Effect of the dwell time deviation constraint on brachytherapy treatment planning for cervical cancer

• Published in: Journal of international medical research Vol. 49; no. 8; p. 3000605211037477
• Main Authors: Yan, Gaoshu, Kang, Shengwei, Tang, Bin, Li, Jie, Wang, Pei, Wang, Xianliang, Lang, Jinyi
• Format: Journal Article
• Language: English
• Published: London, England SAGE Publications 01.08.2021; Sage Publications Ltd; SAGE Publishing
• Subjects: Cervical cancer; Radiation therapy; Retrospective Clinical Research Report; treatment planning; Brachytherapy; high-risk clinical target volume; cervical cancer; dwell time deviation constraint; inverse optimization algorithm
• ISSN: 0300-0605; 1473-2300; 1473-2300
• DOI: 10.1177/03000605211037477

Objective This study aimed to quantify the effect of the dwell time deviation constraint (DTDC) on brachytherapy treatment for cervical cancer. Methods A retrospective study was carried out on 20 patients with radical cervical cancer. The DTDC values changed from 0.0 to 1.0 by a step size of 0.2. We adjusted the optimization objectives to ensure that all plans were optimized to a high-risk clinical target volume (HRCTV) D90 (the dose to 90% of the HRCTV) = 6 Gy, while keeping the dose to the organs at risk as low as possible. The dose–volume histogram parameters and the dwell time data were compared between plans with different DTDC values. Results The HRCTV volume covered by 150% of the prescription dose gradually increased with increasing DTDC values. As the DTDC value increased from 0.0 to 1.0, the effective dwell point proportion increased from 61.78% to 90.30%. The mean dwell time initially decreased with an increase in the DTDC value, reached the minimum value at DTDC = 0.8, then slightly increased at DTDC = 1.0. Conclusions When using inverse planning simulated annealing optimization for radical cervical cancer cases, the recommended DTDC value is approximately 0.6 if the organ dose needs to be limited.