives the boron concentration data of each voxel unit in the 3D voxel prosthesis tissue model according to a calculation result; wherein the treatment plan module calculating the boron concentration of each voxel unit in the 3D voxel prosthesis tissue model according to the boron concentration-related information comprises: calculating an approximate blood image lattice intensity, Image pixel Intensity blood , by using formula 1: SUV blood g / ml = Im age Pixel Intensity blood Bq / ml × Calibration Factor × Body Weight g Injection Dose Bq × 2 Measure Time sec − Scan Time sec Half Time sec = 1 wherein SUV blood is a blood standard uptake value, and Calibration Factor is a correction value of a medical image scanning device; and calculating a ratio of the boron concentration of each voxel unit in the 3D voxel prosthesis tissue model to a blood boron concentration by using formula 2: B pixel ppm B blood ppm = SUV pixel g / ml SUV blood g / ml = Im age Pixel Intensity pixel Bq / ml Im age Pixel Intensity blood Bq / ml wherein B pixel is a boron concentration of each voxel unit in the 3D voxel prosthesis tissue model, B blood is a blood boron concentration, and SUV pixel is a standard uptake value of each voxel unit in the 3D voxel prosthesis tissue model.
  2. The BNCT system of claim 1, wherein the tissue-related information is obtained by a non-radionuclide medical image of the irradiated site, and the treatment plan module automatically or manually defines a tissue type of each voxel unit in the 3D voxel prosthesis tissue model according to a conversion relationship between data of the non-radionuclide medical image and the tissue type.
  3. The BNCT system of claim 1, wherein the treatment plan module gives boron concentration data to different types of tissues of the 3D voxel prosthesis tissue model and is capable of giving different boron concentration data to tissues of the same type.
  4. The BNCT system of claim 1, wherein the boron concentration-related information is obtained by a radionuclide medical image of the irradiated site, the irradiated body ingests a radiolabeled boron-containing drug or a non-boron-containing drug with a tumor cell affinity similar to that of the boron-containing drug to perform scanning of the radionuclide medical image, and the treatment plan module automatically or manually defines a boron concentration of each voxel unit in the 3D voxel prosthesis tissue model according to a conversion relationship between data of the radionuclide medical image and the boron concentration.
  5. The BNCT system of claim 4, wherein the radionuclide medical image is positron emission tomography, PET, and the radiolabeled boron-containing drug is 18 F-BPA.
  6. The BNCT system of claim1, wherein the treatment plan module simulates a boron dose D B , a fast neutron dose D f , an epithermal neutron dose D epi , a thermal neutron dose D th and a photon dose D γ of the 3D voxel prosthesis tissue model per unit time by a Monte Carlo simulation program, and calculates an equivalent dose rate D of the 3D voxel prosthesis tissue model by using formula 3: D(Gy-Eq) = CBE × B pixel (ppm) × D B (Gy/ppm) + RBE f × D f (Gy) + RBE epi × D epi (Gy) + RBE th × D th (Gy) + RBE γ × D γ (Gy ) wherein CBE is a compound biological effectiveness of a boron-containing drug per unit concentration, RBE f is a relative biological effectiveness of a fast neutron, and RBE epi is a relative biological effectiveness of an epithermal neutron, RBE th is a relative biological effectiveness of a thermal neutron, and RBE γ is a relative biological effectiveness of a photon.
  7. The BNCT system of claim 1, wherein the treatment plan module simulates a physical dose rate distribution of the irradiated site during irradiation treatment of the treatment neutron beam by a Monte Carlo simulation program, according to the parameters of the treatment neutron beam generated by the neutron beam irradiation device and the 3D voxel prosthesis tissue model with the tissue type data and the boron concentration data.
  8. The BNCT system of claim 7, wherein the treatment plan module performs an optimum selection to equivalent dose rate distributions simulated and calculated according to sampling of different irradiation angles, to select at least one irradiation angle.
  9. A method for generating a treatment plan of a boron neutron capture therapy, BNCT, system, wherein the method is performed by a treatment plan module and comprises: establishing a corresponding three-dimensional, 3D, voxel prosthesis tissue model with tissue type data according to tissue-related information of medical imaging data of an irradiated site; giving boron concentration data of each voxel unit in the 3D voxel prosthesis tissue model according to boron concentration-related information of medical imaging data of the irradiated site; defining beam parameters in a Monte Carlo simulation program, and performing dose simulation and calculation by sampling of different irradiation angles; and performing an optimum selection to the irradiation angles according to a calculation result, to generate the treatment plan; wherein the step of giving boron concentration data of each voxel unit in the 3D voxel prosthesis tissue model according to boron concentration-related information of medical imaging data of the irradiated site comprises: interpreting the boron concentration-related information of medical imaging data of the irradiated site, to obtain a body weight of an irradiated body, Body Weight, a drug injection dose, Injection Dose, a drug activity measure time, Measure Time, a radiography time, Scan Time, a radionuclide half time, Half Time, and an image lattice intensity, Image Pixel Intensity pixel ; calculating a boron concentration of each voxel unit in the 3D voxel prosthesis tissue model; and giving the boron concentration data of each voxel unit in the 3D voxel prosthesis tissue model according to a calculation result; wherein the step of calculating the boron concentration of each voxel unit in the 3D voxel prosthesis tissue model comprises: calculating an approximate blood image lattice intensity, Image Pixel Intensity blood by using formula 1: SUV blood g / ml = Im age Pixel Intensity blood Bq / ml × Calibration Factor × Body Weight g Injection Dose Bq × 2 Measure Time sec − Scan Time sec Half Time sec = 1 wherein SUV blood is a blood standard uptake value, and Calibration Factor is a correction value of a medical image scanning device; and calculating a ratio of a boron concentration B pixel of each voxel unit in the 3D voxel prosthesis tissue model to a blood boron concentration B blood by using formula 2: B pixel ppm B blood ppm = SUV pixel g / ml SUV blood g / ml = Im age Pixel Intensity pixel Bq / ml Im age Pixel Intensity blood Bq / ml wherein SUV pixel is a standard uptake value of each voxel unit in the 3D voxel prosthesis tissue model.
  10. The method for generating a treatment plan of claim 9, wherein the step of defining beam parameters in the Monte Carlo simulation program, and performing dose simulation and calculation by sampling of different irradiation angles comprises: simulating a physical dose received by each voxel unit of the 3D voxel prosthesis tissue model per unit time under a defined beam irradiation and at a sampled irradiation angle, the physical dose comprising a boron dose D B , a fast neutron dose D f , an epithermal neutron dose D epi , a thermal neutron dose D th and a photon dose D γ ; and calculating an equivalent dose rate D of each voxel unit of the 3D voxel prosthesis tissue model per unit time under a defined beam irradiation by using formula 3: D(Gy-Eq) = CBE × B pixel (ppm) × D B (Gy/ppm) + RBE f × D f (Gy) + RBE epi × D epi (Gy) + RBE th × D th (Gy) + RBE γ × D γ (Gy) wherein CBE is a compound biological effectiveness of a boron-containing drug per unit concentration, RBE f is a relative biological effectiveness of a fast neutron, and RBE epi is a relative biological effectiveness of an epithermal neutron, RBE th is a relative biological effectiveness of a thermal neutron, and RBE γ is a relative biological effectiveness of a photon.

Description

TECHNICAL FIELD An aspect of the invention relates to a radiotherapy system, and in particular to a boron neutron capture therapy (BNCT) system, and another aspect of the invention relates to a treatment plan generation method, and in particular to a method for generating a treatment plan of a BNCT system. BACKGROUND With the development of atomics, radioactive ray therapy, such as cobalt sixty, a linear accelerator, an electron beam, or the like, has become one of the major means to treat cancers. However, traditional photon or electron therapy is restricted by physical conditions of radioactive rays themselves, and thus will also harm a large number of normal tissues on a beam path while killing tumor cells. Furthermore, owing to different levels of sensitivity of tumor cells to radioactive rays, traditional radiotherapy usually has poor treatment effect on malignant tumors (for example, glioblastoma multiforme and melanoma) with radio resistance. In order to reduce radiation injury to normal tissues around tumors, a target therapy concept in chemotherapy is applied to radioactive ray therapy. With respect to tumor cells with high radio resistance, irradiation sources with high relative biological effectiveness (RBE), such as proton therapy, heavy particle therapy, neutron capture therapy, or the like, are also developed actively now. Here neutron capture therapy combines the abovementioned two concepts, for example BNCT, provides a better cancer treatment choice than traditional radioactive rays, by specific aggregation of boron-containing drugs in tumor cells in combination with precise beam regulation and control. A three-dimensional (3D) model is widely applied to the field of analysis and simulation of scientific experiments. For example, in the field of nuclear radiation and protection, in order to simulate absorption dose of a human body under a certain radiation condition to help a doctor to formulate a treatment plan, a computer technology is usually required to perform various processing on medical imaging data, so as to establish an accurate lattice model required by Monte Carlo software, and simulation and calculation are performed in combination with Monte Carlo software. In the field of neutron capture therapy, when a lattice model required by Monte Carlo software is established according to medical imaging data, and dose calculation and evaluation are performed, basic information of organisms reflected by each lattice, such as tissue types, boron concentration information, or the like, needs to be defined in the model, and accuracy and precision of the information determine reliability of a dose calculation result. Generally, the boron concentration information is to obtain boron concentration data of a sample according to blood sample test or slice test, so as to calculate corresponding tissue and tumor boron concentrations therefrom, so that a regional boron concentration value is given in a corresponding model region. Such given boron concentration information does not consider real distribution of boron drugs in the organism and metabolic condition of the boron drugs over time, thereby affecting reliability of the dose calculation result. Therefore, it is necessary to provide a BNCT system and a method for generating a treatment plan thereof. EP 3 357 537 A1 concerns a geometric model establishment method based on medical image data, including: a step of reading medical image data; a step of defining a tissue type by a conversion relationship between the medical image data and the tissue type; a step of deciding the number of tissue clusters; a step of defining a tissue density by a conversion relationship between the medical image data and the density; a step of establishing 3D encoding matrix with information about the tissue and the density; and a step of generating a geometric model. EP 1 658 878 A1 concerns a method of computing the dose delivered to a target region by Boron Neutron Capture Therapy, wherein a target region of a patient is analysed to determine anatomical information as well as the actualin vivodistribution of the boron delivery agent, and wherein the dose delivered by irradiation within every cell of the target region is computed on the basis of said information on the target region's anatomy and on said actualin vivodistribution of the boron delivery agent. US 2019/329067 A1 concerns a process for analyzing elements and mass ratios of elements of a tissue includes approximating the tissue having unknown elements and mass ratios of the unknown elements thereof using the data of the medical image corresponding to a tissue having known elements and mass ratios of the known elements thereof. A method for establishing a geometric model based on a medical image includes: reading data of the medical image; defining a type of a tissue according to a conversion relationship between the data of the medical image and tissue types or according to the process; determining a qu