The complex anatomy and function of the foot and ankle can make it difficult to determine the cause of symptoms in patients with foot and ankle pathology. Following initial clinical and radiographic assessment, additional imaging with magnetic resonance imaging may be required, which is often seen as the modality of choice. Although sensitive to pathological changes in bone metabolism and vascularity, technetium-99m (Tc-99m) bone scintigraphy often lacks the specificity and resolution required to evaluate the structures of the foot and ankle. Tc-99m methylene diphosphonate single-photon emission computed tomography/computed tomography (SPECT/CT) combines this sensitivity with the superior anatomical detail of CT, enabling better localization of pathological uptake and evaluation of associated structural changes. As a result, SPECT/CT has been growing in popularity for the assessment of patients with foot and ankle pathology where it can provide additional information that may change the initial diagnosis and subsequent management plan. Studies have reported modification of the surgical approach and site of intra-articular local anesthetic injections following SPECT/CT with good results. Interpretation of SPECT/CT studies requires an understanding of the pathological changes that result in increased tracer accumulation in addition to the CT changes that may be seen. This review aims to highlight the advantages of SPECT/CT, potential applications and explain the imaging appearances of common pathologies that may be observed.

The detector in single-photon emission computed tomography has played a key role in the quality of the images. Over the past few decades, developments in semiconductor detector technology provided an appropriate substitution for scintillation detectors in terms of high sensitivity, better energy resolution, and also high spatial resolution. One of the considered detectors is cadmium telluride (CdTe). The purpose of this paper is to review the CdTe semiconductor detector used in preclinical studies, small organ and small animal imaging, also research in nuclear medicine and other medical imaging modalities by a complete inspect on the material characteristics, irradiation principles, applications, and epitaxial growth method.

Alzheimer's disease (AD) is a type of dementia which is known as one of a major problem in elderly. Clinicians commonly use mini-mental state examination (MMSE) score to determine the severity of cognitive decline, but MMSE has some limitations such as more subjective, influenced by age, educational degree, and local culture. F-18 fluorodeoxyglucose positron emission tomography (F-18 FDG PET) can be used to assess the process of glucose metabolism in posterior cingulate cortex (PCC) area which endures a central role in supporting cognitive function directly. The purpose of this study is to observe a correlation between metabolic activity value of PCC and MMSE score in predicting the severity of AD. A cross-sectional study was done to 30 subjects suspect AD disease with aged 60 years and older. Characteristic data including gender, age, and education, MMSE scoring by psychiatrist, and imaging of F-18 FDG PET were established. The results of correlation test between the value of FDG metabolic activity and MMSE score shows that the value of metabolic activity in the PCC area tends to increase along with the increase of MMSE score (rs = 0.411, P = 0.024). While from the results of multiple regression test with predictor variable consisting of F-18 FDG metabolic activity in the PCC, gender, age, education level, and the interaction between the metabolic activity of F-18 FDG at PCC and gender, a regression model was obtained. There is a significant correlation observed between the captured of F-18 FDG radioactivity with MMSE score in PCC area which can be used as a tool to predict the severity of AD.

The specific absorbed fraction (SAF) of energy is an essential element of internal dose assessment. Here reported a set of SAFs calculated for selected organs of a human voxel-based phantom. The Monte Carlo transport code GATE version 6.1 was used to simulate monoenergetic photons and electrons with energies ranging from 10 keV to 2 MeV. The particles were emitted from three source organs: kidneys, liver, and spleen. SAFs were calculated for three target regions in the body (kidneys, liver, and spleen) and compared with the results obtained using the MCNP4B and GATE/GEANT4 Monte Carlo codes. For most photon energies, the self-irradiation is higher, and the cross-irradiation is lower in the GATE results compared to the MCNP4B. The results show generally good agreement for photons and high-energy electrons with discrepancies within − 2% ±3%. Nevertheless, significant differences were found for cross-irradiation of photons of lower energy and electrons of higher energy due to statistical uncertainties larger than 10%. The comparisons of the SAF values for the human voxel phantom do not show significant differences, and the results also demonstrated the usefulness and applicability of GATE Monte Carlo package for voxel level dose calculations in nonuniform media. The present SAFs calculation for the Zubal voxel phantom is validated by the intercomparison of the results obtained by other Monte Carlo codes.

Radioiodine imaging of the neck with a pinhole collimator (PinC) is frequently performed in differentiated thyroid cancer (DTC) patients for visualizing individual, and a total number of foci (NOF) of functioning residual thyroid tissue (FRTT) within the thyroid bed in postthyroidectomy patients. The objective of this study was to determine our experience regarding the NOF of FRTT visualized on pretherapy radioiodine PinC images. We performed a retrospective review of radioiodine PinC images of the neck of patients with very low-risk DTC and who had thyroidectomy performed by selected surgeons at MedStar Washington Hospital Center. For each patient's image, the NOF of FRTT was determined by two blind readers. Statistical analysis was performed. One hundred and twenty-six patients met the criteria. Surgeon (S1, S2, S3, and S4) performed 17, 10, 86, and 13 thyroidectomies, respectively. The analysis (mean, range, and standard deviation) of NOF of FRTT was: S1: (2.2, 0-5, 1.3); S2: (1.6, 1–3, 0.8); S3: (2.6, 0–7, 1.5); S4: (3.3, 1–5, 1.3). The percentages of <2, ≤3, ≤4, and <5 foci remaining were 4.9%, 21.5%, 77.0%, and 91.3%, respectively. For the selected surgeons, the NOF of FRTT in the thyroid bed or neck in postthyroidectomy patients never exceeded 7, rarely exceeded 5 (2.4%), and infrequently exceeded 4 (8.7%). Based on these data, our thresholds of the NOF for which we perform further workup for possible locoregional disease are ≥5. Each facility is encouraged to establish their own criteria for their facility and preferably for each of their surgeons.

Neuroendocrine tumor (NET) occurring in association with other endocrine syndromes forms a distinct entity. The aim was to assess the therapy response profile of the routine peptide receptor radionuclide therapy (PRRT) in this relatively uncommon but clinically challenging subgroup of patients. A retrospective analysis was undertaken from the case records from those who were treated with ¹⁷⁷Lu-DOTATATE for metastatic NET. In addition to assessing the therapeutic efficacy, emphasis was also given to study lesional sites and scan pattern. A total of 5 cases were found: In this series of five cases, four belonged to multiple endocrine neoplasia type 1 (MEN1) syndrome; in these four MEN1 syndrome patients, the primary site of NET was thymic region (n = 1), duodenum (n = 1), and pancreas (n = 2). The fifth case was of Cushing's syndrome with the primary site of NET in the thymus. A good symptomatic response was observed in all MEN1 syndrome cases (100%) and progression of symptoms in the patient with Cushing's syndrome. The biochemical response (assessed by measurement of tumor marker serum chromogranin A) demonstrated very good partial response (defined by more than 75% reduction of tumor marker) in 2 MEN1 cases and Cushing's syndrome, good partial response (25–75% reduction of tumor marker) in the remaining 2 MEN1 cases. Scan wise (assessed by technetium [^99mTc]-hydrazinonicotinamide [HYNIC]-tektrotyd [TOC]/⁶⁸Ga-DOTA-NOC/TATE positron emission tomography-computed tomography [PET-CT] and fluorodeoxyglucose [FDG] PET-CT) partial response was observed in 3 MEN1 cases, stable disease was noted in one MEN1 case and disease progression was noted in the patient with Cushing's syndrome. The change in FDG uptake was found to be an important sensitive scan parameter in the treatment evaluation of NETs compared to somatostatin receptor-based imaging in the cases with low MiB1 index. In our series, good palliative response to ¹⁷⁷Lu-DOTA-octreotate (DOTATATE) PRRT was observed in most NET patients associated with MEN1 syndrome without any major hematological or renal toxicity.

Correct staging is the most crucial for the treatment outcome in cancer management. Molecular imaging with ¹⁸F-fluoroestradiol (FES) positron emission tomography-computed tomography (PET-CT) targets estrogen receptor (ER) and may have a higher incremental value in diagnosis by aiding specificity. We enrolled 12 female breast cancer patients prospectively and did ¹⁸F-FES PET-CT and ¹⁸F-fluorodeoxyglucose (FDG) PET-CT within 1 week interval time. Lesion detection sensitivity was compared for a total number of lesions and for nonhepatic lesions only by McNemar test. ¹⁸F-FES PET-CT was taken as reference in case of indeterminate lesions. The incremental value reported by identifying ¹⁸F-FES exclusive lesions and by characterization of ¹⁸F-FDG indeterminate lesions. Spearman rank test was used to correlate ER expression and maximum standardized uptake value (SUVmax). Two ER-negative patients with no ¹⁸F-FES uptake were excluded. Ten ER-positive patients with 154 disease lesions were finally analyzed. ¹⁸F-FDG picked-up 142 lesions (sensitivity 92.21%), whereas ¹⁸F-FES picked-up 116 lesions (sensitivity 75.32%) and this difference was statistically significant. For nonhepatic lesions (n = 136) detectability, ¹⁸F-FDG picked-up 124 (sensitivity 91.18%), whereas ¹⁸F-FES picked-up 116 (sensitivity 85.29%) lesions and this difference was not statistically significant. Beside 12 exclusive lesions, ¹⁸F-FES characterized 41 (27.5%) ¹⁸F-FDG indeterminate lesions. Overall ¹⁸F-FES impacted 20% patient management. The positive trend was also seen with ¹⁸F-FES SUVmax with ER expression and negative with ¹⁸F-FDG SUVmax. We conclude, ¹⁸F-FDG has overall better sensitivity than ¹⁸F-FES PET-CT, however for nonhepatic metastasis difference was not significant. ¹⁸F-FES PET-CT better-characterized lesions and impacted 20% patient management. Therefore, ¹⁸F-FES PET-CT should be used with ¹⁸F-FDG PET-CT in strongly ER expressing patients for better specificity.

Somatostatin receptor positron emission tomography–computed tomography (PET/CT) with ⁶⁸Ga-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) peptides have become an indispensable part of disease assessment in patients with neuroendocrine tumors and forms the basis of personalized therapy with peptide receptor-based radionuclide therapy. With growing utilization of PET/CT in developing countries, availability of the indigenous GMP-certified ⁶⁸Ge/⁶⁸Ga generators is expected to further promote cost-effective molecular imaging service to the cancer patients. We present our initial clinical experience in 32 patients injected with ⁶⁸Ga-DOTA-NOC prepared using ⁶⁸Ga eluted from Bhabha Atomic Research Centre nanoceria-polyacrylonitrile sorbent-based ⁶⁸Ge/⁶⁸Ga generator and freeze-dried DOTA-NOC cold kits.

The aim of this study was to correlate the uptake of ^99mTc-methoxy-isobutyl-isonitrile (MIBI) with ultra-structural features of parathyroid adenomas. Twenty patients with proven primary hyperparathyroidism were evaluated prospectively. Preoperative double-phase ^99mTc-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). ^99mTc-MIBI scan detected 18 of the 21 adenomas. There was positive correlation between the degree of ^99mTc-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. ^99mTc-MIBI uptake is related to the mitochondrial content of the parathyroid adenoma cells.

The main purpose of this study was to investigate dose rate emanating from patients treated with ¹³¹I to evaluate which of the theoretical formulas, inverse-square law (ISL) and International Atomic Energy Agency-International Commission on Radiological Protection (IAEA-ICRP) suggested equation, can provide a sufficiently close approximation of the measured dose rate. Measurements were performed based on the IAEA safety report No. 63 method at 0, 12, 24, and 48 h after administration of radioiodine at a distance of 1 m for 69 patients and for the rest of 67 patients, dose rate was measured at 2, 4, 24, and 48 h at a distance of 2 m. Results revealed that the ISL formula gained better approximation of measured dose rates than the IAEA-ICRP equation with the lesser error. The ISL formula is still more reliable than the novel method of dose calculation in the vicinity of patients. This finding reminded us the prime importance of distance as a radiation protection principle.

Sporadic supply interruptions of select radiopharmaceuticals on the global market require consideration of alternative agents to support continuity of essential nuclear medicine examinations. During an acute shortage of Xenon-133 and technetium-99 metastable (Tc-99m) diethylene-triamine-pentaacetate (DTPA), our institution used aerosolized Tc-99m hydroxymethylene diphosphonate (HDP), a radiopharmaceutical traditionally used in bone scintigraphy, in lieu of traditional ventilation agents, for two cases of suspected pulmonary embolism. Similar to Tc-99m-DTPA, Tc-99m-HDP was readily available and easily compounded in our pharmacy, and tolerated well by patients. Identical delivery equipment was used for administration of Tc-99m-HDP as that used in Tc-99m-DTPA, and thus, there was no requirement for a negative pressure room. Similar to Tc-99m-DTPA and unlike Xenon-133, Tc-99m-HDP allowed direct comparison of all 8 ventilation-perfusion images. In addition, the cost per dose of Tc-99m-HDP proved to be less than Tc-99m-DTPA. Despite these favorable characteristics of Tc-99m-HDP, our experience identified an important challenge in obtaining an optimal flux override ratio of > 3 in a reasonable time frame while obtaining ventilation and perfusion images sequentially despite reversing the imaging order in an attempt to overcome this limitation. Although our experience with Tc-99m-HDP in these two cases was favorable, more clinical experience and investigation are warranted before Tc-99m-HDP can be incorporated as a standard alternative ventilation agent. Disclaimers: The views expressed in this article are those of the authors and do not necessarily reflect the official policy or position of the Department of the Navy, Department of Defense, nor the United States Government. The identification of specific products or scientific instrumentation does not constitute endorsement or implied endorsement on the part of the author, DoD, or any component agency. While we generally excise references to products, companies, manufacturers, organizations, etc. in government produced works, the abstracts produced and other similarly situated researcher presents a special circumstance when such product inclusions become an integral part of the scientific endeavor. Copyright Statement: The first author is a military service member. This work was prepared as part of the authors official duties. Title 17 U.S.C 105 provides that 'Copyright protection under this title is not available for any work of the United States Government.' Title 17 U.S.C. 101 defines a U.S. Government work as a work prepared by a member or employee of the U.S. Government as a part of that person's official duties.

A “cold” defect or an area of decreased radiotracer deposition is the less common appearance of acute hematogenous osteomyelitis (AHO) on a Tc99 m-methylene disphosphonate (Tc99 m-MDP) bone scan. Group A beta-hemolytic Streptococcus (GABHS) is a significantly less common cause of AHO than Staphylococcus aureus, particularly when the infection involves the pelvis or flat bones such as the ribs. Here, we present a case report of isolated acute “cold” hematogenous osteomyelitis in a rib of a child with GABHS bacteremia that was detected on 99Tc-MDP bone scan, with magnetic resonance imaging correlation, and pathologic confirmation after rib resection. Disclaimer: The views expressed herein are those of the author(s) and do not necessarily reflect the official policy or position of the Department of Navy, Department of Defense, or the U.S. Government.

Bone scintigraphy with ^99mTc diphosphonates may exhibit extraosseous lesions in addition to metastatic lesions. Multiple factors can affect extraosseous ^99mTc methylene diphosphonate (MDP) uptake. Similar uptake pattern of ^99mTc MDP and fluorine-18 fluorodeoxyglucose (¹⁸F FDG) in hepatic metastasis was not already notified. In our case, initial tumor necrosis and subsequent intracellular calcification resulted in similar ^99mTc MDP and ¹⁸F FDG accumulation in the metastatic area.

We present a case of a 15-year-old male with primary bone lymphoma who was initially referred for suspicion of chronic osteomyelitis of the mandible. A bone scan and gallium scan demonstrated congruent uptake in the mandible, suggestive of chronic osteomyelitis. A biopsy subsequently showed B-cell lymphoma of the bone with low Ki-67. A fluorodeoxyglucose positron emission tomography (FDG-PET) scan performed before therapy for staging revealed no increased uptake in the mandible. This case shows an atypical presentation of a rare disorder and is presented to emphasize the importance of baseline FDG-PET.

We report a case of a 29-year-old female with the family history of medullary thyroid carcinoma (MTC) presenting with hematuria and tachycardia, who was found to have bilateral adrenal masses on abdominal computed tomography and biochemical testing compatible with pheochromocytoma. Iodine-123 (I-123) metaiodobenzylguanidine (MIBG) scintigraphy for preoperative planning prior to planned adrenalectomy revealed incidental synchronous unifocal MTC, along with expected bilateral adrenal pheochromocytomas. Pathology confirmed these findings, and subsequent genetic testing confirmed a rearranged during transfection proto-oncogene mutation on exon 11, confirming the clinical diagnosis of multiple endocrine neoplasia 2A (MEN 2A). The unexpected incidental finding of synchronous MTC highlights the importance of considering MEN in the differential diagnosis when encountered with newly diagnosed pheochromocytoma and highlights the utility of I-123 MIBG scintigraphy in diagnostic workup of newly diagnosed pheochromocytoma.

Calciphylaxis, also known as calcific uremic arteriolopathy, is an uncommon disease, typically found in patients with the end-stage renal disease. Pathophysiological features include small vessel vasculopathy with mural calcification, fibrosis, and thrombosis. The clinical presentation varies but often consists of the necrosis of skin and subcutaneous tissues, with or without visceral organ involvement due to small vessel vasculopathy. This condition has a significant morbidity and mortality, making accurate diagnosis imperative. We present a case of calciphylaxis investigated using planar bone scintigraphy and single-photon emission computed tomography-computed tomography (SPECT-CT). This case stresses the value of SPECT-CT to accurately localize the abnormal uptake in subcutaneous soft tissue microcalcifications and confirms the exact location and extent of pathology.