de Ridder Mischa, de Bree Remco, de Keizer Bart
University Medical Center Utrecht, Department of Radiotherapy, Netherlands (the).
University Medical Center Utrecht, Department of Head and Neck Surgical Oncology, Netherlands (the).
Phys Imaging Radiat Oncol. 2025 Jun 5;35:100792. doi: 10.1016/j.phro.2025.100792. eCollection 2025 Jul.
Radiotherapy is a cornerstone in the treatment of head and neck squamous cell carcinoma (HNSCC). Imaging plays an important role in target delineation in order to achieve adequate target dose and on the other hand limit radiation-induced toxicity to surrounding healthy tissues. Advancements in imaging techniques, including functional imaging with positron emission tomography (PET), have improved accurate target delineation, allowed for adaptive radiotherapy, and improved response evaluation. This review explores the potential role of fibroblast activation protein inhibitor (FAPI)-PET/CT in radiotherapy planning for HNSCC, comparing its efficacy to the current standard, fluorine-18 fluorodeoxyglucose (18F-FDG) PET/CT. FAPI-PET/CT is an emerging imaging modality that for pretreatment imaging may increase lesion detection, especially near the skull base. For target delineation FAPI PET/CT may enhance the specificity of tumor delineation, particularly in distinguishing tumor tissue from normal tissue. Current evidence suggests that FAPI-PET increases the GTV volume, but whether this represents more accurate tumor delineation or overestimation remains unclear. For response monitoring after treatment, there is no evidence in head and neck cancer, but for rectal cancer FAPI-PET/CT showed promising results in detection of residual disease after neo-adjuvant radiotherapy. For now, FAPI-PET/CT could be used as additional imaging, and should not be used as replacement for other imaging modalities. There is an urgent need for prospective validation studies to determine the clinical impact of FAPI-PET on radiotherapy planning and response monitoring.
放射治疗是头颈部鳞状细胞癌（HNSCC）治疗的基石。成像在靶区勾画中起着重要作用，以便实现足够的靶区剂量，另一方面限制对周围健康组织的辐射诱导毒性。成像技术的进步，包括正电子发射断层扫描（PET）功能成像，提高了靶区勾画的准确性，实现了自适应放射治疗，并改善了疗效评估。本综述探讨了成纤维细胞活化蛋白抑制剂（FAPI）-PET/CT在HNSCC放射治疗计划中的潜在作用，并将其疗效与当前标准氟代脱氧葡萄糖（18F-FDG）PET/CT进行比较。FAPI-PET/CT是一种新兴的成像方式，用于治疗前成像可能会增加病变检测，尤其是在颅底附近。对于靶区勾画，FAPI PET/CT可能会提高肿瘤勾画的特异性，特别是在区分肿瘤组织与正常组织方面。目前的证据表明，FAPI-PET会增加大体肿瘤体积（GTV），但这是代表更准确的肿瘤勾画还是高估尚不清楚。对于治疗后的疗效监测，头颈部癌尚无证据，但对于直肠癌，FAPI-PET/CT在新辅助放疗后检测残留疾病方面显示出有前景的结果。目前，FAPI-PET/CT可作为补充成像，不应替代其他成像方式。迫切需要进行前瞻性验证研究，以确定FAPI-PET对放射治疗计划和疗效监测的临床影响。
