RefleXion Medical, Hayward, CA, USA.
Br J Radiol. 2021 Jan 1;94(1117):20200873. doi: 10.1259/bjr.20200873. Epub 2020 Oct 30.
The emerging biological understanding of metastatic cancer and proof-of-concept clinical trials suggest that debulking all gross disease holds great promise for improving patient outcomes. However, ablation of multiple targets with conventional external beam radiotherapy systems is burdensome, which limits investigation and utilization of complete metastatic ablation in the majority of patients with advanced disease. To overcome this logistical hurdle, technical innovation is necessary. Biology-guided radiotherapy (BgRT) is a new external beam radiotherapy delivery modality combining positron emission tomography-computed tomography (PET-CT) with a 6 MV linear accelerator. The key innovation is continuous response of the linear accelerator to outgoing tumor PET emissions with beamlets of radiotherapy at subsecond latency. This allows the deposited dose to track tumors in real time. Multiple new hardware and algorithmic advances further facilitate this low-latency feedback process. By transforming tumors into their own fiducials after intravenous injection of a radiotracer, BgRT has the potential to enable complete metastatic ablation in a manner efficient for a single patient and scalable to entire populations with metastatic disease. Future trends may further enhance the utility of BgRT in the clinic as this technology dovetails with other innovations in radiotherapy, including novel dose painting and fractionation schemes, radiomics, and new radiotracers.
转移性癌症的新兴生物学理解和概念验证临床试验表明，清除所有大体疾病对改善患者预后具有巨大潜力。然而，用传统的外束放射治疗系统消融多个靶标是很繁重的，这限制了在大多数晚期疾病患者中对完全转移性消融的研究和应用。为了克服这一后勤障碍，需要技术创新。生物学引导放疗（BgRT）是一种新的外束放疗输送方式，它将正电子发射断层扫描-计算机断层扫描（PET-CT）与 6MV 线性加速器相结合。关键的创新是线性加速器对肿瘤发出的 PET 发射的连续反应，以亚秒级的延迟发出放射束。这使得沉积的剂量能够实时跟踪肿瘤。多项新的硬件和算法进展进一步促进了这一低延迟反馈过程。通过在静脉注射放射性示踪剂后将肿瘤转化为自身的基准，BgRT 有可能以对单个患者有效的方式实现完全转移性消融，并可扩展到患有转移性疾病的整个人群。随着该技术与放射治疗的其他创新相结合，包括新的剂量绘制和分割方案、放射组学和新的放射性示踪剂，未来的趋势可能会进一步提高 BgRT 在临床中的应用。
