磁共振影像学改变评估肝癌立体定向放疗精度的研究进展

AProgress in assessing the treatment accuracy of liver stereotactic body radiotherapy through post-therapeutic magnetic resonance imaging morphologic alterations

在原发性肝癌和转移性肝癌治疗中,可以采用立体定向放射治疗技术(SBRT)给予肿瘤高剂量以达到消融治疗的效果。由于SBRT单次高剂量的特点,使其对放疗精度有更高的要求。尤其是肝癌受摆位误差与呼吸运动的影响,需要同时使用呼吸运动管理和影像引导。然而,现有研究者报道的放疗精度验证均使用模体进行间接验证,而不是在患者治疗实施过程中进行在体验证,使得最终的治疗精度受到怀疑。肝脏在接受一定放射治疗剂量后会在磁共振影像中呈现相应的形态学改变,可以反映放射治疗的精度。该文将就肝癌体部立体定向放射治疗后磁共振影像改变的发生原理、表现形式和出现时间、精度评价方式、临床困境及未来发展方向进行讨论分析。

In the treatment of primary liver cancer and metastatic liver cancer,stereotactic body radiotherapy(SBRT)can be utilized to administer high doses of radiation for achieving ablative therapeutic effects.Given the singular nature of delivering high-dose radiation through SBRT,a higher level of precision is required in radiation therapy.Particularly,liver cancer is susceptible to positioning errors and respiratory motion,necessitating the implementation of respiratory motion management and image guidance techniques.However,existing accuracy verification methods for radiation therapy primarily rely on phantom studies,making it challenging to conduct in-vivo verification during treat-ment execution.Research has indicated that the liver exhibits corresponding morphological changes in magnetic reso-nance imaging following exposure to specific doses of radiation therapy,thereby serving as an indicator for assessing treatment accuracy.This article aims to discuss and analyze the principles underlying magnetic resonance imaging alterations after stereotactic body radiotherapy for liver cancer,including their manifestations,timing of appearance,evaluation methodologies for accuracy assessment,clinical challenges encountered during implementation,as well as future directions for development.