Incorporating GSA-SPECT into CT-based dose-volume histograms for advanced hepatocellular carcinoma radiotherapy

Figure 7 Comparison of dose-volume histograms between actual treatment plans (solid lines) and hypothetical treatment plans (dotted lines). A: Comparison of the DVH for normal liver. In this case, the percentage of the normal liver irradiated with ≥ 20 Gy (_NLV_20Gy) was 23.1% for the hypothetical treatment plan vs 30.8% for the actual treatment plan. Therefore, irradiation of normal liver is lower for the hypothetical treatment plan than for the actual treatment plan; B: Comparison of the DVH for functional liver. In this case, the percentage of functional liver irradiated with ≥ 20 Gy (_FLV_20Gy) was 43.7% for the hypothetical treatment plan vs 23.8% for the actual treatment plan. Therefore, irradiation of functional liver is lower for the actual treatment plan than for the hypothetical treatment plan. The difference between _NLV_20Gy and _FLV_20Gy in these two settings is due to the uneven distribution of functional liver. DVH: Dose-volume histograms; HCC: Hepatocellular carcinoma.