Iranian Journal of Nuclear Medicine

99mTc-MIBI SPECT/CT imaging contribution in the diagnosis of patients with hyperparathyroidism

2019-05-22T18:34:25+00:00

Introduction: Hyperparathyroidism is presented with increased parathyroid hormone (PTH) secretion due to hyperfunctioning of one or more of the four parathyroid glands. Primary hyperparathyroidism (p-HPT) can be due to parathyroid adenoma, hyperplasia or carcinoma of the parathyroid gland. Secondary hyperparathyroidism (s-HPT) is usually a response to hypocalcaemia and consecutive hyperplasia of the glands. Our aim was to compare the efficacy of 99mTcmethoxyisobutylisonitrile (MIBI) SPECT/CT in identification of the location of the lesion(s) in cases of HPT by comparing these results with the findings of ultrasound (US) and planar scintigraphy. Methods: Forty one consecutive patients (54±17 age, 12 males and 29 females) with primary or secondary hyperparathyroidism were included. All patients were examined by US and afterwards patients underwent conventional double-phase 99mTc-MIBI scintigraphy combined with neck SPECT/CT procedure. Planar images (early and delayed), US and SPECT/CT image sets were evaluated for adenoma localization at the neck and thorax. Regions of interest (ROIs), equal sized, were selected and compared, over the hyperfunctioning parathyroid tissue (accumulated impulses-counts value) and over the contralateral lobe of the thyroid gland (control counts value). Results: The ultrasonography detected 24 positive findings. The late phase of planar scan detected 26 positive findings. SPECT/CT presented with bigger detection rate than late planar phase or US (75.6%, 63.4%, 61.5%) and with higher sensitivity (100%, 83.8%, 77.4%), respectively. Conclusion: The SPECT/CT study seems reliable, sensitive and with added value in diagnosing hyperparathyroidism as a complementary method to planar scintigraphy. US as compatible method, should be performed prior the scintigraphy protocols.

Monte Carlo-based optimization of a gamma probe system for sentinel lymph node mapping

2019-05-22T18:33:59+00:00

Introduction: Sentinel lymph node biopsy (SLNB) is a standard surgical technique to identify sentinel lymph node (SLN) for the staging of early breast cancer. Nowadays, two methods are used for the identification of SLN: blue dye method aiding visually and radioactive dye using gamma detector. A wide range of gamma probe systems with different design and performance are used in intra-operative surgery. The performance of the probes is evaluated by some parameters such as sensitivity, spatial resolution, angular resolution, and shielding efficiency. Methods: In this study, we simulated a gamma probe system, SURGEOGUIDE II based on CsI(Tl) scintillator, a silicon photomultiplier (SiPM), and a tungsten collimator, using the MCNP4C Monte Carlo (MC) method and comparing with experimental measurement. Finally we modeled a series of probe with various crystal material, crystal length, and collimator hole length to evaluate the sensitivity and the spatial resolution in order to propose the optimal configuration. Results: The sensitivity of the system was measured as 2040 cps/MBq in 30 mm distance from the source. The spatial resolution and angular resolution were 43 mm and 70

Diastolic left ventricular functional indices: Comparison between gated myocardial perfusion SPECT and echocardiography

2019-05-22T18:33:34+00:00

Introduction: Many patients have only diastolic dysfunction without any abnormality in systolic function. We compared cardiac diastolic parameters obtained by gated myocardial perfusion SPECT (Gated SPECT) with those evaluated by echocardiography. Methods: Forty-nine patients (aged 37-85 years, 19 males and 30 women) underwent Gated SPECT and echocardiography. Gated SPECT images were obtained with 16 frame/cardiac cycles. We derived the following diastolic indices: peak filling rate (PFR), time to PFR (TTPFR), mean filling rate in the first 1/3 of the diastole (MFR/3) and second filling rate (PFR2) due to left atrial contraction. In echocardiography we obtained the indices of ventricular filling: E wave, A wave, the E/A ratio, and the E wave deceleration time (DT) were considered. The LV isovolumic relaxation time (IVRT) was also determined. Results: There was no significant correlation between echocardiographic findings and diastolic gated SPECT findings. Using Post-Hoc One-way analysis significant difference was seen only in MFR/3 between diastolic dysfunction groups (P value=0.02). There was no significant difference in other diastolic gated SPECT variables in these groups. Conclusion: Diastolic parameters obtained from 16-frame/cardiac cycle gated SPECT didn’t correlate with echocardiographic indices.

Evaluation of radiochemical purities of routinely used radiopharmaceuticals: Three years’ experience of a single institute

2019-05-22T18:33:08+00:00

Introduction: Radiochemical purity (RCP) is a routine quality control test carried out at nuclear medicine to determine the concentration of various chemical species present in the radiopharmaceuticals (RPs). The present work describes three years of experience in a single institute for the measurement of these impurities in the RPs preparations. Methods: The RCP of different cold kit preparations were performed by chromatographic methods. Specifically, a small drop of the aliquot was spotted on the specific paper acting as the stationary phase and then developed in different solvents as mobile phases. The developed chromatograms were then quantified for various chemical species by Mini TLC scanner or well type counter. Results: The retention factor (Rf) values for the different chemical species in the labeling of RP were measured by using single, double or triple solvent systems. It was observed that 2.70% of the kits had RCP less than the acceptable limit whereas 97.30% kits were found within the permissible levels. Conclusion: Chromatographic techniques used for the assessment of RCP offer sufficiently good results for identification and separation of different chemical impurities.

Scintigraphic evaluation of gastric emptying after greater curvature plication in comparison with sleeve gastrectomy

2019-05-22T18:32:43+00:00

Introduction: Laparoscopic gastric plication (LGP) is a relatively new restrictive bariatric procedure that emerged to avoid the problems and to reduce the cost of laparoscopic sleeve gastrectomy. In this study we present the initial short-term outcome of LGP and its effect on gastric emptying and compare it with the results of laparoscopic sleeve gastrectomy (LSG). Methods: From May 2016 to April 2017, a total of 50 patients were allocated to undergo either LGP (n = 25) or LSG (n = 25). Data on the operative time, complications, hospital stay, overall cost of LSG and LGCP, body mass index loss (BMIL), post-operative gastric emptying (the first study to asses gastric emptying after LGP), percentage of excess weight loss (%EWL), and improvement of comorbidities were collected during the follow-up examinations. Results: All procedures were completed laparoscopically. The mean operative time was significantly higher for the LGP group. The mean hospital stay, cost and %EWL were significantly higher in the LSG group. The mean gastric emptying t1/2 was 40 ± 13 minutes for LGP group and 28.3 ± 8.31 minutes for LSG group (P = 0.001). Conclusion: There is significant acceleration of gastric emptying after LSG more than after LGP with significant effect on weight loss.

Design and performance evaluation of spheroid geometry for brain PET scanner using Monte Carlo modeling

2019-05-22T18:32:17+00:00

Introduction: There has been a curiosity about the spheroid geometry for PET scanners developments since several years ago, therefore in this study, we are aiming to evaluate the performance of this geometry and compare its performance with cylindrical geometry using Monte Carlo simulation. Methods: We simulated a spheroid geometry with a radius of 199 mm, patient bore with of radius of 175 mm, which is compatible with brain size. In second design, cylindrical geometry was simulated with transaxial FOV and ring radius of 175 mm as well. Photon detection efficiency (PDE), NEMA line source sensitivity, spatial resolution and Derenzo phantom image quality were analyzed. Results: We obtained PDE about 21.7% versus 23.8% in 250-750 keV and 19.5% versus 21.3% in 410-613 keV for point source in center of FOV for spheroid and cylindrical PET respectively. The results of NEMA sensitivity measurements indicate 3.29 kcps/MBq versus 3.64 kcps/MBq for spheroid and cylindrical designs. The spatial resolution (FWHM) calculations using MLEM reconstruction algorithm show around 1.6 mm for transvers and axial resolution for point source placed in center of FOV for both scanners. Also we found for spheroid and cylindrical designs 4.8 and 2.7 mm versus 4 and 3.6 mm as transvers and axial mean resolution for off-center point sources. Conclusion: Performance evaluation study indicates that the spheroid geometry delivers better axial resolution whereas cylindrical design can still provide higher sensitivity and transvers spatial resolution than the spheroid geometry PET with same scanner bore size.

Knowledge, attitude and practice of nuclear medicine staff towards radiation protection

2019-05-22T18:31:52+00:00

Introduction: Ionizing radiation in medical imaging is one of the dominant sources of exposure, and correct knowledge of radiation protection, affects staff safety behaviors during procedures. This study aimed to assess the radiation protection Knowledge, Attitude and Practice (KAP) amongst nuclear medicine centers' staff in Iran. Methods: To evaluate the level of radiation protection KAP, a validated questionnaire was distributed between 243 participants considering demographic characteristics in different geographical regions in Iran from 2014 to 2015. Results: There were statistically significant differences in the level of nuclear medicine staff KAP radiation protection with gender (p<0.05), practice age KAP level and radiation protection (p<0.05) among nuclear medicine staff with different working regions and healthcare market. There is no significant connection between educational age and KAP level of radiation protection of nuclear medicine department staff (p>0.05). Conclusion: Our findings have shown that radiation protection KAP level of nuclear medicine staff was inadequate in some regions. This might be due to the lack of continuous training and absence of adequate safety knowledge about ionizing radiation. It seems that awareness about radiation protection rules and regulations, along with continuous training and preparations has a direct effect on radiation practice leading to enhanced KAP of staff in nuclear medicine centers.

Incidental thyroid uptake during 99mTc-methylene diphosphonate bone scintigraphy in oncologic patients

2019-05-22T18:31:26+00:00

Introduction: Extraosseous accumulation of 99mTc – methylene diphosphonate (MDP) may be due to neoplastic, dystrophic, hormonal, inflammatory, ischemic, traumatic or excretory disorders. 99mTc-MDP incidental thyroid uptake is not frequent and is possibly caused by the presence of dystrophic or metastatic calcification, biopsy procedure and presence of benign or malignant thyroid nodules. To analyze the etiological factors leading to 99mTc-MDP uptake in the thyroid gland. Methods: Fifty patients (pts), 19 females (38%) and 31 males (62%), 62±12 years, with no pervious history of thyroid disease, were included in the study. In the period January 2016 – January 2018, all pts underwent MDP bone scintigraphy due to oncologic indication and incidental tracer uptake was noted in the region of the thyroid gland. Ultrasonography (US) was performed in all pts. Patients with detected nodules underwent 99mTc-pertechnetate scintigraphy and fine needle aspiration cytology (FNAC). Thyroid hormone and autoantibodies levels were also analyzed. SPECT/CT procedure was performed in all patients to precisely localize the MDP uptake. Results: Thirty-nine patients had calcifications in the thyroid gland (29 with microcalcifications and 10 with macrocalcifications). In 23 patients, thyroid nodules were detected. 99mTc-pertechnetate scintigraphy presented 15 cold nodules and 8 nodules with increased tracer uptake. FNAC in 3 patients presented nuclear anisocariosis, with Hurthle cell metaplasia, and surgery was advised. In 11 patients, thyroid cartilage calcifications were detected. Conclusion: Incidental findings of thyroid 99mTc-MDP accumulation during bone scintigraphy indicate presence of additional, previously unexpected, active disease processes.

Meningioma: A false positive finding of metastasis from prostate adenocarcinoma using 68Ga-PSMA PET/CT scan

2019-05-22T18:31:01+00:00

A 73-year-old man with history of prostatic adenocarcinoma radical prostatectomy underwent 99mTc-MDP whole-body bone scan and subsequent 68Ga-labeled prostate-specific membrane antigen (PSMA) ligand PET/CT for restaging due to a gradual rise of prostate-specific antigen levels. Whole-body bone scan showed two focal zones of slightly increased uptake in the right fronto-parietal and temporal bones. 68Ga-PSMA PET/CT scan showed local recurrence in the prostatic bed and two foci of slightly increased uptake in the right temporal and fronto-parietal lobes. A brain CT scan, with IV contrast confirmed that foci of increased uptake in the temporal and parietal lobes were consistent with typical meningioma.

18F-FDG PET/CT findings in a possible MELAS syndrome: A case study

2019-05-22T18:30:35+00:00

Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome is a rare congenital disorder of mitochondrial DNA, presenting a wide range of clinical symptoms comprising headaches, seizures, aphasia, hearing loss, visual defects, and hemiparesis. Herein we report a case of a previously asymptomatic 40-year-old male who presented with recurrent headache, seizures, Wernicke’s aphasia, and impaired visual acuity. Investigations included CT, MRI, MR venography, MR spectroscopy, and PET/CT with 18F-fluorodeoxyglucose (18F-FDG-PET) of the brain. PET imaging showed diffuse increased 18F-FDG uptake in the right hemisphere and left temporal lobe; additionally, decreased 18F-FDG uptake was observed in the left frontoparietal lobe. The patient underwent treatment by levetiracetam, co-enzyme Q10, riboflavin, L-carnitine, and lacosamide, followed by improvement of his clinical signs and symptoms indicative of partial response to the therapy. Key

Pancake kidney: An unusual type of renal fusion anomaly found in 99mTc-DMSA renal scintigraphy

2019-05-22T18:30:10+00:00

A 2.5-year-old boy with a history of the previous incidental finding of an ectopic kidney in ultrasonography was referred to our nuclear medicine center for 99mTc-DMSA renal scintigraphy. The scan showed an unusual type of ectopic fused kidneys on the right side of the lower abdomen. In this anomaly, kidneys were fused completely across the medial portion of both upper and lower poles, as well as hilum with no septum. Each kidney, however, demonstrated separate consists of own collecting system. 99mTc-DMSA renal scintigraphy is a valuable imaging detection of different shape anomalies such as pancake kidney. We report this extremely rare case of ectopic fused types of renal anomaly including pancake kidney