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

New forms of radionuclide therapy with ^{90}Y in oncology

BACKGROUND: Currently, there is growing interest in the use of the beta emitter 90Y in systemic therapy in oncology. For successful therapy, an appropriate ligand is chosen to carry the isotope to the place of its action. As well as performing this function, the type of the ligand influences both the course and the side effects of the treatment. For RIT of lymphomas, bone marrow becomes the critical organ; in NET patients treated with labelled somatostatin analogues, increased kidney irradiation can occur. The aim of this study was to evaluate the side effects of therapy using 90Y associated with different ligands, depending on the charge to critical organs after treatment in two groups of patients: those with neuroendocrine tumours and those with non-Hodgkin's lymphomas. MATERIAL AND METHODS: 32 patients with histopathologically confirmed NET treated with 90Y-DOTATATE (7.4 GBq/m2 cumulative dose) and 30 NHL patients treated with 90Y-ibritumomab tiuxetan (1200 MBq max dose) were enrolled in the study. The kidney function and changes of blood indices were assessed during the course of the therapy. RESULTS: 59% of NET patients treated with 90Y-DOTATATE displayed transient reduction of blood indices, the largest after cycles III and IV of therapy. After 5 months an increase in creatinine level was noticed, but no statistically important changes in creatinine level and GFR were observed. In the group of patients with NHL, the change of haematological indices after RIT concerned mainly PLT, ANC and WBC. The reduction of the average PLT and WBC values started in the first weeks after the treatment application, reaching nadir in the 6th week and 8th week, respectively. No life threatening infections were observed in either group of patients. CONCLUSIONS: After treatment with the use of the 90Y radionuclide, no significant treatment toxicity, including disorders involving the critical organs for both types of therapies, was found in the groups of neuroendocrine tumour and non-Hodgkin's lymphoma patients

^{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

Przydatność fuzji SPECT/TK w weryfikacji zmian wykrytych w scyntygrafii receptorów somatostatynowych oraz w ocenie skuteczności terapii u pacjentów z guzami neuroendokrynnymi przewodu pokarmowego

Background: Somatostatin receptor scintigraphy (SRS) is one of the most important studies in the diagnostics of patients with gastroenteropancreatic neuroendocrine tumors (GEP NET), but Single Photon Emission Computed Tomography (SPECT) study does not provide sufficient information about location of lesions. Computed Tomography (CT) combined with SPECT may solve this problem by adding morphological information to functional data. The aim of the study was to determine the usefulness of SPECT/CT fusion on GEP NET diagnostics and therapy. Material/Methods: 77 patients with GEP NET were analyzed using SPECT/CT software fusion: • in 12 patients the anatomical location of primary tumor was assessed; • in 14 patients clinically suspicious for NET, the presence of lesions was verified in CT, causing an increased accumulation of tracer found in SRS; • in 41 patients with proved NET, an increased local accumulation of the tracer, seen in SRS, was verified;• in 10 patients, the response to somatostatin analogue therapy was verified. SPECT was performed 3-4 h after injection of 740MBq 99mTc-EDDA/HYNIC-octreotate. CT was performed using multidetector CT scanner and standard protocols. SPECT/CT fusion was performed on SyngoMI (Siemens) workstation. Results: In the first subgroup of 12 patients, the primary tumor was localized in 11 cases (91.7%); • in the second subgroup of 14 patients, NET was confirmed in CT in 10 cases (71.4%), and not confirmed (a false positive scintigraphy) in 4 cases (28.6%), affecting therapy; • in the third subgroup of 41 patients, pathological accumulation of the tracer was confirmed in 10 cases (24.4%), in 23 (56.1%) the local accumulation of tracer was evaluated in fusion as the false positive scintigraphy (retention of tracer in intestines), and in 8 (19,5%) was verified as accumulation in normal adrenal glands; • in the fourth subgroup of 10 patients in all cases SPECT/CT fusion confirmed response to therapy, with SRS and CT compliance. Conclusions: SPECT/CT fusion, by combining assessment of morphological and functional imaging, may be a useful tool both in the initial diagnostics of GEP NET improving specificity of lesions detected by SRS alone and in the monitoring of therapy effects

Hyperinsulinemic hypoglycemia in three generations of a family with glucokinase activating mutation, c.295T>C (p.Trp99Arg)

Familial Hyperinsulinemic Hypoglycemia (FHH) is a very rare disease with heterogeneous clinical manifestations. There are only a few reports of heterozygous activating mutations of glucokinase (GCK) attributable to FHH, with no reports describing effects in the course in pregnancy with affected mother/affected child. A large kindred with FHH and GCK:c.295T>C (p.Trp99Arg) pathogenic variant was identified in which four family members from three generations were affected. The clinical follow up in one clinical center lasted up to 30 years, with different times of diagnosis ranging from neonate period to adulthood. The severity of hypoglycemia was mild/severe and fasting was the trigger for hypoglycemia. Response to diazoxide varied from good, in the neonate, to moderate/poor, in childhood/adulthood; however, this was biased by poor compliance. Treatment with somatostatin analogues was discontinued due to side effects. Over time, patients developed clinical adaptation to very low glucose levels. During pregnancy, episodes of severe hypoglycemia in the first trimester were observed, which responded very well to steroids. The clinical course of the GCK:c.295T>C (p.Trp99Arg) mutation varied in the same family, with the development of clinical adaptation to very low glucose levels over time. Treatment with steroids might prevent hypoglycemia during pregnancy in an affected mother