Combination of liquid scintillation counting and passive sampling strategy for the determination of ¹³¹I in air and application to estimate the inhalation dose to the staff of a nuclear medicine service.

(131)I, commonly used in nuclear medicine, can be incorporated into the human body in a variety of chemical and physical forms. This study describes a sensitive method for the determination of (131)I concentration and its application to the estimation of the amount of airborne (131)I inhaled by staff workers of a Nuclear Medicine Department. Our method uses passive sampling with charcoal canisters followed by liquid scintillation counting, a very sensitive technique for the determination of low concentrations of airborne (131)I. We have studied the effects caused on the measured (131)I concentration in air by both, the doses administered to the patients and the distance of sampling canisters to the patient. We have found a direct relationship between the amount of (131)I activity administered and the airborne (131)I activity concentration. We have estimated the contribution of inhaled (131)I to the effective dose received by staff, finding differences between physicians and non-physician personnel. However, the measured exposure was quite low in both cases, thus suggesting that there is no need to introduce additional safety measures to the current ones.

Usefulness of the FDG PET/CT in the management of cystic echinococcosis: A pilot study.

OBJECTIVES: Cystic echinococcosis is a zoonotic disease caused by the cestode Echinococcus granulosus. The activity of the cysts is assessed through the WHO-IWGE standardized classification based on ultrasound features. However, viability of the cysts is not always concordant with the activity assessed by ultrasound. The aim of the present study is to describe the metabolic activity of cysts in patients with cystic echinococcosis through FDG-PET. METHODS: Prospective observational study where adult patients diagnosed of cystic echinococcosis were offered to undergo FDG PET/CT before treatment onset. Demographic, clinical, radiological, and histopathological information was collected from all patients. RESULTS: Sixteen patients were included, 50% were male, and age ranged from 18 to 85 years. Most of the patients had liver involvement, and all patients had CE3, CE4 or CE5 stage of the WHO-IWGE classification. Only one patient (CE5) had an increased 18F-FDG uptake of the cyst in the FDG PET/CT. From the 5 patients who underwent surgical treatment, only one showed signs of viability of the cyst: a patient with CE5 with no increased 18F-FDG uptake of the cyst. CONCLUSION: In our pilot study, we did not find the correlation between the FDG PET/CT imaging and the cystic echinococcosis cyst bioactivity.

18F-FDG PET/CT in ovarian cancer recurrence: Clinical impact, correlation with ceCT and CA-125, and prognostic value.

AIM: To evaluate 18F-FDG-PET/CT for suspected ovarian cancer relapse with negative/inconclusive conventional imaging, or restaging potentially resectable ovarian cancer relapse. MATERIAL AND METHODS: Thirty-six cases and 140 locations were studied. PET/CT, ceCT and serum CA-125 was conducted in all cases. Nineteen cases were requested for restaging, 17 for suspected relapse. We compared ceCT and PET/CT, assessed by histopathology or radiological follow-up, calculating sensitivity (S) and positive predictive value (PPV) by cases and lesions. We evaluated the correlation between size, number, uptake of the lesions and CA-125. We conducted survival analysis, using ROC curves to calculate the optimal cut-off of SUVmax for survival prediction. We checked whether PET/CT modify the therapeutic attitude vs. conventional imaging. RESULTS: PET/CT and ceCT were concordant in 12 cases: 11 positives (30 lesions), all confirmed. There was 1 FN. In the 24 non-concordant, PET/CT was positive in 19 (97 lesions); ceCT in 21 (59 lesions); 54% of the lesions were concordant. Overall, PET/CT detected 127 lesions, with S=97% and PPV=100%. ceCT detected 89 lesions, with S=61% and PPV=90%. No significant correlation was found between CA-125 and the other parameters. PET/CT detected 10 positive cases, with normal CA-125. PET/CT modified therapeutic management in 15 cases. Significant differences were found in survival with SUVmax=11.8 CONCLUSIONS: PET/CT plays an important role in ovarian cancer relapse, with sensitivity and PPV higher than ceCT, modified therapeutic management in up to 42% of cases, and could be a valuable tool for predicting survival.

Radioguided surgery of primary hyperparathyroidism in a population with a high prevalence of thyroid pathology.

PURPOSE: Patients with concomitant thyroid pathology are usually excluded from minimally invasive radioguided parathyroidectomy (MIRP). We assessed the value in these patients of the gamma probe, alone or in combination with other techniques, in MIRP and unilateral or bilateral approaches. We evaluated its performance in association with intraoperative determination of intact parathyroid hormone (ioPTHi) and preoperative (99m)Tc-MIBI dual phase scintigraphy. METHODS: Included in the study were 87 patients with a diagnosis of primary hyperparathyroidism who underwent radioguided surgery. They were divided into two groups depending on the presence of concomitant thyroid pathology (TP group, 33 patients) or absence of concomitant thyroid pathology (NTP group, 54 patients). RESULTS: In the TP group, ioPTHi achieved the highest accuracy (90.9%), followed by the gamma probe (81.8%) and scintigraphy (69.7%). In the NTP group, the probe (94.4%) performed better than ioPTH and scintigraphy (both 85.2%). In the TP group, scintigraphy in combination with the gamma probe had a success rate of 90.9%, and 94% in combination with ioPTHi. The three techniques are applied together had a success rate of 97%. For all patients undergoing MIRP, the probe alone worked well, irrespective of the presence or absence of concomitant thyroid pathology. CONCLUSION: Patients with concomitant thyroid pathology should not be a priori excluded from a MIRP, as long as other adjuvant techniques (scintigraphy or ioPTHi) are used in conjunction with the gamma probe. In these patients, the probe can also be helpful in unilateral or bilateral surgery.

18F-FDG PET/CT of Lung Adenocarcinoma With Ovarian Metastases.

Patient was a 52-year-old woman with medical history of lung adenocarcinoma operated in 2009 (stage I, T2 N0 M0), showing increasing levels of tumor markers and a doubtful retrocrural adenopathy by means of CT scan with intravenous contrast. An F-FDG PET/CT was performed, which showed 2 hypermetabolic foci in both annexes. The anatomopathological study detected bilateral ovarian adenocarcinoma compatible with metastases of pulmonary origin.

Large cell neuroendocrine carcinoma of the lung with atypical evolution and a remarkable response to lutetium Lu 177 dotatate.

Large cell neuroendocrine carcinoma of the lung (LCNEC) is a high-grade, poorly differentiated tumor that typically does not express somatostatin receptors. Thus, it does not benefit from treatment with somatostatin analogs and peptide receptor radionuclide therapy (PRRT). The current study objective was to demonstrate that treatment with PRRT may be a valid option in neuroendocrine carcinomas with high expression of somatostatin receptors. This is a case report of a 58-year-old man who was diagnosed with LCNEC and received chemotherapy treatment with little benefit. Extensive hepatic and bone metastasis was detected on 111In-pentetreotide scintigraphy following high uptake of the radionuclide by the tumors. The patient benefitted from neuroendocrine treatment initially and from lutetium Lu 177 dotatate subsequently. A significant clinical and radiological response was observed, along with an improvement in quality of life. The use of PRRT is a valid alternative to chemotherapy in patients with LCNEC involving the expression of somatostin receptors.

Recurrent pneumonia due to bronchial carcinoid tumour in a young patient: the role of (111)in-pentetreotide in imaging studies.

Bronchial carcinoid tumours are an uncommon cause of recurrent pneumonia in young patients. Diagnosis is determined from imaging studies, bronchoscopy, and histological confirmation, and treatment is generally surgical. Two cases are reviewed in order to examine the value of (111)In-DTPA-Phe-octreotide ((111)In-pentetreotide) scintigraphy in the pre-surgical evaluation of these patients. After a suspicious area was observed in other tests (standard X-ray, CT), a neuroendocrine tumour was diagnosed using this technique and the presence of regional or distant disease was ruled out. Comparison with the less valuable (18)F-FDG PET (carried out in one of the cases) highlights the usefulness of SPECT-CT, which performs notably better in terms of the localization and characterisation of findings.

Contribution of ¹¹¹In-pentetreotide SPECT/CT imaging to conventional somatostatin receptor scintigraphy in the detection of neuroendocrine tumours.

AIM: The aim of the study was to assess the contribution of 111In-pentetreotide single-photon emission computed tomography/computed tomography (SPECT/CT) imaging to conventional somatostatin receptor scintigraphy (SRS) in terms of lesion characterization and localization in the detection of neuroendocrine tumours (NETs). MATERIALS AND METHODS: A total of 107 patients with suspected or confirmed NET underwent SRS and SPECT/CT after the injection of 148-222 MBq of 111In-pentetreotide. SRS and SPECT/CT images were interpreted independently. Each site of abnormal tracer uptake was recorded according to the anatomical localization, and as being consistent or not with NET. The findings were confirmed with pathological and/or clinical/imaging follow-up data. RESULTS: A final diagnosis of NET was achieved in 49/107 patients (45.8%). No evidence of NET was found in the rest. SPECT/CT resulted in a significant reduction of indeterminate cases [14/107 (13.1%) vs. 1/107 (0.9%); P<0.001] and correctly reclassified one patient as negative for NET and another as positive for NET. SPECT/CT had 87.8% sensitivity and 96.6% specificity on a patient-based analysis, statistically higher than SRS (P<0.001). A total of 160 foci were detected (108 NETs and 52 physiological/benign tumours). SRS correctly classified 105/160 foci (65.6%) and remained inaccurate for 55 lesions. These 55 included 31 indeterminate lesions, 12 lesions detected only by SPECT/CT and 12 false-positive lesions. The number of foci correctly classified on the SPECT/CT images was 151/160 (94.4%), whereas two remained indeterminate and seven were false-positive findings. CONCLUSION: SPECT/CT provides incremental diagnostic value over SRS, mainly because of a precise anatomical localization that helps discriminate between tumour lesions and physiological uptake. SPECT/CT may detect unsuspected lesions in a small proportion of patients.

The value of early SPECT/CT and hand-held γ-camera in radio-guided surgery: a case of a hard-to-locate parathyroid adenoma.

A patient with primary hyperparathyroidism underwent radio-guided surgery by means of a γ-probe and a hand-held γ-camera. Before surgery, a parathyroid double-phase planar scintigraphy and an early SPECT/CT with 99mTc-MIBI were performed and suggested an ectopic parathyroid adenoma with early washout. The hand-held γ-camera was very useful for the localization of a parathyroid adenoma, which could not be found with the probe probably due to its faint uptake and to a high blood pool activity because it was localized next to the great vessels. Besides, it demonstrated the complete extirpation of the parathyroid tissue.

[Familial paraganglioma syndrome: phenotype and relevance of a new SDHB mutation]. / Síndrome de paraganglioma familiar: expresividad clínica y relevancia de una nueva mutación en SDHB.

BACKGROUND AND OBJECTIVE: Advances in molecular biology have discovered new genes involved in the development of familial paraganglioma syndrome (PGL) including those encoding mitochondrial succinate dehydrogenase complex (SDH). We describe the diagnosis, clinical expression and genetic counselling in a family diagnosed of PGL due to a new SDHB mutation. PATIENTS AND METHOD: Genetic study by PCR-direct sequencing SDHB gene and biochemical determination in blood/urine fractionated catecholamine 24h, metanephrines and conventional (computed tomography/magnetic resonance imaging) and functional imaging ((123)I-MIBG) in all members of a family diagnosed of PGL. RESULT: DNA sequencing showed a non-described SDHB heterozygous mutation (c.287-3C>G intron3/exon4) in 5 of the subjects (71%). The estimated penetrance of the mutation's carriers was 40%, with a mean age of 35 years at diagnosis. All patients with active illness required surgical treatment after imaging and laboratory confirmation. CONCLUSIONS: We describe the pathogenicity, diagnostic algorithm, genetic counselling and clinical expression of a new SDHB mutation (c.287-3C>G) in a family diagnosed of PGL.

111In-pentetreotide uptake in an ovarian teratoma and impact of SPECT/CT imaging.

We present a 19-year-old woman with a neuroendocrine tumor of the appendix diagnosed during an acute appendicitis. An 111In-pentetreotide scan was performed to establish the extension of the disease. Scintigraphy showed an abnormal focal uptake in the right side of the pelvis. The SPECT/CT images demonstrated a round-shaped mass in the right ovary. Pathology revealed a benign cystic mature teratoma. In our case, hybrid imaging combining SPECT and CT contributed to localize the unusual 111In-pentetreotide accumulation within the anatomical context.

Efficacy of in-vivo counting in parathyroid radioguided surgery and usefulness of its association with scintigraphy and intraoperative PTHi.

AIM: To evaluate the efficacy of the γ probe, alone and in combination with other techniques, in primary hyperparathyroidism surgery, as well as its ability to distinguish between single-gland and multiple-gland diseases. MATERIALS AND METHODS: Sixty-three patients with primary hyperparathyroidism submitted to radioguided parathyroidectomy, with a minimum follow-up of 1 year, were included. A preoperatory scintigraphy with technetium-99m methoxyisobutylisonitrile was performed in all cases and the excised specimens were histopathologically examined. Intraoperative intact parathyroid hormone (ioPTHi) data were available for 59 patients. RESULTS: Sixty-three patients underwent radioguided parathyroidectomy: 30 minimally invasive radioguided parathyroidectomy, 18 unilateral, and 15 bilateral surgeries. A receiver operating characteristic curve analysis was carried out to distinguish between normal and pathological glands. Using a cut-off value of 1.15 for the γ-probe in-vivo index, we obtained 87% sensitivity, 95% specificity, and 97% positive predictive value (PPV). There were statistically significant differences among in-vivo indexes sorted by type of gland histology (Kruskall-Wallis; P=0.001). A receiver operating characteristic curve was again used to discriminate between single-gland and several-gland pathologies. For a cut-off of 1.51, we achieved 67% sensitivity, 87% specificity, and 95% PPV. CONCLUSION: Pathological glands can be detected by the γ probe (in-vivo index>1.15) with a PPV of 97%. Although an in-vivo index greater than 1.51 is suggestive of a solitary adenoma (PPV=95%), there are a significant number of cases (27%) with lower indexes, these would erroneously lead to an extended surgery in search of a multiglandulary disease. For this reason, the combined determination of the intraoperative intact parathyroid hormone is recommended to identify multiglandulary disease.