Valuation of advanced Dosimetry in Transarterial Radioembolization of Hepatocellular Carcinoma with 90Y microspheres

Abstract

Objective : The aim of our study was to analyze the relationships between tumor (T) and normal tissue (N) absorbed dose in relation to the clinical outcomes in hepatocellular carcinoma (HCC) patients treated with 90Y microspheres. Materials and methods : After transarterial radioembolization of HCC with 90Y microspheres, 62 patients (10 females: 52 males, mean age 68.2±8.2 years) were imaged using a four-ring, time-of-flight (TOF), PET/CT system. Low dose, non-diagnostic CT images from PET/CT were utilized for localization of the 90Y microspheres and attenuation correction of PET images. Response assessment was conducted using mRECIST criteria on MRI one month post treatment and subsequently every three months after 90Y treatment. Results : Among 62 patients, mean liver, tumor, and normal tissue doses (mean ± SD) were 51.38±23.32 Gy, 682.60±785.19 Gy and 45.54±21.19 Gy, respectively. Out of these patients, 39 exhibited complete response (CR), 11 showed partial response (PR), 2 had stable disease (SD), and 10 showed progression of the disease (PD). For CR+PR patients the mean T was 824.63±833.10 Gy, whereas for PD patients, the mean T was significantly lower at 205.70±183.22 Gy. The mean liver and normal tissue doses were comparable; for CR+PR patients had liver and normal tissue doses of 51.01±22.55 Gy and 45.18±20.68 Gy, respectively, and for PD patients, these values were 54.34±26.73 Gy and 49.10±22.97 Gy, respectively. Conclusion : Despite not considering the partial volume effect and having a limited number of PD cases, our data indicates a statistically significant lower (P = 0.0001) tumor dose in patients with disease progression compared to those with complete and partial response. These results suggest that post-therapy personalized, and image-based dosimetry provides promising predictive outcomes in 90Y microsphere radiation therapy for liver cancers.