Least Significant Changes and Reproducibility of 131I Uptake Test.

ABSTRACT: Radioactive iodine uptake (RAIU) is one of the important tests performed in the departments of nuclear medicine, testing thyroid function by measuring the amount of 131I uptake after oral administration. A RAIU value measured 4 and 24 h after administration has been widely used for differential diagnosis of thyroid function and for the calculation of treatment dose. This study was performed to define practical methods for reproducibility and least significant change (LSC) values replicating thyroid measurements. In the study were 119 patients referred to the nuclear medicine department for examination of thyroid gland function with the diagnosis of Graves' disease (60), toxic multinodular goiter (29), thyroiditis (10), thyroid cancer (6), and unknown etiology (14). The level of thyroid stimulating hormone (TSH) among the patients was 2.07 ± 6.74 µIU mL-1. RAIU measurements were carried out by two different technicians, who have performed an equal number of measurements from each diagnosis in reference to the clinical diagnosis. Measurement of each patient was performed twice at 4 and 24 h after the administration under stable geometry and counting conditions using a standard procedure. Data were evaluated using statistical methods. For assessment of the reproducibility, three parameters were used: reproducibility coefficient (RC), the root-mean-square standard deviation (SDRMS), and the least significant change values. The average RAIU values of the first and second measurements were found as 23.71 ± 16.52% and 23.94 ± 16.64% at 4 h (p >0.05), and 35.33 ± 19.22% and 35.49 ± 19.19% at 24 h (p >0.05), respectively. For thyroid uptake values repeated at 4 and 24 h after radioiodine administration, the mean difference was found to be -0.24 ± 0.62% [limits of agreement (%); -1.44 to 0.97] at 4 h and -0.16 ± 0.44% [limits of agreement (%); -1.02 to 0.70] at 24 h. Confidence intervals were within the limits of agreement (d̅-1.96 SD and d̅+1.96 SD). When the correlation between the repeated RAIU measurements was examined taking the differences and averages into account, there was a negative correlation between 4-h measurement pairs (r=-0.203, p <0.05). On the other hand, a significant correlation was not found between the 24-h measurement pairs (r=0.074, p >0.05). RC, SDRMS, and LSC were calculated as 0.70%, 0.46%, and 1.29% for the 4 h measurements and 0.54%, 0.33%, and 0.91% for the 24-h measurements, respectively. Although there was a minor difference between measurement pairs at 4 and 24 h post-administration, the difference appeared to be insignificant without an apparent effect in the clinical settings.

Giant Abdominal Aortic Aneurysm in Bone Scan

Abdominal aortic aneurysm (AAA) may be incidentally detected in three-phased bone scintigraphy. AAA should be diagnosed prior to the development of symptoms to perform elective repair surgery. We present a rare case who presented with back pain and underwent a 3-phase bone scan with Tc-99m methylene diphosphonate, which revealed a giant AAA on blood-flow and blood-pool phases in addition to bone metastases. F-18-fluorodeoxyglucose positron emission tomography/computed tomography (CT) identified hypermetabolic liver, lung, and bone lesions, and CT component of the study confirmed the diagnosis of AAA with a maximum diameter of 92 mm. The initial two phases of a 3-phase bone scintigraphy are decisive to identify vascular pathologies that may be life-threatening, if left untreated.

Doughnut Shaped Parathyroid Adenoma

A 52-year-old woman presented with a complaint of neck swelling. The patient showed signs of hyperparathyroidism: hypercalcemia, and hypophosphatemia. Tc-99m MIBI dual-phase parathyroid scintigraphy and SPECT revealed increased activity in a regular-bordered, "doughnut"-shaped mass on the left side of the thyroid gland with a central hypoactive area. The cervical ultrasound identified a mixed echoic thyroid nodule with a central large cystic portion, and no parathyroid gland abnormality. Total thyroidectomy and parathyroid exploration was performed. Pathological evaluation of the resected thyroid specimen reported a giant intra-thyroidal hemorrhagic parathyroid adenoma.

Infliximab-induced hot kidneys on bone scintigraphy.

99mTechnetium-methylene diphosphonate bone scintigraphy is widely used in various clinical settings to detect bone abnormalities. Many reasons may cause abnormal tracer uptake in soft tissues on bone scintigraphy. Here, we present a 70-year-old man diagnosed with rheumatoid arthritis receiving chimeric anti-tumor necrosis factor alpha (TNF-α) therapy (infliximab). In order to evaluate the bone involvement of rheumatic disease, the patient underwent a whole-body bone scan that revealed left side dominant diffuse uptake in both kidneys defined as the "hot kidneys." Since the patient had no other identifiable reason, anti-TNF-α therapy might be responsible for the "hot kidneys" on bone scan. Thus, therapy regiment of the patient changed from the chimeric anti-TNF-α to a human monoclonal TNF inhibitor (golimumab). After 6 months of the change of the therapy, the bone scintigraphy was repeated and revealed that the previous "hot kidneys" finding had disappeared.

Earlier Phases of Bone Scintigraphy Can Better Delineate the Extent of Soft Tissue Involvement of Bone Metastasis.

Three-phase bone scintigraphy is sometimes of great value in the detection of uncharacteristic metastases and assists the management of patients in terms of primary focus detection. While evaluating the skeletal system with whole-body bone scintigraphy, other system pathologies may also be detected incidentally. In this case, we present the extraordinary findings on the 3-phase MDP bone scintigraphy and F-FDG PET/CT imaging of the complicated bone metastases in a patient with thyroid carcinoma.

The value of transient ischemic dilation for detecting restenosis after coronary artery revascularization.

AIM: Transient ischemic dilation (TID) is a marker of severe coronary artery disease (CAD). We aimed to assess the incremental value of TID in a cohort of patients with known significant CAD who had recurrence of symptoms after revascularization. METHODS: We identified in our databases 104 patients who had recent coronary revascularization and recurrence of symptoms. 62 patients had PCI (75 arteries) and 42 patients had CABG (104 arteries). All had follow-up stress SPECT MPI and repeat coronary angiography. Myocardial perfusion findings of ischemia and TID were correlated with presence of significant obstructive CAD (>70% stenosis). RESULTS: Follow-up stress Tc-99m Sestamibi SPECT MPI revealed inducible ischemia in 38 patients (36.5%) and TID > 1.20 in 49 patients (47%). Subsequent coronary angiography showed significant obstructive CAD in 44 patients (42%). The sensitivity for detecting obstructive CAD was 61% for SPECT MPI alone, but increased significantly to 93% by the addition of TID as a diagnostic criterion (P < 0.0001). CONCLUSIONS: In this selected patient cohort with prior coronary revascularization, TID is an important marker of obstructive CAD and has incremental value over SPECT MPI alone.

Protective/restorative Role of the Adipose Tissue-derived Mesenchymal Stem Cells on the Radioiodine-induced Salivary Gland Damage in Rats.

BACKGROUND: To analyze protective/regenerative effects of adipose tissue-derived mesenchymal stem cells (ADMSC) on 131I-Radioiodine (RAI)-induced salivary gland damage in rats. MATERIALS AND METHODS: Study population consisted of controls (n:6) and study groups (n:54): RAI (Group 1), ADMSC (Group 2), amifostine (Group 3), RAI+amifostine (Group 4), concomitant RAI+ADMSC (Group 5) and RAI+ADMSC after 48 h (Group 6). We used light microscopy (LM), transmission electron microscopy (TEM), and salivary gland scintigraphy (SGS), and analyzed data statistically. RESULTS: We observed the homing of ADMSC in salivary glands at 1st month on LM. RAI exposure affected necrosis, periductal fibrosis, periductal sclerosis, vascular sclerosis and the total sum score were in a statistically significant manner (P < 0.05). Intragroup comparisons with LM at 1st and 6th months revealed statistically significant improvements in Group 6 (P < 0.05) but not in Groups 4 and 5. Intergroup comparisons of the total score showed that Groups 4 and 5 in 1st month and Group 6 in 6th month had the lowest values. TEM showed vacuolization, edema, and fibrosis at 1st month, and an improvement in damage in 6th month in Groups 5 and 6. SGSs revealed significant differences for the maximum secretion ratio (Smax) (P = 0.01) and the gland-to-background ratio at a maximum count (G/BGmax) (P = 0. 01) at 1st month, for G/BGmax (P = 0.01), Smax (P = 0.01) and the time to reach the maximum count ratio over the time to reach the minimum count (Tmax/Tmin) (P = 0.03) at 6th month. 1st and 6th month scans showed differences for Smax and G/BGmax (P = 0.04), but not for Tmax/Tmin (p > 0.05). We observed a significant deterioration in gland function in group 1, whereas, mild to moderate deteriorations were seen in protective treatment groups. CONCLUSIONS: Our results indicated that ADMSC might play a promising role as a protective/regenerative agent against RAI-induced salivary gland dysfunction.

A rare case of ectopic ACTH syndrome originating from malignant renal paraganglioma

SUMMARY Ectopic adrenocorticotropic hormone (ACTH) syndrome is characterized by hypercortisolism due to the hypersecretion of a non-pituitary ACTH-secreting tumor leading to Cushing's syndrome. Only a few cases have been reported previously as causing ectopic ACTH related to paraganglioma. Herein, we present a case of Cushing's syndrome, in who was proved to be attributable to an ACTH-secreting renal malignant paraganglioma. A 40-year-old woman presented with a five-month history of newly diagnosed hypertension and diabetes, weakness, hyperpigmentation, oligomenorrhea, hirsutism, and acneiform lesions. She showed cushingoid features, including moon face, facial hirsutism, facial and truncal acne, hyperpigmentation, and severe muscle weakness of the limbs. She did not have other findings such as striae, supraclavicular fat accumulation, and buffalo hump. Laboratory examination showed the presence of hypopotasemia, hyperglycemia, hyperthyroidism, and leukocytosis. The serum levels of ACTH, cortisol, and urine-free cortisol were markedly elevated. Results of an overnight 2-mg dexamethasone suppression test included a basal serum cortisol of 61.1 mcg/dL (normal range: 4.6-22.8 mcg/dL) and a cortisol value of 46.1 mcg/dL after dexamethasone administration. There was no suppression found after 2-day 8-mg dexamethasone administration. Magnetic resonance imaging (MRI) of the pituitary gland indicated two microadenomas. An abdominal MRI scan revealed horseshoe kidney, bilateral adrenal hyperplasia, and masses with dimensions of 35 x 31 mm in the left kidney. Inferior petrosal sinus sampling showed no evidence of a central-to-peripheral gradient of ACTH. A positron emission tomography/computed tomography scan showed intense increased activity in the lower pole of the left kidney. Left adrenalectomy and left partial nephrectomy were performed. The resected tumor was diagnosed as the ACTH-secreting paraganglioma in the pathological examination, which was confirmed by immunohistochemical studies with chromogranin A, synaptophysin, and ACTH. Only a few cases of paragangliomas as a cause of ectopic ACTH syndrome have been reported. To our knowledge, this is the first case of renal paraganglioma resulting in Cushing's syndrome due to ectopic ACTH hypersecretion.

Cyst-to-kidney volume ratio in the sonographic diagnosis of unilateral multicystic dysplastic kidney in children.

AIMS: To evaluate the usefulness of the cyst-to-kidney volume ratio determined by ultrasonography (US) in unilateral multicystic dysplastic kidney (MCDK) in children. MATERIAL AND METHODS: Our study group included 21 children (average age: 431 days) with unilateral MCDK and 22 children (average age: 440 days) with unilateral grade IV hydronephrosis due to ureteropelvic junction obstruction as the control group. All the children underwent transabdominal US. In children with MCDK, we calculated cyst-to-kidney volume ratios (volume of the largest cyst/volume of the MCDK) and in the control group the volume ratios of the renal pelvis and the largest calyx (volume of the pelvis or largest calyx/volume of the ipsilateral hydronephrotic kidney). Ellipsoid formula was used to calculate kidney and pelvis volumes. Sphere volume formula was used to calculate the largest cyst and calyx volumes. RESULTS: The mean cyst-to-kidney volume ratio (0.38±0.21) was significantly higher than the mean volume ratios of the renal pelvises (0.10±0.05) and the largest calyces (0.04±0.02) (p<0.05). There was no significant correlation between cyst-to-kidney volume ratio and the ages of the children (r=0.141, p=0.541). CONCLUSIONS:  With the aid of both the qualitative sonographic criteria and the newer data that we have proposed, US is a useful tool in the initial diagnosis of MCDK and for differentiation of MCDKs from grade IV hydronephrotic kidneys in children. The cyst-tokidney volume ratio is independent of age and thus, it can be helpful in the diagnosis of unilateral MCDK at any age.

A rare case of ectopic ACTH syndrome originating from malignant renal paraganglioma.

Ectopic adrenocorticotropic hormone (ACTH) syndrome is characterized by hypercortisolism due to the hypersecretion of a non-pituitary ACTH-secreting tumor leading to Cushing's syndrome. Only a few cases have been reported previously as causing ectopic ACTH related to paraganglioma. Herein, we present a case of Cushing's syndrome, in who was proved to be attributable to an ACTH-secreting renal malignant paraganglioma. A 40-year-old woman presented with a five-month history of newly diagnosed hypertension and diabetes, weakness, hyperpigmentation, oligomenorrhea, hirsutism, and acneiform lesions. She showed cushingoid features, including moon face, facial hirsutism, facial and truncal acne, hyperpigmentation, and severe muscle weakness of the limbs. She did not have other findings such as striae, supraclavicular fat accumulation, and buffalo hump. Laboratory examination showed the presence of hypopotasemia, hyperglycemia, hyperthyroidism, and leukocytosis. The serum levels of ACTH, cortisol, and urine-free cortisol were markedly elevated. Results of an overnight 2-mg dexamethasone suppression test included a basal serum cortisol of 61.1 mcg/dL (normal range: 4.6-22.8 mcg/dL) and a cortisol value of 46.1 mcg/dL after dexamethasone administration. There was no suppression found after 2-day 8-mg dexamethasone administration. Magnetic resonance imaging (MRI) of the pituitary gland indicated two microadenomas. An abdominal MRI scan revealed horseshoe kidney, bilateral adrenal hyperplasia, and masses with dimensions of 35 x 31 mm in the left kidney. Inferior petrosal sinus sampling showed no evidence of a central-to-peripheral gradient of ACTH. A positron emission tomography/computed tomography scan showed intense increased activity in the lower pole of the left kidney. Left adrenalectomy and left partial nephrectomy were performed. The resected tumor was diagnosed as the ACTH-secreting paraganglioma in the pathological examination, which was confirmed by immunohistochemical studies with chromogranin A, synaptophysin, and ACTH. Only a few cases of paragangliomas as a cause of ectopic ACTH syndrome have been reported. To our knowledge, this is the first case of renal paraganglioma resulting in Cushing's syndrome due to ectopic ACTH hypersecretion.

Initial Fludeoxyglucose (18F) Positron Emission Tomography-Computed Tomography (FDG-PET/CT) Imaging of Breast Cancer - Correlations with the Primary Tumour and Locoregional Metastases.

BACKROUND: We aimed to evaluate initial PET/CT features of primary tumour and locoregional metastatic lymph nodes (LNs) in breast cancer and to look for potential relationships between several parameters from PET/CT. MATERIAL/METHODS: Twenty-three women (mean age; 48.66±12.23 years) with a diagnosis of primary invasive ductal carcinoma were included. They underwent PET/CT imaging for the initial tumour staging and had no evidence of distant metastates. Patients were divided into two groups. The LABC (locally advanced breast cancer) group included 17 patients with ipsilateral axillary lymph node (LN) metastases. The Non-LABC group consisted of six patients without LN metastases. PET/CT parameters including tumour size, axillary LN size, SUVmax of ipsilateral axillary LNs (SUVmax-LN), SUVmax of primary tumour (SUVmax-T) and NT ratios (SUVmax-LN/SUVmax-T) were compared between the groups. Correlations between the above-mentioned PET/CT parameters in the LABC group as well as the correlation between tumour size and SUVmax-T within each group were evaluated statistically. RESULTS: The mean values of the initial PET/CT parameters in the LABC group were significantly higher than those of the non-LABC group (p<0.05). The correlation between tumour size and SUVmax-T value within both LABC and non-LABC groups was statistically significant (p<0.05). In the LABC group, the correlations between the size and SUVmax-LN values of metastatic axillary LNs, between tumour size and metastatic axillary LN size, between SUVmax-T values and metastatic axillary LN size, between SUVmax-T and SUVmax-LN values, and between tumour size and SUVmax-LN values were all significant (p<0.05). CONCLUSIONS: We found significant correlations between PET/CT parameters of the primary tumour and those of metastatic axillary LNs. Patients with LN metastases had relatively larger primary tumours and higher SUVmax values.

Sentinel Lymph Node Detection by 3D Freehand Single-Photon Emission Computed Tomography in Early Stage Breast Cancer.

We herein present our first experience obtained by 3D freehand single-photon emission computed tomography (SPECT) (F-SPECT) guidance for sentinel lymph node detection (SLND) in two patients with early stage breast cancer. F-SPECT guidance was carried out using one-day protocol in one case and by the two-day protocol in the other one. SLND was performed successfully in both patients. Histopathologic evaluation showed that the excised nodes were tumor negative. Thus, patients underwent breast-conserving surgery alone.

Transformation of nonfunctioning pancreatic tumor into malignant insulinoma after 3 years: an uncommon clinical course of insulinoma.

A 62-year-old man admitted to our outpatient clinic with two months of recurrent life threatening hypoglycemia episodes. He was diagnosed as malignant insulinoma with multiple metastases of liver and peripancreatic lymph nodes. Liver biopsy specimen was demonstrated grade 2 neuroendocrine tumor compatible with clinical and radiological results. He was followed under the treatment of continuous intravenous glucose infusion during the diagnostic procedures. He had a pancreatic lesion history measured 20 x 12 mm in diameter via the abdominal tomography examination approximately two years before the diagnosis. Unusual course of this case suggests the transformation of nonfunctioning pancreatic neuroendocrine tumor into functional insulin secreting tumor with metastases. The patient was found inoperable and started on chemotherapy.

Transformation of nonfunctioning pancreatic tumor into malignant insulinoma after 3 years: an uncommon clinical course of insulinoma

A 62-year-old man admitted to our outpatient clinic with two months of recurrent life threatening hypoglycemia episodes. He was diagnosed as malignant insulinoma with multiple metastases of liver and peripancreatic lymph nodes. Liver biopsy specimen was demonstrated grade 2 neuroendocrine tumor compatible with clinical and radiological results. He was followed under the treatment of continuous intravenous glucose infusion during the diagnostic procedures. He had a pancreatic lesion history measured 20 x 12 mm in diameter via the abdominal tomography examination approximately two years before the diagnosis. Unusual course of this case suggests the transformation of nonfunctioning pancreatic neuroendocrine tumor into functional insulin secreting tumor with metastases. The patient was found inoperable and started on chemotherapy. Arch Endocrinol Metab. 2015;59(3):270-2.

Nonadenomatous nonencapsulated thymic parathyroid tissue concomitant with primary hyperparathyroidism due to ectopic parathyroid adenoma / Tecido tímico paratireoidiano não edematoso e não encapsulado concomitante com hiperparatireoidismo devido a adenoma paratireoidiano ectópico

Primary hyperparathyroidism due to ectopic parathyroid adenoma is not infrequent. Primary hyperparathyroidism caused by unusual thymic nonadenomatous nonencapsulated parathyroid tissue has been reported before. Both can cause unsuccessful neck explorations. Here we presented for the first time a patient with hyperparathyroidism due to ectopic parathyroid adenoma concomitant to the presence of thymic nonadenomatous nonencapsulated parathyroid tissue.

O hiperparatireodismo primário devido a adenoma ectópico paratireoidiano não é raro. O hiperparatireodismo primário causado por tecido tímico paratireoidiano não edematoso e não encapsulado incomum já foi relatado anteriormente. Ambos podem levar à exploração cervical malsucedida. Apresentamos aqui, pela primeira vez, uma paciente com hiperparatireoidismo decorrente de um adenoma paratireoidiano concomitante com a presença de tecido tímico paratireoidiano não edematoso e não encapsulado.

The contributions of gamma probe to lesion detectability and surgical safety in recurrent thyroid cancer at risk.

UNLABELLED: In patients, who underwent thyroid surgery or treated with I-131 radioiodine previously for differentiated thyroid cancer, a second surgical intervention carries higher risks due to distortion of the natural anatomy and development of fibrotic/cicatricial tissue. In addition, accurate assessment of current status about extent of the disease is important in terms of success of the surgery. In this case report, we present the positive contribution of intraoperative gamma probe used for lesion detectability and for surgical safety in a patient operated for several times and administered high cumulative dose of radioiodine therapy for diffentiated thyroid carcinoma previously. CONFLICT OF INTEREST: None declared.

Scintigraphic comparison of renal ischemia-reperfusion injury models in rats: correlations with biochemical and histopathological findings.

OBJECTIVE: This study aimed to compare the effect on renal functions of ischemia-reperfusion (I-R) injury models by renal scintigraphy and to investigate possible correlations among scintigraphic, biochemical and pathological findings. METHODS: An experimental I-R injury was performed on the left kidneys of 40 Wistar rats: pedincular continuous clamping in Group 1 (n = 10), pedincular cyclic clamping in Group 2 (n = 10), arterial continuous clamping in Group 3 (n = 10) and arterial cyclic clamping in Group 4 (n = 10). A functional and morphological assessment was made by (99m)Tc-MAG3 scintigraphy, biochemical tests and histopathological examination in the late period of I-R injury. Data were analyzed statistically. RESULTS: Statistically significant differences were found in the peak counting (C max), normalized residual activity (NORA), renal retention (RR), split renal function (SRF) and the time to the C max (T max) parameters between the right and left kidneys in each group (p < 0.001). In multiple group comparisons for the left kidney statistically significant differences were determined for C max (F = 4.75, df = 3, p < 0.05), NORA (F = 4.362, df = 3, p < 0.05), RR (F = 10.49, df = 3, p < 0.001) and SRF (F = 4.17, df = 3, p < 0.05) but not T max (F = 1.13, df = 3, p > 0.05). The total scores of Groups 1, 2, 3, and 4 were, respectively, found to be 18, 30, 20 and 24 by grading of renogram curves and 22, 28, 23 and 25 by pathological scoring system. There was a significant correlation among the two score data (r = 0.867, p < 0.001). CONCLUSIONS: (99m)Tc-MAG3 scintigraphy was a reliable method to evaluate renal dysfunction in the late period of I-R injury. Cyclic clamping, especially pedincular type was compatible with higher tubular dysfunction and structural damage.

The efficacy of patient-dependent practices on exposure rate in patients undergoing iodine-131 ablation.

The authors investigated the efficacy of the patient-dependent practices (micturition, defecation, and taking a shower) after I ablation therapy in patients with thyroid cancer. Exposure rates were measured from a 1-m distance at 2, 4, and 24 h after the I administration. The comparisons for 2-4 h and 2-24 h time intervals were carried out among the patients with good and poor compliance, according to the relative amount of the patient-dependent practices, over mean values calculated for an effective half-life (h) or exposure rate decline ratio (%). In the 2-4 h interval, the mean values for good versus poor compliance were found to be: 4.16 h versus 8.14 h and 31% versus 17% in micturition; 5.70 h versus 6.84 h and 26% versus 21% in defecation; and 6.68 h versus 5.69 h and 24% versus 24% in taking a shower. Among patients with good versus poor compliance during a 2-24 h interval, the mean values were: 11.63 h versus 16.62 h and 74% versus 61% in micturition; 12.75 h versus 15.88 h and 71% versus 63% in defecation; and 13.77 h versus 14.21 h and 68% versus 67% in taking a shower.

Nonadenomatous nonencapsulated thymic parathyroid tissue concomitant with primary hyperparathyroidism due to ectopic parathyroid adenoma.

Primary hyperparathyroidism due to ectopic parathyroid adenoma is not infrequent. Primary hyperparathyroidism caused by unusual thymic nonadenomatous nonencapsulated parathyroid tissue has been reported before. Both can cause unsuccessful neck explorations. Here we presented for the first time a patient with hyperparathyroidism due to ectopic parathyroid adenoma concomitant to the presence of thymic nonadenomatous nonencapsulated parathyroid tissue.

Importance of bladder radioactivity for radiation safety in nuclear medicine.

OBJECTIVE: Most of the radiopharmaceuticals used in nuclear medicine are excreted via the urinary system. This study evaluated the importance of a reduction in bladder radioactivity for radiation safety. METHODS: The study group of 135 patients underwent several organ scintigraphies [40/135; thyroid scintigraphy (TS), 30/135; whole body bone scintigraphy (WBS), 35/135; myocardial perfusion scintigraphy (MPS) and 30/135; renal scintigraphy (RS)] by a technologist within 1 month. In full and empty conditions, static bladder images and external dose rate measurements at 0.25, 0.50, 1, 1.5 and 2 m distances were obtained and decline ratios were calculated from these two data sets. RESULTS: External radiation dose rates were highest in patients undergoing MPS. External dose rates at 0.25 m distance for TS, TKS, MPS and BS were measured to be 56, 106, 191 and 72 µSv h-1 for full bladder and 29, 55, 103 and 37 µSv h-1 for empty bladder, respectively. For TS, WBS, MPS and RS, respectively, average decline ratios were calculated to be 52%, 55%, 53% and 54% in the scintigraphic assessment and 49%, 51%, 49%, 50% and 50% in the assessment with Geiger counter. CONCLUSION: Decline in bladder radioactivity is important in terms of radiation safety. Patients should be encouraged for micturition after each scintigraphic test. Spending time together with radioactive patients at distances less than 1 m should be kept to a minimum where possible. CONFLICT OF INTEREST: None declared.