Validation of the liver mean dose in terms of the biological effective dose for the prevention of radiation-induced liver damage

Publication date: July–August 2017
Source:Reports of Practical Oncology & Radiotherapy, Volume 22, Issue 4
Author(s): Hiroshi Doi, Norihisa Masai, Kenji Uemoto, Osamu Suzuki, Hiroya Shiomi, Daisaku Tatsumi, Ryoong-Jin Oh
AimThe purpose of this study was to determine the optimal mean liver biologically effective dose (BED) to prevent radiation-induced liver disease (RILD) in stereotactic body radiation therapy (SBRT).BackgroundThe actual mean doses appropriate for liver irradiation in modern radiotherapy techniques have not been adequately investigated, although SBRT is sometimes alternatively performed using fractionated regimens.Materials and methodsSBRT treatment plans for liver tumors in 50 patients were analyzed. All distributions of the physical doses were transformed to BED2 using the linear-quadratic model. The relationship between physical doses and the BED2 for the liver were then analyzed, as was the relationship between the mean BED2 for the liver and the planning target volume (PTV).ResultsA significantly positive correlation was observed between the mean physical dose for the background liver and the mean BED2 for the whole liver (P<0.0001, r=0.9558). Using the LQ model, a mean BED2 of 73 and 16Gy for the whole liver corresponded to the hepatic tolerable mean physical dose of 21 and 6Gy for Child–Pugh A- and B-classified patients, respectively. Additionally, the PTV values were positively correlated with the BEDs for the whole liver (P<0.0001, r=0.8600), and the background liver (P<0.0001, r=0.7854).ConclusionA mean BED2 of 73 and 16Gy for the whole liver appeared appropriate to prevent RILD in patients with Child–Pugh classes A and B, respectively. The mean BED2 for the liver correlated well with the PTV.



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