4-D IMRT: Imaging, Planning and Delivery

描述（由申请人提供）：过去十年进行的研究表明，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，通过降低给予健康肺组织的剂量，可以显著减少肺癌放疗的主要副作用——肺炎。平衡这些相互冲突的目标是困难的，特别是因为肺肿瘤随着呼吸运动平均移动1.5-2厘米。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。该技术的第四个维度或时间组成部分意味着肿瘤的运动在成像、计划和放疗过程中被考虑在内。在治疗期间用放射束跟踪肿瘤，可以减少束缘，从而减少暴露于高剂量的健康组织的体积。该技术的IMRT部分允许我们对肿瘤给予足够高的剂量，对健康肺组织给予可接受的低剂量。我们将研究4D IMRT将导致的假设：1。与常规IMRT相比，改进的治疗方案；与常规IMRT相比，暴露于有害剂量的正常组织体积减少，2。3 .与呼吸门控IMRT相比，分娩时间缩短；4 .比屏气技术适用性更广；与传统和呼吸控制技术相比，递送剂量分布的准确性更高。虽然这里的研究主要集中在肺癌，但4D IMRT适用于所有受呼吸运动影响的部位，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.