Dose–function histogram evaluation using [hrt]99mTc-GSA SPECT/CT images for stereotactic body radiation therapy planning for hepatocellular carcinoma patients: A dosimetric parameter comparison

Abstract

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 [hrt]99mTc-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) ×100. 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 D10, D15, and D20 (p<0.05). Conclusion: Previous treatment significantly influences the parametric discrepancy between DFH and DVH.