4D dose verification based on Calypso electromagnetic real-time tracking system
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《中国医学物理学杂志》[ISSN:1005-202X/CN:44-1351/R]
- Issue:
- 2019年第5期
- Page:
- 513-516
- Research Field:
- 医学放射物理
- Publishing date:
Info
- Title:
- 4D dose verification based on Calypso electromagnetic real-time tracking system
- Author(s):
- CAI Chunya; DAI Zhenhui; ZHANG Bailin; ZHU Lin; ZHAO Shiwu; YANG Geng; ZHU Yuanhu; LI Fei; WANG Xuetao
- CAI Chunya, DAI Zhenhui, ZHANG Bailin, ZHU Lin, ZHAO Shiwu, YANG Geng, ZHU Yuanhu, LI Fei, WANG Xuetao
- Keywords:
- ; Keywords: respiratory motion; 4D dose verification; real-time tracking; Calypso system
- PACS:
- R312；TL72
- DOI:
- DOI:10.3969/j.issn.1005-202X.2019.05.004
- Abstract:
- Abstract: Objective To investigate the feasibility of 4D dose verification based on Calypso electromagnetic real-time tracking system and evaluate the effectiveness of using Calypso system to improve the accuracy of radiotherapy dose of motion targets. Methods The fields of 5 cm×5 cm and 10 cm×10 cm, a circle field of 10 cm in diameter, 5 cases of IMRT plans and 5 cases of VMAT plans were transplanted to Delta4 three-dimensional dose verification system, and the Delta4 phantom was placed on the self-developed respiratory motion stage to simulate the respiratory in SI direction. The period of the respiratory motion stage was set to 5 s and the amplitude was ±10 mm. Dose distributions obtained with Delta4 software under the static, dynamic non-tracking and Calypso tracking with the motion thresholds of ±2, ±3 and ±5 mm were compared with the dose distributions obtained with treatment planning system. Results The average gamma passing rates of the static, Calypso tracking with the motion thresholds of ±2, ±3 and ±5 mm, and dynamic non-tracking were (97.5±2.4)%, (95.9±2.8)%, (93.9±3.8)%, (86.2±8.6)% and (65.0±11.1) %, respectively. No significant difference was found in the gamma passing rates between static field and Calypso tracking with the motion thresholds of ±2 and ±3 mm (P>0.05). However, there was statistical difference between Calypso tracking with the motion threshold of ±5 mm and dynamic non-tracking (P<0.05). Conclusion For patients with thoracic and abdominal tumors, using the combination of Calypso electromagnetic real-time tracking system and Delta4 three-dimensional verification system to perform the real-time 4D dose verification of the motion targets is proved to be feasible. The dose accuracy is significantly improved while using Calypso tracking during radiotherapy.
Last Update: 2019-05-23