Medical Radiation Physics, Stockholm University, Sweden.
Acta Oncol. 2012 Feb;51(2):222-30. doi: 10.3109/0284186X.2011.599815. Epub 2011 Aug 28.
The study presents the implementation of a novel method for incorporating hypoxia information from PET-CT imaging into treatment planning and estimates the efficiency of various optimization approaches. Its focuses on the feasibility of optimizing treatment plans based on the non-linear conversion of PET hypoxia images into radiosensitivity maps from the uptake properties of the tracers used.
PET hypoxia images of seven head-and-neck cancer patients were used to determine optimal dose distributions needed to counteract the radiation resistance associated with tumor hypoxia assuming various scenarios regarding the evolution of the hypoxic compartment during the treatment. A research planning system for advanced studies has been used to optimize IMRT plans based on hypoxia information from patient PET images. These resulting plans were compared in terms of target coverage for the same fulfilled constraints regarding the organs at risk.
The results of a planning study indicated the clinical feasibility of the proposed method for treatment planning based on PET hypoxia. Antihypoxic strategies would lead to small improvements in all the patients, but higher effects are expected for the fraction of patients with hypoxic tumors. For these, individualization of the treatment based on hypoxia PET imaging could lead to improved treatment outcome while creating the premises for limiting the irradiation of the surrounding normal tissues.
The proposed approach offers the possibility of improved treatment results as it takes into consideration the heterogeneity and the dynamics of the hypoxic regions. It also provides early identification of the clinical cases that might benefit from dose escalation as well as the cases that could benefit from other counter-hypoxic measures.
本研究提出了一种将 PET-CT 成像中的缺氧信息纳入治疗计划的新方法，并估计了各种优化方法的效率。重点关注基于所使用示踪剂摄取特性将 PET 缺氧图像非线性转换为放射敏感性图来优化治疗计划的可行性。
使用七例头颈部癌症患者的 PET 缺氧图像来确定需要的最佳剂量分布，以抵消肿瘤缺氧相关的辐射抗性，假设在治疗过程中缺氧区的演变存在各种情况。使用高级研究的研究计划系统，基于患者 PET 图像中的缺氧信息来优化 IMRT 计划。在满足危及器官相同约束的情况下，比较这些生成计划的靶区覆盖情况。
一项计划研究的结果表明，基于 PET 缺氧进行治疗计划的所提出方法具有临床可行性。抗缺氧策略将导致所有患者的微小改善，但对于缺氧肿瘤患者的比例，预计会有更高的效果。对于这些患者，基于缺氧 PET 成像进行个体化治疗可能会改善治疗结果，同时为限制周围正常组织的照射创造前提。
所提出的方法提供了改善治疗结果的可能性，因为它考虑了缺氧区域的异质性和动态性。它还可以早期识别可能受益于剂量递增的临床病例，以及可能受益于其他抗缺氧措施的病例。
