Normal liver tissue change after proton beam therapy
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Normal liver tissue changes after proton beam therapy (PBT) were investigated in patients at 1 and 2 years after the therapy.
Materials and methods
Changes in normal liver tissue volume were examined. The dose distribution of the normal liver tissue was also simulated on the follow-up CTs.
The normal liver tissue volume was 1149 ± 215 cm3 before treatment, 1089 ± 188 cm3 at 1 year, and 1080 ± 236 cm3 at 2 years after treatment. The normal liver tissue volume was increased in 10 and decreased in 20 patients at 2 years and was smaller than that before the treatment in total (P = 0.03). The simulated volume that received more than 30 Gray equivalent [V30 (cm3)] at 1 year was 258 ± 187 cm3 and that at 2 years (244 ± 171 cm3) was smaller than that before treatment (297 ± 140 cm3) (P = 0.03).
The changes in the shape and volume of normal liver tissue are not constant, which cause a large dose distribution discrepancy in the normal liver for 2 years. Therefore, careful consideration of the dose distribution of normal liver tissue is required when planning re-irradiation.
KeywordsImage registration Liver Proton beam therapy HCC
This study was partially supported by Grants-in-Aid for Scientific Research in Japan (No. 17H04256 and 16K10383). We really appreciate Flaminia Miyamasu, Medical English Communications Center, University of Tsukuba, for grammatical revision of the manuscript.
Compliance with ethical standards
Conflicts of interest
The authors declare that they have no conflicts of interest.
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional research committee.
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