Erasmus MC Cancer Institute, University Medical Center Rotterdam, Department of Radiotherapy, Dr.Molewaterplein 40, Rotterdam, 3015 GD, The Netherlands.
J Appl Clin Med Phys. 2021 Mar;22(3):35-47. doi: 10.1002/acm2.13172. Epub 2021 Jan 21.
Recently, VOLO™ was introduced as a new optimizer for CyberKnife® planning. In this study, we investigated possibilities to improve treatment plans for MLC-based prostate SBRT with enhanced peripheral zone dose while sparing the urethra, and central lung tumors, compared to existing Sequential Optimization (SO). The primary focus was on reducing OAR doses. For 25 prostate and 25 lung patients treated with SO plans, replanning with VOLO™ was performed with the same planning constraints. For equal PTV coverage, almost all OAR plan parameters were improved with VOLO™. For prostate patients, mean rectum and bladder doses were reduced by 34.2% (P < 0.001) and 23.5% (P < 0.001), with reductions in D of 3.9%, 11.0% and 3.1% for rectum, mucosa and bladder (all P ≤ 0.01). Urethra D and D were 3.8% and 3.0% lower (P ≤ 0.002). For lung patients, esophagus, main bronchus, trachea, and spinal cord D was reduced by 18.9%, 11.1%, 16.1%, and 13.2%, respectively (all P ≤ 0.01). Apart from the dosimetric advantages of VOLO™ planning, average reductions in MU, numbers of beams and nodes for prostate/lung were 48.7/32.8%, 26.5/7.9% and 13.4/7.9%, respectively (P ≤ 0.003). VOLO™ also resulted in reduced delivery times with mean/max reductions of: 27/43% (prostate) and 15/41% (lung), P < 0.001. Planning times reduced from 6 h to 1.1 h and from 3 h to 1.7 h for prostate and lung, respectively. The new VOLO™ planning was highly superior to SO planning in terms of dosimetric plan quality, and planning and delivery times.
最近，推出了一种新的优化器 VOLO™，用于 CyberKnife® 计划。在这项研究中，我们研究了通过增强前列腺周围区域剂量来改善基于 MLC 的前列腺 SBRT 治疗计划的可能性，同时保护尿道和中央肺肿瘤，与现有的顺序优化 (SO) 相比。主要重点是降低 OAR 剂量。对于 25 例前列腺和 25 例肺患者的 SO 计划进行重新规划，使用相同的规划约束条件对 VOLO™ 进行重新规划。对于相同的 PTV 覆盖范围，几乎所有的 OAR 计划参数都通过 VOLO™ 得到了改善。对于前列腺患者，直肠和膀胱的平均剂量分别降低了 34.2%（P<0.001）和 23.5%（P<0.001），直肠、黏膜和膀胱的 D 降低了 3.9%、11.0%和 3.1%（均 P≤0.01）。尿道 D 和 D 分别降低了 3.8%和 3.0%（P≤0.002）。对于肺患者，食管、主支气管、气管和脊髓的 D 分别降低了 18.9%、11.1%、16.1%和 13.2%（均 P≤0.01）。除了 VOLO™ 计划的剂量优势外，前列腺/肺的 MU、光束和节点数量的平均减少分别为 48.7%/32.8%、26.5%/7.9%和 13.4%/7.9%（均 P≤0.003）。VOLO™ 还降低了治疗时间，平均减少了 27%/43%（前列腺）和 15%/41%（肺）（P<0.001）。前列腺和肺的治疗时间分别从 6 小时减少到 1.1 小时和从 3 小时减少到 1.7 小时。新的 VOLO™ 计划在剂量学计划质量、计划和治疗时间方面都明显优于 SO 计划。
