Methods, systems, and programs for analyzing the dose distribution of radiation doses.

Abstract

To provide a method for calibrating an error of a simple transmission type chromic film.SOLUTION: An analysis method for dose distribution of a radiation dose using a chromic film and a transmission type scanner includes: (1) a process for dividing a chromic film irradiated with a radiation into a plurality of regions in parallel with respect to a direction that the transmission type scanner is scanned; (2) a process for arranging each of the divided regions of the chromic film so as to be positioned in a central scanning part of a scanner face that is scanned by a central part of a line light source of the transmission type scanner, causing the transmission type scanner to perform scanning, and acquiring image data of each of the divided regions using the central part of the line light source; and (3) a process for analyzing the dose distribution by combining image data of each of the divided regions acquired by the central part of the line light source.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a method for analyzing the dose distribution of radiation dose, an analysis system, and an analysis program. According to the present invention, it is possible to analyze the dose distribution of accurate radiation dose.

Background Art

[0002] Radiation therapy for cancer plays an important role in cancer treatment together with surgery and administration of anticancer drugs. Radiation therapy is advantageous not only in that it is a local treatment that treats only cancer tissue and its surroundings like surgical therapy, but also in that it does not require organ removal like surgical therapy and can preserve organs. However, in radiation therapy, since it is necessary to irradiate a large amount of radiation to the lesion, in order to reduce or prevent side effects, it is required to irradiate an optimal radiation dose to the cancer tissue to cause damage, while irradiating the surrounding normal tissue with as little radiation dose as possible to suppress damage.

[0003] For example, in intensity modulated radiotherapy (IMRT), which is one of radiation therapies, first, it is necessary to create a treatment plan and set irradiation conditions that can accurately perform radiation irradiation with a predetermined absorbed dose distribution on the affected part. Furthermore, it is necessary to experimentally verify the validity of such a treatment plan in advance. In this case, since it is not possible to insert a dosimeter into the human body to perform test dose measurement, for example, a two-dimensional dosimeter is inserted into a human phantom (that is, a phantom) composed of a human equivalent substance to analyze the dose distribution.

[0004] As a two-dimensional dosimeter to be inserted into a phantom for use in dose distribution analysis, a chromic film is widely used. This chromic film has the advantage of forming a radiation image without development when it is sensitized to X-rays. It is possible to obtain optical density data from the radiation image thus obtained with an image scanner and determine the radiation exposure dose from the optical density data.

[0005] To determine the radiation dose from the aforementioned optical density data, it is necessary to create a calibration curve (standard curve) between optical density and radiation dose in advance. Since chromic film is relatively expensive, its calibration curve is created, for example, by the following method: Radiation images are successively formed at multiple locations on a single chromic film with multiple types of radiation doses, and the optical density of these radiation images is read by a scanner to form a calibration curve between radiation dose and optical density.

[0006] However, it has been reported that optical density data obtained by scanning a radiation image formed on a transmission chromic film with a transmission image scanner is subject to measurement errors depending on the reading position, and correction methods have been proposed for errors (non-flatness) that occur perpendicular to the scanning direction (for example, Non-Patent Documents 1 and 2). Furthermore, it is known that in chromic films, the slope of the trend component (non-flatness component) changes with increasing irradiation dose, so simply subtracting the base component (background value) from the non-irradiated base component from the trend component does not allow for obtaining flat density information for the irradiated image. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2017-189311 [Non-patent literature]

[0008] [Non-Patent Document 1] Ryuzo Uehara, et al., "Efforts to Improve the Accuracy of Radiochromic Film Dosimetry in Dose Distribution Analysis - A Combination of Correction Methods for Flatbed Scanner Effects and Color Component-", Journal of the Japanese Society of Radiological Technology, June 2013, Vol. 69, No. 6, pp. 617-631. [Non-Patent Document 2] Shigeyoshi Kamada, et al., "Improvement of Flatness Characteristics When Using Flat Bed Scanners," [online], November 19, 2015, 7th Gafchromic Film Research Meeting, [Retrieved March 4, 2016], Internet <URL:http: / / www.veritastk.co.jp / attached / 5875 / 2_gafchromic.pdf#search='flatbed%E5%9E%8B%E3%82%B9%E3%82%AD%E3%83%A3%E3%83%8A%E4%BD%BF%E7%94%A8+%E5%AE%AE%E6%B2%A2'> [Overview of the Initiative] [Problems that the invention aims to solve]

[0009] The inventors have developed a means for calibrating errors in transmissive chromic films (Patent Document 1). However, there was a need for a simpler correction method. Therefore, an object of the present invention is to provide a simple method for calibrating errors in a transmissive chromic film. [Means for solving the problem]

[0010] The inventors diligently researched a simple method for calibrating the errors of transmission-type chromic films and, as a result, surprisingly discovered that the dose distribution of radiation can be easily analyzed using a chromic film by moving and scanning the film. This invention is based on these findings. Therefore, the present invention is [1] A method for analyzing the dose distribution of radiation using a chromic film and a transmission scanner, comprising: (1) dividing a chromic film irradiated with radiation into multiple regions parallel to the direction in which the transmission scanner is scanned; (2) arranging each divided region of the chromic film so as to be located in the central scanning portion of the scanner surface scanned by the central portion of the line light source of the transmission scanner, scanning with the transmission scanner, and acquiring image data of each divided region using the central portion of the line light source; and (3) analyzing the dose distribution by combining the image data of each divided region acquired by the central portion of the line light source. [2] (i) The method for analyzing the dose distribution of radiation dose according to [1], wherein the plurality of regions of the chromic film are two divided regions A and divided region B, and in step (2), image data A of divided region A is acquired using the central part of the line light source, and image data B of divided region B is acquired using the central part of the line light source, and in step (3), the dose distribution is analyzed by combining the image data A and image data B, or (ii) The plurality of regions of the chromic film are three divided regions A, divided region B, and divided region C, and in step (2), image data A of divided region A is acquired using the central part of the line light source, image data B of divided region B is acquired using the central part of the line light source, and image data C of divided region C is acquired using the central part of the line light source, and in step (3), the dose distribution is analyzed by combining the image data A, image data B, and image data C. [3] A radiation dose distribution analysis system using a chromic film and a transmission scanner, comprising: (1) means for dividing a chromic film irradiated with radiation into a plurality of regions parallel to the direction in which the transmission scanner is scanned; (2) means for arranging each divided region of the chromic film so as to be located in the central scanning portion of the scanner surface scanned by the central portion of the line light source of the transmission scanner, scanning with the transmission scanner, and acquiring image data of each divided region using the central portion of the line light source; and (3) means for analyzing the dose distribution by combining the image data of each divided region acquired by the central portion of the line light source. [4] (i) The chromic film comprises two divided regions A and B, and means (2) acquires image data A of divided region A using the central portion of a line light source, and acquires image data B of divided region B using the central portion of a line light source, and means (3) analyzes the dose distribution by combining image data A and image data B, or (ii) The chromic film comprises three divided regions A, B and C, and means (2) acquires image data A of divided region A using the central portion of a line light source, acquires image data B of divided region B using the central portion of a line light source, and acquires image data C of divided region C using the central portion of a line light source, and means (3) analyzes the dose distribution by combining image data A, image data B and image data C, as described in [3], [5] A program for analyzing the dose distribution of radiation using a chromic film and a transmission scanner, wherein the chromic film irradiated with radiation is divided into multiple regions parallel to the direction in which the transmission scanner is scanned, each divided region is positioned in the central scanning portion of the scanner surface scanned by the central portion of the line light source of the transmission scanner, the transmission scanner is scanned, image data of the obtained divided regions is acquired using the central portion of the line light source, and the dose distribution is analyzed by combining the respective image data, and [6] (i) The dose distribution analysis program for radiation dose described in [5], wherein the plurality of regions of the chromic film are two divided regions A and divided region B, and the obtained image data A of divided region A and image data B of divided region B are combined to analyze the dose distribution, or (ii) The plurality of regions of the chromic film are three divided regions A, divided region B, and divided region C, and the dose distribution is analyzed by combining the obtained image data A of divided region A, image data B of divided region B, and image data C of divided region C. Regarding. [Effects of the Invention]

[0011] According to the radiation dose distribution analysis method, analysis system, and analysis program of the present invention, the radiation dose distribution of chromic film can be analyzed simply and accurately. [Brief explanation of the drawing]

[0012] [Figure 1] This figure shows the flatness (scanning position dependence) characteristics when scanning chromic film with a flatbed scanner. [Figure 2] This is a schematic diagram illustrating the operation in the image data acquisition process (2) in which the chromic film is divided into divided region A, divided region B, and divided region C in order to acquire image data. [Figure 3]This is a photograph showing the operation of obtaining image data by dividing a chromic film into three divided regions, i.e., divided region A, divided region B, and divided region C, in the image data acquisition step (2). [Figure 4] This is a schematic diagram showing the operation of obtaining image data by dividing a chromic film into two divided regions, i.e., divided region A and divided region B, in the image data acquisition step (2). [Figure 5] This is a photograph showing the analysis of the dose distribution of radiation dose by combining image data A, image data B, and image data C from a chromic film irradiated with radiation to the lungs. [Figure 6] This is a photograph (upper part) showing the analysis of radiation dose with one piece of image data from a chromic film irradiated with radiation to the lungs, and a photograph (lower part) showing the analysis of radiation dose with three pieces of image data of the present invention.

Embodiments for Carrying Out the Invention

[0013] [1] Method for Analyzing Dose Distribution of Radiation Dose The method for analyzing the dose distribution of radiation dose of the present invention includes: (1) a step of dividing a chromic film irradiated with radiation into a plurality of regions in parallel with respect to the direction in which a transmission scanner scans; (2) arranging each divided region of the chromic film so as to be located in the central scanning portion of the scanner surface scanned by the central portion of the line light source of the transmission scanner, scanning the transmission scanner, and using the central portion of the line light source to obtain image data of each divided region; and (3) a step of combining the image data of each divided region obtained by the central portion of the line light source to analyze the dose distribution.

[0014] 《Chromic Film》 The chromic film used in the present invention is not particularly limited as long as it is a transmission chromic film. Commercially available products include EBT4 and EBT-XD (Veritas Co., Ltd., Artec Co., Ltd.).

[0015] The size of the chromic film is not particularly limited, but the main types used for IMRT verification as a transmissive chromic film are as follows. EBT4 0810: 8 inches x 10 inches, 0.1 Gy to 20 Gy EBT4 1317: 13 inches x 17 inches, 0.1 Gy to 20 Gy EBT4 XD: 8 inches x 10 inches, 0.1 Gy to 60 Gy

[0016] 《Transmissive Scanner》 The transmissive scanner used in the present invention is not particularly limited, and examples include a flatbed scanner or a sheet-fed scanner, with a flatbed scanner being preferred. As the light source of the transmissive scanner, a xenon fluorescent lamp or a white LED can be mentioned. As the sensor of the transmissive scanner, a line color CCD can be mentioned. As commercially available transmissive scanners, ES-10000G (Epson, now out of production), DS-G20000 (Epson), etc. can be used.

[0017] The inventors scanned the chromic film with a transmissive scanner and measured the reading position dependency (flatness characteristics) for each density in the CCD array direction. As shown in FIG. 1(A), regardless of the density, the central scanning part (-4 to 0 to 4) of the line light source in the scanning direction is flat, but it was found that the scanning parts at both ends of the line light source (-4 to -12 and 4 to 12) are not flat, and depending on the density, the ADC value may extremely decrease. That is, as shown in FIG. 1(B), there is no error in the central part 4 of the line light source 3 in the central scanning part 2 being scanned. However, it was found that there are errors in the scanning parts 9 at both ends away from the central part of the line light source, and it may not be possible to accurately measure the radiation dose. To solve the above problem, the inventors considered that the radiation dose could be accurately measured by scanning a chromic film using the central portion 4 of the line light source 3. That is, they considered that the radiation dose could be accurately measured without error by scanning the chromic film in the central scanning portion 2 scanned by the central portion 4 of the line light source 3 on the scanning surface 1 of the transmission scanner shown in Figure 1(B).

[0018] While there are no particular limitations on the size of the scanning surface of a transmissive scanner, for example, with the DS-G20000, the effective scanning area is 310 x 437 mm (12.2 x 17.2 inches). The length of the central portion 4 of the line light source is not particularly limited, but for example, the lower limit is 50 mm or more, in some embodiments it is 60 mm or more, in some embodiments it is 70 mm or more, in some embodiments it is 80 mm or more, and in some embodiments it is 90 mm or more. The upper limit is, for example, 150 mm or less, in some embodiments it is 140 mm or less, in some embodiments it is 130 mm or less, in some embodiments it is 120 mm or less, and in some embodiments it is 110 mm or less. The upper and lower limits can be arbitrarily combined to form a range for the length of the central portion 4. For example it may be 100 mm. By being within this range, the reading position dependence is flat and the radiation dose can be measured accurately. Also, the length of the side of the central scanning portion perpendicular to the scanning direction is the same as the length of the central portion 4.

[0019] 《Dividing process (1)》 In the division step (1) of this analysis method, the chromic film irradiated with radiation is divided into multiple regions parallel to the direction in which the transmission scanner is scanned. "Dividing the chromic film into multiple regions parallel to the direction in which the transmission scanner is scanned" means, for example, as shown in Figure 2(A), dividing it into divided region A(5), divided region B(6), and divided region C(7) parallel to the scanning direction of the line light source on the scanning surface 1, and it is not necessary to actually cut it. It may be divided for convenience in the system or program of the present invention described later. The number of divisions of the chromic film is not particularly limited, as long as the chromic film can be scanned in the central scanning portion 2 of the scanner, for example, 2 to 100 divisions. However, specifically, 2, 3, 4, or 5 divisions are used, preferably 2 to 4 divisions, and more preferably 3 divisions. Specifically, it may be divided into 3 as shown in Figure 2, or into 2 as shown in Figure 4. The length of the side perpendicular to the scanning direction of the divided region is not particularly limited, but for example, the lower limit is 50 mm or more, in some embodiments it is 60 mm or more, in some embodiments it is 70 mm or more, in some embodiments it is 80 mm or more, and in some embodiments it is 90 mm or more. The upper limit is, for example, 150 mm or less, in some embodiments it is 140 mm or less, in some embodiments it is 130 mm or less, in some embodiments it is 120 mm or less, and in some embodiments it is 110 mm or less. The upper and lower limits can be arbitrarily combined to form a range of side lengths perpendicular to the scanning direction of the divided region. For example it may be 100 mm. By being within this range, the reading position dependence is flat and the radiation dose can be measured accurately.

[0020] Image data acquisition process (2) In the image data acquisition step (2) of this analysis method, each divided region of the chromic film is positioned in the central scanning portion of the scanner surface scanned by the central portion of the line light source of the transmissive scanner, and the transmissive scanner is scanned to acquire image data of each divided region using the central portion of the line light source. Embodiments for a 3-division case and a 2-division case will be described below as examples, although they are not limited to these embodiments.

[0021] (An embodiment of three divided regions) In the case of three divided regions, the chromic film is divided into three regions A, B, and C, as shown in Figures 2 and 3. Then, image data A is acquired from region A using the central part of the line light source, image data B is acquired from region B using the central part of the line light source, and image data C is acquired from region C using the central part of the line light source. Specifically, as shown in Figure 2(A) or Figure 3(A), the divided region A(5) of the chromic film 8 is placed in the central operation area 2 of the scanner surface 1, and the through-beam scanner is scanned to acquire image data A of the divided region A(5) using the central part 4 of the line light source. Next, as shown in Figure 2(B) or Figure 3(B), the divided region B(6) of the chromic film 8 is placed in the central operation area 2 of the scanner surface 1, and the through-beam scanner is scanned to acquire image data B of the divided region B(6) using the central part 4 of the line light source. Next, as shown in Figure 2(C) or Figure 3(C), the divided region C(7) of the chromic film 8 is placed in the central operation area 2 of the scanner surface 1, and the through-beam scanner is scanned to acquire image data C of the divided region C(7) using the central part 4 of the line light source.

[0022] (Embodiment of two divided regions) In the case of two divided regions, as shown in Figure 4, the chromic film is divided into two divided regions, A and B. Then, image data A is acquired from divided region A using the central part of the line light source, and image data B is acquired from divided region B using the central part of the line light source. Specifically, as shown in Figure 4(A), the divided region A(5) of the chromic film 8 is placed in the central operating area 2 of the scanner surface 1, and the transmissive scanner is scanned to acquire image data A of the divided region A(5) using the central part 4 of the line light source. Next, as shown in Figure 4(B), the divided region B(6) of the chromic film 8 is placed in the central operating area 2 of the scanner surface 1, and the transmissive scanner is scanned to acquire image data B of the divided region B(6) using the central part 4 of the line light source.

[0023] In the case of four divided regions, the process can be carried out similarly, except that the divided regions become divided regions A to D, and the resulting image data becomes image data A to D. The same applies to cases with five or more divided regions.

[0024] 《Dose Distribution Analysis Process (3)》 In the dose distribution analysis step (3) of this analysis method, the dose distribution is analyzed by combining the image data of each divided region acquired by the central part of the line light source. For example, in the case of a three-part division, the dose distribution is analyzed by combining image data A, image data B, and image data C obtained in step (2) above. For example, Figure 5 shows that image data A, image data B, and image data C were obtained from a chromic film obtained after irradiating the lungs with radiation, according to step (2) above. As shown in the photograph on the right, the irradiation dose is analyzed by combining image data A from the top of the chromic film, image data B from the center of the chromic film, and image data C from the bottom of the chromic film. Figure 6 shows a photograph (top) showing the radiation dose analyzed using one image data, and a photograph (bottom) showing the radiation dose analyzed using three image data according to the present invention. When analyzing with a single image data in the conventional method, the matching rate was 60.344%, while when analyzing with three image data according to the present invention, the matching rate was 98.781%.

[0025] First, the central portion of the line light source is used to scan divided region A of the chromic film. Next, the central portion of the line light source is used to scan divided region B of the chromic film. Then, the central portion of the line light source is used to scan divided region C of the chromic film. Since all divided regions are scanned using the central portion of the line light source, the ADC values ​​of divided region A, divided region B, and the divided regions of the chromic film are all flat and do not decrease. Therefore, by combining image data A, image data B, and image data C, it is possible to obtain an accurate dose distribution of radiation levels in the chromic film.

[0026] Furthermore, in the case of a two-part division, the dose distribution is analyzed by combining image data A and image data B in step (3). Furthermore, in the case of a four-part division, the dose distribution is analyzed by combining image data A, image data B, image data C, and image data D in step (3). Furthermore, in the case of a five-part division, the dose distribution is analyzed by combining image data A, image data B, image data C, image data D, and image data E in step (3).

[0027] The method for analyzing the dose distribution of radiation according to the present invention can also be considered to be implemented as follows. The case of three divisions is described below. The method for analyzing the dose distribution of radiation dose uses a chromic film and a transmission scanner, and involves the steps of: (i) scanning the chromic film irradiated with radiation with the transmission scanner and acquiring first image data (image data B) including central region data of the chromic film obtained by scanning the central part of the line light source of the transmission scanner; and (ii) moving the chromic film perpendicular to the scanning direction of the scanner so that one end region of the chromic film is located in the central part of the line light source of the transmission scanner, scanning with the transmission scanner, and acquiring second image data (image) including one end region data obtained by scanning the central part of the line light source of the transmission scanner. The process includes: (iii) acquiring data A), moving the chromic film perpendicular to the scanning direction of the scanner so that the other end region of the chromic film is positioned in the central part of the line light source of the transmission scanner, scanning with the transmission scanner, and acquiring third image data (image data C) including the data of the other end region acquired by scanning the central part of the line light source of the transmission scanner, and (iv) analyzing the dose distribution by combining the central region data of the first image data (image data B), the data of one end region of the second image data (image data A), and the data of the other end region of the third image data (image data C).

[0028] [2] Radiation dose distribution analysis system The radiation dose distribution analysis system of the present invention is a radiation dose distribution analysis system using a chromic film and a transmission scanner, and includes: (1) means for dividing a chromic film irradiated with radiation into a plurality of regions parallel to the direction in which the transmission scanner is scanned; (2) means for arranging each divided region of the chromic film so as to be located in the central scanning portion of the scanner surface scanned by the central portion of the line light source of the transmission scanner, scanning with the transmission scanner, and acquiring image data of each divided region using the central portion of the line light source; and (3) means for analyzing the dose distribution by combining the image data of each divided region acquired by the central portion of the line light source. In the radiation dose distribution analysis system of the present invention, the "chromic film," "transmission scanner," "divided region," "image data," etc., are the same as those described in the section "[1] Method for analyzing the radiation dose distribution." The radiation dose distribution analysis system of the present invention may also include a transmission scanner, a computer, a program, etc.

[0029] [3] Program for analyzing the dose distribution of radiation doses The present invention is a radiation dose distribution analysis program that analyzes the radiation dose distribution using a chromic film and a transmission scanner. The program divides a chromic film irradiated with radiation into multiple regions parallel to the direction in which the transmission scanner is scanned. Each divided region is positioned in the central scanning portion of the scanner surface scanned by the central portion of the line light source of the transmission scanner. The transmission scanner is then scanned, and image data of the obtained divided regions is captured using the central portion of the line light source. The respective image data are combined to analyze the dose distribution. In the radiation dose distribution analysis program of the present invention, "chromic film," "transmission scanner," "divided region," "image data," etc., are the same as those described in the section "[1] Method for analyzing the radiation dose distribution." The radiation dose distribution analysis program of the present invention may be stored on a storage medium and operated by a computer or the like. [Industrial applicability]

[0030] The radiation dose distribution analysis method, analysis system, and analysis program of the present invention can be easily used for analyzing the radiation dose distribution using chromic film. [Explanation of Symbols]

[0031] 1...Scanned surface; 2. Central scanning section; 3. Linear light source; 4. The central part of the line light source; 5...Divided area A; 6...Divided area B; 7...Divided area C; 8. Chromic film; 9. Scanning portions at both ends;

Claims

1. A method for analyzing the dose distribution of radiation using chromic film and a transmission scanner, (1) A process of dividing a chromic film irradiated with radiation into multiple regions parallel to the direction in which the transmission scanner is scanned, (2) A step of arranging each divided region of the chromic film so that it is located in the central scanning portion of the scanner surface scanned by the central portion of the line light source of a transmissive scanner, scanning with the transmissive scanner, and acquiring image data of each divided region using the central portion of the line light source, The central portion of the line light source is a portion having a length of 50 to 150 mm on either side of the center of the line light source, and the central scanning portion of the scanner surface is the portion scanned by the central portion of the line light source, and the length of the side perpendicular to the scanning direction of the central scanning portion is 50 to 150 mm, and (3) A process of analyzing the dose distribution by combining the image data of each divided region acquired by the central part of the line light source, A method for analyzing the dose distribution of radiation doses, including [specific radiation].

2. (i) The plurality of regions of the chromic film are two divided regions A and divided region B, and in step (2), image data A of divided region A is acquired using the central part of the line light source, and image data B of divided region B is acquired using the central part of the line light source, In step (3) above, the dose distribution is analyzed by combining image data A and image data B, or (ii) The plurality of regions of the chromic film are three divided regions A, B, and C, and in step (2), image data A of divided region A is acquired using the central part of the line light source, image data B of divided region B is acquired using the central part of the line light source, and image data C of divided region C is acquired using the central part of the line light source. In step (3) above, the dose distribution is analyzed by combining image data A, image data B, and image data C. The method for analyzing the dose distribution of radiation dose according to claim 1.

3. A system for analyzing the dose distribution of radiation using chromic film and a transmission scanner, (1) Means for dividing a chromic film irradiated with radiation into multiple regions parallel to the direction in which a transmission scanner is scanned, (2) A means for arranging each divided region of a chromic film so that it is located in the central scanning portion of the scanner surface scanned by the central portion of the line light source of a transmissive scanner, scanning with the transmissive scanner, and acquiring image data of each divided region using the central portion of the line light source, The means and (3) A means for analyzing the dose distribution by combining the image data of each divided region acquired by the central part of the line light source, A system for analyzing the dose distribution of radiation, including [specific radiation levels].

4. (i) The plurality of regions of the chromic film are two divided regions A and divided region B, and by means (2), image data A of divided region A is acquired using the central part of the line light source, and image data B of divided region B is acquired using the central part of the line light source. The above means (3) is used to analyze the dose distribution by combining image data A and image data B, or (ii) The plurality of regions of the chromic film are three divided regions A, B, and C, and by means (2), image data A of divided region A is acquired using the central part of the line light source, image data B of divided region B is acquired using the central part of the line light source, and image data C of divided region C is acquired using the central part of the line light source. The dose distribution is analyzed by combining image data A, image data B, and image data C using the means (3) described above. The radiation dose distribution analysis system according to claim 3.

5. A program for analyzing the dose distribution of radiation using chromic film and a transmission scanner, A chromic film irradiated with radiation is divided into multiple regions parallel to the direction in which the transmission scanner is scanned. Each divided region is positioned so as to be located in the central scanning area of ​​the scanner surface, which is scanned by the central part of the transmission scanner's line light source. The transmission scanner is then operated, and image data from the obtained divided regions is captured using the central part of the line light source. The dose distribution is then analyzed by combining the respective image data. A radiation dose distribution analysis program wherein the central portion of the line light source is a portion having a length of 50 to 150 mm on either side of the center of the line light source, and the central scanning portion of the scanner surface is the portion scanned by the central portion of the line light source, and the length of the side perpendicular to the scanning direction of the central scanning portion is 50 to 150 mm.

6. (i) The plurality of regions of the chromic film are two divided regions A and B, and the dose distribution is analyzed by combining the obtained image data A of divided region A and image data B of divided region B, or (ii) The multiple regions of the chromic film are three divided regions A, B, and C, and the dose distribution is analyzed by combining the obtained image data A of divided region A, image data B of divided region B, and image data C of divided region C. A dose distribution analysis program for radiation doses according to claim 5.

Images