CN108671419A - A kind of calculating of quick afterloading radiotherapy dosage, verification method - Google Patents
A kind of calculating of quick afterloading radiotherapy dosage, verification method Download PDFInfo
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Abstract
The invention discloses a kind of calculating of quick afterloading radiotherapy dosage, verification methods, and the corresponding DICOM file of patient is exported from treatment planning systems, are saved in a glue file folder；Glue file folder is scanned, required Rapid Dose Calculation information is read from DICOM file；Radioactive source parameter is obtained, Distribution of dose rate table is established, determines radioactive source direction, and carry out Rapid Dose Calculation；Dose Results in the Dose Results and treatment planning systems of calculating are compared, deviation Dev and γ verification result is obtained；After the completion of comparison, by deviation Dev and γ verification result preserve to glue file press from both sides in, and be automatically deleted glue file folder in DICOM file.The present invention can carry out dosage verifying before the treatment, simply, quickly, improve accuracy and efficiency, entire verification process only needs a few minutes, too many human-computer interaction is not needed, and can be used for various Afterloading radiotherapy planning systems, quality control and guarantee to Afterloading radiotherapy are improved, suitable for promoting.
Description
Technical Field
The invention relates to the technical field of afterloading radiotherapy, in particular to a method for calculating and verifying a radiotherapy dose by fast afterloading.
Background
Afterloading radiotherapy is an effective cancer treatment method, and the accuracy of evaluating dose calculation is crucial to ensuring accurate afterloading radiotherapy; the radiation therapy protocol is a dose verification of the treatment plan after approval of the treatment plan and before delivery begins.
After a foreign physicist or dosimeter finishes designing a Treatment plan through a Treatment Planning System (TPS), which is an existing software for the physicist or dosimeter to design a patient radiation Treatment plan, another experienced physicist usually performs dose verification of the Treatment plan, but the clinical task of the physicist in China is heavy, and dose verification of the Treatment plan by the other physicist is difficult to achieve. The european radiotherapy institute recommends that each afterloading radiotherapy center should have a dose verification method independent of the treatment planning system as early as 2004, but China has not yet found a study on the afterloading radiotherapy dose verification method.
Disclosure of Invention
Therefore, in order to solve the above problems, it is necessary to provide a method for calculating and verifying radiation therapy dose quickly and afterloading, which simplifies the afterloading radiation therapy process, increases the dose calculation and verification speed, and ensures the accuracy of the afterloading radiation therapy.
The technical scheme of the invention is as follows:
a calculation and verification method for radiotherapy dose after loading quickly comprises the following steps:
a. deriving a DICOM file corresponding to the patient from the treatment planning system, and storing the DICOM file in a fixed folder;
b. scanning the fixed folder, and reading required dosage calculation information from the DICOM file;
c. acquiring parameters of a radioactive source, and establishing a dose rate distribution table;
d. determining the direction of a radioactive source, and calculating the dose according to the dose calculation information to obtain a dose calculation result;
e. comparing the obtained dose calculation result with a dose result in a treatment planning system to obtain deviation values Dev and gamma verification results;
f. after the comparison is completed, the deviation value Dev and gamma verification result is stored in the fixed folder, and the DICOM file in the fixed folder is automatically deleted.
In the technical scheme, the automatic treatment is realized as much as possible from the perspective of a physicist or a doser, so that the manual intervention is reduced, and the time is saved; comparing the calculation result of a Treatment Planning System (TPS) with the relatively independent calculation result of the technical scheme to obtain deviation value Dev and gamma verification results, and judging whether the dosage is reasonable according to the deviation value Dev and gamma verification results to avoid medical accidents; after the dwell position and the dwell time of a radiation source in a treatment planning system are led in, the three-dimensional dose distribution can be automatically calculated, errors which are usually not easy to be discovered can be detected by comparing the dose distribution read in the treatment planning system with the dose distribution calculated by the technical scheme, such as accidental change or damage of a radiation source parameter database, calibration date and activity input errors after the radiation source is replaced and the like, and the safety is further ensured; moreover, after the comparison is completed, the technical scheme can automatically output the result to a file named by the user for future check, and automatically delete a DICOM (digital Imaging and Communications in medicine) file (namely a standard format file of a medical image) in the fixed folder, so that the problems of large memory burden and data errors caused by data redundancy are avoided.
Preferably, in the step c, the radioactive source parameters are acquired according to the data recommended by the AAPM and the estrro. To ensure independence of dose calculation by the software, radiation source parameters are not obtained from the radiation treatment planning system, but rather, AAPM (American Association of Physicists in medicine) and ESTRO (European Society for radiotherapy and Oncology) recommended data are used.
Preferably, the step c of establishing the dose rate distribution table comprises the following steps:
calculating dose rate at a dose calculation pointWherein,dose rate at the point is calculated for the dose, r is the distance from the dose calculation point to the center of the radiation source, r01cm, theta is the included angle between the dose calculation point and the long axis V direction of the radioactive source in a polar coordinate system, and theta0＝π/2，SkThe air kerma intensity is obtained, wherein Λ is a dose rate constant, G is a geometric factor, G is a radial dose function, and F is an anisotropic function;
according to the symmetry of dose distribution around the radioactive source, two-dimensional dose rate distribution tables T (m, n) along the direction of the long axis V of the radioactive source and the direction perpendicular to the long axis U of the radioactive source are calculated and stored in a computer memory.
In the technical scheme, the dosage rate at a certain dosage calculation point is calculated according to an AAPM TG-43(Task Group 43) report recommended formulaThe formula recommended by the AAPM TG-43(Task Group 43) report is a formula conventionally used in the art, based on the calculated dose rateThe dose of the treatment planning system can be obtained, and the subsequent dose comparison is convenient; in order to increase the dose calculation speed on the premise of ensuring the dose calculation accuracy, and in combination with the symmetry of dose distribution around the radioactive source, a two-dimensional dose rate distribution table T (m, n) along the long axis direction (V direction) of the radioactive source and perpendicular to the long axis direction (U direction) of the radioactive source is calculated before the start of dose calculation and stored in a computer memory, wherein the resolutions of the dose rate distribution table in the U direction and the V direction are both 0.1cm, the range of the U direction is 20cm, and the range of the V direction is from-20 cm to 20 cm.
Preferably, the step d of determining the direction of the radiation source comprises the following steps:
setting the ith dwell of the radiation sourcePosition Si(xi，yi，zi) And passes through the parking position Si(xi，yi，zi) And the next dwell position Si+1(xi+1，yi+1，zi+1) Formed vectorDetermining the direction and vector of the radiation source in the human body coordinate systemBecause the used radioactive source is a line source, the line source needs to consider the difference between a radioactive source coordinate system and a human body coordinate system, so that the direction of the radioactive source in the human body coordinate system is calculated, and subsequent dose calculation is facilitated.
Preferably, before the dose calculation in step d, the dose calculation point is set to be P (x, y, z), and the total number of applicator channels is set to be NAThe total number of the radiation source residence positions in each applicator pipeline is NSThe dose rate contribution at P (x, y, z) of the ith dwell position in the jth applicator tube is dj，iThe residence time of the ith residence position in the jth applicator pipeline is tj，i. And preparing dose calculation, namely calculating the dose result of the same dose calculation point according to the dose calculation information read from the exported DICOM file, wherein the dose result is the same as the data of the treatment planning system, so that the calculation accuracy is higher, and the subsequent comparison is convenient.
Preferably, the calculation of the dose at P (x, y, z) in said step d comprises the steps of:
d101, calculating the ith dwell position S of P (x, y, z) from the radiation sourcei(xi，yi，zi) A distance r' of
d102, according to the vector Is calculated to obtainAndangle therebetween
d103, respectively calculating the ith dwell position S of P (x, y, z) from the radiation sourcei(xi，yi，zi) A distance V in the V direction and a distance U in the U direction, where V is r' cos θ,
d104, looking up the dose rate distribution table T (m, n), if m x 0.1cm is less than (m +1) x 0.1cm and n x 0.1cm is less than (n +1) x 0.1cm, then for dj，iCarrying out bilinear interpolation calculation on dose rate distribution corresponding to (u, v) to obtain dj，i(u，v)＝w1T(m，n)+w2T(m，n+1)+w3T(m+1，n)+w4T(m+1，n+1)
Wherein w is1、w2、w3And w4Weights at T (m, n), T (m, n +1), T (m +1, n) and T (m +1, n +1) in the dose rate profile table, respectively;
d105, calculating the dose D (x, y, z) at P (x, y, z),
in the present solution, each radiation source contributes d to the dose rate at P (x, y, z)j，i(u, v) both dependent on memory fetchesThe data are obtained by simple interpolation without adopting a formula recommended by an AAPM TG-43(Task Group 43) report to carry out repeated calculation; the size of the dose calculation grid is consistent with that of a treatment planning system in the scheme, and the dose calculation grid is 0.1 multiplied by 0.1cm3Considering that the dose in the 0.5cm range around the source is very high, and this region is not the focus of clinical dose attention, the dose within 0.5cm of the assumed distance source is equal to the dose at 0.5cm from the source; and further, the calculation accuracy is guaranteed, and meanwhile, the calculation speed is improved.
Preferably, the calculating the deviant Dev in the step e includes the following steps:
e101 obtaining dosimetry parameters D from the RT Dose of the treatment planning systemTPS；
e102, obtaining the dosimetry parameters D after dose calculationQA；
e103, according to the dosimetry parameters DTPSAnd the parameters of dosimetry DQACalculating the deviation Dev to obtain
In this embodiment, the Dose distribution calculated by the treatment planning system is read from the RT Dose, and compared with the Dose distribution calculated by the present embodiment, we define Dx％Exposure dose of x% of the volume of the organ, DyccIs y cm of organ3The irradiation dose of the volume is calculated according to the ESTRO recommendation, and the target area D is counted100％，D90％Normal organ D0.1cc、D1ccAnd D2cc(ii) a Thus, the dosimetry parameters D are respectively countedQAAnd the parameters of dosimetry DQAThen calculating a deviation value Dev according to the comparison; the method can quickly evaluate the accuracy of afterloading dose calculation and ensure the accuracy of afterloading radiotherapy.
Preferably, the gamma verification in the step e comprises the following steps: :
e101, reading Dose from RT Dose of the treatment planning system;
e102, calculating a gamma value by taking the dose after dose calculation as a standard;
e103, if the gamma value is larger than 1, the dose verification is not passed, and if the gamma value is smaller than or equal to 1, the dose verification is passed.
The gamma verification is another verification method, which is a conventional verification method, wherein the calculation method of the gamma value is disclosed in the literature (Low D A, Harms W B, Mutic S, et al. A technical for the quantitative evaluation of Dose distributions [ J ]. Medical Physics,1998,25(5): 656) and the calculated Dose is mainly used as a standard to compare with the Dose read in a treatment planning system RT Dose (a file for storing Dose in DICOM file) to judge whether the verification is passed; the accuracy of the dose can be judged according to the deviation value Dev and gamma verification, the accuracy of the after-loading radiotherapy is ensured, the safety is further improved, and medical accidents are avoided.
The invention has the beneficial effects that:
the invention provides a simple and quick afterloading dose verification tool capable of carrying out dose verification before treatment, which improves the verification accuracy and efficiency, only takes a few minutes in the whole verification process, reduces the waiting time of patients, does not need too much man-machine interaction, saves time and labor cost, can be used for various afterloading radiotherapy planning systems, plays a role in strengthening and promoting the quality control and quality guarantee of afterloading radiotherapy, greatly reduces the occurrence rate of medical accidents, is suitable for popularization, and is very valuable.
Drawings
FIG. 1 is a flow chart of a method for rapid afterloading radiotherapy dose calculation and verification according to an embodiment of the present invention;
FIG. 2 is a schematic view of a dose calculation coordinate system according to an embodiment of the present invention;
FIG. 3 is a graph of the present invention at D for CTV100％A schematic representation of the difference in dosimetry parameters of the treatment planning system and protocol under circumstances;
FIG. 4 is a graph of the present invention at D for CTV90％A schematic representation of the difference in dosimetry parameters of the treatment planning system and protocol under circumstances;
FIG. 5 is a graph of the bladder at D according to an embodiment of the present invention0.1ccA schematic representation of the difference in dosimetry parameters of the treatment planning system and protocol under circumstances;
FIG. 6 is a graph of the bladder at D according to an embodiment of the present invention1ccA schematic representation of the difference in dosimetry parameters of the treatment planning system and protocol under circumstances;
FIG. 7 is a graph of the bladder at D according to an embodiment of the present invention2ccA schematic representation of the difference in dosimetry parameters of the treatment planning system and protocol under circumstances;
FIG. 8 is a schematic representation of the embodiment of the present invention in D for rectum0.1ccA schematic representation of the difference in dosimetry parameters of the treatment planning system and protocol under circumstances;
FIG. 9 is a schematic representation of the embodiment of the present invention in D for rectum1ccA schematic representation of the difference in dosimetry parameters of the treatment planning system and protocol under circumstances;
FIG. 10 is a schematic representation of the embodiment of the present invention in D for rectum2ccA schematic representation of the difference in dosimetry parameters of the treatment planning system and protocol under circumstances;
FIG. 11 is a graph of the small intestine at D in accordance with an embodiment of the present invention0.1ccA schematic representation of the difference in dosimetry parameters of the treatment planning system and protocol under circumstances;
FIG. 12 is a graph of the small intestine at D in accordance with an embodiment of the present invention1ccA schematic representation of the difference in dosimetry parameters of the treatment planning system and protocol under circumstances;
FIG. 13 is a graph of the small intestine at D in accordance with an embodiment of the present invention2ccCondition treatment planning system and methodSchematic diagram of the difference of dosage parameters of case;
fig. 14 is a flow chart of performing gamma verification according to an embodiment of the present invention.
Detailed Description
Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
Example 1
As shown in fig. 1, a method for calculating and verifying a radiotherapy dose by rapid afterloading comprises the following steps:
a. deriving a DICOM file corresponding to the patient from the treatment planning system, and storing the DICOM file in a fixed folder;
b. scanning the fixed folder, and reading required dosage calculation information from the DICOM file;
c. acquiring parameters of a radioactive source, and establishing a dose rate distribution table;
d. determining the direction of a radioactive source, and calculating the dose according to the dose calculation information to obtain a dose calculation result;
e. comparing the obtained dose calculation result with a dose result in a treatment planning system to obtain deviation values Dev and gamma verification results;
f. after the comparison is completed, the deviation value Dev and gamma verification result is stored in the fixed folder, and the DICOM file in the fixed folder is automatically deleted.
In the embodiment, from the perspective of a physicist or a dosimeter, the automatic treatment is performed as much as possible, so that the manual intervention is reduced, and the time is saved; comparing the calculation result of a Treatment Planning System (TPS) with the relatively independent calculation result of the technical scheme to obtain deviation value Dev and gamma verification results, and judging whether the dosage is reasonable according to the deviation value Dev and gamma verification results to avoid medical accidents; in this embodiment, after the dwell position and time of the radiation source in the treatment planning system are imported, the three-dimensional dose distribution can be automatically calculated, and errors which are usually not easy to be found, such as unexpected change or damage of the radiation source parameter database, calibration date and activity input errors after the radiation source is replaced, and the like, can be detected by comparing the dose distribution read in the treatment planning system with the dose distribution calculated by the technical scheme, so as to ensure the safety; moreover, after the comparison is completed, the embodiment automatically outputs the result to the file named by the user for future verification, and automatically deletes the dicom (digital Imaging and Communications in medicine) file in the fixed folder, thereby avoiding the memory burden and data errors caused by data redundancy.
Example 2
This embodiment is based on embodiment 1, and the radioactive source parameters are obtained according to the data recommended by AAPM and estrro in step c. To ensure independence of dose calculation by the software, radiation source parameters are not obtained from the radiation treatment planning system, but rather, AAPM (American Association of Physicists in medicine) and ESTRO (European society for Radiotherapy and Oncology) recommended data are used.
Example 3
In this embodiment, on the basis of embodiment 2, the step of establishing the dose rate distribution table in step c includes the following steps:
calculating dose rate at a dose calculation pointWherein,dose rate at the point is calculated for the dose, r is the distance from the dose calculation point to the center of the radiation source, r01cm, theta is the included angle between the dose calculation point and the long axis V direction of the radioactive source in a polar coordinate system, and theta0＝π/2，SkThe air kerma intensity is obtained, wherein Λ is a dose rate constant, G is a geometric factor, G is a radial dose function, and F is an anisotropic function;
according to the symmetry of dose distribution around the radioactive source, two-dimensional dose rate distribution tables T (m, n) along the direction of the long axis V of the radioactive source and the direction perpendicular to the long axis U of the radioactive source are calculated and stored in a computer memory.
In this embodiment, the dose rate at a dose calculation point is calculated according to the formula recommended by the AAPM TG-43(Task Group 43) reportThe formula recommended by the AAPM TG-43(Task Group 43) report is a formula conventionally used in the art, based on the calculated dose rateThe dose of the treatment planning system can be obtained, and the subsequent dose comparison is convenient; in order to increase the dose calculation speed on the premise of ensuring the dose calculation accuracy, and in combination with the symmetry of dose distribution around the radioactive source, a two-dimensional dose rate distribution table T (m, n) along the long axis direction (V direction) of the radioactive source and perpendicular to the long axis direction (U direction) of the radioactive source is calculated before the start of dose calculation and stored in a computer memory, wherein the resolutions of the dose rate distribution table in the U direction and the V direction are both 0.1cm, the range of the U direction is 20cm, and the range of the V direction is from-20 cm to 20 cm.
Example 4
This embodiment is based on embodiment 2, and as shown in fig. 2, the determining the direction of the radiation source in step d includes the following steps:
setting the ith dwell position of the radiation source to Si(xi，yi，zi) And passes through the parking position Si(xi，yi，zi) And the next dwell position Si+1(xi+1，yi+1，zi+1) Formed vectorDetermining the direction and vector of the radiation source in the human body coordinate systemBecause the used radioactive source is a line source, the line source needs to consider the difference between a radioactive source coordinate system and a human body coordinate system, so that the direction of the radioactive source in the human body coordinate system is calculated, and subsequent dose calculation is facilitated.
Example 5
In this embodiment, on the basis of embodiment 1, before the dose calculation in step d, a dose calculation point P (x, y, z) is set, and the total number of applicator channels is NAThe total number of the radiation source residence positions in each applicator pipeline is NSThe dose rate contribution at P (x, y, z) of the ith dwell position in the jth applicator tube is dj，iThe residence time of the ith residence position in the jth applicator pipeline is tj，i。
Example 6
In this embodiment, on the basis of embodiment 4, before the dose calculation in step d, a dose calculation point P (x, y, z) is set, and the total number of applicator channels is NAThe total number of the radiation source residence positions in each applicator pipeline is NSThe dose rate contribution at P (x, y, z) of the ith dwell position in the jth applicator tube is dj，iThe residence time of the ith residence position in the jth applicator pipeline is tj，i。
And preparing dose calculation, namely calculating the dose result of the same dose calculation point according to the dose calculation information read from the exported DICOM file, wherein the dose result is the same as the data of the treatment planning system, so that the calculation accuracy is higher, and the subsequent comparison is convenient.
Example 7
This example is based on example 6, and the calculation of the dose at P (x, y, z) in step d includes the following steps:
d101, calculating the ith dwell position S of P (x, y, z) from the radiation sourcei(xi，yi，zi) A distance r' of
d102, according to the vector Is calculated to obtainAndangle therebetween
d103, respectively calculating the ith dwell position S of P (x, y, z) from the radiation sourcei(xi，yi，zi) A distance V in the V direction and a distance U in the U direction, where V is r' cos θ,
d104, checking the dose rateIn the cloth table T (m, n), if m × 0.1 cm. ltoreq. u < (m +1) × 0.1cm and n × 0.1 cm. ltoreq. v < (n +1) × 0.1cm, then for dj，iCarrying out bilinear interpolation calculation on the dose distribution corresponding to (u, v) to obtain dj，i(u，v)＝w1T(m，n)+w2T(m，n+1)+w3T(m+1，n)+w4T(m+1，n+1)
Wherein w is1、w2、w3And w4Weights at T (m, n), T (m, n +1), T (m +1, n) and T (m +1, n +1) in the dose rate profile table, respectively;
d105, calculating the dose D (x, y, z) at P (x, y, z),
in this embodiment, each radiation source contributes d to the dose rate at P (x, y, z)j，i(u, v) are obtained by simple interpolation of data extracted from the memory without adopting a formula in a treatment planning system for repeated calculation; the size of the dose calculation grid is consistent with that of a treatment planning system in the scheme, and the dose calculation grid is 0.1 multiplied by 0.1cm3Considering that the dose in the 0.5cm range around the source is very high, and this region is not the focus of clinical dose attention, the dose within 0.5cm of the assumed distance source is equal to the dose at 0.5cm from the source; and further, the calculation accuracy is guaranteed, and meanwhile, the calculation speed is improved.
Example 8
In this embodiment, based on embodiment 7, the calculating the deviation Dev in step e includes the following steps:
e101 obtaining dosimetry parameters D from the RT Dose of the treatment planning systemTPS；
e102, obtaining the dosimetry parameters D after dose calculationQA；
e103, according to the dosimetry parameters DTPSAnd dosimetryParameter DQACalculating the deviation Dev to obtain
In this example, the Dose distribution calculated by the treatment planning system is read from the RT Dose and compared to the Dose distribution calculated by the protocol, we define Dx％Exposure dose of x% of the volume of the organ, DyccIs y cm of organ3The irradiation dose of the volume is calculated according to the ESTRO recommendation, and the target area D is counted100％，D90％Normal organ D0.1cc、D1ccAnd D2cc(ii) a Thus, the dosimetry parameters D are respectively countedQAAnd the parameters of dosimetry DQAThen calculating a deviation value Dev according to the comparison; the method can quickly evaluate the accuracy of afterloading dose calculation and ensure the accuracy of afterloading radiotherapy;
for CTV (tumor clinical target volume), the differences in the dosimetry parameters of the treatment planning system and the protocol of the present invention are shown in FIGS. 3 and 4, and FIG. 2 is D100％Wherein the maximum value is 1.76%, the minimum value is 0.08%, and the average value of the difference of 20 patients is 0.85%; FIG. 3 is D90％Wherein the maximum value is 1.37%, the minimum value is 0.15%, and the average value of the difference of 20 patients is 0.70%;
for organs at risk, differences in the dosimetry parameters of the treatment planning system and protocol of the invention are shown in FIGS. 5-13, where 20 patients with bladder and small intestine D were selected0.1ccThe maximum deviation is less than 1.10%, rectum D0.1ccWith a maximum deviation of 1.41%, bladder, rectum and small intestine D1ccThe average values of the differences of (1) were 0.49%, 0.66% and 0.52%, respectively, D2ccIs less than D1ccAnd D0.1cc。
Example 9
In this embodiment, on the basis of embodiment 7, as shown in fig. 14, the γ verification in step e includes the following steps: :
e101, reading Dose from RT Dose of the treatment planning system;
e102, calculating a gamma value by taking the dose after dose calculation as a standard;
e103, if the gamma value is larger than 1, the dose verification is not passed, and if the gamma value is smaller than or equal to 1, the dose verification is passed.
The gamma verification is another verification method, which is a conventional verification method, wherein the calculation method of the gamma value is disclosed in the literature (Low D A, Harms W B, Mutic S, et al. A technical for the quantitative evaluation of Dose distributions [ J ]. Medical Physics,1998,25(5): 656) and the calculated Dose is mainly used as a standard to compare with the Dose read in a treatment planning system RT Dose (a file for storing Dose in DICOM file) to judge whether the verification is passed; the accuracy of the dose can be judged according to the deviation value Dev and gamma verification, the accuracy of the after-loading radiotherapy is ensured, the safety is further improved, and medical accidents are avoided.
The above-mentioned embodiments only express the specific embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention.
Claims (8)
1. A calculation and verification method for radiotherapy dose after loading is characterized by comprising the following steps:
a. deriving a DICOM file corresponding to the patient from the treatment planning system, and storing the DICOM file in a fixed folder;
b. scanning the fixed folder, and reading required dosage calculation information from the DICOM file;
c. acquiring parameters of a radioactive source, and establishing a dose rate distribution table;
d. determining the direction of a radioactive source, and calculating the dose according to the dose calculation information to obtain a dose calculation result;
e. comparing the obtained dose calculation result with a dose result in a treatment planning system to obtain deviation values Dev and gamma verification results;
f. after the comparison is completed, the deviation value Dev and gamma verification result is stored in the fixed folder, and the DICOM file in the fixed folder is automatically deleted.
2. The method for calculation and verification of rapid afterloading radiotherapy dose of claim 1, wherein the radioactive source parameters are obtained according to AAPM and ESTRO recommended data in step c.
3. The method for calculating and verifying a rapid afterloading radiotherapy dose according to claim 1 or 2, wherein the step c of establishing a dose rate distribution table comprises the following steps:
calculating dose rate at a dose calculation pointWherein,dose rate at the point is calculated for the dose, r is the distance from the dose calculation point to the center of the radiation source, r0Theta is the included angle between the dose calculation point and the long axis V direction of the radioactive source in a polar coordinate system, theta 0 is pi/2, and SkThe air kerma intensity is obtained, wherein Λ is a dose rate constant, G is a geometric factor, G is a radial dose function, and F is an anisotropic function;
according to the symmetry of dose distribution around the radioactive source, two-dimensional dose rate distribution tables T (m, n) along the direction of the long axis V of the radioactive source and the direction perpendicular to the long axis U of the radioactive source are calculated and stored in a computer memory.
4. The method for calculation and verification of rapid afterloading radiotherapy dose of claim 1, wherein said step d of determining the direction of the radioactive source comprises the steps of:
setting the ith dwell position S of the radiation sourcei(xi，yi，zi) And passes through the parking position Si(xi，yi，zi) And the next dwell position Si+1(xi+1，yi+1，zi+1) Formed vectorDetermining the direction and vector of the radiation source in the human body coordinate system
5. The method for calculation and verification of radiotherapy dose afterloading in accordance with claim 1 or 4, wherein before the dose calculation in step d, the dose calculation point is set to P (x, y, z), the total number of applicator channels is set to NAThe total number of the radiation source residence positions in each applicator pipeline is NSThe dose rate contribution at P (x, y, z) of the ith dwell position in the jth applicator tube is dj，iThe residence time of the ith residence position in the jth applicator pipeline is tj，i。
6. The method for calculation and verification of an afterloader radiotherapy dose according to claim 5, wherein the calculation of the dose at P (x, y, z) in step d comprises the steps of:
d101, calculating the ith dwell position S of P (x, y, z) from the radiation sourcei(xi，yi，zi) A distance r' of
d102, according to the vector Is calculated to obtainAndangle therebetween
d103, respectively calculating the ith dwell position S of P (x, y, z) from the radiation sourcei(xi，yi，zi) A distance V in the V direction and a distance U in the U direction, where V is r' cos θ,
d104, looking up the dose rate distribution table T (m, n), if m × 0.1cm is less than (m +1) × 0.1cm and n × 01cm is less than v is less than (n +1) × 0.1cm, then for dj，iCarrying out bilinear interpolation calculation on dose rate distribution corresponding to (u, v) to obtain dj，i(u，v)＝w1T(m，n)+w2T(m，n+1)+w3T(m+1，n)+w4T(m+1，n+1)，
Wherein, w1、w2、w3And w4Weights at T (m, n), T (m, n +1), T (m +1, n) and T (m +1, n +1) in the dose rate profile table, respectively;
d105, calculating the dose D (x, y, z) at P (x, y, z),
7. the method for calculation and verification of rapid afterloading radiotherapy dose as claimed in claim 6, wherein the step e of calculating the deviant Dev comprises the steps of:
e101 obtaining dosimetry parameters D from the RT Dose of the treatment planning systemTPS；
e102, obtaining the dosimetry parameters D after dose calculationQA；
e103, according to the dosimetry parameters DTPSAnd the parameters of dosimetry DQACalculating the deviation Dev to obtain
8. The method for calculating and verifying the rapid afterloading radiotherapy dose according to claim 6, wherein the γ verification in the step e comprises the following steps:
e101, reading Dose from RT Dose of the treatment planning system;
e102, calculating a gamma value by taking the dose after dose calculation as a standard;
e103, if the gamma value is larger than 1, the dose verification is not passed, and if the gamma value is smaller than or equal to 1, the dose verification is passed.
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| CN113117253A (en) * | 2021-04-20 | 2021-07-16 | 中北大学 | Dose calculation system based on anisotropic kernel |
| CN115607861A (en) * | 2022-12-19 | 2023-01-17 | 安徽慧软科技有限公司 | Nuclear magnetic guided three-dimensional Monte Carlo dose independent verification method and system |
| CN117839101A (en) * | 2023-12-29 | 2024-04-09 | 广东省人民医院 | Post-loading three-dimensional dose calculation method, medium and terminal based on Monte Carlo |
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