title: Threshold doses and prediction of visually apparent liver dysfunction after stereotactic body radiation therapy in cirrhotic and normal livers using magnetic resonance imaging.
abstract: The purpose of the present study was to investigate the threshold dose for focal liver damage after stereotactic body radiation therapy (SBRT) in cirrhotic and normal livers using magnetic resonance imaging (MRI). A total of 64 patients who underwent SBRT for liver tumors, including 54 cirrhotic patients with hepatocellular carcinoma (HCC) and 10 non-cirrhotic patients with liver metastases, were analyzed. MRI was performed 3-6 months after SBRT, using gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced T1-weighted sequences. All MRI datasets were merged with 3D dosimetry data. All dose distributions were corrected to the biologically effective dose using the linear-quadratic model with an assumed α/β ratio of 2 Gy. The development of liver dysfunction was validly correlated with isodose distribution. The median biologically effective dose (BED2) that provoked liver dysfunction was 57.3 (30.0-227.9) and 114.0 (70.4-244.9) Gy in cirrhotic and normal livers, respectively (P = 0.0002). The BED2 associated with a >5% risk of liver dysfunction was 38.5 in cirrhotic livers and 70.4 Gy in normal livers. The threshold BED2 for liver dysfunction was not significantly different between Child-Pugh A and B patients (P = 0.0719). Moreover, the fractionation schedule was not significantly correlated with threshold BED2 for liver dysfunction in the cirrhotic liver (P = 0.1019). In the cirrhotic liver, fractionation regimen and Child-Pugh classification did not significantly influence the threshold BED2 for focal liver damage after SBRT. We suggest that the threshold BED2 for liver dysfunction after SBRT is 40 and 70 Gy in the cirrhotic and normal liver, respectively.
authors.affiliation: Miyakojima IGRT Clinic, 1-16-22 Miyakojima-ku, Osaka, 534-0021, Japan Department of Radiology, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo, 663-8501, Japan h-doi@hyo-med.ac.jp.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Doi
authors.affiliation: Miyakojima IGRT Clinic, 1-16-22 Miyakojima-ku, Osaka, 534-0021, Japan Department of Radiology, Saito Yukoukai Hospital, 7-2-18 Asagi, Saito, Ibaraki, Osaka, 567-0085, Japan.
authors.forename: Hiroya
authors.initials: H
authors.lastname: Shiomi
authors.affiliation: Miyakojima IGRT Clinic, 1-16-22 Miyakojima-ku, Osaka, 534-0021, Japan.
authors.forename: Norihisa
authors.initials: N
authors.lastname: Masai
authors.affiliation: Miyakojima IGRT Clinic, 1-16-22 Miyakojima-ku, Osaka, 534-0021, Japan.
authors.forename: Daisaku
authors.initials: D
authors.lastname: Tatsumi
authors.affiliation: Department of Gastroenterology, Ikeda Municipal Hospital, 3-1-18 Johnan, Ikeda, Osaka, 563-8510, Japan.
authors.forename: Takumi
authors.initials: T
authors.lastname: Igura
authors.affiliation: Department of Gastroenterology, Ikeda Municipal Hospital, 3-1-18 Johnan, Ikeda, Osaka, 563-8510, Japan.
authors.forename: Yasuharu
authors.initials: Y
authors.lastname: Imai
authors.affiliation: Miyakojima IGRT Clinic, 1-16-22 Miyakojima-ku, Osaka, 534-0021, Japan.
authors.forename: Ryoong-Jin
authors.initials: RJ
authors.lastname: Oh
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004307:Dose-Response Relationship, Radiation; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008099:Liver / Q000503:physiopathology*; D008103:Liver Cirrhosis / Q000503:physiopathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011336:Probability; D016634:Radiosurgery / Q000009:adverse effects*
keywords: hepatocellular carcinoma; metastatic liver tumor; radiation-associated liver injury; radiation-induced liver disease; radiotherapy; stereotactic body radiation therapy