Fraass B A, Lash K L, Matrone G M, Volkman S K, McShan D L, Kessler M L, Lichter A S
Department of Radiation Oncology, University of Michigan Health Systems, Ann Arbor, USA.
Int J Radiat Oncol Biol Phys. 1998 Oct 1;42(3):651-9. doi: 10.1016/s0360-3016(98)00244-2.
To analyze treatment delivery errors for three-dimensional (3D) conformal therapy performed at various levels of treatment delivery automation and complexity, ranging from manual field setup to virtually complete computer-controlled treatment delivery using a computer-controlled conformal radiotherapy system (CCRS).
All treatment delivery errors which occurred in our department during a 15-month period were analyzed. Approximately 34,000 treatment sessions (114,000 individual treatment segments [ports]) on four treatment machines were studied. All treatment delivery errors logged by treatment therapists or quality assurance reviews (152 in all) were analyzed. Machines "M1" and "M2" were operated in a standard manual setup mode, with no record and verify system (R/V). MLC machines "M3" and "M4" treated patients under the control of the CCRS system, which (1) downloads the treatment delivery plan from the planning system; (2) performs some (or all) of the machine set up and treatment delivery for each field; (3) monitors treatment delivery; (4) records all treatment parameters; and (5) notes exceptions to the electronically-prescribed plan. Complete external computer control is not available on M3; therefore, it uses as many CCRS features as possible, while M4 operates completely under CCRS control and performs semi-automated and automated multi-segment intensity modulated treatments. Analysis of treatment complexity was based on numbers of fields, individual segments, nonaxial and noncoplanar plans, multisegment intensity modulation, and pseudoisocentric treatments studied for a 6-month period (505 patients) concurrent with the period in which the delivery errors were obtained. Treatment delivery time was obtained from the computerized scheduling system (for manual treatments) or from CCRS system logs. Treatment therapists rotate among the machines; therefore, this analysis does not depend on fixed therapist staff on particular machines.
The overall reported error rate (all treatments, machines) was 0.13% per segment, or 0.44% per treatment session. The rate (per machine) depended on automation and plan complexity. The error rates per segment for machines M1 through M4 were 0.16%, 0.27%, 0.12%, 0.05%, respectively, while plan complexity increased from M1 up to machine M4. Machine M4 (the most complex plans and automation) had the lowest error rate. The error rate decreased with increasing automation in spite of increasing plan complexity, while for the manual machines, the error rate increased with complexity. Note that the real error rates on the two manual machines are likely to be higher than shown here (due to unnoticed and/or unreported errors), while (particularly on M4) virtually all random treatment delivery errors were noted by the CCRS system and related QA checks (including routine checks of machine and table readouts for each treatment). Treatment delivery times averaged from 14 min to 23 min per plan, and depended on the number of segments/plan, although this analysis is complicated by other factors.
Use of a sophisticated computer-controlled delivery system for routine patient treatments with complex 3D conformal plans has led to a decrease in treatment delivery errors, while at the same time allowing delivery of increasingly complex and sophisticated conformal plans with little increase in treatment time. With renewed vigilance for the possibility of systematic problems, it is clear that use of complete and integrated computer-controlled delivery systems can provide improvements in treatment delivery, since more complex plans can be delivered with fewer errors, and without increasing treatment time.
分析在不同治疗交付自动化和复杂程度下进行的三维适形治疗的治疗交付误差，范围从手动野设置到使用计算机控制适形放射治疗系统（CCRS）的几乎完全计算机控制的治疗交付。
分析了我们科室在15个月期间发生的所有治疗交付误差。研究了四台治疗机上约34,000次治疗疗程（114,000个单独治疗段[射野]）。分析了治疗师记录或质量保证审查记录的所有治疗交付误差（共152个）。机器“M1”和“M2”以标准手动设置模式运行，没有记录与验证系统（R/V）。MLC机器“M3”和“M4”在CCRS系统控制下治疗患者，该系统（1）从计划系统下载治疗交付计划；（2）为每个射野执行部分（或全部）机器设置和治疗交付；（3）监测治疗交付；（4）记录所有治疗参数；（5）记录电子处方计划的例外情况。M3上没有完全的外部计算机控制；因此，它尽可能多地使用CCRS功能，而M4在CCRS控制下完全运行并执行半自动和自动多段调强治疗。治疗复杂性分析基于在与获得交付误差的时间段同时的6个月期间（505名患者）研究的射野数量、单独段数量、非轴向和非共面计划、多段调强以及伪等中心治疗。治疗交付时间从计算机化调度系统（用于手动治疗）或CCRS系统日志中获取。治疗师在各台机器之间轮转；因此，该分析不依赖于特定机器上固定的治疗师人员。
总体报告的误差率（所有治疗、所有机器）为每个段0.13%，或每个治疗疗程0.44%。误差率（每台机器）取决于自动化程度和计划复杂性。M1至M4机器每个段的误差率分别为0.16%、0.27%、0.12%、0.05%，而计划复杂性从M1到M4逐渐增加。机器M4（计划和自动化最复杂）的误差率最低。尽管计划复杂性增加，但随着自动化程度提高误差率降低，而对于手动操作的机器，误差率随复杂性增加。请注意，两台手动机器的实际误差率可能高于此处所示（由于未注意到和/或未报告的误差），而（特别是在M4上）几乎所有随机治疗交付误差都被CCRS系统及相关质量保证检查（包括每次治疗时对机器和治疗床读数的常规检查）记录下来。每个计划的治疗交付时间平均为14分钟至23分钟，并且取决于每个计划的段数，尽管该分析因其他因素而变得复杂。
使用复杂的计算机控制交付系统对具有复杂三维适形计划的常规患者进行治疗可减少治疗交付误差，同时允许交付日益复杂和精细的适形计划，而治疗时间几乎没有增加。鉴于对系统性问题可能性的重新警觉，很明显使用完整且集成的计算机控制交付系统可改善治疗交付，因为更复杂的计划可以以更少的误差交付，且不增加治疗时间。
