Changes in the liver parenchyma after proton beam radiotherapy: evaluation with MR imaging

Monitoring of hepatocellular carcinoma, following proton radiotherapy, with contrast-enhanced color Doppler ultrasonography

“…The mean value of ∆TBFR in the lesions defined as "increased" by CT was significantly higher than that in the lesions defined as "decreased" ( § P Ͻ 0.05) determinant of the therapeutic efficacy. 28,29 The changes in tumor vascularity were detected by CECDU in sensitive manner over time (Fig. 3), and the sensitivity of this modality was similar to that of conventional CT (Fig.…”

“…9,12,30 Furthermore, it has been reported that the pathological changes in human tissues irradiated with proton beams are similar to those occurring with conventional irradiation. 29 Although the above 9,12,29,30 reports mainly focused upon the pathological changes in irradiated normal liver tissues, the same events could occur in peritumoral liver tissues. Therefore, reduced clearance of blood drained from the irradiated volume, due to selective occlusion of the venous channel in the area around the tumor, was considered to be the cause of the sustained presence of the contrast medium in the irradiated tumor.…”

“…We have already reported that these pathological changes in liver parenchyma after proton irradiation were recognized as intensified contrast enhancement on dynamic CT and MRI. 29 The retention of Levovist in the irradiated area can be also recognized, and this may result in an increase of TBFR. In comparison with other therapeutic modalities, the tumoral blood flow was not detectable immediately after TACE 20 or RFA.…”

In Vivo Proton Beam Range Verification Using Spine MRI Changes

“…For instance, respiration causes uncertainty in proton range when treating liver tumors. Liver hypointensity on T1-weighted MRI has been observed after irradiation (16).…”

Image-guided Treatment in the Hepatobiliary System: Role of Imaging in Treatment Planning and Posttreatment Evaluation

“…Treatment failure is indicated by gradual increase in the size of the lesion, with lobulated, thick, heterogeneous enhancement of the irradiated tumor (61). At MR imaging, the liver parenchyma in the zone of radiation demonstrates well-demarcated areas of T1 hypointensity and slight T2 hyperintensity due to increased free water content in the zone of radiation compared with the surrounding hepatic parenchyma (62). T2 signal changes that are progressive and irreversible represent characteristic findings of radiation injury to the liver (62).…”