Effects of CT value of carbon fiber couch on dose distribution in radiotherapy plan for intracranial tumor(PDF)
《中国医学物理学杂志》[ISSN:1005-202X/CN:44-1351/R]
- Issue:
- 2020年第8期
- Page:
- 965-970
- Research Field:
- 医学放射物理
- Publishing date:
Info
- Title:
- Effects of CT value of carbon fiber couch on dose distribution in radiotherapy plan for intracranial tumor
- Author(s):
- HUANG Wei1; DENG Guanhua2; ZHANG Hongdan1; LONG Liang1; WU Qidi1; PAN Yi1
- 1. Department of Radiation Oncology, Guangdong Provincial Peoples Hospital, Guangzhou 510080, China 2. Department of Oncology, Guangdong Sanjiu Brain Hospital, Guangzhou 510510, China
- Keywords:
- Keywords: carbon fiber couch absorbed dose difference coefficient intracranial tumor dose distribution
- PACS:
- R815.6
- DOI:
- DOI:10.3969/j.issn.1005-202X.2020.08.005
- Abstract:
- Abstract: Objective To quantitatively analyze the effects of the CT value of carbon fiber couch on the dose distribution in radiotherapy plan for intracranial tumor. Methods The carbon fiber couch with 9 difference CT values and an uniform cylindrical water phantom model were established in Varian Eclipse 13.6 treatment planning system (TPS), and the phantom was positioned at the center of the couch. Isocentric irradiation in the field of 10 cm[×]10 cm was realized by 6 MV X ray and at gantry angles from 0° to 180°, with an interval of 10°, and the absorbed dose difference coefficient [δ] for the carbon fiber couch with difference CT values was calculated. A total of 15 patients with intracranial tumor were enrolled in the study. The plan which was designed by Eclipse TPS and based on carbon fiber couch with default CT value was taken as template plan. The template plan was directly transplanted to the images of 8 different couches with different CT values and no flux optimization for the recalculation of dose distribution. The D2%, D50%, D98%, conformity index, homogeneity index and gradient index in 9 plans based on different couches were recorded and analyzed. Results In the range of -700 HU to -300 HU, [δ] was gradually decreased with the increase of Panel Surface CT value, while in the range of -1 000 HU to -900 HU, [δ] was gradually increased with the increase of Panel Interior CT value. There were significant differences in D2%, D50%, D98% and gradient index between the plan based on carbon fiber couch with default CT value and the other 8 plans (P<0.05), but no significant difference was found in homogeneity index (P>0.05). Conclusion During radiotherapy planning, the carbon fiber couch model should be constructed according to the measured CT value of carbon fiber couch.
Last Update: 2020-08-27