Influence factors of CT value-relative electron density conversion and its effects on dose calculation(PDF)
《中国医学物理学杂志》[ISSN:1005-202X/CN:44-1351/R]
- Issue:
- 2019年第2期
- Page:
- 157-162
- Research Field:
- 医学放射物理
- Publishing date:
Info
- Title:
- Influence factors of CT value-relative electron density conversion and its effects on dose calculation
- Author(s):
- WU Xianxiang1; GUO Hongbo2; FEI Zhenle1; 3; CUI Xiangli4; NIU Zhenyang3; LIU Lingling4
- 1. Department of Biomedical Engineering, College of Life Sciences Anhui Medical University, Hefei 230032, China; 2. Department of Biomedical Engineering, College of Life Sciences University of Science and Technology of China, Hefei 230026, China; 3. Department of Radiation Oncology, No.901 Hospital of PLA, Hefei 230031, China; 4. Cancer Hospital, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
- Keywords:
- ; Keywords: CT value; tumor; relative electron density; volumetric modulated arc therapy; treatment planning system
- PACS:
- R815.6
- DOI:
- DOI:10.3969/j.issn.1005-202X.2019.02.007
- Abstract:
- Abstract: Objective To study the effects of different scanning conditions on the conversion of CT values to relative electron density (HU-RED) and dose calculation of radiotherapy plan. Methods With the use of CT simulator and electron density module, the CT values of various tissue substitutes under different scanning conditions were analyzed and the corresponding HU-RED conversion relationship was established. Radiotherapy plans were designed for 8, 8, 6 and 6 cases of head, thoracic, abdominal and pelvic tumors. The parameters of radiotherapy plan remained unchanged, and HU-RED conversion curves under different voltages were selected to perform dose calculation. The D2, D50, D95, D98 of target areas and the Dmean, Dmax of organs-at-risk were analyzed to evaluate the effects of scanning voltage on the dose distribution. Results Slice thickness and scanning current had trivial effects on the HU-RED conversion. However, scanning voltage has a great influence on the HU-RED conversion. There were significant differences in the D2, D50, D95, D98 of head and neck and pelvic tumors (P≤0.029), and the D50, D95, D98 of thoracic and abdominal tumors, and the average dose of brain stem, ipsilateral kidney, small intestine, bilateral femoral head, spinal cord, bladder, and the maximum dose of spinal cord (P≤0.036). Conclusion The scanning voltage of the CT simulator can significantly affect the dose calculation. Therefore, the HU-RED conversion curve which is consistent with the CT scan voltage should be used for dose calculation.
Last Update: 2019-02-26