Comparison of cone beam and fan beam (tomotherapy) adaptive radiotherapy: physical and clinical developments and evaluation of new approaches of intensity modulated raditotherapy

断层治疗是一种新的放射治疗方式。虽然仍处于临床初期，但初步结果令人鼓舞。一种临床优越的放射传递装置的潜力是比较目前的直线加速器放射传递和质子和重离子照射所承诺的临床治疗可能性。应根据临床需求对治疗方式进行排序。断层治疗结合了计算机断层扫描和辐射输送系统。该单元将治疗计划，患者定位和治疗交付集成到一个系统中。它具有显著改善患者护理的潜力，因为它提高了治疗递送的精确度，这可能导致毒性降低和剂量增加。虽然临床医生对这些潜在的临床益处持乐观态度，但这一点尚未确定。此外，由于在诊所引入断层治疗而导致的实践变化可能会影响当前的组织结构。例如，精度的提高可能会减少分数的数量，图像引导患者定位的影响可能会导致虚拟模拟取代立体治疗的数量增加。本提案的目的是评估放射肿瘤学中未来断层治疗的作用。断层治疗，特别是以螺旋形式提供，代表了一种将放射治疗提供给任意形状的靶体积的新方法。我们想要证明，在临床条件下，断层治疗的潜在优势，如更高的剂量与靶体积的一致性，以及在更快的治疗时间内更好地保留正常结构。在线成像的可能性允许校正日常设置的不确定性，甚至可以考虑到内部运动。断层治疗需要一个全新的治疗单元，包括治疗计划和交付。目前，正在开发使用配备多叶准直器的传统线性加速器进行治疗的不同方法。因此，对断层治疗方法进行系统评估似乎是合理的。我们建议比较一组参数，包括医学物理特性、治疗计划参数、放射生物学实验、社会经济考虑和应用安全性，以及在经验丰富的用户手中使用直线加速器和离子束的IMRT的临床结果。临床研究将集中于乳腺癌、前列腺癌、肺癌包括间皮瘤、上胃肠道肿瘤、前列腺癌和中枢神经系统肿瘤。患者将被纳入I/II期和随机II期研究。目的是确定将从一种或另一种形式的放射治疗中受益的患者的特征，并预测这些患者的最佳治疗方式。最后，应该估计最终需要的断层治疗单位的数量。

Tomotherapy is a new form of radiation delivery. Although still in its clinical infancy, preliminary results are encouraging. The potential of a clinical superior radiation delivery device is to be compared with the present day linear accelerator radiation delivery and the clinical treatment possibilities promised by proton and heavy ion irradiation. A ranking of treatment modalities depending on the clinical demands should be provided. Tomotherapy combines computed tomography with a radiation delivery system. The unit integrates treatment planning, patient positioning, and treatment delivery into one system. It has the potential to significantly improve patient care by virtue of its increased precision in treatment delivery, which may result in reduced toxicity and dose escalation. While clinicians are optimistic about these potential clinical benefits, this has not yet been established. Further, changes in practice resulting from the introduction of tomotherapy in the clinic would likely impact the current organizational structure. For example, increased precision may allow a reduction in the number of fractions, the impact of image guided positioning of the patient may lead to a rising number of virtual simulations replacing stereotatic treatments.The aim of this proposal is to evaluate the future role of tomotherapy in radiation oncology. Tomotherapy especially delivered in its helical form represents a new way to deliver radiation therapy to arbitrarily shaped target volumes. We want to show if potential advantages of tomotherapy such as higher dose conformality to the target volume and better sparing of normal structures at faster treatment time hold true under clinical conditions. The possibility of online imaging allows for correction of daily setup uncertainties and even may allow to take into account intrafractional movement. The tomotherapy requires a whole new treatment unit which includes the treatment planning and delivery. Currently different approaches of treatment delivery with conventional linearaccelerators equipped with multileafcollimators are being developed. Therefore a systematic evaluation of the tomotherapy approach seems to be justified. We propose to compare one set of parameters which includes medical physics characteristics, treatment planning parameters, radiobiological experiments, socioeconomical considerations and the safety of application and also clinical results of the tomotherapy approach to that of IMRT with linacs and ion beams in the hands of experienced users.The clinical studies will focus on breast cancer, prostate cancer, lung cancer including mesothelioma, upper gastrointestinal tract tumors, prostate cancer and CNS tumors. Patients will be included in phase I/II and in randomized phase II studies. The aim is to identify the characteristics of patients who will benefit from one or the other form of radiation therapy and to predict the best modality for these patients. Finally the number of tomotherapy units which would be eventually necessary should be estimated.