[18F]mFBG PET-CT for detection and localisation of neuroblastoma: a prospective pilot study

Purpose Meta-[F-18]fluorobenzylguanidine ([F-18]mFBG) is a positron emission tomography (PET) radiotracer that allows for fast and high-resolution imaging of tumours expressing the norepinephrine transporter. This pilot study investigates the feasibility of [F-18]mFBG PET-CT for imaging in neuroblastoma. Methods In a prospective, single-centre study, we recruited children with neuroblastoma, referred for meta-[I-123]iodobenzylguanidine ([I-123]mIBG) scanning, consisting of total body planar scintigraphy in combination with single-photon emission computed tomography-CT (SPECT-CT). Within two weeks of [I-123]mIBG scanning, total body PET-CTs were performed at 1 h and 2 h after injection of [F-18]mFBG (2 MBq/kg). Detected tumour localisations on scan pairs were compared. Soft tissue disease was quantified by number of lesions and skeletal disease by SIOPEN score. Results Twenty paired [I-123]mIBG and [F-18]mFBG scans were performed in 14 patients (median age 4.9 years, n = 13 stage 4 disease and n = 1 stage 4S). [F-18]mFBG injection was well tolerated and no related adverse events occurred in any of the patients. Mean scan time for [F-18]mFBG PET-CT (9.0 min, SD 1.9) was significantly shorter than for [I-123]mIBG scanning (84.5 min, SD 10.5), p < 0.01. Most tumour localisations were detected on the 1 h versus 2 h post-injection [F-18]mFBG PET-CT. Compared to [I-123]mIBG scanning, [F-18]mFBG PET-CT detected a higher, equal, and lower number of soft tissue lesions in 40%, 55%, and 5% of scan pairs, respectively, and a higher, equal, and lower SIOPEN score in 55%, 30%, and 15% of scan pairs, respectively. On average, two more soft tissue lesions and a 6-point higher SIOPEN score were detected per patient on [F-18]mFBG PET-CT compared to [I-123]mIBG scanning. Conclusion Results of this study demonstrate feasibility of [F-18]mFBG PET-CT for neuroblastoma imaging. More neuroblastoma localisations were detected on [F-18]mFBG PET-CT compared to [I-123]mIBG scanning. [F-18]mFBG PET-CT shows promise for future staging and response assessment in neuroblastoma.Analysis and Stochastic

The Efficacy of Coil Embolization to Obtain Intrahepatic Redistribution in Radioembolization: Qualitative and Quantitative Analyses

Purpose: To evaluate the efficacy of coil embolization to obtain intrahepatic redistribution in patients undergoing radioembolization. Materials and Method: All patients treated with radioembolization at our institute were retrospectively analyzed, and all cases in which a tumor-feeding vessel was coil-embolized were selected. Two nuclear medicine physicians visually assessed the effect of redistribution. Furthermore, the redistribution of microspheres was measured by quantifying the activity distributed to the coil-embolized (dependent) segment relative to the other (non-dependent) segments and to the tumor(s) in that segment. Quantitative analysis was performed on post-treatment 90Y-PET and 166Ho-SPECT using Simplicit90Y software. Lesion response was measured according to RECIST 1.1 criteria at 3 months post-treatment. Results: Out of 37 cases, 32 were suitable for quantitative analysis and 37 for qualitative analysis. In the qualitative analysis, redistribution was deemed successful in 69% of cases. The quantitative analysis showed that the median ratio of the activity to the dependent embolized segments and the non-dependent segments was 0.88 (range 0.26–2.05) and 0.80 (range 0.19–1.62) for tumors in dependent segments compared with tumors in non-dependent segments. Using a cutoff ratio of 0.7 (30% lower activity concentration in comparison with the rest of the liver), 57% of cases were successful. At 3 months post-treatment, 6% of dependent tumors had partial response, 20% progressive disease, and 74% stable disease. In non-dependent tumors, this was, respectively, 16%, 20%, and 64%. Conclusion: Coil embolization of hepatic arteries to induce redistribution of microspheres has a limited success rate. Qualitative assessment tends to overrate redistribution

Personalised radioembolization improves outcomes in refractory intra-hepatic cholangiocarcinoma: a multicenter study

Purpose: Reported outcomes of patients with intra-hepatic cholangiocarcinoma (IH-CCA) treated with radioembolization are highly variable, which indicates differences in included patients’ characteristics and/or procedure-related variables. This study aimed to identify patient- and treatment-related variables predictive for radioembolization outcome. Methods: This retrospective multicenter study enrolled 58 patients with unresectable and chemorefractory IH-CCA treated with resin 90Y-microspheres. Clinicopathologic data were collected from patient records. Metabolic parameters of liver tumor(s) and presence of lymph node metastasis were measured on baseline 18F-FDG-PET/CT. 99mTc-MAA tumor to liver uptake ratio (TLRMAA) was computed for each lesion on the SPECT-CT. Activity prescription using body-surface-area (BSA) or more personalized partition-model was recorded. The study endpoint was overall survival (OS) starting from date of radioembolization. Statistical analysis was performed by the log-rank test and multivariate Cox’s proportional hazards model. Results: Median OS (mOS) post-radioembolization of the entire cohort was 10.3 months. Variables associated with significant differences in terms of OS were serum albumin (hazard ratio (HR) = 2.78, 95%CI:1.29–5.98, p = 0.002), total bilirubin (HR = 2.17, 95%CI:1.14–4.12, p = 0.009), aspartate aminotransferase (HR = 2.96, 95%CI:1.50–5.84, p < 0.001), alanine aminotransferase (HR = 2.02, 95%CI:1.05–3.90, p = 0.01) and γ-GT (HR = 2.61, 95%CI:1.31–5.22, p < 0.001). The presence of lymph node metastasis as well as a TLRMAA < 1.9 were associated with shorter mOS: HR = 2.35, 95%CI:1.08–5.11, p = 0.008 and HR = 2.92, 95%CI:1.01–8.44, p = 0.009, respectively. Finally, mOS was significantly shorter in patients treated according to the BSA method compared to the partition-model: mOS of 5.5 vs 14.9 months (HR = 2.52, 95%CI:1.23–5.16, p < 0.001). Multivariate analysis indicated that the only variable that increased outcome prediction above the clinical variables was the activity prescription method with HR of 2.26 (95%CI:1.09–4.70, p = 0.03). The average mean radiation dose to tumors was significantly higher with the partition-model (86Gy) versus BSA (38Gy). Conclusion: Radioembolization efficacy in patients with unresectable recurrent and/or chemorefractory IH-CCA strongly depends on the tumor radiation dose. Personalized activity prescription should be performed.SCOPUS: ar.jinfo:eu-repo/semantics/publishe