Dose-function Histogram Evaluation Using 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 ^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.

Keywords: Hepatocellular carcinoma; dose–function histogram; dose–volume histogram; radiation-induced liver disease; stereotactic body radiation therapy.