Adams Elizabeth J, Convery David J, Cosgrove Vivian P, McNair Helen A, Staffurth John N, Vaarkamp Jaap, Nutting Christopher M, Warrington Alan P, Webb Steve, Balyckyi Jan, Dearnaley David P
Joint Department of Physics, The Royal Marsden NHS Trust, Downs Road, Sutton, Surrey SM2 5PT, UK.
Radiother Oncol. 2004 Jan;70(1):1-10. doi: 10.1016/j.radonc.2003.09.004.
Two systems have been developed for treating patients with locally advanced prostate cancer using intensity-modulated radiotherapy (IMRT): one using dynamic multi-leaf collimator delivery and the other using step-and-shoot. This paper describes the clinical implementation of these two techniques, and presents results from the first 14 patients treated in a clinical setting (nine dynamic, five step-and-shoot).
Dynamic treatments were planned using Corvus, and step-and-shoot using Helax-TMS; all were delivered using Elekta accelerators. Prior to the first clinical treatments, validation measurements were carried out for each system, including measurements for a complete IMRT treatment. The reproducibility of dynamic delivery and the characteristics of the accelerator for low-monitor-unit (MU) deliveries were also assessed. An extensive quality assurance (QA) program was performed for each of the patients. Additionally, timing measurements were carried out to assess the practicalities of the technique.
The planning objectives were met in most cases. Absolute doses for complete IMRT treatments were within 2%, on average, with dose distributions generally showing agreement within 3% or 3 mm. Beam modulation measurements made throughout each patient's treatment indicated that both delivery methods were reproducible. The dynamic plans required an average of 765 MU per beam, with a treatment delivery time of 14 min; corresponding results for step-and-shoot plans were 105 MU and 10 min.
Two IMRT techniques for this group of patients have been successfully implemented in the clinic. The more complex dynamic treatments showed no advantages over the step-and-shoot approach. QA results have shown accurate and reproducible delivery for both techniques, giving increased confidence in the techniques and allowing a reduction in the QA program.
已开发出两种利用调强放射治疗（IMRT）治疗局部晚期前列腺癌患者的系统：一种使用动态多叶准直器投照，另一种使用步进式投照。本文描述了这两种技术的临床应用，并展示了在临床环境中治疗的首批14例患者（9例动态投照、5例步进式投照）的结果。
动态治疗计划使用Corvus制定，步进式投照计划使用Helax-TMS制定；所有治疗均使用医科达加速器进行。在首次临床治疗前，对每个系统进行了验证测量，包括完整IMRT治疗的测量。还评估了动态投照的可重复性以及加速器在低监测单位（MU）投照时的特性。对每位患者都执行了广泛的质量保证（QA）程序。此外，还进行了时间测量以评估该技术的实用性。
大多数情况下达到了计划目标。完整IMRT治疗的绝对剂量平均在2%以内，剂量分布一般在3%或3毫米以内显示出一致性。在每位患者治疗过程中进行的射束调制测量表明，两种投照方法都是可重复的。动态计划每束平均需要765 MU，治疗投照时间为14分钟；步进式投照计划的相应结果为105 MU和10分钟。
这两种针对该组患者的IMRT技术已在临床中成功应用。更复杂的动态治疗与步进式投照方法相比没有优势。QA结果表明两种技术的投照准确且可重复，增强了对这些技术的信心，并允许减少QA程序。
