4-D IMRT: Imaging, Planning and Delivery

描述（由申请人提供）：过去十年进行的研究证明，对于肺癌，增加放疗剂量将导致更好的局部控制和生存。进一步的研究表明，主要的肺癌放疗副作用，肺炎，可以显着减少通过降低剂量传递到健康的肺组织。平衡这些相互冲突的目标是困难的，特别是因为肺部肿瘤随着呼吸运动平均移动1.5-2 cm。该项目旨在开发和实施一种名为4D IMRT（四维调强放射治疗）的技术。该技术的第四维或时间分量意味着在成像、规划和辐射输送期间考虑肿瘤运动。在治疗递送期间用辐射束跟踪肿瘤允许减小射束裕度，并且因此减小暴露于高剂量的健康组织的体积。该技术的调强放射治疗部分允许我们给予肿瘤足够高的剂量和健康肺组织可接受的低剂量。我们将调查的假设，4D调强放疗将导致：1。与常规IMRT相比，改善了治疗计划，2.与常规IMRT相比，暴露于损伤剂量的正常组织体积减少，3.与呼吸门控IMRT相比，减少了输送时间，4. 比屏气技术更广泛的适用性，和5.虽然这里的研究主要集中在肺癌上，但4D IMRT适用于受呼吸运动影响的所有部位，包括乳腺癌和肝癌，甚至宫颈癌和前列腺癌。

DESCRIPTION (provided by applicant): Studies performed over the past decade give evidence that for lung cancer, increased radiotherapy dose will lead to better local control and survival. Further studies show that the main lung cancer radiotherapy side effect, pneumonitis, can be significantly reduced by lowering the dose delivered to healthy lung tissue. Balancing these conflicting goals is difficult, especially since a lung tumor moves on average 1.5-2 cm with respiratory motion. This project aims to develop and implement a technique entitled 4D IMRT (4-Dimensional Intensity Modulated Radiation Therapy). The 4th dimension, or time, component of the technique means that the tumor motion is accounted for during the imaging, planning and delivery of radiation. Tracking the tumor with the radiation beam during treatment delivery allows a reduction in beam margin and consequently a reduction in the volume of healthy tissue exposed to a high dose. The IMRT component of the technique allows us to give a sufficiently high dose to the tumor and an acceptably low dose to the healthy lung tissue. We will investigate the hypotheses that 4D IMRT will lead to: 1. improved treatment plans compared with conventional IMRT, 2. reduced volumes of normal tissue exposed to injurious doses compared with conventional IMRT, 3. reduced delivery time compared with respiration-gated IMRT, 4. wider applicability than breath-hold techniques, and 5. higher accuracy in delivered dose distributions compared with conventional and respiration-gated techniques.Though the studies here will concentrate mainly on lung cancer, 4D IMRT is applicable to all sites affected by respiratory motion, including breast and liver cancer, and even cervix and prostate cancer.