Optimization of image reconstruction method for SPECT studies performed using [99mTc-EDDA/HYNIC] octreotate in patients with neuroendocrine tumors

BACKGROUND: Somatostatin receptor scintigraphy (SRS)is a useful tool in the assessment of GEP-NET (gastroenteropancreaticneuroendocrine tumor) patients. The choiceof appropriate settings of image reconstruction parameters iscrucial in interpretation of these images. The aim of the studywas to investigate how the GEP NET lesion signal to noise ratio(TCS/TCB) depends on different reconstruction settings for Flash3D software (Siemens).METHODS: SRS results of 76 randomly selected patients withconfirmed GEP-NET were analyzed. For SPECT studies the datawere acquired using standard clinical settings 3–4 h after theinjection of 740 MBq 99mTc-[EDDA/HYNIC] octreotate. To obtainfinal images the OSEM 3D Flash reconstruction with differentsettings and FBP reconstruction were used. First, the TCS/TCBratio in voxels was analyzed for different combinations of thenumber of subsets and the number of iterations of the OSEM3D Flash reconstruction. Secondly, the same ratio was analyzed for different parameters of the Gaussian filter (with FWHM = 2–4times greater from the pixel size). Also the influence of scattercorrection on the TCS/TCB ratio was investigated.RESULTS: With increasing number of subsets and iterations, theincrease of TCS/TCB ratio was observed. With increasing settingsof Gauss [FWHM coefficient] filter, the decrease of TCS/TCB ratiowas reported. The use of scatter correction slightly decreasesthe values of this ratio.CONCLUSIONS: OSEM algorithm provides a meaningfullybetter reconstruction of the SRS SPECT study as compared tothe FBP technique. A high number of subsets improves imagequality (images are smoother). Increasing number of iterationsgives a better contrast and the shapes of lesions and organs aresharper. The choice of reconstruction parameters is a compromisebetween image qualitative appearance and its quantitativeaccuracy and should not be modified when comparing multiplestudies of the same patient

Biokinetics of ^{131}I after endogenous and exogenous stimulation of TSH in patients with DTC

BACKGROUND: The effective radioiodine treatment of patients with DTC is possible only after raising the TSH value over 30 μUI/ml. This effect might be obtained by either endogenous or exogenous stimulation. The aim of this study was to evaluate differences in 131I biokinetics of selected regions of interest (ROIs) in cases of endogenous and exogenous stimulation. MATERIAL AND METHODS: Two groups of 50 patients were enrolled in the study. All patients were treated with 3.7 GBq of 131I; the first group after thyroid hormone withdrawal (THW), the second group after rhTSH administration (rhTSH). On the basis of post-treatment images, the uptake ratios over selected ROIs (thyroid remnants, mediastinum, liver, stomach, abdomen, and whole-body) were compared between groups. RESULTS: In the case of uptake over the whole-body and the liver, statistically significant higher values were received for the THW group. For the remaining regions, the differences between groups were statistically insignificant, but uptake ratios in the rhTSH group were generally numerically lower compared to the THW group. CONCLUSIONS: The revealed difference in radioiodine biokinetics after thyroid hormone withdrawal or administration of recombinant human TSH may influence many important aspects of patients with DTC treatment, such as the choice of proper therapeutic scheme, the cost of therapy, and the dose assessment

Biokinetics of 131I after endogenous and exogenous stimulation of TSH in patients with DTC

BACKGROUND: The effective radioiodine treatment of patients with DTC is possible only after raising the TSH value over 30 μUI/ml. This effect might be obtained by either endogenous or exogenous stimulation. The aim of this study was to evaluate differences in 131I biokinetics of selected regions of interest (ROIs) in cases of endogenous and exogenous stimulation. MATERIAL AND METHODS: Two groups of 50 patients were enrolled in the study. All patients were treated with 3.7 GBq of 131I; the first group after thyroid hormone withdrawal (THW), the second group after rhTSH administration (rhTSH). On the basis of post-treatment images, the uptake ratios over selected ROIs (thyroid remnants, mediastinum, liver, stomach, abdomen, and whole-body) were compared between groups. RESULTS: In the case of uptake over the whole-body and the liver, statistically significant higher values were received for the THW group. For the remaining regions, the differences between groups were statistically insignificant, but uptake ratios in the rhTSH group were generally numerically lower compared to the THW group. CONCLUSIONS: The revealed difference in radioiodine biokinetics after thyroid hormone withdrawal or administration of recombinant human TSH may influence many important aspects of patients with DTC treatment, such as the choice of proper therapeutic scheme, the cost of therapy, and the dose assessment. Nuclear Med Rev 2010; 13, 2: 55–5

Yttrium-90 distribution following radiosynoviorthesis of the knee joint in rheumatoid arthritis patients : a SPECT/CT study

Objective To examine yttrium-90 distribution 1 and 72 h following its injection into a knee joint in patients with rheumatoid arthritis (RA). Methods In 14 RA patients we injected yttrium-90 into the affected knee joint using lateral approach. To assess the radioisotope distribution in the joint, the superimposed sequential SPECT and CT imaging was performed 1 and 72 h after the injection. We analyzed the percentage of radioisotope distribution in three predefined compartments of the knee joint (lower, upper medial, upper lateral). Results After 1 and 72 h, the mean percentage distributions were, respectively, 7.14 and 23.07 % in lower; 21.42 and 15.38 % in upper medial, and 71.42 and 61.53 % in upper lateral compartment. The percentage of isotope deposition did not change significantly with time in any of the compartments (all p > 0.26). The deposition of isotope, both at 1 and 72 h, was significantly greater in upper lateral compartment, where the injection was performed, than in all other compartments (all p < 0.05). Conclusions Using the SPECT/CT hybrid method, we proved that the majority of isotope is located at the compartment adjacent to the injection. Two injections targeting different compartments might improve the clinical efficacy of the procedure

Efficacy and safety of 90Y-DOTATATE therapy in neuroendocrine tumours

Wstęp: Celem pracy była ocena skuteczności oraz toksyczności celowanej terapii receptorowej (PRRT) guzów neuroendokrynnych z wykorzystaniem analogu somatostatyny Tyr3-octreotate znakowanego 90Y (90Y-DOTATATE). Materiał i metody: Do badania włączono 46 pacjentów z rozsianym lub nieoperacyjnym guzem NET. 90Y-DOTATATE podawano w 3&#8211;5 kursach w odstępach 4&#8211;9-tygodniowych. Każdorazowo wyznaczano aktywność terapeutyczną, uwzględniając taką całkowitą powierzchnię ciała, by nie przekroczyć sumarycznej wartości 7,4 GBq/m2. Przed terapią i po niej wykonano oznaczenia parametrów morfotycznych, nerkowych oraz wątrobowych, a także stężenia chromograniny A. Wyniki: Spośród 46 leczonych pacjentów jeden chory zmarł przed zakończeniem pełnego cyklu terapeutycznego, a 16 po zakończeniu terapii, w tym jeden z powodu zawału serca. W 12. miesiącu obserwacji stwierdzono 47% stabilizacji, 31% częściowych odpowiedzi oraz 9% progresji wśród 45 pacjentów, którzy ukończyli leczenie. Pięciu chorych zmarło przed 12. miesiącem obserwacji. W jednym przypadku utracono możliwość uzyskania informacji o chorym po 12 miesiącach. Okres czasu bez progresji choroby wyniósł 37,4 miesiąca. W ciągu pierwszego roku od zakończenia terapii zaobserwowano jedynie przejściowe obniżenie wartości morfotycznych krwi oraz przejściowy wzrost stężenia kreatyniny i spadek wartości przesączania kłębuszkowego (GFR). Wnioski: Celowana terapia receptorowa z użyciem 90Y-DOTATATE może być skuteczną oraz stosunkowo bezpieczną metodą leczenia prowadzącą do częściowej odpowiedzi lub stabilizacji choroby u większości pacjentów. (Endokrynol Pol 2011; 62 (5): 392&#8211;400)Background: The aim of this study was to assess the efficacy and toxicity of peptide receptor radionuclide therapy (PRRT) with the use of the high affinity somatostatin receptor subtype 2 analogue, 90Y labelled Tyr3-octreotate, (90Y-DOTATATE) in neuroendocrine tumours (NETs). Material and methods: 46 patients with disseminated or non-operable NET were enrolled in this study. The 90Y-DOTATATE therapeutic activity was calculated per total body surface area up to a total of 7.4 GBq/m2 administered in three to five cycles, repeated every four to nine weeks. Before and after the therapy, blood tests for haematology, kidney and liver function, and chromogranin A were performed. Results: Out of 46 90Y-DOTATATE treated patients, one died before completing the therapy and 16 died after completing the therapy, among them one due to myocardial infarction. After 12 month follow-up, stabilisation of disease was observed in 47%, partial remission in 31%, and progression in 9% of the 45 patients who completed the therapy. Five patients died before completion of 12 months of follow-up. One of the patients died due to myocardial infarction. In one case, the information after 12 months is incomplete. The progression free survival was 37.4 months. During 12 months follow-up, transient decrease of PLT, WBC and haemoglobin values was observed. A transient increase of creatinine level (within normal ranges) and decrease of GFR values were found. Conclusions: NETs 90Y-DOTATATE therapy results in symptomatic relief and tumour mass reduction. The mild critical organ toxicity does not limit the PRRT of NETs. (Pol J Endocrinol 2011; 62 (5): 392&#8211;400

Glucagon-like peptide-1 receptor imaging with [Lys^{40}(Ahx-HYNIC-^{99m}Tc/EDDA)NH_2]-Exendin-4 for the diagnosis of recurrence or dissemination of medullary thyroid cancer : a preliminary report

Introduction. Epidemiological studies on medullary thyroid cancer (MTC) have shown that neither a change in stage at diagnosis nor improvement in survival has occurred during the past 30 years. In patients with detectable serum calcitonin and no clinically apparent disease, a careful search for local recurrence, and nodal or distant metastases, should be performed. Conventional imaging modalities will not show any disease until basal serum calcitonin is at least 150 pg/mL. The objective of the study was to present the first experience with labelled glucagon-like peptide-1 (GLP-1) analogue [Lys40(Ahx-HYNIC-99mTc/EDDA)NH2]-exendin-4 in the visualisation of MTC in humans. Material and Method. Four patients aged 22–74 years (two with sporadic and two with MEN2 syndrome-related disseminated MTC) were enrolled in the study. In all patients, GLP-1 receptor imaging was performed. Results. High-quality images were obtained in all patients. All previously known MTC lesions have been confirmed in GLP-1 scintigraphy. Moreover, one additional liver lesion was detected in sporadic MTC male patient. Conclusions. GLP-1 receptor imaging with [Lys40(Ahx-HYNIC-99mTc/EDDA)NH2]-exendin-4 is able to detect MTC lesions. GLP-1 scintigraphy can serve as a confirmatory test in MTC patients, in whom other imaging procedures are inconsistent

^{99m}Tc labeled glucagon-like peptide-1-analogue (^{99m}Tc-GLP1) scintigraphy in the management of patients with occult insulinoma

INTRODUCTION: The aim of this study was to assess the utility of [Lys(40)(Ahx-HYNIC-(99m)Tc/EDDA)NH(2)]-exendin-4 scintigraphy in the management of patients with hypoglycemia, particularly in the detection of occult insulinoma. MATERIALS AND METHODS: Forty patients with hypoglycemia and increased/confusing results of serum insulin and C-peptide concentration and negative/inconclusive results of other imaging examinations were enrolled in the study. In all patients GLP-1 receptor imaging was performed to localise potential pancreatic lesions. RESULTS: Positive results of GLP-1 scintigraphy were observed in 28 patients. In 18 patients postsurgical histopathological examination confirmed diagnosis of insulinoma. Two patients had contraindications to the surgery, one patient did not want to be operated. One patient, who presented with postprandial hypoglycemia, with positive result of GLP-1 imaging was not qualified for surgery and is in the observational group. Eight patients were lost for follow up, among them 6 patients with positive GLP-1 scintigraphy result. One patient with negative scintigraphy was diagnosed with malignant insulinoma. In two patients with negative scintigraphy Munchausen syndrome was diagnosed (patients were taking insulin). Other seven patients with negative results of (99m)TcGLP-1 scintigraphy and postprandial hypoglycemia with C-peptide and insulin levels within the limits of normal ranges are in the observational group. We would like to mention that (99m)Tc-GLP1-SPECT/CT was also performed in 3 pts with nesidioblastosis (revealing diffuse tracer uptake in two and a focal lesion in one case) and in two patients with malignant insulinoma (with the a focal uptake in the localization of a removed pancreatic headin one case and negative GLP-1 1 scintigraphy in the other patient). CONCLUSIONS: (99m)Tc-GLP1-SPECT/CT could be helpful examination in the management of patients with hypoglycemia enabling proper localization of the pancreatic lesion and effective surgical treatment. This imaging technique may eliminate the need to perform invasive procedures in case of occult insulinoma

Glucagon-like peptide-1 receptor imaging with [Lys^{40}(Ahx-HYNIC-^{99m}Tc/EDDA)NH_2]-exendin-4 for the detection of insulinoma

PURPOSE: The objective of this article is to present a new method for the diagnosis of insulinoma with the use of [Lys(40)(Ahx-HYNIC-(99m)Tc/EDDA)NH(2)]-exendin-4. METHODS: Studies were performed in 11 patients with negative results of all available non-isotopic diagnostic methods (8 with symptoms of insulinoma, 2 with malignant insulinoma and 1 with nesidioblastosis). In all patients glucagon-like peptide-1 (GLP-1) receptor imaging (whole-body and single photon emission computed tomography/CT examinations) after the injection of 740 MBq of the tracer was performed. RESULTS: Both sensitivity and specificity of GLP-1 receptor imaging were assessed to be 100 % in patients with benign insulinoma. In all eight cases with suspicion of insulinoma a focal uptake in the pancreas was found. In six patients surgical excision of the tumour was performed (type G1 tumours were confirmed histopathologically). In one patient surgical treatment is planned. One patient was disqualified from surgery. In one case with malignant insulinoma pathological accumulation of the tracer was found only in the region of local recurrence. The GLP-1 study was negative in the other malignant insulinoma patient. In one case with suspicion of nesidioblastosis, a focal accumulation of the tracer was observed and histopathology revealed coexistence of insulinoma and nesidioblastosis. CONCLUSION: [Lys(40)(Ahx-HYNIC-(99m)Tc/EDDA)NH(2)]-exendin-4 seems to be a promising diagnostic tool in the localization of small insulinoma tumours, but requires verification in a larger series of patients