Radioembolization versus portal vein embolization for contralateral liver lobe hypertrophy: effect of cirrhosis.

PURPOSE: Preoperative hypertrophy induction of future liver remnant (FLR) reduces the risk of postoperative liver insufficiency after partial hepatectomy. One of the most commonly used methods to induce hypertrophy of FLR is portal vein embolization (PVE). Recent studies have shown that transarterial radioembolization (TARE) also induces hypertrophy of the contralateral liver lobe. The aim of our study was to evaluate contralateral hypertrophy after TARE versus after PVE taking into account the effect of cirrhosis. METHODS: Forty-nine patients undergoing PVE before hemihepatectomy and 24 patients with TARE as palliative treatment for liver malignancy were retrospectively included. Semi-automated volumetry of the FLR/contralateral liver lobe before and after intervention (20 to 65 days) was performed on CT or MRI, and the relative increase in volume was calculated. Cirrhosis was evaluated independently by two radiologists on CT/MRI, and interrater reliability was calculated. RESULTS: Hypertrophy after PVE was significantly more pronounced than after TARE (25.3% vs. 7.4%; p < 0.001). In the subgroup of patients without cirrhosis, the difference was also statistically significant (25.9% vs. 8.6%; p = 0.002), whereas in patients with cirrhosis, the difference was not statistically significant (18.2% vs. 7.4%; p = 0.212). After PVE, hypertrophy in patients without cirrhosis was more pronounced than in patients with cirrhosis (25.9% vs. 18.2%; p = 0.203), while after TARE, hypertrophy was comparable in patients with and without cirrhosis (7.4% vs. 8.6%; p = 0.928). CONCLUSION: TARE induces less pronounced hypertrophy of the FLR compared to PVE. Cirrhosis seems to be less of a limiting factor for hypertrophy after TARE, compared to PVE.

[Development of a system for risk analysis in treatment with unsealed radioactive substances in nuclear medicine]. / Entwicklung eines Systems zur Risikoanalyse bei der Behandlung mit offenen radioaktiven Stoffen in der Nuklearmedizin.

PURPOSE: With respect to the amendment of the Radiation Protection law it is required to estimate the risks of treatments with ionizing radiation regarding patient safety. This task is in the responsibility of a medical physics expert. MATERIAL AND METHODS: The risks were estimated using the Failure Mode and Effects Analysis (FMEA) as suggested by the Federal Office for Radiation Protection (BfS) and the scientific societies. For Radioiodine Therapy, Radiosynoviorthesis, Peptide Receptor Radionuclide Therapy, and Selective Internal Radiation Therapy, respectively, the involved processes were analyzed, structured and scored. This was done both individually by all people involved in the process and by all participants together. For processes with risk priority numbers > 125 countermeasures were introduced. The risk priority number (RPZ) was calculated as the product of severity of the event, the probability of the occurrence of the event and the detection probability. RESULTS: The greatest risks were mistaken identity, incorrect estimations of activity and organ masses and a lack of compliance of the patients. The individual risk estimation revealed a high variability between the different professions, that was reduced significantly by discussion led by an external moderator. For the highest RPZ countermeasures were formulated which impact needs to be reviewed in the future. CONCLUSIONS: Nuclear medical therapies were assessed as very safe, the revealed risks are very low in respect to patient safety. FMEA method was a useful tool to identify processes with potential for optimization. The chosen procedure can be easily adopted in other nuclear medicine facilities considering structure specific aspects like technical and personal equipment and procedures. Then further risks might be detected or the here identified risk might be assessed differently.

Induction and rejoining of DNA double-strand breaks in the lymphocytes of prostate cancer patients after radium-223 treatment as assessed by the γH2AX foci assay.

AIM: The aim of this study is to assess if the number of radiation-induced double strand breaks (DSB) in lymphocytes of prostate cancer patients is affected after repeated Ra-223 therapies. In addition, we investigated the repair of ex vivo induced DSB to investigate the repair proficiency in patient's lymphocytes over the therapy course. METHODS: Before each of six therapy cycles, blood samples were obtained from seventeen patients. After separation of lymphocytes, the cells were subjected to immunofluorescence staining for detection of DSB-marking γH2AX foci. The number of foci per cell per patient sample was determined for each cycle (X1-X6, baseline foci per cell). Additionally, appropriate samples were exposed ex vivo to an X-ray dose of 1 Gy. The number of γH2AX foci per cell were analyzed after 0.5 h, 2 h and 24 h of recovery. RESULTS: Patient-specific linear regression of the baseline foci per cell over the therapy cycles revealed no significant slopes in the regression lines. Likewise, the mean baseline foci per cell of all patients for cycles X2-X6 was not significantly elevated in comparison to the pre-therapeutic value (X1). The differences between the percentages of residual DSB and cycles were not significant, both at 2 h and 24 h repair time. Consideration of the X6/X1 ratios of both the number of lymphocytes and the amount of residual damage at 24 h indicated a significant correlation. CONCLUSION: Our findings indicate that the number of γH2AX foci per cell was not changed in dependence on the Ra-223 therapy cycles. The ability of patient's lymphocytes to repair ex vivo induced DSB remained unaffected throughout the entire therapy course.

Holmium-166 Radioembolization in Hepatocellular Carcinoma: Feasibility and Safety of a New Treatment Option in Clinical Practice.

PURPOSE: To investigate clinical feasibility, technical success and toxicity of 166Ho-radioembolization (166Ho-RE) as new approach for treatment of hepatocellular carcinomas (HCC) and to assess postinterventional calculation of exact dosimetry through quantitative analysis of MR images. MATERIALS AND METHODS: From March 2017 to April 2018, nine patients suffering from HCC were treated with 166Ho-RE. To calculate mean doses on healthy liver/tumor tissue, MR was performed within the first day after treatment. For evaluation of hepatotoxicity and to rule out radioembolization-induced liver disease (REILD), the Model for End-Stage Liver Disease (MELD) Score, the Common Terminology Criteria for Adverse Events and specific laboratory parameters were used 1-day pre- and posttreatment and after 60 days. After 6 months, MR/CT follow-up was performed. RESULTS: In five patients the right liver lobe, in one patient the left liver lobe and in three patients both liver lobes were treated. Median administered activity was 3.7 GBq (range 1.7-5.9 GBq). Median dose on healthy liver tissue was 41 Gy (21-55 Gy) and on tumor tissue 112 Gy (61-172 Gy). Four patients suffered from mild postradioembolization syndrome. No significant differences in median MELD-Score were observed pre-, posttherapeutic and 60 days after 166Ho-RE. No deterioration of liver function and no indicators of REILD were observed. One patient showed a complete response, four a partial response, three a stable disease and one a progressive disease at the 6 months follow-up. CONCLUSION: 166Ho-RE seems to be a feasible and safe treatment option with no significant hepatotoxicity for treatment of HCC.