Glomerular filtration rate (GFR) can accurately be determined using 51 Cr-ethylenediaminetetraacetic acid (EDTA) plasma clearance counting but is time-consuming and requires technical skills and equipment not always available in imaging departments. 68 Ga-EDTA can be readily available using an onsite generator, and PET/CT enables both imaging of renal function and accurate camera-based quantitation of clearance of activity from blood and its appearance in the urine. This study aimed to assess agreement between 68 Ga-EDTA GFR ( 68 Ga-GFR) and 51 Cr-EDTA GFR ( 51 Cr-GFR), using serial plasma sampling and PET imaging. Methods: 68 Ga-EDTA and 51 Cr-EDTA were injected concurrently in 31 patients. Dynamic PET/CT encompassing the kidneys was acquired for 10 min followed by 3 sequential 3-min multibed step acquisitions from kidneys to bladder. PET quantification was performed using renal activity at 1-2 min (PET initial ), renal excretion at 2-10 min (PET early ), and, subsequently, urinary excretion into the collecting system and bladder (PET late ). Plasma sampling at 2, 3, and 4 h was performed, with 68 Ga followed by 51 Cr counting after positron decay. The level of agreement for GFR determination was calculated using a Bland-Altman plot and Pearson correlation coefficient (PCC). Results: 51 Cr-GFR ranged from 10 to 220 mL/min (mean, 85 mL/min). There was good agreement between 68 Ga-GFR and 51 Cr-GFR using serial plasma sampling, with a BlandAltman bias of −14 ± 20 mL/min and a PCC of 0.94 (95% confidence interval, 0.88-0.97). Of the 3 methods used for camera-based quantification, the strongest correlation was for plasma sampling-derived GFR with PET late (PCC of 0.90; 95% confidence interval,. Conclusion: 68 Ga-GFR agreed well with 51 Cr-GFR for estimation of GFR using serial plasma counting. PET dynamic imaging provides a method to estimate GFR without plasma sampling, with the additional advantage of enabling renal imaging in a single study. Additional validation in a larger cohort is warranted to further assess utility.

PurposeTo review the response and outcomes of 177Lu-DOTA-octreotate chemoradionuclide therapy (LuTate PRCRT) in patients with neuroendocrine tumour (NET) expressing high levels of somatostatin receptors with uncontrolled symptoms or disease progression.MethodsA total of 68 patients (39 men; 17 – 76 years of age) who had completed an induction course of at least three cycles of LuTate PRCRT between January 2006 and June 2010 were reviewed. Ten patients were treated for uncontrolled symptoms and 58 had disease progression despite conventional treatment. The majority had four induction LuTate cycles (median treatment duration 5 months and cumulative activity 31 GBq), and 63 patients had concomitant 5-FU radiosensitizing infusional chemotherapy. Factors predicting overall survival were assessed using the log-rank test and Cox proportional hazards regression.ResultsOf those treated for uncontrolled symptoms, 70 % received benefit maintained for at least 6 months after treatment. Among patients with progressive disease 68 % showed stabilization or regression on CT, 67 % on molecular imaging and 56 % biochemically up to 12 months after treatment; 32 patients died. Overall survival rates at 2 and 5 year were 72.1 % and 52.1 %, respectively. Median overall survival was not estimable at a median follow-up of 60 months (range 5 – 86 months). Nonpancreatic primary sites, dominant liver metastases, lesion size <5 cm and the use of 5-FU chemotherapy were statistically significantly associated with objective response. A disseminated pattern and a high disease burden (whole-body retention index) were associated with an increased risk of death. Objective biochemical, molecular imaging and CT responses were all associated with longer overall survival.ConclusionA high proportion of patients with progressive NET or uncontrolled symptoms received therapeutic benefit from LuTate with concomitant 5-FU chemotherapy. The achievement of objective biochemical, molecular or CT responses within 12 months was associated with improved overall survival. Patients with a primary pancreatic site and larger lesions (>5 cm) appeared to have lower objective response rates and may need a more aggressive treatment approach.Electronic supplementary materialThe online version of this article (doi:10.1007/s00259-014-2788-5) contains supplementary material, which is available to authorized users.

Carboplatin dosing using a pharmacological formula based on GFR produces accurate targeting of the carboplatin AUC. Tc99mDTPA clearance can be used to measure GFR instead of Cr51EDTA clearance, which is both more convenient and has potential cost savings. Estimates of renal function using the Cockcroft and Gault formula or measured 24 hour creatinine clearance are insufficiently accurate to use for carboplatin dosing.

HA-Oc+5FU achieve a high rate of symptomatic response associated with stabilization/improvement in hormonal and functional scan abnormalities. Combination treatment achieved disease stabilization in the majority of patients with previously progressive disease. There was no significant observed increase in toxicity with additional 5FU, making it a promising adjunct to radiopeptide receptor therapy for progressive NET.

Optimal management of paediatric thyroid carcinoma necessitates a multidisciplinary approach. Radioiodine therapy under rhTSH is an effective and safe adjuvant treatment in this special subgroup.