Comparison of three-dimensional conformal radiotherapy planning algorithms for lung cancer
based on personalized tissue-equivalent phantom(PDF)
《中国医学物理学杂志》[ISSN:1005-202X/CN:44-1351/R]
- Issue:
- 2019年第7期
- Page:
- 755-759
- Research Field:
- 医学放射物理
- Publishing date:
Info
- Title:
- Comparison of three-dimensional conformal radiotherapy planning algorithms for lung cancer
based on personalized tissue-equivalent phantom
- Author(s):
- HE Yaoyao1; 2; 3; JING Liang4; HUANG Xiaohua1; 2; 3; JU Nan1; 2; 3; ZHANG Fuquan1; 2; 3; PAN Jueyu1; 2; 3; QIU Jianfeng1; 2; 3; XING Xiaoying1; 2; 3;
LIUWenqian1; 2; 3; HOU Lixia3
- 1. Research Center of Medical Engineering Technology, Shandong First Medical University & Shandong Academy of Medical
Sciences, Tai’an 271016, China; 2. Imaging-X Joint Laboratory, Tai’an 271016, China; 3. School of Radiology, Shandong First Medical
University, Tai’an 271016, China; 4. Department of Radiotherapy, Tai’an Cancer Hospital, Tai’an 271000, China
- Keywords:
- Keywords: phantom; collapse cone convolution algorithm; pencil beam convolution algorithm; Monte Carlo algorithm; threedimensional
conformal radiotherapy
- PACS:
- R814.2；R318
- DOI:
- DOI:10.3969/j.issn.1005-202X.2019.07.003
- Abstract:
- Abstract: Objective To compare the difference of radiation dose between the calculated value and the measured value, and then
compare the differences among Monte Carlo (MC) algorithm, pencil beam convolution (PBC) algorithm and collapse cone
convolution (CCC) algorithm of Treatment Planning System (TPS) in three-dimensional stereotactic radiotherapy for lung cancer.
Methods The CT images of anthropomorphic thorax phantom were imported to TPS. The target areas were delineated and a
suitable projection plan was established. Three measurement points of tumor tissues, normal lung tissues and spinal cord were
inserted into ionization chamber, separately. After the corresponding equivalent materials were used to fill the remaining 2
measurement points, CT scan was performed. The projection plan was implemented based on the image fusion for registration
and the unification of target areas, and all 3 algorithms were used for dose calculation. Results The CT numbers of adipose tissues,
muscle tissues, bone and tumor of anthropomorphic thorax phantom were (-100±30), (40±20), (210±90) and (33±16) HU,
respectively, which were similar to the CT numbers of patients. The errors of CCC, MC and PBC algorithms in the calculation of the dose of normal lung tissues were 2.51%, -2.51% and 1.02%, respectively; the errors in the calculation of tumor tissue dose
were 0.18%, 0.66% and 0.42%, respectively; and the errors in the calculation of spinal cord dose were 7.32%, 9.76% and -53.66%,
respectively. Conclusion The dose calculation of MC, PBC and CCC algorithms in three-dimensional conformal radiotherapy
was compared with the use of tissue-equivalent phantom. Both MC and CCC algorithms overestimate the doses of tumor tissues,
normal lung tissues and spinal cord. MC algorithm is slightly better than CCC algorithm in the calculation of tumor tissue dose,
but is inferior to CCC algorithm in the calculation of the doses of normal lung tissue and spinal cord. PBC algorithm is not
recommended, because it does not consider the effect of scattering lines around the calculating points on the calculation of
inhomogeneous tissue dose, which results in a large error in the calculation of spinal cord tissue dose.
Last Update: 2019-07-24