Effects of mismatch between CT scanning voltage and CT-RED conversion curve on radiotherapy dose(PDF)
《中国医学物理学杂志》[ISSN:1005-202X/CN:44-1351/R]
- Issue:
- 2021年第3期
- Page:
- 312-316
- Research Field:
- 医学放射物理
- Publishing date:
Info
- Title:
- Effects of mismatch between CT scanning voltage and CT-RED conversion curve on radiotherapy dose
- Author(s):
- KONG Fantu1; CHEN Luxi1; JIN Jinhui2; DONG Jie1; HE Yadi2; LI Zhenghuan1
- 1. Department of Radiation Oncology, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou 510630, China 2.School of Biomedical Engineering, South Medical University, Guangzhou 510515, China
- Keywords:
- Keywords: CT scanning voltage CT number relative electron density radiotherapy plan dose calculation
- PACS:
- R318；R811
- DOI:
- 1005-202X（2021）03-0312-05
- Abstract:
- Abstract: Objective To explore the effects of different voltages selected for computed tomography (CT) positioning and CT number-relative electron density (CT-RED) conversion curves on the calculation of radiotherapy dose. Methods Under the voltages of 80, 100, 120 and 140 kV, CIRS 062M phantom were scanned by a large-aperture CT simulator, thereby establishing CT-RED conversion curves under different voltages. A known high-density material was embedded in the center of a uniform paraffin phantom, and by setting a series of combinations of different voltages and CT-RED conversion curves, radiotherapy plans with different irradiation angles were established in treatment planning system. The variations of doses (DI1, DI2 and DI3) delivered to 3 points of interest (I1, I2 and I3) selected at the front, middle and rear of the high-density material and the changes in the Dmean, D2 and D98 of the high-density material were analyzed when voltages mismatched with CT-RED conversion curves. Results Under the mismatch between voltages and CT-RED conversion curves, the doses of radiotherapy plan were significantly different, among which Dmean, D98, DI2, DI3 were most affected, with statistical differences (all P<0.05). Conclusion The voltage for CT positioning needs to match with CT-RED conversion curve selected for radiotherapy planning. Otherwise, it will lead to great differences in the calculations of dose in the high-density material and the dose at the exit of radiation field, thus affecting radiotherapy accuracy.
Last Update: 2021-03-30