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Objectives: The aims of the study were to assess the prevalence of steatopygia on bone scintigraphy of obese patients and to evaluate its effect on the appearance of the lumbar spine, and the added benefit of single photon emission computed tomography (SPECT) and SPECT/computed tomography (SPECT/CT) in overcoming possible artifacts., Methods: Patients with BMI ≥30 who underwent bone scintigraphy between 2016 and 2019 were included. Three nuclear medicine consultants reviewed the studies to determine whether significant steatopygia was present, and whether it resulted in attenuation of underlying lumber spine and crease edge artifact. SPECT or SPECT/CT images were reviewed to evaluate their impact on diagnosis., Results: 56 out of the 100 patients were noted to have steatopygia on planar images. Among the group of 80 obese patients, 50% showed steatopygia, while in the group of 20 morbidly obese patients, 80% showed steatopygia. 32 of the 56 patients with steatopygia had significant attenuation at the lower lumber vertebrae. Nine of these patients showed crease edge artifact. SPECT and SPECT/CT clarified the scintigraphic abnormalities noted in all patients including those with edge artifact alleviating diagnostic difficulty. Among the 9 patients with edge artifact, 6 patients showed normal appearance on SPECT/CT images while three showed true abnormalities., Conclusions: Steatopygia is common on bone scintigraphy of obese patients, higher in females and morbidly obese patients. Obesity-related artifacts in bone scintigraphy, including attenuation effect and edge artifact, are common in this patient group. SPECT or SPECT/CT improves the diagnostic accuracy by overcoming the effects of steatopygia seen on planar images., (© 2023 The Author(s). Published by S. Karger AG, Basel.)

Oral glucose and intravenous insulin (G/I) loading protocols are commonly used in 18 F-fluorodeoxyglucose (FDG) positron emission tomography (PET) cardiac viability studies. Although the amount of insulin to be given per blood glucose range has been well described in guidelines, the amount of glucose to be given is not detailed well. In this retrospective study, we aimed to assess if certain parameters, particularly the amount of glucose and insulin given, may affect 18 F-FDG uptake in the hibernating myocardium and also determine the problems with this protocol. 18 F-FDG PET cardiac viability study with G/I loading protocols was performed in 49 patients. Fasting blood glucose (FBG), amount of glucose given, blood glucose level after glucose load, amount of insulin given, and blood glucose level at the time of 18 F-FDG injection were recorded. Statistical analysis was performed to determine if there is any difference in the above values in PET viable and PET nonviable groups and also in subgroups assessing 18 F-FDG uptake also in normal myocardium. For G/I loading, we used our local protocol in 43 patients, and other protocols in six. 18 F-FDG PET showed viability in 31 patients, and it was negative for viability in 18. In 22 patients, mainly in PET viable group, there was varying degree of reduced 18 F-FDG uptake in normal myocardium. There was no significant difference in FBG, amount of glucose given, blood glucose level after glucose load, amount of insulin given, and blood glucose level at the time of 18 F-FDG injection in PET viable and PET nonviable groups and also in subgroups. The problems with G/I loading protocol included deciding on the amounts of glucose and insulin given, maximum amount of insulin to be given, handling diabetics, optimal time to measure blood glucose after insulin administration, and interpretation of findings in cases with diffusely reduced 18 F-FDG uptake. Further improvements in current guidelines are necessary to obtain images in optimal conditions for accurate results., Competing Interests: There are no conflicts of interest., (Copyright: © 2020 World Journal of Nuclear Medicine.)

Purpose: Heterotopic ossification (HO) is the abnormal osteogenesis in non-skeletal tissue. It can be difficult to detect, as it can mimic other conditions clinically and on imaging studies. The purpose of this study was to find the added value of SPECT-CT in accurate detection of HO., Materials and Methods: A total of 1780 reports on the PACS system of patients underwent bone scintigraphy at the Department of Nuclear Medicine and were filtered for the term "HO" or "heterotopic bone formation" and "SPECT-CT". Thirty-four patients fulfilled this criterion. All patients had bone scintigraphy and SPECT/CT in the same occasion. Images were reviewed by two nuclear medicine physicians blindly. The certainty of the presence of extra-skeletal soft tissue ossification on the planar with SPECT was graded as "definitely present", "maybe present", or "not present", and the same was determined on planar with SPECT-CT images., Results: Based on SPECT/CT, 23 (67.6%) patients were found to have HO, and 11 (32.4%) did not have confirming findings. Of the 23 positive patients on SPECT/CT, eight (34.8%) showed "definitely present" and 12 (52.2%) patients were under "maybe present" on SPECT only. Three (13%) patients were negative on the SPECT and showed evidence of HO on CT. Of the 11 patients that did not demonstrate definite evidence of HO on SPECT/CT, seven (63.6%) were negative on SPECT alone and, four (36.4%) were under "maybe present" on SPECT. The definite detection of HO was statistically significant higher when CT is added to SPECT., Conclusions: Our findings suggest that adding the CT component to SPECT is valuable in the detection of HO.

The aim of this study is to investigate the relationship between brown adipose tissue (BAT) activation and myocardial fluorine-18-fluorodeoxyglucose ([ 18 F] FDG) uptake in terms of intensity and patterns. The patients were divided into two groups as follows: BAT and control groups. The BAT group consists of 34 cases that showed BAT uptake. The control group, with no BAT uptake, included 68 patients who were matched for body mass index, gender, and season. The scans were retrospectively reviewed by two nuclear medicine physicians who visually evaluated the intensity of myocardial [ 18 F] FDG uptake. The myocardial [ 18 F] FDG uptake was visually classified into the following three patterns: diffuse, heterogeneous, and focal. The regions of activated BAT distribution were noted. The mean myocardial [ 18 F] FDG uptake was 2.50 ± 0.75 for the BAT group and 2.13 ± 0.88 for the control group with a statistically significant difference ( P = 0.031). The myocardial [ 18 F] FDG uptake pattern was similar in the BAT and control groups with the diffuse pattern being the most common, followed by the heterogeneous and less commonly focal. In the BAT group, the anatomical distribution of BAT was mainly in supraclavicular, paravertebral, and axillary and to a lesser extent in cervical regions. BAT group had a significantly higher intensity of [ 18 F] FDG myocardial uptake compared to that of the control group. The presence of activated BAT did not affect the pattern of myocardial uptake. Knowledge of these findings may help in understanding the variability of myocardial [ 18 F] FDG uptake and consequently in avoiding misinterpretation of cardiac findings in positron-emission tomography/computed tomography studies., Competing Interests: There are no conflicts of interest., (Copyright: © 2020 World Journal of Nuclear Medicine.)

Objective: The aim of this study is to investigate the effect of microbiological characteristics of causative organisms on the scintigraphic patterns of labeled-white blood cells (WBC) scan in cases of proven osteomyelitis., Materials and Methods: Retrospective analysis of 25 patients referred with suspected osteomyelitis and had both bone and labeled-WBC scans performed and complete records of the microbiological culture of the causative organism. The bone and labeled-WBC scans were retrieved and reviewed by two nuclear medicine physicians. Any definite focal accumulation of labeled WBCs within the bone was considered positive for osteomyelitis. Diagnosis of osteomyelitis in the discharge summary was considered the reference standard and was based on a combination of the clinical scenario, imaging, and laboratory findings including microbiology. Correlation of the pattern of labeled WBC and the type of microorganisms was done., Results: A total of 16 patients were included in this study, seven females and nine males. Of these, seven patients had Gram-positive whereas nine patients had Gram-negative organisms. The majority (85.7%) of Gram-positive organisms showed increased accumulation of labeled WBCs, whereas only one-third (33.3%) of patients with Gram-negative organisms had such finding., Conclusion: The pattern observed in this study shows that the false-negative results of labeled-WBC scans were mainly noted in patients with Gram-negative as opposed to Gram-positive infections. This confirms the experimental animal study findings that the secretion of anti-chemotactic factors by Gram-negative organisms, seems to be inhibiting the migration of labeled WBCs to the site of infection. The inhabitation is decreasing the accumulation of labeled WBCs and consequently resulting in a false-negative finding. The study adds to evidence that microbiological characteristics of the causative organisms are another explanation for the false-negative WBC in proven osteomyelitis., Competing Interests: There are no conflicts of interest.

Background and Objective: Calcium channel blockers (CCBs) are among the most widely used prescribed drugs for the treatment of cardiovascular diseases. The present study investigates the effect of verapamil, which is most commonly used as a CCB, on kidney function using radionuclide imaging., Methods: Ten New Zealand white rabbits were used in vitro (4) and in vivo (6) studies. Isometric tensions were recorded for isolated renal artery ring segments, while renographic studies were performed using Technetium-99m mercaptoacetyltriglycine and Gamma camera. Time to peak activity (Tmax) and time from peak to 50% activity (T1/2), were calculated from the renograms for control and treated rabbits with verapamil., Results: In vitro, verapamil shifted the curve of phenylephrine concentration-dependent contraction on renal artery to the right, and decrease the highest contraction by 30 ± 3%. In vivo, the average values of Tmax for control and treated rabbits were 2.8 ± 0.1 and 2.2 ± 0.2 min respectively. The T1/2 for control and treated rabbits were 4.7 ± 0.05 and 4.2 ± 0.08 min respectively. The differences were statistically significant: p < 0.05. There is 30 ± 4% decrease in the 2 values. This indicates that there is a rapid renal uptake of the tracer and clearance of the radioactivity after verapamil., Conclusion: Verapamil dilates the renal artery and accelerates both the Tmax and T1/2 in the renogram. It increases renal blood perfusion and protects kidney function and therefore improves its work. However, verapamil should not be used while performing renograms to avoid misleading results., (© 2019 S. Karger AG, Basel.)

18 F-FDG PET brain imaging is commonly used in the early detection and differential diagnosis of various subtypes of dementias. 18 F-FDG PET images are mainly evaluated visually, and semiquantitative analysis programs are also commonly used in many centers. However, visual and semiquantitative analysis carry certain limitations. Visual assessment is subjective and dependent on expertise. Commercially available semiquantitative analysis programs have certain limitations such as suboptimal selection of brain areas or erroneous uptake normalization procedures that may provide inaccurate results, and physicians reporting semiquantitative results should be aware of these. In this pictorial review article, we will discuss the current status of 18 F-FDG PET brain imaging in patients with dementia and present figures and semiquantitative analysis results of various subtypes of dementias as well as certain artifacts seen on 18 F-FDG PET brain imaging studies., (© 2018 by the Society of Nuclear Medicine and Molecular Imaging.)

The use of F-18 sodium fluoride (NaF) positron emission tomography/computed tomography (PET/CT) bone scan is increasing because of its higher sensitivity and specificity over standard bone scintigraphy (BS). Studies previously reported a prostate-specific antigen (PSA) cutoff value for ordering standard BS. However, this has not been determined for NaF PET yet. In this study, our goal was to determine a PSA cutoff level for ordering NaF PET/CT bone scan. Newly diagnosed and previously treated prostate cancer patients who had NaF PET/CT scan and PSA measurements within 2 mos of PET study were selected for analysis. When available, other parameters, such as Gleason score (GS), clinical stage, alkaline phosphatase levels, skeletal symptoms, and correlative image findings, were recorded. Receiver operating characteristic (ROC) analysis was performed to determine PSA cutoff values. Sixty-two patients (32 newly diagnosed and 30 previously treated) met the inclusion criteria. Near half of previously treated patients were on hormone therapy. NaF PET/CT was positive in 9 newly diagnosed (PSA mean: 91.6 ng/ml, range: 6.2-226 ng/ml) and in 6 previously treated patients (PSA mean: 146.4 ng/ml, range: 6.6-675 ng/ml). ROC analysis indicated that PSA cutoff value for NaF PET/CT positivity was >20 ng/ml in newly diagnosed and >6 ng/ml in previously treated patients. PSA cutoff value for ordering NaF PET/CT in newly diagnosed patients does not seem significantly different than the previous results for BS (>20 ng/ml). However, we found a lower PSA cutoff value of >6 ng/ml in previously treated patients., Competing Interests: There are no conflicts of interest.

On radionuclide somatostatin receptor imaging studies, the spleen shows high physiologic uptake. Reducing the intensity of the image settings helps to better assess the distribution of radiotracer in the spleen. In our routine studies, we incidentally recognized that 68 Ga-DOTANOC PET provides higher-resolution splenic images than 111 In-octreotide SPECT. Autoradiography and immunohistochemistry studies have shown that somatostatin receptors are located mainly in the red pulp of the spleen. The distribution of 68 Ga-DOTANOC in the spleen appears to correlate with the distribution of red pulp. In this article, we present 68 Ga-DOTANOC PET/CT spleen images of our patients., (© 2018 by the Society of Nuclear Medicine and Molecular Imaging.)

Objective: F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) has been increasingly used in myocardial viability imaging. In routine PET viability studies, oral glucose and intravenous insulin loading is commonly utilized. In an optimal study, glucose and insulin loading is expected to cause FDG uptake both in hibernating and normal myocardium. However, in routine studies it is not uncommon to see absent or reduced FDG uptake in normal myocardium. In this retrospective study we further analyzed our PET viability images to evaluate FDG uptake status in myocardium under the oral glucose and intravenous insulin loading protocol that we use in our hospital., Methods: Patients who had both myocardial perfusion single photon emission computed tomography (SPECT) and FDG PET cardiac viability studies were selected for analysis. FDG uptake status in normal and abnormal myocardial segments on perfusion SPECT was evaluated. Based on SPECT and PET findings, patients were divided into two main groups and four subgroups. Group 1 included PET viable studies and Group 2 included PET-nonviable studies. Subgroups based on FDG uptake in normal myocardium were 1a and 2a (normal uptake) and 1b and 2b (absent or significantly reduced uptake)., Results: Seventy-one patients met the inclusion criteria. Forty-two patients were PET-viable and 29 were PET-nonviable. In 33 of 71 patients (46.4%) there was absent or significantly reduced FDG uptake in one or more normal myocardial segments, which was identified more in PET-viable than PET-nonviable patients (59.5% vs. 27.5%, p  = 0.008). This finding was also more frequent in diabetic than nondiabetic patients (53% vs. 31.8%), but the difference was not significant ( p  = 0.160)., Conclusions: In nearly half of our patients, one or more normal myocardial segments showed absent or significantly reduced FDG uptake. This finding, particularly if it is diffuse, could be from suboptimal study, inadequacy of current glucose and insulin loading protocols, or various other patient-related causes affecting FDG uptake both in the normal and hibernating myocardium. In cases with significantly reduced FDG uptake in normal myocardium, PET images should be interpreted cautiously to prevent false-negative results for viability.

Objective: The prevalence of coronary artery disease (CAD) is high in patients with diabetes. Because ischemia and infarction are often silent in diabetic patients, diagnosis of CAD occurs inevitably late. It is essential to identify the presence of CAD in diabetic patients to start early treatment. Therefore, the aim of this study was to determine the prevalence of abnormal myocardial perfusion in asymptomatic type 2 diabetic patients using myocardial perfusion imaging., Methods: Fifty-nine patients with type 2 diabetes, who did not have any history of CAD, but did have risk factors underwent myocardial perfusion single-photon emission computed tomography (SPECT) imaging using 99m Tc-tetrofosmin and a 2-day stress-rest protocol. Two nuclear medicine specialists independently interpreted the images. Statistical analysis was performed to determine if there is a correlation between the presence of perfusion abnormalities and the history of diabetes (duration of disease, type of treatment, level of control, and presence and type of complications). The influence of other factors such as age, sex, smoking history, and family history of CAD, with abnormal scans were also studied., Results: Of the 59 patients, abnormal scans were detected in 22 (37%) including 16 with reversible defects due to stress-induced ischemia. Hence the prevalence was 37%. Duration of diabetes, use of insulin, nephropathy, and neuropathy were significantly associated with abnormal scans ( p  = 0.048, p  = 0.045, p  = 0.006, and p  = 0.03, respectively). Additionally, positive family history of CAD was highly associated with perfusion abnormalities ( p  < 0.001). No significant association was found between other risk factors, such as hyperlipidemia and the presence of perfusion defects., Conclusions: We found a high prevalence of myocardial perfusion abnormalities in asymptomatic type 2 diabetic patients. Perfusion abnormalities on myocardial perfusion SPECT images were associated with disease duration, insulin use, nephropathy, and neuropathy. Asymptomatic diabetic patients might be candidates with CAD abnormalities that can be studied using myocardial perfusion SPECT.

Aim: This study was carried out to compare the efficacy of Y, Lu, and combination of both radiotracers (tandem) peptide receptor radionuclide therapy (PRRT) in patients with inoperable and metastatic neuroendocrine tumors., Materials and Methods: Systematic searches of PubMed and SciVerse Scopus databases were performed till December of 2016. The data were categorized into three groups: Y-PRRT, Lu-PRRT, and tandem-PRRT. Each group was subdivided on the basis of the response criteria used: Response Evaluation Criteria in Solid Tumors (RECIST) or Southwest Oncology Group (SWOG) criteria. Disease response and disease control rates of each group were analyzed., Results: For the RECIST group, Y-PRRT disease response rates ranged from 22.81 to 56.1%, with a pooled random effect of 42.92%, and the disease control rate was 100%. Lu-PRRT disease response rates ranged from 27.63 to 57.35%, with a pooled random effect of 33.41%, and disease control rates ranged between 71.88 and 100%, with a pooled fixed effect of 79.32%. As for tandem-PRRT, disease response rates ranged between 42.11 and 66.67%, with a pooled fixed effect of 50.52%, and the disease control rate ranged between 93.33 and 100%, with a pooled fixed effect of 98.97%.For the SWOG group, Y-PRRT disease response rates ranged from 5.13 to 26.56%, with a pooled random effect of 13.4%, and disease control rates ranged between 76.56 and 85.9%, with a pooled fixed effect of 80.93%. Lu-PRRT disease response rates ranged from 6.06 to 60.29%, with a pooled random effect of 26.4%, and the disease control rates between 48.48 and 85.29%, with a pooled random effect of 74.53%., Conclusion: Y-PRRT had the highest disease control rates under both RECIST and SWOG criteria. Tandem-PRRT had the highest disease response rate in the RECIST criteria, indicating that PRRT should be customized to each patient individually for maximum benefit.

Fluorine-18-sodium fluoride (F-NaF) PET/CT is a relatively new and high-resolution bone imaging modality. Since the use of F-NaF PET/CT has been increasing, it is important to accurately assess the images and be aware of normal distribution and major artifacts. In this pictorial review article, we will describe the normal uptake patterns of F-NaF in the bone tissues, particularly in complex structures, as well as its physiologic soft tissue distribution and certain artifacts seen on F-NaF PET/CT images.

The aim of this study was to correlate the uptake of 99m Tc-methoxy-isobutyl-isonitrile (MIBI) with ultra-structural features of parathyroid adenomas. Twenty patients with proven primary hyperparathyroidism were evaluated prospectively. Preoperative double-phase 99m Tc-MIBI scintigraphy was performed in all patients and the degree of tracer uptake by the parathyroid lesions was assessed visually and semi-quantitatively. The excised glands were examined histologically and ultrastructurally, and their features were correlated with the degree of the radiotracer uptake. At surgery, 21 parathyroid adenomas were removed (double adenoma in one patient and a solitary adenoma in each of the remaining 19 patients). 99m Tc-MIBI scan detected 18 of the 21 adenomas. There was positive correlation between the degree of 99m Tc-MIBI uptake and the mitochondrial contents of the parathyroid adenoma cells. Four adenomas with intense uptake had high content of mitochondria in the cells. The three false-negative scans had low-to-moderate mitochondrial content. 99m Tc-MIBI uptake is related to the mitochondrial content of the parathyroid adenoma cells., Competing Interests: There are no conflicts of interest.

Objective: The goal of the study was to investigate whether or not gram-negative organisms that secrete antichemotactic factors cause the nonaccumulation pattern of 111In-oxine-labeled white blood cell (111In-WBC) scans., Materials and Methods: Staphylococcus aureus (gram-positive) (group 1) was injected into 25 rabbits and Escherichia coli (gram-negative) (group 2) into another 25 to induce infection in the lumbar vertebrae or left thigh bone (femur). Sixteen successfully infected and surviving rabbits from each group were used for imaging and analysis. Of the 16 rabbits, each group included 8 with vertebral infection and 8 with femur infection. For imaging, each rabbit was injected intravenously with 11.1 MBq (300 μCi) 111In-WBC, and images were acquired 24 h later. Microscopic histopathology was performed after decalcification to confirm osteomyelitis., Results: The 111In-WBC accumulation was observed in 7 (87.5%) of the 8 rabbits infected with S. aureus in the vertebrae and thigh bone. Of the rabbits infected with the gram-negative vertebrae, 1 (12.5%) showed little accumulation of 111In-WBC. Of the 8 rabbits with gram-negative-infected femurs, 1 had high accumulation and another had low accumulation of 111In-WBC, while the rest did not show any uptake. Osteomyelitis was confirmed by histopathology in all the successfully infected rabbits used for imaging., Conclusion: In the majority of the gram-positive-infected rabbit vertebrae there was high accumulation of 111In-WBC. However, no accumulation of 111In-WBC was observed in most of the vertebrae infected with gram-negative organisms, which release antichemotactic factors that prevent adequate accumulation of WBC at the infected area., (© 2017 The Author(s) Published by S. Karger AG, Basel.)

The practice of nuclear medicine in Kuwait began in 1965 as a clinic for treating thyroid diseases. The practice developed gradually and until 1981 when the Faculty of Medicine established the Division of Nuclear Medicine in the Department of Radiology, which later became a separate department responsible for establishing and managing the practice in all hospitals of Kuwait. In 1987, a nuclear medicine residency program was begun and it is administered by Kuwait Institute for Medical Specializations originally as a 4-year but currently as a 5-year program. Currently there are 11 departments in the ministry of health hospitals staffed by 49 qualified attending physicians, mostly the diplomats of the Kuwait Institute for Medical Specializations nuclear medicine residency program, 4 academic physicians, 2 radiopharmacists, 2 physicists, and 130 technologists. These departments are equipped with 33 dual-head gamma cameras, 10 SPET/CT, 5 PET/CT, 2 cyclotrons, 1 breast-specific gamma imaging, 1 positron-emitting mammography, 10 thyroid uptake units, 8 technegas machines, 7 PET infusion systems, and 8 treadmills. Activities of nuclear medicine in Kuwait include education and training, clinical service, and research. Education includes nuclear medicine technology program in the Faculty of Allied Health Sciences, the 5-year residency program, medical school teaching distributed among different modules of the integrated curriculum with 14 didactic lecture, and other teaching sessions in nuclear medicine MSc program, which run concurrently with the first part of the residency program. The team of Nuclear Medicine in Kuwait has been active in research and has published more than 300 paper, 11 review articles, 12 book chapters, and 17 books in addition to 36 grants and 2 patents. A PhD program approved by Kuwait University Council would begin in 2016., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Thyroid scintigraphy plays an important role in the anatomical and functional evaluation of thyroid nodules which carry the risk of malignancy. The presence of multiple nodules carries overall smaller risk of cancer than solitary nodule. Missing nodules, whether solitary or multiple, may mean delaying detection of possible cancer. Therefore, it is important to improve the delectability of thyroid scintigraphy using most optimal imaging techniques. For pinhole thyroid imaging, there is a recent trend to omit oblique projections by some laboratories. The objective of this study was to reevaluate the impact of oblique projections in the detection of thyroid nodules. A total of 92 cases with nodular thyroid disease on routine pinhole thyroid scintigraphy was reviewed retrospectively. Two nuclear medicine physicians recorded the number of nodules based on the anterior view only and another time with adding the oblique views. A total of 192 nodules was detected using the three views. Sixty nodules (31%) were only seen on the oblique views and were missed on the anterior projections. Oblique pinhole projections are mandatory for adequate thyroid scintigraphy since 31% of nodules are missed if only anterior projection was used for interpretation. Following proper techniques will avoid missing of detection of nodule that may harbor cancer.

Unlabelled: Renal function and disease are commonly evaluated by radionuclide studies. The choice of radiopharmaceutical agent for various studies is crucial for proper interpretation. (99m)Tc-mercaptoacetyltriglycine ((99m)Tc-MAG3) is excreted almost exclusively by the renal tubules, whereas (99m)Tc-diethylenetriamine pentaacetic acid ((99m)Tc-DTPA) is predominantly excreted by glomerular filtration. The present study compared the effect of the nonsteroidal antiinflammatory drug (NSAID) diclofenac, which is the most commonly used drug to relieve kidney pain, on the kinetic behavior of administered (99m)Tc-MAG3 and (99m)Tc-DTPA in experimental animals., Methods: Two groups of 12 New Zealand White rabbits ((99m)Tc-MAG3 and (99m)Tc-DTPA) were used for the renography. Each rabbit served as its own control. The animals were given 60 mL of saline intravenously 30 min before each renographic study. A baseline study (control) was done by injecting 48 MBq (1.3 mCi) of (99m)Tc-MAG3, and renography was performed. Two days later, a single intravenous dose of diclofenac (2 mg/kg) (treated animals) was given, and after 20 min, (99m)Tc-MAG3 renography was performed. This procedure was repeated for the (99m)Tc-DTPA group after administration of 96 MBq (2.6 mCi) of the tracer. Dynamic images (as 2-s frames for the first minute and 30-s frames for the next 30 min on a 64 × 64 matrix) were acquired using a γ-camera equipped with a low-energy high-resolution collimator interfaced with a computer. Regions of interest were drawn over the whole kidneys. Time-activity curves were generated from the region of interest. Time to peak activity (T(max)), time from peak to 50% activity (T(1/2)), and the uptake slope of each kidney were calculated from the renograms for control and treated rabbits., Results: Administration of diclofenac shifted the experimental renogram curves to the right, compared with the control curves, indicating that there was a delayed renal uptake of the 2 tracers and clearance of the radioactivity. The calculated average values of T(max) for control and treated rabbits using (99m)Tc-MAG3 were 1.8 ± 0.5 and 6.35 ± 0.4 min, respectively, whereas those of (99m)Tc-DTPA were 3.4 ± 0.4 and 18.2 ± 2 min, respectively. The T1/2 for control and treated rabbits for (99m)Tc-MAG3 were 3.2 ± 0.07 and 6.6 ± 0.07 min, respectively, whereas those for (99m)Tc-DTPA were 10.1 ± 1 and 35 ± 4 min, respectively. The differences were statistically significant (P < 0.05)., Conclusion: This study showed that diclofenac delayed both T(max) and T1/2. The NSAID-induced kinetic changes were considerably greater for (99m)Tc-DTPA than for (99m)Tc-MAG3. On the basis of these findings, it is suggested that (99m)Tc-MAG3 be used to perform renography for studies involving the use of NSAID administration to decrease any change that may occur due to the type of tracer and not to the condition of the kidney.

Metabolic bone disease due to hyperparathyroidism is characterized by increased bone resorption and new bone formation. (99m)Tc- hexakis-2-methoxyisobutylisonitrile ((99m)Tc MIBI) accumulation is controlled by metabolic function and cell viability. To investigate, for the first time, the potential of whole body (99m)Tc MIBI scan for detecting, visually and with the aid of quantitative analysis, bony changes associated with hyperparathyroidism. Eighty-six patients with hyperparathyroidism, referred routinely for parathyroid localization, were included in this case-control prospective study. Each patient was injected with 20-25 mCi of (99m)Tc MIBI. Routine anterior cervico-thoracic images were obtained for parathyroid localization. Two extra whole body images were acquired and assessed visually and by drawing regions of interest over the mandible, sternum, femur, humeri, spine, and the soft tissue adjacent to the bone. The ratios of bone to soft tissue were calculated and compared to ratios drawn in a control group routinely referred for cardiac imaging and injected with (99m)Tc MIBI, after confirming the absence of any bone disease. The visual interpretation of the scans showed 48 patients to have increased bone uptake. Quantitative assessment showed significant difference between the mean ratios of the case and control groups. The Kruskal-Wallis test showed significant agreement between visual and quantitative ratios drawn from delayed right and left femora and left humerus images (P < 0.05). (99m)Tc MIBI whole body imaging is a potentially useful technique for assessing metabolic bone disease associated with hyperparathyroidism. Quantitative analysis helped in confirming the visual findings.

Introduction and Objective: Pinhole has been the main standard collimator to be used for thyroid imaging. There has been a gradually increasing trend to replace pinhole with the use of high-resolution low-energy parallel-hole collimator with zoom in thyroid imaging. The objective of this study is to compare parallel-hole collimator acquisition of thyroid gland with that obtained by pinhole collimator to find the effect on the diagnostic information in nodular thyroid disease., Material and Methods: A total of 29 patients, 24 women and 5 men, aged 18 to 70 years who were routinely referred for thyroid imaging for the assessment of nodular disease were studied. Each patient was injected with 185 MBq (5 mCi) of Tc-99m sodium pertechnetate intravenously. After 20 minutes, acquisition using pinhole followed by parallel-hole collimators was obtained. For pinhole acquisition, a 3-mm insert was used, and 3 images were obtained in the anterior and anterior oblique projections. For parallel-hole acquisition, anterior view was obtained for 250 K. The collimator was placed as close as possible to the patient. The image quality, number, and definition of nodules were evaluated by 2 independent, qualified nuclear medicine physicians. Differences were resolved by consensus., Results: There were 14 patients who had nodular patterns and 15 had no apparent nodules. There were 40 nodules of different sizes detected by pinhole imaging. Only 10 (25%) of these nodules were observed on parallel-hole images., Conclusion: Pinhole imaging must be used for thyroid imaging particularly in patients suspected of having nodular disease.

Obesity, with its alarming increase among adults and children, represents a significant health problem with serious medical, social, psychologic, and economic reverberations. The burden of this problem significantly affects the medical care system, including medical imaging. The effect of obesity on nuclear medicine imaging spans many aspects, from preimaging patient preparation to radiotracer administration, image acquisition, and image interpretation. The acquired images may be suboptimal because of artifacts due to soft-tissue attenuation and incomplete whole-body coverage, and quantification may be suboptimal, especially for PET. Other difficulties include mechanical problems such as the weight limit of the imaging table and the bore size of the PET or SPECT/CT scanner and the need to alter the timing, duration, or protocol of many imaging procedures. These issues are discussed in this review, which clarifies the impact of this epidemic health problem on nuclear medicine services and proposes possible solutions to overcome obesity-related difficulties encountered in nuclear medicine practice.

Introduction: Post-poliomyelitis syndrome causes variable musculoskeletal manifestations including pain, muscle weakness and fatigue. These manifestations are commonly secondary to overuse and misuse of muscles and joints and could follow a fall. Bone scan can be useful in determining the underlying cause and follow-up. The objective of this study was to describe the late scintigraphic patterns on bone scan following poliomyelitis., Materials and Methods: Bone scans of 8 adult patients (7 female and 1 male), aged 35 to 53 years, who were known to have paralytic poliomyelitis, were retrospectively studied. Six patients had unilateral while 1 had bilateral disease. All patients had three-phase bone scan and 5 had SPECT study as well. Studies were reviewed by two qualified nuclear medicine physicians and findings were recorded and analyzed., Results: Several patterns were consistently identified: decreased blood pool activity in the affected lower limb of all patients; deformed ipsilateral hemi-pelvis with reduced uptake on the affected side in all patients with unilateral disease; stress changes with increased uptake in the bones of the contra-lateral lower extremity; and degenerative changes in multiple joints (shoulder, knee, hip, ankle and spine). Significant scoliosis was only noted in the patient with bilateral disease., Conclusion: Scintigraphic patterns on bone scan associated with the post-poliomyelitis syndrome and persistent weakness following a distant episode of poliomyelitis have been described. Awareness of these characteristic scintigraphic findings may facilitate an accurate diagnosis and lead to more appropriate patient management.

The diagnosis of presence, location and load of metastatic, bone involvement has important implication on patient management and prognosis. This requires collection of data obtained using different imaging modalities. Bone scintigraphy is a highly sensitive and cost-effective screening modality. However, to overcome its lower specificity and its limitation in evaluation of vertebral metastases, CT, PET or MRI can be utilized to verify the nature of suspicious lesions. Expansion of SPECT/ CT may fine tune the highly sensitive bone scintigraphy. PET has an emerging and leading role in many tumors, occasionally obviating the need for bone scintigraphy, particularly in evaluation of response to therapy. PET and whole body MRI offers a potentially important tool to provide the earliest clue of bone marrow metastasis. The value of F-18 PET as a sensitive bone imaging tool needs to be further evaluated on a larger scale in different setting including treated and untreated cancer patients and to evaluate also whether potentially better resolution would lead to more benign lesions detection mimicking metastasis such as fractures, inflammatory, infection, and degenerative involvement of bone. The added value of PET-CT is also to be further examined with this regard.

Several pathologies have been reported to cause scintigraphic patterns similar to multiple bony metastases. Heterotopic bone formation is known to mimic several inflammatory and neoplastic conditions including recurrent tumors. However, no reports on multifocal heterotopic bone formation simulating the typical pattern of randomly distributed foci of increased uptake of metastases on bone scan were found in literature. We present a case of a young adult who was repeatedly assaulted by others over a period of one month and on bone scan had a pattern similar to bony metastasis due to multiple foci of heterotopic bone formation and fractures.

Hyperthermia may be a consequence of environmental conditions, bacterial or viral infections and/or thyroid storm. This study investigates the acute effect of body temperature elevation on thyroid function and on its scintigraphy studies. Thyroid scintigraphy was performed on New Zealand White rabbits weighing approximately 3-3.5 kg. Each rabbit was injected with 115 MBq (3.1 mCi) technetium-99 m pertechnetate ((99m)Tc pertechnetate). Studies were performed using Gamma camera equipped with a low energy, high resolution, pinhole collimator interfaced with a computer. Static images were acquired 20 min after administration of the radiotracer. Two days later the same protocol was repeated for the same rabbit after increasing the body temperature by 2 degrees C. The experiment was repeated again after a 2-day interval at 3 degrees C, and then after another 2-day interval at 4 degrees C. Plasma free thyroxine (FT(4)), free triiodothyronine (FT(3)) and thyroid stimulating hormone (TSH) were measured at control and at different hyperthermic temperatures (+2, 3, 4 degrees C). We recorded isometric tension of rabbit thyroid artery strips in organ baths during stepwise temperature elevation. During hyperthermia the decrease in thyroid function and thyroid scintigraphy studies was proportional to body temperature elevation. The recording of isometric tension in rabbit thyroid artery strips in organ baths showed vasoconstriction during hyperthermia which is proportional to the heating temperature. Plasma FT(4) and FT(3) level were decreased while TSH levels were not affected by acute fever. Our results indicate that hyperthermia causes a transient decrease in thyroid gland function and scintigraphic patterns on radionuclide studies. Thus, body temperatures must be measured before radionuclide studies in order to ensure that interpretation of data is not influenced by hyperthermia.

PET enhances staging of lymphoma and is superior to CT scan. It consequently provides more accurate basis for treatment regimens. It provides a better assessment of response to therapy and is the most useful non-invasive modality to differentiate residual tumor from fibrosis/necrosis. Persistent uptake during and after chemotherapy appear to have a high sensitivity in predicting subsequent relapse although some patients may remain in prolonged remission. A negative finding after therapy indicates a very favorable prognosis. We still need better refinement to set off patients who could really benefit from the additional information and better definition of the optimal timing of imaging in clinical practice, The use of early PET response in determining choice of therapy should be utilized with caution until some critical questions are answered. These include: When is the best time to use PET for response assessment? what is the most suitable methodology, visual or quantitative? can early responders be cured with less intensive therapy? will survival be better for patients treated more intensively because they have a poor interim metabolic response?. Further evaluation of alternative PET radiotracers and whether they are superior to FDG and evaluation of the added value of dual FDG-PET acquisition are needed. When PET is not available, Ga-67 imaging of lymphoma can also provide information regarding the presence or absence of active lymphoma particularly in assessing the response to therapy and predicting the outcome.

Objective: Neurological complications have been reported in patients with sickle-cell disease (SCD) using positron emission tomography (PET), magnetic resonance imaging (MRI), and computed tomography (CT), but not with single photon emission computed tomography (SPECT). The objective of this study was to investigate brain perfusion in the patients with SCD using SPECT after technetium-99m hexamethylpropylene amine oxime (99mTc-HMPAO), was administered and compare the findings with those of demography, physical examination, MRI and hematological profile., Methods: The study involved 21 patients (12 males, 9 females, age at study 8-45 years) who were known to be having SCD for a duration of at least 5 years. The patients were not in acute crisis and had normal neurological assessments with no known history of stroke or transient ischemic episode or previous abnormal CT or MRI brain scan, and were right-handed. The brain SPECT was performed after intravenous injection of 740 MBq (20 mCi) 99mTc-HMPAO in adults or an appropriate dose in pediatric patients. The scans were visually interpreted by two nuclear medicine physicians and a decision was reached by consensus. An MRI done 3 months later was interpreted by a radiologist. The demographic data and hematological profile were obtained from the medical records of the patients., Results: Of the 21 patients, 7 (age 11-22 years) had brain perfusion deficit mostly in the frontal lobe either alone or in combination with temporal and/or parietal lobe. The MRI was abnormal in 2 patients. The brain perfusion deficit was not associated with the demographic data of the patients or hematological profiles., Conclusions: The findings show that SPECT was useful in detecting brain perfusion deficit in SCD patients, and such an early detection may be clinically useful in the subsequent follow-up of such patients, since it is known that cerebral perfusion deficit can lead to silent infarct and/or overt stroke, and affect cognitive skills.

Hyperthermia can be the result of many causes such as environmental conditions, brain tumors and infectious diseases. Since hyperthermia is very common, its role in causing stroke through a decrease in cerebral blood flow needed further emphasis. The aim of this study was to record cerebral blood flow in vitro by using isolated rabbit carotid artery strips and in-vivo using radioactive isotope scanning during temperature elevation. The recording of isometric tension in rabbit carotid artery strips in organ baths, and the scintigraphic cerebral imaging of technetium-99m-hexamethyl-propyleneamineoxime (99mTc-HMPAO) using Gamma camera, were acquired at control and higher body temperature by 4 degrees C. Blood pressure was measured through femoral artery and cerebral blood flow was measured through carotid artery. Elevating temperature by 4 degrees C induced reproducible contraction. During hyperthermia, the carotid artery contraction leads to a decrease in cerebral blood flow although the blood pressure did not decrease. The uptake of 99mTc-HMPAO in the brain was significantly reduced. This decrease in cerebral perfusion is regionally dependent, which is more in the frontal area, the cerebral hemispheres than the cerebellum. The decrease was 36+/-3, 37+/-2, 22+/-2%, respectively. Hyperthermia causes carotid artery contraction leading to decrease in cerebral blood flow, which was confirmed by 99mTc-HMPAO images. The decrease is regionally dependent. Since the blood pressure did not decrease by heating, the reduction in cerebral perfusion is mainly due to carotid contraction. The applied neck cooling may be considered as a promising therapeutic strategy for the hyperthermic patient to avoid brain damage. This can be achieved by external application of an ice-water-perfused neck collar.