Estimated collective effective dose to the population from nuclear medicine diagnostic procedures in Croatia: A comparison of 2010 and 2015.

OBJECTIVE: This study presents national surveys of patient exposure from nuclear medicine (NM) diagnostic procedures in 2010 and 2015 in the Republic of Croatia. METHODS: The survey was performed according to the European Commission Dose DataMed (DDM) project methodology. 28 most frequent NM diagnostic procedures were identified. Data about frequencies of procedures and average administered activities of radioisotopes used in those procedures were collected. Average administered activities were converted to effective doses according to the dose conversion coefficients. Then the collective effective dose to the population and an effective dose per capita were calculated based on the number of the most frequent NM diagnostic procedures and the average effective dose per procedure. RESULTS: In 2010, 41200 NM diagnostic procedures led to 146.7 manSv collective effective dose to the population and in 2015, 42000 NM diagnostic procedures led to 146.8 manSv collective effective dose to the population. The frequencies of NM diagnostic procedures were 9.7 and 9.8 annually per 1000 population with 34.1 µSv and 34.2 µSv effective dose per capita for 2010 and 2015, respectively. The main contributors to the annual collective dose from NM in Croatia are examinations of the bone, heart, thyroid and PET/CT tumour diagnostic. Average administered activities have not changed considerably from 2010 to 2015. Nevertheless, within the frequency of some of the procedures, significant changes were found in five-year period. CONCLUSIONS: Frequencies, average administered activities and collective effective dose to the population from NM diagnostic procedures in Croatia are comparable to the values reported by other European surveys. Changes were found between 2010 and 2015 and we intend to perform this study periodically to identify possible trends, but also to raise awareness about the potential dose optimization.

Incremental value of 99mTc-HYNIC-TOC SPECT/CT over whole-body planar scintigraphy and SPECT in patients with neuroendocrine tumours.

AIM: The aim of this study was to evaluate the additional value of 99mTc-HYNIC-TOC SPECT/CT over planar whole-body (WB) scintigraphy and SPECT alone in the detection and accurate localisation of neuroendocrine tumour (NET) lesions. METHODS: This study included 65 patients with a definitive histological diagnosis of NET prior to scintigraphy. Planar WB scintigraphy, SPECT, and SPECT/CT images were acquired at 4 h post-administration of 670 MBq 99mTc-HYNIC-TOC. Additional SPECT images at 10 min after tracer administration were also acquired. Clinical and imaging follow-up findings were considered as the reference standards (minimum follow-up period, 15 months). Patient and lesion-based analyses of the efficacies of the imaging modalities were performed. RESULTS: While 38 patients exhibited metastasis of NETs, 27 presented no evidence of metastasis. Upon patient-based analysis, the sensitivity and specificity of SPECT/CT were found to be 88.9 and 79.3 %, respectively. The diagnostic accuracies of WB scintigraphy, 4h-SPECT, and SPECT/CT were 72.3, 73.8, and 84.6 %, respectively. The area under curve (AUC) value for SPECT/CT (0.84) was the highest, followed by those for 4h-SPECT (0.75) and WB scintigraphy (0.74). The accuracy and AUC values of SPECT/CT were significantly better compared to those of WB scintigraphy (p < 0.001), 10 min-SPECT (p < 0.001), and 4 h-SPECT (p = 0.001). The findings of SPECT/CT led to the change in treatment plan of 11 patients (16.9 %). CONCLUSION: The sensitivity and diagnostic accuracy of SPECT/CT in the evaluation of NET lesions outperforms planar WB imaging or SPECT alone.

99mTc-EDDA/HYNIC-TOC in management of patients with head and neck somatostatin receptor positive tumors.

BACKGROUND: Aim of this study was to determine the value of technetium-99m-hydrazinonicotinyl-Tyr3-octreotide (99mTc-ED-DA/HYNIC-TOC) in patients with somatostatin receptor (SSR) positive tumors of head and neck region. MATERIAL AND METHODS: A total number of 16 patients were enrolled in this study. Planar whole body (WB) and single photon emission computed tomography (SPECT) images were acquired at 2 and 4 hours after the injection of approximately 670 MBq of 99mTc-EDDA/HYNIC-TOC. Additional single photon emission computed tomography/computed tomography (SPECT/CT) images of the head and neck region were acquired at 4h post tracer injection. Clinical and imaging follow up were taken as the reference standard. RESULTS: There were 10 female and 6 male patients of age 57.7 ± 12.9 years (58.5; 32-78) years. 99mTc-EDDA/HYNIC-TOC somatostatin receptor scintigraphy (SRS) was TP in 13 patients, TN in two and FP in one. Follow up period for SRS was 31.1 ± 19.4 (29; 2-63) months. 99mTc-EDDA/HYNIC-TOC scintigraphy provided additional information in 50% of patients, with impact on patient management in the same percentage of patients. Distant metastases were found in nine out of 16 patients (56%). 99mTc-EDDA/HYNIC-TOC SRS had sensitivity of 100% (75.3-100%), specificity of 66.7% (9.4-99.2%), accuracy of 93.7%, positive predictive value of 92.9% (66.1-99.8%), and negative predictive value of 100% (15.8-100%). CONCLUSION: Somatostatin receptor scintigraphy using 99mTc-EDDA/HYNIC-TOC is very useful imaging method in the evalu-ation of patients with SSR positive tumors of head and neck region.

How to treat an extensive form of primary intestinal lymphangiectasia?

We report a case of a 42-year-old man with a rare disorder known as primary intestinal lymphangiectasia, which is characterized by dilated intestinal lymphatics that lead to the development of protein-losing enteropathy. The patient presented with a grand mal seizure caused by malabsorption-derived electrolytes and a protein disorder. Signs of the disease, including chronic diarrhea and peripheral edema, manifested 10 years ago, but a diagnosis was never made. The diagnosis was suspected because of the clinical manifestations, laboratory tests, imaging and endoscopic findings. Hyperemic and edematous mucosa of the small intestine corresponded to scattered white spots with dilated intestinal lymphatics and whitish villi in the histological specimen of the biopsied jejunal mucosa. Although numerous therapeutic strategies are available, only octreotide therapy proved to be an effective means of therapeutic resolution in this patient. Although the patient had a partial remission following the use of a slow release formula of octreotide, his prognosis, clinical course, and future treatment challenges are yet to be determined.

[Consensus guidelines for diagnosis, treatment and follow-up of patients with pancreatic neuroendocrine tumors]. / Postupnik za dijagnostiku, lijecenje i pracenje oboljelih od neuroendokrinih tumora gusterace.

Pancreatic neuroendocrine tumors (PETs) are increasingly recognized. In order to assure an optimal treatment of patients and to propose an efficient diagnostic algorithm we were prompted to organize meetings, with participating experts, specialists in different fields of expertise. The idea for the meetings was to try to give a standardized approach, which would in future help in stratification of PET patients. Results of meetings are given in a form of Consensus guidelines for diagnosis, treatment and follow-up of patients with pancreatic neuroendocrine tumors.

Concurrent radiotherapy and tumor targeting with 111In-HMFG1-F(ab')2 in patients with MUC1-positive non-small cell lung cancer.

BACKGROUND: Combining external radiotherapy (XRT) and radioimmunotargeting might enhance tumor radiation without affecting morbidity, due to different toxicity profiles. AIM: To assess 111In-F(ab')2-HMFG1 biodistribution, the influence of "low-dose" lysine on F(ab')2 renal uptake and provide data forfurther concurrent XRT and RIT. PATIENTS AND METHODS: Twenty-three patients received injections of 111n-HMFG1-F(ab')2, with or without lysine co-infusion, 7 and 21 days after the initiation of XRT. Whole-body images, blood and urine activity were monitored. RESULTS: Despite clear visualization of 111In-F(ab')2-HMFG1, the residence time and absorbed dose in tumors were low. The co-infusion of "low-dose" lysine did not reduce renal uptake, thus contradicting previously published results. The biodistribution differences after the first and the second injection might be attributed to human anti-mouse antibody (HAMA) response or Ag-complexation. CONCLUSION: Low-dose lysine is not feasible. Larger amounts of lysine during extended infusion time are therefore advocated. It is proposed that repeated MAb injection be given during the first fractions of XRT.