Effects of dose calculation grid size on physical dose and biological dose in radiotherapy for cervical cancer(PDF)
《中国医学物理学杂志》[ISSN:1005-202X/CN:44-1351/R]
- Issue:
- 2020年第8期
- Page:
- 971-976
- Research Field:
- 医学放射物理
- Publishing date:
Info
- Title:
- Effects of dose calculation grid size on physical dose and biological dose in radiotherapy for cervical cancer
- Author(s):
- CHEN Feihu; LI Yijiang; BAI Han; LIU Xuhong; ZHU Sijin; WU Xingrao
- Department of Radiation Oncology, Yunnan Cancer Hospital/the Third Affiliated Hospital of Kunming Medical University/Yunnan Cancer Center, Kunming 650118, China
- Keywords:
- Keywords: cervical cancer dose calculation grid size physical dose biological dose
- PACS:
- R737.33；R811.1
- DOI:
- DOI:10.3969/j.issn.1005-202X.2020.08.006
- Abstract:
- Abstract: Objective To quantitatively investigate the effects of dose calculation grid size (DCGS) on the physical dose and biological dose in radiotherapy for cervical cancer. Methods Twelve treatment plans of cervical cancer designed in Pinnacle3 treatment planning system were selected and then optimized with the default DCGS of 4.0 mm. As the DCGS were changed from 1.0 mm to 7.0 mm, the doses of target areas and organs-at-risk (OAR) were recalculated to explore the changes of physical dose and biological dose of target and OAR with different DCGS. Results The physical doses of target areas and OAR were decreased with the increase of DCGS, and the dose-volume curves showed an overall shift to the lower dose region in dose-volume histogram.Except for the NTCP of femoral heads, both the tumor control probability (TCP) of target areas and the normal tissue complication probability (NTCP) of OAR were slowly decreased with the increase of DCGS. The decline rate of TCP of PGTVnd was about 0.7%/mm, and that of TCP of PTV was about 0.6%/mm. However, the decrease rates of NTCP of the bladder and the rectum were relatively faster, and the maximum decrease rate of NTCP was 15.0% for the bladder and 13.5% for the rectum. Conclusion The physical dose and biological dose in radiotherapy for cervical cancer are decreased with the increase of DCGS, and the dose-volume curves of target areas and OAR show an overall shift to the lower dose region in dose-volume histogram, which will induce the underestimations of the TCP of target areas and the NTCP of OAR.
Last Update: 2020-08-27