Perez C A, Purdy J A, Harms W, Gerber R, Matthews J, Grigsby P W, Graham M L, Emami B, Lee H K, Michalski J M
Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, MO.
Int J Radiat Oncol Biol Phys. 1994 Nov 15;30(4):887-97. doi: 10.1016/0360-3016(94)90365-4.
We describe the conceptual structure and process of a fully integrated three-dimensional (3-D) computed tomography (CT) simulator and present a preliminary clinical and financial evaluation of our current system.
This is a preliminary report on 117 patients treated with external beam radiation therapy alone on whom a 3-D simulation and treatment plan and delivery were carried out from July 1, 1992, through June 30, 1993. The elements of a fully integrated 3-D CT simulator were identified: (a) volumetric definition of tumor volume and patient anatomy obtained with a CT scanner, (b) virtual simulation for beam setup and digitally reconstructed radiographs, (c) 3-D treatment planning for volumetric dose computation and plan evaluation, (d) patient-marking device to outline portal on patient's skin, and (e) verification (physical) simulation to verify portal placement on the patient. Actual time-motion (time and effort) recording was made by each professional involved in the various steps of the 3-D simulation and treatment planning on computer-compatible forms. Data were correlated with the anatomic site of the primary tumor being planned. Cost accounting of revenues and operation of the CT simulator and the 3-D planning was carried out, and projected costs per examination, depending on case load, were generated.
Average time for CT volumetric simulation was 74 min without or 84 min with contrast material. Average times were 36 min for contouring of tumor/target volume and 44 min for normal anatomy, 78 min for treatment planning, 53 min for plan evaluation/optimization, and 58 min for verification simulation. There were significant variations in time and effort according to the specific anatomic location of the tumor. Portal marking of patient on the CT simulator was not consistently satisfactory, and this procedure was usually carried out on the physical simulator. Based on actual budgetary information, the cost of a volumetric CT simulation (separate from the 3-D treatment planning) showed that 1500 examinations per year (six per day in 250 working days) must be performed to make the operation of the device cost effective. The same financial projections for the entire 3-D planning process and verification yielded five plans per day. Some features were identified that will improve the use of the 3-D simulator, and solutions are offered to incorporate them in existing devices.
Commercially available CT simulators lack some elements that we believe are critical in a fully integrated 3-D CT simulator. Sophisticated 3-D simulation and treatment planning can be carried out in a significant number of patients at a reasonable cost. Time and effort and therefore cost vary according to the anatomic site of the tumor being planned and the number of procedures performed. Further efforts are necessary, with collaboration of radiation oncologists, physicists, and manufacturers, to develop more versatile and efficient 3-D CT simulators, and additional clinical experience is required to make this technology cost effective in standard radiation therapy of patients with cancer.
我们描述了一个完全集成的三维（3-D）计算机断层扫描（CT）模拟器的概念结构和流程，并对我们当前的系统进行了初步的临床和财务评估。
这是一份关于117例仅接受外照射放疗患者的初步报告，这些患者于1992年7月1日至1993年6月30日期间接受了三维模拟、治疗计划制定及实施。确定了完全集成的三维CT模拟器的组成部分：（a）通过CT扫描仪获得肿瘤体积和患者解剖结构的容积定义；（b）用于射野设置和数字重建射线照相的虚拟模拟；（c）用于容积剂量计算和计划评估的三维治疗计划；（d）用于在患者皮肤上勾勒射野的患者标记装置；（e）用于验证患者射野位置的验证（物理）模拟。参与三维模拟和治疗计划各个步骤的每个专业人员都以计算机兼容的表格形式进行了实际的时间-动作（时间和工作量）记录。数据与所计划的原发肿瘤的解剖部位相关。对CT模拟器和三维计划的收入及运营进行了成本核算，并根据病例负荷生成了每次检查的预计成本。
CT容积模拟的平均时间，不使用造影剂时为74分钟，使用造影剂时为84分钟。肿瘤/靶区容积勾画的平均时间为36分钟，正常解剖结构的平均时间为44分钟，治疗计划制定的平均时间为78分钟，计划评估/优化的平均时间为53分钟，验证模拟的平均时间为58分钟。根据肿瘤的具体解剖位置，时间和工作量存在显著差异。在CT模拟器上对患者进行射野标记并不总是令人满意，该操作通常在物理模拟器上进行。根据实际预算信息，容积CT模拟（与三维治疗计划分开）的成本表明，每年必须进行1500次检查（250个工作日中每天6次）才能使该设备的运营具有成本效益。对整个三维计划过程和验证的相同财务预测得出每天可完成五个计划。确定了一些可改善三维模拟器使用的功能，并提供了将其纳入现有设备的解决方案。
市售的CT模拟器缺少一些我们认为在完全集成的三维CT模拟器中至关重要的元素。可以以合理的成本对大量患者进行复杂的三维模拟和治疗计划。时间和工作量以及因此产生的成本会根据所计划肿瘤的解剖部位和执行的程序数量而有所不同。需要放疗肿瘤学家、物理学家和制造商的合作，进一步努力开发更通用、高效的三维CT模拟器，并且需要更多的临床经验以使该技术在癌症患者的标准放射治疗中具有成本效益。
