title: Investigation of dosimetric variations of liver radiotherapy using deformable registration of planning CT and cone-beam CT.
abstract: Many patients with technically unresectable or medically inoperable hepatocellular carcinoma (HCC) had hepatic anatomy variations as a result of interfraction deformation during fractionated radiotherapy. We conducted this retrospective study to investigate interfractional normal liver dosimetric consequences via reconstructing weekly dose in HCC patients. Twenty-three patients with HCC received conventional fractionated three-dimensional conformal radiation therapy (3DCRT) were enrolled in this retrospective investigation. Among them, seven patients had been diagnosed of radiation-induced liver disease (RILD) and the other 16 patients had good prognosis after treatment course. The cone-beam CT (CBCT) scans were acquired once weekly for each patient throughout the treatment, deformable image registration (DIR) of planning CT (pCT) and CBCT was performed to acquire modified CBCT (mCBCT), and the structural contours were propagated by the DIR. The same plan was applied to mCBCT to perform dose calculation. Weekly dose distribution was displayed on the pCT dose space and compared using dose difference, target coverage, and dose volume histograms. Statistical analysis was performed to identify the significant dosimetric variations. Among the 23 patients, the three weekly normal liver D50increased by 0.2 Gy, 4.2 Gy, and 4.7 Gy, respectively, for patients with RILD, and 1.0 Gy, 2.7 Gy, and 3.1 Gy, respectively, for patients without RILD. Mean dose to the normal liver (Dmean) increased by 0.5 Gy, 2.6 Gy, and 4.0 Gy, respectively, for patients with RILD, and 0.4 Gy, 3.1 Gy, and 3.4 Gy, respectively, for patients without RILD. Regarding patients with RILD, the average values of the third weekly D50and Dmeanwere both over hepatic radiation tolerance, while the values of patients without RILD were below. The dosimetric consequence showed that the liver dose between patients with and without RILD were different relative to the planned dose, and the RILD patients suffered from liver dose over hepatic radiation tolerance. Evaluation of routinely acquired CBCT images during radiation therapy provides biological information on the organs at risk, and dose estimation based on mCBCT could potentially form the basis for personalized response adaptive therapy.
authors.affiliation: Shandong Province Key Laboratory of Medical Physics and Image Processing Technology, Institute of Biomedical Sciences, School of Physics and Electronics, Shandong Normal University, Jinan, Shandong, China.
authors.forename: Pu
authors.initials: P
authors.lastname: Huang
authors.affiliation: Shandong Province Key Laboratory of Medical Physics and Image Processing Technology, Institute of Biomedical Sciences, School of Physics and Electronics, Shandong Normal University, Jinan, Shandong, China.
authors.forename: Gang
authors.initials: G
authors.lastname: Yu
authors.affiliation: Department of Radiation Oncology, Shandong Cancer Hospital, Jinan, China.
authors.forename: Jinhu
authors.initials: J
authors.lastname: Chen
authors.affiliation: Department of Radiation Oncology, Shandong Cancer Hospital, Jinan, China.
authors.forename: Changsheng
authors.initials: C
authors.lastname: Ma
authors.affiliation: Shandong Province Key Laboratory of Medical Physics and Image Processing Technology, Institute of Biomedical Sciences, School of Physics and Electronics, Shandong Normal University, Jinan, Shandong, China.
authors.forename: Shaohua
authors.initials: S
authors.lastname: Qin
authors.affiliation: Department of Radiation Oncology, Shandong Cancer Hospital, Jinan, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Yin
authors.affiliation: Department of Radiation Oncology, Shandong Cancer Hospital, Jinan, China.
authors.forename: Yueqiang
authors.initials: Y
authors.lastname: Liang
authors.affiliation: Department of Radiation Oncology, Shandong Cancer Hospital, Jinan, China.
authors.forename: Hongsheng
authors.initials: H
authors.lastname: Li
authors.affiliation: Shandong Province Key Laboratory of Medical Physics and Image Processing Technology, Institute of Biomedical Sciences, School of Physics and Electronics, Shandong Normal University, Jinan, Shandong, China.
authors.forename: Dengwang
authors.initials: D
authors.lastname: Li
mesh_terms: D000328:Adult; D000368:Aged; D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy*; D054893:Cone-Beam Computed Tomography / Q000379:methods*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008099:Liver / Q000000981:diagnostic imaging / Q000473:pathology / Q000528:radiation effects; D008113:Liver Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D009381:Neoplasms, Radiation-Induced / Q000000981:diagnostic imaging* / Q000209:etiology / Q000473:pathology; D011379:Prognosis; D011832:Radiation Injuries / Q000000981:diagnostic imaging* / Q000209:etiology / Q000473:pathology; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D020266:Radiotherapy, Conformal / Q000009:adverse effects / Q000379:methods; D012189:Retrospective Studies
keywords: cone beam CT; deformable image registration; hepatocellular carcinoma; radiation‐induced liver disease