Traceable calibration with Lu and comparison of activity meters at hospitals in Norway and Sweden.

Introduction: The activity meter is used to determine the activity of delivered radiopharmaceuticals, administered activity to patients and reference activity when gamma-cameras are calibrated prior to imaged-based dosimetry. The aim is to describe a procedure for cross-calibration of activity meters at different clinical sites, and report on Lu activity results when using factory-set calibration factors compared to when calibration is performed with traceability to a primary standard.

Methods: Thirty activity meters placed at seven hospitals in Norway and Sweden from four manufacturers: Capintec, Commecer, NuviaTech and Veenstra were included.

THE POTENTIAL TO USE TLD MEASUREMENTS TO VALIDATE THE OCCUPATIONAL RADIATION PROTECTION AT THE DEPARTMENT OF NUCLEAR MEDICINE.

Diagnostic examinations in nuclear medicine increase. This can cause a higher radiation burden to the personnel. The aim of this study was to create and apply a method to validate the occupational radiation protection at the Department of Nuclear Medicine using thermoluminescence dosemeters (TLD).

Transcriptional effects of Lu-octreotate therapy using a priming treatment schedule on GOT1 tumor in nude mice.

Background: Lu-octreotate is used for therapy of somatostatin receptor expressing neuroendocrine tumors with promising results, although complete tumor remission is rarely seen. Previous studies on nude mice bearing the human small intestine neuroendocrine tumor, GOT1, have shown that a priming injection of Lu-octreotate 24 h before the main injection of Lu-octreotate resulted in higher Lu concentration in tumor, resulting in increased absorbed dose, volume reduction, and time to regrowth. To our knowledge, the cellular effects of a priming treatment schedule have not yet been studied.

Time-dependent transcriptional response of GOT1 human small intestine neuroendocrine tumor after Lu[Lu]-octreotate therapy.

Introduction: Patients with neuroendocrine tumors expressing somatostatin receptors are often treated with Lu[Lu]-octreotate. Despite being highly effective in animal models, Lu[Lu]-octreotate-based therapies in the clinical setting can be optimized further. The aims of the study were to identify and elucidate possible optimization venues for Lu[Lu]-octreotate tumor therapy by characterizing transcriptional responses in the GOT1 small intestine neuroendocrine tumor model in nude mice.

Priming increases the anti-tumor effect and therapeutic window of Lu-octreotate in nude mice bearing human small intestine neuroendocrine tumor GOT1.

Background: Lu-[DOTA, Tyr]-octreotate (Lu-octreotate) is used for treatment of patients with somatostatin receptor (SSTR) expressing neuroendocrine tumors. However, complete tumor remission is rarely seen, and optimization of treatment protocols is needed. In vitro studies have shown that irradiation can up-regulate the expression of SSTR1, 2 and 5, and increase Lu-octreotate uptake.

Evaluation of retinol binding protein 4 and carbamoylated haemoglobin as potential renal toxicity biomarkers in adult mice treated with (177)Lu-octreotate.

Background: The kidneys are regarded as one of the main dose-limiting organs in the treatment of neuroendocrine tumours with (177)Lu-[DOTA(0), Tyr(3)]-octreotate ((177)Lu-octreotate), despite the successful use of kidney uptake blocking agents such as lysine and arginine. To avoid renal toxicity but still give each patient as high amount of (177)Lu-octreotate as possible, there is a need for methods/biomarkers that indicate renal injury in an early stage of the treatment. The aim of this study was to investigate the potential of using urinary retinol binding protein 4 (RBP4) and carbamoylated haemoglobin (Hb) in blood as biomarkers of nephrotoxic effects on adult mice after (177)Lu-octreotate treatment.

Gastrointestinal stromal tumors (GISTs) express somatostatin receptors and bind radiolabeled somatostatin analogs.

Background: Gastrointestinal stromal tumors (GISTs) can be effectively treated with tyrosine kinase inhibitors (TKIs). However, some patients with GIST develop drug resistance, and alternative treatment strategies are therefore needed. The aim of this study was to analyze the expression of somatostatin receptors (SSTR) in GIST as a target for peptide receptor-mediated radiotherapy (PRRT).

Biodistribution of 177Lu-octreotate and 111In-minigastrin in female nude mice transplanted with human medullary thyroid carcinoma GOT2.

To be able to evaluate new radiopharmaceuticals and optimize diagnostic and therapeutic procedures, relevant animal models are required. The aim of this study was to evaluate the medullary thyroid carcinoma GOT2 animal model by analyzing the biodistribution of 177Lu-octreotate and 111In-minigastrin (MG0). BALB/c nude mice, subcutaneously transplanted with GOT2, were intravenously injected with either 177Lu-octreotate or 111In-MG0, with or without excess of unlabeled human minigastrin simultaneously with 111In-MG0.