Dose-function Histogram Evaluation Using Tc-99m-GSA SPECT/CT Images for Stereotactic Body Radiation Therapy Planning for Hepatocellular Carcinoma Patients: A Dosimetric Parameter Comparison

摘要

Background/Aim: We evaluated the influence of previous treatments on the parametric discrepancies between dose-volume histograms (DVHs) and dose-function histograms (DFHs) generated based on Tc-99m-GSA SPECT images of hepatocellular carcinoma (HCC) patients treated with stereotactic body radiation therapy (SBRT). Patients and Methods: Twelve patients underwent SBRT at 30-40 Gy. Registration between planning CT and SPECT/CT images was performed, and DFH parameters were calculated as follows: Fx=(sum of the counts within the liver volume receiving a dose of more than x Gy/sum of the counts within the whole liver volume) x100. The discrepancy between Fx and Vx (Dx) was also calculated. Results: The number of previous treatments for lesions other than SBRT-treated lesions (= 2 vs. 2) exhibited a significant influence on the absolute values of D-10, D-15, and D-20 (p0.05). Conclusion: Previous treatment significantly influences the parametric discrepancy between DFH and DVH.