The progressive integration of positron emission tomography/computed tomography (PET/CT) imaging in radiation therapy has its rationale in the biological intertumoral and intratumoral heterogeneity of malignant lesions that require the individual adjustment of radiation dose to obtain an effective local tumor control in cancer patients. PET/CT provides information on the biological features of tumor lesions such as metabolism, hypoxia, and proliferation that can identify radioresistant regions and be exploited to optimize treatment plans. Here, we provide an overview of the basic principles of PET-based target volume selection and definition using ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) and then we focus on the emerging strategies of dose painting and adaptive radiotherapy using different tracers. Previous studies provided consistent evidence that integration of ¹⁸F-FDG PET/CT in radiotherapy planning improves delineation of target volumes and reduces the uncertainties and variabilities of anatomical delineation of tumor sites. PET-based dose painting and adaptive radiotherapy are feasible strategies although their clinical implementation is highly demanding and requires strong technical, computational, and logistic efforts. Further prospective clinical trials evaluating local tumor control, survival, and toxicity of these emerging strategies will promote the full integration of PET/CT in radiation oncology.

正电子发射断层扫描/计算机断层扫描（PET / CT）成像在放射治疗中的逐步整合在其恶性病变的生物瘤内和瘤内异质性方面具有其基本原理，需要对肿瘤患者进行放射线剂量的单独调整以获得有效的局部肿瘤控制。PET / CT提供有关肿瘤病变的生物学特征的信息，例如代谢，缺氧和增殖，这些信息可以识别放射线抗性区域并被用于优化治疗计划。在此，我们概述了使用¹⁸ F-氟代脱氧葡萄糖（¹⁸（^18）F-FDG），然后我们关注使用不同示踪剂的剂量绘画和适应性放射治疗的新兴策略。先前的研究提供了一致的证据，表明¹⁸ F-FDG PET / CT在放射治疗计划中的整合可改善目标体积的轮廓，并减少肿瘤部位解剖轮廓的不确定性和可变性。基于PET的剂量绘画和适应性放射治疗是可行的策略，尽管它们的临床实施要求很高，并且需要强大的技术，计算和后勤工作。评估这些新兴策略的局部肿瘤控制，生存率和毒性的进一步前瞻性临床试验将促进PET / CT在放射肿瘤学中的完全整合。