Lymph node staging plays an important role in planning initial management in nonmetastatic prostate cancer. This article compares the role of ⁶⁸Gallium (⁶⁸Ga)-prostate specific membrane antigen (PSMA) positron emission tomography-computed tomography (PET-CT) with magnetic resonance imaging (MRI), which is considered the standard staging modality. Out of 39 high-risk prostate cancer patients who underwent ⁶⁸Ga-PSMA PET-CT for staging (December 2014–December 2015), 12 patients underwent radical prostatectomy along with ePLND and were included in the analysis. Findings of the PSMA PET and MRI were compared with final histopathology. Sensitivity, specificity, positive predicative value (PPV), negative predicative value (NPV), and accuracy of ⁶⁸Ga-PSMA PET-CT and MRI were calculated for numbers of patients and pelvic lymph node metastasis. Chi-square test, McNemar's test, and receiver operating characteristic (ROC) analysis were also done. ⁶⁸Ga-PSMA PET-CT and MRI sensitivity, specificity, PPV, NPV, and accuracy for number of patients detection were 100%, 80%, 87.5%, 100%, 91.67%, and 57.14%, 80%, 80%, 57.4%, 66.67%, respectively. For detection of metastatic lymph node, it was 66.67%, 98.61%, 85.71%, 95.95%, 95.06% and 25.93%, 98.61%, 70%, 91.42%, 90.53%, respectively. Difference of lymph nodal detectability was statistically significant on Chi-square test. On McNemar's test,P value was statistically insignificant for number of patient detection (P = 0.250) but statistically significant for lymph nodal detection (P = 0.001) for ⁶⁸Ga-PSMA PET-CT. In ROC analysis, area under the curve was also significantly high for lymph node detectability by ⁶⁸Ga-PSMA PET-CT. Our initial experience shows that ⁶⁸GaPSMA PET-CT is a very promising tracer for N staging in the initial workup of prostate cancer. It has the potential to impact patient's initial management and can up- and down-stage effectively.

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Radiosynovectomy is a well-established therapy in arthritis and involves an intra-articular injection of small radioactive particles to treat a synovitis. In Europe, frequent indications are rheumatoid and poly-arthritis. Especially in Germany radiosynovectomy is the second common therapy in Nuclear Medicine with about 40,000-60,000 treated joints per year. In Spain, USA, Turkey, Argentines and Philippines the therapy is more use in hemophilic arthritis with excellent results. Especially in developing countries with low availability of clotting factors, the radiosynovectomy represent a cost effective therapeutic option for repeated bleedings in hemophilic arthropathy. The special focus in these countries is maintaining of mobility and work ability. Often only the knee and medium joints (ankle, elbow and shoulder) are treated using yttrium-90, rhenium-186 or phosphorus-32. However, in rheumatoid arthritis most common affected joints are the fingers. For the treatment in these small joints, erbium-169 is necessary. Unfortunately, erbium-169 is only available in Europe. Further indications for radiosynovectomy are osteoarthritis and the articular effusion after joint replacement. The reported response rates in rheumatoid and poly-arthritis range from 60% to 80% depends from the stage of previous arthrosis. The best effectiveness of therapy was observed in hemophilic arthritis with response rate of 90% and significant reducing of bleeding frequency. The therapy is well-tolerated with low rate of side effects. In respect of the specific uptake of particles in the synovia and short range of beta radiation, the radiation exposure outside the joint is very low. The radiosynovectomy has efforts in comparison to surgical synovectomy: it's a minor intervention with low costs; and simultaneous treatments of multiple joints or treatment in short intervals are possible. The presented paper summarized the published papers and reports our own experiences in >15,000 treated joints.

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Radiopharmaceutical therapy, once touted as the "magic bullet" in radiation oncology, is increasingly being used in the treatment of a variety of malignancies; albeit in later disease stages. With ever-increasing public and medical awareness of radiation effects, radiation dosimetry is becoming more important. Dosimetry allows administration of the maximum tolerated radiation dose to the tumor/organ to be treated but limiting radiation to critical organs. Traditional tumor dosimetry involved acquiring pretherapy planar scans and plasma estimates with a diagnostic dose of intended radiopharmaceuticals. New advancements in single photon emission computed tomography and positron emission tomography systems allow semi-quantitative measurements of radiation dosimetry thus allowing treatments tailored to each individual patient.

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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.

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Understanding the range and variability of normal, benign degenerative, and malignant ¹⁸ F sodium fluoride ( ¹⁸ F NaF) positron emission tomography/computed tomography (PET/CT) uptake is important in influencing clinical interpretation. Further, it is essential for the development of realistic semiautomated quantification techniques and simulation models. The purpose of this study is to determine the range of these values in a clinically relevant patient population with prostate cancer. ¹⁸ F NaF PET/CT scans were analyzed in patients with prostate cancer (n = 47) referred for evaluation of bone metastases. Mean and maximum standardized uptake values [SUVs (SUV _mean and SUV _max )] were made in normal background regions (n = 470) including soft tissues (liver, aorta, bladder, adipose, brain, and paraspinal muscle) and osseous structures (T12 vertebral body, femoral diaphyseal cortex, femoral head medullary space, and ribs). Degenerative joint disease (DJD; n = 281) and bone metastases (n = 159) were identified and quantified by an experienced reader using all scan information including coregistered CT. For normal bone regions, the highest ¹⁸ F NaF PET SUV _mean occurred in T12 (6.8 ± 1.4) and it also showed the lowest coefficient of variation (cv = 21%). For normal soft tissues, paraspinal muscles showed very low SUV _mean (0.70 ± 0.11) and also showed the lowest variability (cv = 16%). Average SUV _mean in metastatic lesions is higher than uptake in benign degenerative lesions but values showed a wide variance and overlapping values (16.3 ± 13 vs 11.1 ± 3.8; P < 0.00001). The normal ¹⁸ F NaF PET uptake values for prostate cancer patients in normal background, benign degenerative disease, and osseous metastases are comparable to those reported for a general population with a wide variety of diagnoses. These normal ranges, specifically for prostate cancer patients, will aid in clinical interpretation and also help to establish the basis of normal limits in a semiautomated data analysis algorithm.

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Positron emission tomography (PET) is currently the most advanced technique of metabolic imaging available for tumor diagnosis and follow-up. The aim of this study was to examine the versatility and accuracy of fluorodeoxyglucose (FDG) PET/computed tomography (CT) in the metastasis detection of renal cell carcinoma (RCC). We also compared our findings to other similar studies from the literature. This is the biggest study so far to examine the sensitivity and specificity of FDG PET/CT in the management of RCC. A retrospective review was carried out on all the FDG PET/CT studies done from January 1999 to January 2014 at our institution. Biopsy results were considered the gold standard. For our patients (n = 315) with biopsy results, FDG PET/CT studies exhibited 100% sensitivity, 100% specificity. Our results were better than results achieved by other studies. The use of FDG PET/CT in restaging and metastasis detection of RCC has many advantages, in addition to high accuracy. This imaging technique has great potential in influencing treatment decisions. We recommend the incorporation of FDG PET/CT in routine standard protocols for RCC.

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Ovarian cancer (OC) often presents at an advanced stage with frequent relapses despite optimal treatment; thus, accurate staging and restaging are required for improving treatment outcomes and prognostication. Conventionally, staging of OC is performed using contrast-enhanced computed tomography (CT). Nevertheless, recent advances in the field of hybrid imaging have made positron emission tomography/CT (PET/CT) and PET/magnetic resonance imaging (PET/MRI) as emerging potential noninvasive imaging tools for improved management of OC. Several studies have championed the role of PET/CT for the detection of recurrence and prognostication of OC. We provide a systematic review and meta-analysis of the latest publications regarding the role of molecular imaging in the management of OC. We retrieved 57 original research articles with one article having overlap in both diagnosis and staging; 10 articles (734 patients) regarding the role of PET/CT in diagnosis of OC; 12 articles (604 patients) regarding staging of OC; 22 studies (1429 patients) for detection of recurrence; and 13 articles for prognostication and assessment of treatment response. We calculated pooled sensitivity and specificity of PET/CT performance in various aspects of imaging of OC. We also discussed the emerging role of PET/MRI in the management of OC. We aim to give the readers and objective overview on the role of molecular imaging in the management of OC.

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Lacrimal outflow can be compromised by anatomical obstructions or stenoses (nonfunctional epiphora) or by defective lacrimal "pump" function (functional epiphora). Although classic imaging modalities, such as X-ray dacryocystography, computed tomography, or magnetic resonance imaging can effectively evaluate the former, their success is much less in the evaluation of the latter. This is largely due to the fact that forced diagnostic injection of fluid into the canalicular system can overcome partial obstruction sites. On the other hand, lacrimal scintigraphy mimicks "physiological" lacrimal outflow, being performed under pressure gradients present in everyday life. This is why it is considered more suitable for the study of functional epiphora. Furthermore, quantitative lacrimal scintigraphy (with time-activity curves) enables the accurate measurement of lacrimal clearance from the conjunctival fornices and may be used to study the physiology of the lacrimal "pump." Data obtained from the scintigraphic study of lacrimal outflow may be used to design more effective procedures in the management of functional and nonfunctional epiphora. This is a review article, based on a literature search with emphasis on recent publications and on those supporting interdisciplinary cooperation between ophthalmology and nuclear medicine.

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¹⁷⁷ Lu-ethylenediaminetetramethylene phosphonic acid (EDTMP) is presently suggested as an excellent bone seeking radionuclide for developing metastatic bone pain (MBP) palliation agent owing to its suitable nuclear decay characteristics. To find the exact dosage and its efficiency, this clinical study was performed on the human being, using ¹⁷⁷ Lu-EDTMP for MBP palliation. ¹⁷⁷ Lu-EDTMP was prepared by Iran, atomic energy organization. Thirty consecutive patients with determined tumors, incontrollable MBP, and positive bone scan at 4 weeks before the beginning of the study participated in this study in the nuclear medicine ward. ¹⁷⁷ Lu-EDTMP in the form of sterile slow IV injection was administered with a dose of 29.6 MBq/kg. Short form of brief pain inventory questionnaire was used to evaluate the efficiency of the intervention. Questionnaires were filled out by an expert nuclear physician every 2 weeks while the cell blood count was also checked every 2 weeks up to 12 weeks for evaluation of bone marrow suppression and hematological toxicity. Furthermore, whole body scan was done at days 1, 3, and 7. Twenty-five patients showed a significant pain relief since 2 weeks after the injection, and continued until the end of the follow up period (12 weeks). There were no significant early complications such as bone marrow suppression, hematological toxicity, and no systemic adverse effects. No complication was observed in renal function. Twenty one patients showed flare phenomenon that was started after the 12.2 ± 1.78 h lasting for 38.4 ± 23.08. Sixteen patients (53%) were completely treated; nine patients (30%) showed a partial response, and five patients (17%) had no response to treatment. Total response to treatment was achieved in 25 patients (83%). At the end of the evaluation, no bone marrow suppression or hematologic toxicity was observed. ¹⁷⁷ Lu-EDTMP has shown suitable physical and biological properties with good results in long term bone pain relief for patients with bone metastasis.

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The aim of this study is to assess the effectiveness of Radiosynovectomy (RSV) using ¹⁷⁷ Lu-labeled hydroxyapatite ( ¹⁷⁷ Lu-HA) in the treatment of painful synovitis and recurrent joint effusion of knee joints in rheumatoid arthritis (RA). Ten patients, diagnosed with RA and suffering from chronic painful resistant synovitis of the knee joints were referred for RSV. The joints were treated with 333 ± 46 MBq of ¹⁷⁷ Lu-HA particles administered intra-articularly. Monitoring of activity distribution was performed by static imaging of knee joint and whole-body gamma imaging. The patients were evaluated clinically before RSV and at 6 months after the treatment by considering the pain improvement from baseline values in terms of a 100-point visual analog scale (VAS), the improvement of knee flexibility and the pain remission during the night. RSV response was classified as poor (VAS < 25), fair (VAS ≥ 25-50), good (VAS ≥ 50-75) and excellent (VAS ≥ 75), with excellent and good results considered to be success, while fair and poor as failure and also by range of motion. Three phase bone scan (BS) was repeated after 6 months and changes in the second phase of BS3 were assessed visually, using a four-degree scale and in the third phase, semiquantitatively with J/B ratio to see the response. Biochemical analysis of C-reactive protein (CRP) and fibrinogen was repeated after 48 h, 4 and 24 weeks. In all 10 patients, no leakage of administered activity to nontarget organs was visible in the whole-body scan. Static scans of the joint at 1 month revealed complete retention of ¹⁷⁷ Lu-HA in the joints. All patients showed decreased joint swelling and pains, resulting in increased joint motion after 6 months. The percentage of VAS improvement from baseline values was 79.5 ± 20.0% 6 months after RS and found to be significantly related to patients' age (P = 0.01) and duration of the disease (P = 0.03). Knees with Steinbrocker's Grades 0 and I responded better than those with more advanced changes (Steinbrocker's Grades III and IV) in terms of VAS improvement (75% vs. 45.8%) (P < 0.001). The overall success rate (VAS ≥ 50) was 80%. Remission of pain during the night was achieved in 100%, and knee flexibility was improved in 80%. The changes in the blood pool phase before RSV were 3.2 ± 0.7 and after the therapy 1.4 ± 0.7 (P < 0.001). The J/B ratio was: Before RSV 2.4 ± 0.3; after treatment 1.0 ± 0.2 (P < 0.05). CRP concentration 4 and 24 weeks after the therapy was significantly lower than before treatment. The fibrinogen level was not different before and after RSV. RSV side-effects assessed for the whole follow-up period were minor and not significant. RSV with ¹⁷⁷ Lu-HA was safe and effective in patients with knee joint chronic painful synovitis of rheumatoid origin. It exhibited significant therapeutic effect after 6 months follow-up period with no significant side-effects. The preliminary investigations reveal that ¹⁷⁷ Lu-labeled HA particles hold considerable promise as a cost-effective agent for RSV. More elaborate and controlled clinical trials are necessary to evaluate the therapeutic efficacy and safety of the agent compared with the treatment with other radionuclides and glucocorticosteroids.

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Hydrocephalus-related symptoms that worsen after shunt placement may indicate a malfunctioning or obstructed shunt. The assessment of shunt patency and site of obstruction is important for planning of treatment. The radionuclide cerebrospinal fluid (CSF) shunt study provides a simple, effective, and low-radiation-dose method of assessing CSF shunt patency. The radionuclide CSF shuntography is a useful tool in the management of patients presenting with shunt-related problems not elucidated by conventional radiological examination. This article described the imaging technique of ventriculoperitoneal (VP) shunt and lumbar puncture (LP) shunt. The normal finding, abnormal finding of completed obstruction and partial obstruction is present by our cases experience. The radiopharmaceutical (Tc-99m diethylenetriaminepentaacetic acid) was injected via the reservoir for VP shunt and via lumbar puncture needle in subarachnoid space for LP shunt, then serial image in the head and abdominal area. The normal function of VP and LP shunt usually rapid spillage of the radioactivity in the abdominal cavity diffusely. The patent proximal tube VP shunt demonstrates ventricular reflux. The early image of patent LP shunt reveals no activity in the ventricular system contrast to distal LP shunt reveals early reflux of activity in the ventricular system. The completed distal VP and LP shunt obstruction show absence of tracer in the peritoneal area or markedly delayed appearance of abdominal activity. The partial distal VP and LP shunt obstruction recognized by slow transit or accumulation of tracer at the distal end or focal tracer in the peritoneal cavity near the tip of distal shunt. The images of the normal and abnormal CSF shunt as describe before are present in the full paper. Radionuclide CSF shuntography is a reliable and simple procedure for assessment shunt patency.

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The ⁶⁸ Ga-prostate-specific membrane antigen ( ⁶⁸ Ga-PSMA) has been recently developed to be used, as a ligand, in positron emission tomography/computed tomography (PET/CT) prostate cancer imaging, to detect prostate disease. The main objective of this review was to collect data and findings from other studies and articles to assess, theoretically, if ⁶⁸ GA-PSMA PET/CT is a more appropriate prostate cancer diagnostic technique in comparison with others available such as CT, ¹⁸ F-fluoro-2-deoxyglucose PET/CT, or ¹⁸ F-fluoromethylcholine ( ¹⁸ F-choline) PET/CT. For that purpose, PubMed, the online scientific articles' database, was consulted where the keywords "PSMA" and "PET" were used to find relevant articles. The clinicaltrials.gov, clinical trials' database, was also consulted where the keywords " ⁶⁸ Ga-PSMA" and "prostate" were used to search clinical trials. Based on the reviewed scientific literature, several studies were conducted to assess and compare the ⁶⁸ Ga-PSMA PET/CT detection rate in prostate cancer with other available techniques. One of those studies, conducted by Giesel et al., concluded, within study sample, that 75% of patients with lymph nodes detected by ⁶⁸ Ga-PSMA PET/CT would have not been identified using other conventional morphological criteria based techniques. In Eiber et al.'s study, ⁶⁸ Ga-PSMA PET detected prostatic disease findings in 67% of patients with prostate-specific antigen levels <1 ng/mL, when compared with choline-based PET that presented detection rates between 19% and 36%. In Bluemel et al.'s study, ⁶⁸ Ga-PSMA identified positive prostatic disease in 43.8% of the patients with negative findings in F-choline PET/CT. Findings from this review demonstrate that ⁶⁸ Ga-PSMA PET/C is more effective in detecting metastases, lymph nodes, and recurrent prostate cancer when compared to ¹⁸ F-choline-based PET/CT and CT. ⁶⁸ Ga-PSMA PET/CT presents also more imaging contrast and can be more cost-effective. ⁶⁸ Ga-PSMA has already been subjected to first-in-human trials, and it is now being tested in Phase II and III trials.

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Ablative approaches using radioiodine are increasingly proposed for the treatment of Graves' disease (GD) but their ophthalmologic and biological autoimmune responses remain controversial and data concerning clinical and biochemical outcomes are limited. The aim of this study was to evaluate thyroid function, TSH-receptor antibodies (TRAb) and Graves' ophthalmopathy (GO) occurrence after radioiodine thyroid ablation in GD. We reviewed 162 patients treated for GD by iodine-131 (¹³¹ I) with doses ranging from 370 to 740 MBq, adjusted to thyroid uptake and sex, over a 6-year period in a tertiary referral center. Collected data were compared for outcomes, including effectiveness of radioiodine therapy (RIT) as primary endpoint, evolution of TRAb, and occurrence of GO as secondary endpoints. The success rate was 88.3% within the first 6 months after the treatment. The RIT failure was increased in the presence of goiter (adjusted odds ratio = 4.1, 95% confidence interval 1.4-12.0, P = 0.010). The TRAb values regressed with time (r = −0.147; P = 0.042) and patients with a favorable outcome had a lower TRAb value (6.5 ± 16.4 U/L) than those with treatment failure (23.7 ± 24.2 U/L, P < 0.001). At the final status, 48.1% of patients achieved normalization of serum TRAb. GO occurred for the first time in 5 patients (3.7%) who were successfully cured for hyperthyroidism but developed early and prolonged period of hypothyroidism in the context of antithyroid drugs (ATD) intolerance (P = 0.003) and high TRAb level (P = 0.012). On the basis the results of this study we conclude that ablative RIT is effective in eradicating Graves' hyperthyroidism but may be accompanied by GO occurrence, particularly in patients with early hypothyroidism and high pretreatment TRAb and/or ATD intolerance. In these patients, we recommend an early introduction of LT4 to reduce the duration and the degree of the radioiodine-induced hypothyroidism.

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Although ¹⁸ F-fludeoxyglucose-positron emission tomography (PET) is the most applied diagnostic method in tumor staging, its role in prostate cancer (PCA) is limited because glucose metabolism tends to be low unless PCA has high Gleason score. Alternatively, choline PET was introduced as a valuable imaging method. Kinetic analysis of PET acquisition has increasingly gained momentum as an investigative tool because it provides a non-invasive approach to obtain kinetic and metabolic data from tissues of interest including transport and metabolism of the administered material. In this regard, we sought to apply it in ¹⁸ F-fluoroethylcholine (FECH)-PET/computed tomography (CT) in patients with PCA. 64 patients, the mean age 69 (range: 47-87 years) with primary/recurrent PCA were encompassed. They underwent ¹⁸ F-FECH-PET started with a dynamic acquisition using a 20-frame each 30 s over the prostate region and followed at 1 h post-injection by a static whole body imaging. The kinetic evaluation of the data was performed using the software package PMOD (PMOD Technologies Ltd., Zürich, Switzerland). Significant increase in mean values for K1, K3, FD, standardized uptake value (SUV) and global influx in tumor tissue versus normal tissue (P < 0.05). Moderate but significant correlation (r: 0.28, P = 0.023) between SUV and K1. By contrast, no correlation between SUV and K3 (r: −0.08, P = 0.79). In patients with recurrent tumors, there is no significant difference in all kinetic parameters and SUV (P > 0.1) between the different types of recurrences. The kinetic analysis of dynamic FECH-PET provides a novel method in primary PCA diagnosis and could be of potential value in the delineation of tumor focus.

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Focal ¹⁸ F-fluorodeoxyglucose (FDG) colonic activity can be incidentally seen in positron emission tomography/computed tomography (PET/CT) scans. Its clinical significance is still unclear. The purpose of this study was to assess the significance of focal FDG activity in PET/CT scans by correlating the imaging findings to colonoscopy results, and come up with some guidelines for recommendation of follow-up colonoscopy. A total of 133 patients who underwent both ¹⁸ F-FDG PET/CT for different oncological indications and colonoscopy within 3 months were retrospectively studied. Imaging, colonoscopy and pathology results were analyzed. Of the 133 FDG-PET/CT scans, 109/133 (82%) did not show focal colonic FDG activity, and 24/133 (18%) did. Of the 109/133 PET/CTs without focal colonic FDG activity, 109/109 (100%) did not have evidence of colon cancer after colonoscopy and histology. Of the 24/133 PET/CTs with focal colonic FDG activity, 10/24 (42%) had pathologic confirmation of colon cancer and 14/24 (58%) did not have evidence of colon cancer after colonoscopy and histological analysis. Sensitivity was 10/10 (100%), specificity 109/123 (89%), positive predictive value (PPV) 10/24 (42%) and negative predictive value (NPV) 109/109 (100%). Incidental focal ¹⁸ FDG activity in PET/CT imaging shows a high sensitivity, specificity and NPV for malignancy, with a not so high PPV of 42%. Although some people would argue that a 42% chance of malignancy justifies colonoscopy, this maybe is not possible in all cases. However, the high sensitivity of the test does not allow these studies to be overlooked. We provide our recommendations as per when to send patients with focal FDG colonic activity to have further characterization with colonoscopy.

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Prostate-specific membrane antigen (PSMA) is a transmembrane protein that is highly expressed on the surface of prostate cancer (PC) cells, making it an excellent radiotracer for both therapeutic and diagnostic purposes. In this prospective study, we investigated the efficacy and toxicity of ¹⁷⁷Lutetium (Lu)-PSMA in metastatic castration-resistant PC (mCRPC) patients for the establishment and approval of this therapy in Iran. Fourteen mCRPC patients (mean age 70.57 ± 7.3 years) were treated with a single dose of ¹⁷⁷Lu-PSMA. Complete blood count, liver function tests (aspartate aminotransferase and alanine aminotransferase), alkaline phosphatase levels, renal function tests (urea and creatinine), and prostate-specific antigen (PSA) levels were obtained for the patients at baseline and every 2 weeks. A majority of the patients (11 patients, 64.2%) experienced a decline in their PSA levels; in 5 (45.4%) of these patients, the PSA levels declined > 50%.The severity of pain decreased in 8 (57.1%) patients, and performance status was improved in 5 (45.4%) patients. The treatment was well tolerated, and no severe hematological or nonhematological side effects were observed. Our findings show that ¹⁷⁷Lu-PSMA had a high efficacy and a low toxicity in an Iranian population and is a promising treatment option for PC patients.

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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.

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Bladder carcinoma is the most frequent tumor of the urinary tract and accounts 7% of all malignancies in men and 2% of all malignancies in women. This retrospective study was carried out to assess the diagnostic utility of F18-fludeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in the imaging evaluation of bladder carcinoma. Seventy-seven consecutive patients diagnosed to have carcinoma urinary bladder referred for F18-FDG PET/CT were included in this study. Thirty-four patients were for initial staging after transurethral biopsy and remaining 43 patients were for restaging. All patients also underwent CT scan of the abdomen and pelvis. PET/CT findings were correlated with diagnostic CT scan and histopathological findings. In 30 of the 34 patients for initial staging, both PET/CT and CT confirmed the primary lesion in the bladder. Histopathology report was available in 23 patients. Lymph nodes FDG uptake reported to be metastatic in 10/23 patients while CT detected lymph node metastasis in 12 patients. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy have been calculated to be 87.5%, 80%, 70%, 92%, 82% for PET/CT and 66%, 57%, 50%, 72%, 60% for CT respectively. PET/CT detected metastatic disease in 8 patients whereas CT detected in 4 patients. Of the 43 patients for restaging, local recurrence was detected in 24 patients on both PET/CT and CT. Histopathology report was available in 17 patients. Sensitivity, specificity, PPV, NPV and accuracy were 85%, 60%, 60%, 85%, 70% for PET/CT and 80%, 50%, 40%, 85%, 58% for CT respectively. Nineteen patients were detected to have metastatic disease by PET/CT, whereas CT detected metastases in 11 patients. F-18 FDG PET/CT is a very useful modality in pre-operative staging and monitoring after surgery, chemotherapy or radiotherapy of patients with carcinoma urinary bladder.

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The efficacy of the whole body (WB) ¹⁸ F-fluorodeoxyglucose ( ¹⁸ F-FDG) positron emission tomography-computed tomography (PET-CT) as a part of conventional initial staging in all cases of head and neck squamous cell carcinoma (HNSCC) is still controversial with various studies in literature giving contradictory reports. We conducted this study at a government tertiary care oncology center in India to identify the impact of WB ¹⁸ F-FDG PET-CT scan on HNSCC staging and treatment. A prospective clinical study of patients of HNSCC who were evaluated and treated at our center was performed. The patients included in the study were HNSCC of the oral cavity, oropharynx, hypopharynx, larynx, nasopharynx, and carcinoma of unknown primary site (CUPS) with cervical metastasis. The study design was to evaluate the cases of HNSCC initially by staging with conventional investigations followed by staging with the information derived from WB ¹⁸ F-FDG PET-CT scan. At the end of the conventional investigations, a tumor, node, metastasis (TNM) staging as per AJCC 7 ^th edition, and a detailed treatment plan as per NCCN 2012 guidelines was decided in consultation with the multidisciplinary oncology team of the hospital. WB ¹⁸ F-FDG PET-CT scan was carried out in all these patients. The findings of WB ¹⁸ F-FDG PET-CT were then interpreted with the staging with conventional investigations to identify the cases with change in staging and also those in whom the treatment protocol would be affected. Descriptive analysis of demographic data and analytical analysis of the sensitivity and specificity of WB ¹⁸ F-FDG PET-CT scan and also the change in staging and treatment plan after WB ¹⁸ F-FDG PET-CT scan was analyzed using SPSS version 18. A total of 131 patients met the inclusion criteria, which included 123 males and 8 females. The various sites involved among the study group are oral cavity 11 (8.3%), oropharyn × 39 (29.7%), hypopharyn × 31 (23.6%), laryn × 34 (25.9%), nasopharyn × 4 (3%), and CUPS 12 (9.1%). The majority of cases studied were of T2 and T3 stage, and changes in T staging after WB ¹⁸ F-FDG PET-CT scan were minimal and not statistically significant (P > 0.5). In the nodal staging after WB ¹⁸ F-FDG PET-CT scan, there was a statistically significant change in identification of nodal metastasis in N0 group and also identification of additional multiple/bilateral nodes (N2b and N2c). 3 (2.2%) patients had a change in M status with identification of distant metastasis in lungs (2 patients) and in the liver and lung (1 patient). Of the 131 patients, 75 (57.25%) underwent surgical management with or without adjuvant treatment (Group I) and 56 (42.74%) patients underwent nonsurgical management (Group II). There was no significant statistical difference in sensitivity and specificity of ¹⁸ F-FDG PET-CT scan in detecting cancer among the two groups. Considering all the patients in this study, WB ¹⁸ F-FDG PET-CT scan showed an overall sensitivity of 95.2% and specificity of 80%. In this study, change in TNM staging after WB ¹⁸ F-FDG PET-CT was seen in 22 (16.8%) patients and an alteration in the treatment in 21 (16.1%) patients, which were both found to be statistically significant (P < 0.5). In our study, WB ¹⁸ F-FDG PET-CT scan has shown to have an impact on initial staging of disease affecting the change in treatment protocol in a significant number of patients. The effect of this change in staging and treatment on the eventual morbidity and mortality rates is not known. In practice, the use of ¹⁸ F-FDG PET-CT scan is limited, owing to the high cost and low availability. A realistic evaluation of cost versus benefit needs to be undertaken to identify the impact of using ¹⁸ F-FDG PET-CT scan as a mode for initial evaluation of HNSCC.

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Inflammatory myofibroblastic tumor (IMT) is a rare neoplasm, most commonly seen in children and adolescents. It can occur in nearly every part of the body. Imaging properties and the clinical presentation of IMT can mimic malignant process. A 41-year-old female presented with cough of 3 months duration. Chest X-ray showed a coin shadow in the right upper lobe. Positron emission tomography/computed tomography scan showed a 3.2 × 2.4 cm lesion with homogeneous appearance with a very high fluorodeoxyglucose uptake value, suggesting a neoplastic process. She underwent lobectomy and the final diagnosis was IMT.

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Single-photon emission computed tomography (SPECT)-based tracers are easily available and more widely used than positron emission tomography (PET)-based tracers, and SPECT imaging still remains the most prevalent nuclear medicine imaging modality worldwide. The aim of this study is to implement an image-based Monte Carlo method for patient-specific three-dimensional (3D) absorbed dose calculation in patients after injection of ^99m Tc-hydrazinonicotinamide (hynic)-Tyr ³ -octreotide as a SPECT radiotracer. ^99m Tc patient-specific S values and the absorbed doses were calculated with GATE code for each source-target organ pair in four patients who were imaged for suspected neuroendocrine tumors. Each patient underwent multiple whole-body planar scans as well as SPECT imaging over a period of 1-24 h after intravenous injection of ^99m hynic-Tyr ³ -octreotide. The patient-specific S values calculated by GATE Monte Carlo code and the corresponding S values obtained by MIRDOSE program differed within 4.3% on an average for self-irradiation, and differed within 69.6% on an average for cross-irradiation. However, the agreement between total organ doses calculated by GATE code and MIRDOSE program for all patients was reasonably well (percentage difference was about 4.6% on an average). Normal and tumor absorbed doses calculated with GATE were slightly higher than those calculated with MIRDOSE program. The average ratio of GATE absorbed doses to MIRDOSE was 1.07 ± 0.11 (ranging from 0.94 to 1.36). According to the results, it is proposed that when cross-organ irradiation is dominant, a comprehensive approach such as GATE Monte Carlo dosimetry be used since it provides more reliable dosimetric results.

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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.

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The aim of our study was to correlate tumor uptake of ⁶⁸Ga-DOTA-NOC positron emission tomography/computed tomography (PET/CT) with the pathological grade of neuroendocrine tumors (NETs). ⁶⁸Ga-DOTA-NOC PET/CT examinations in 41 patients with histopathologically proven NETs were included in the study. Maximum standardized uptake value (SUV_max) and averaged SUV SUV_mean of “main tumor lesions” were calculated for quantitative analyses after background subtraction. Uptake on main tumor lesions was compared and correlated with the tumor histological grade based on Ki-67 index and pathological differentiation. Classification was performed into three grades according to Ki-67 levels; low grade: Ki-67 <2, intermediate grade: Ki-67 3–20, and high grade: Ki-67 >20. Pathological differentiation was graded into well- and poorly differentiated groups. The values were compared and evaluated for correlation and agreement between the two parameters was performed. Our study revealed negatively fair agreement between SUV_max of tumor and Ki-67 index (r = −0.241) and negatively poor agreement between SUV_mean of tumor and Ki-67 index (r = −0.094). SUV_max of low-grade, intermediate-grade, and high-grade Ki-67 index is 26.18 ± 14.56, 30.71 ± 24.44, and 6.60 ± 4.59, respectively. Meanwhile, SUV_mean of low-grade, intermediate-grade, and high-grade Ki-67 is 8.92 ± 7.15, 9.09 ± 5.18, and 3.00 ± 1.38, respectively. As expected, there was statistically significant decreased SUV_max and SUV_mean in high-grade tumors (poorly differentiated NETs) as compared with low- and intermediate-grade tumors (well-differentiated NETs). SUV of ⁶⁸Ga-DOTA-NOC PET/CT is not correlated with histological grade of NETs. However, there was statistically significant decreased tumor uptake of ⁶⁸Ga-DOTA-NOC in poorly differentiated NETs as compared with the well-differentiated group. As a result of this pilot study, we confirm that the lower tumor uptake of ⁶⁸Ga-DOTA-NOC may be associated with aggressive behavior and may, therefore, result in poor prognosis.

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Peptide receptor radionuclide therapy (PRRT) has recently been established as an important treatment modality for somatostatin receptor (SSTR)-positive tumors. The purpose of this study was to evaluate the clinical response, side-effects as well as the quality of life following ⁹⁰ Y-DOTA-lanreotide (DOTALAN) and/or ⁹⁰ Y-DOTA-Tyr ³ -DPhe ¹ -octreotide (DOTATOC) therapy in patients with progressive metastatic disease during a 6-year follow-up period. Following dosimetric evaluation with ¹¹¹ In-DOTALAN and ¹¹¹ In-DOTATOC, 13 patients with estimated absorbed tumor doses of >5 Gy/GBq (carcinoid, n = 5; radioiodine-negative thyroid cancer, n = 4; gastrinoma, n = 1; insulinoma, n = 1; glucagonoma, n = 1; glomus jugularis tumor, n = 1) were assigned for PRRT. A dose of 925 MBq of ⁹⁰ Y-DOTALAN (four patients) or 1.85-3.7 GBq of ⁹⁰ Y-DOTATOC (10 patients) was administered intravenously and repeated every 4-8 weeks. Tumor dosimetry was performed prior to and under therapy, re-staging every 2-3 months. Pain intensity, Karnofsky score and general symptoms were evaluated in order to determine quality of life. Patients were followed until death. Altogether, 53 infusions of PRRT (1.85-14.1 GBq) were administered. After the first follow-up of 3 months of ⁹⁰ Y-DOTALAN therapy, stable disease (SD) was observed in one patient and progressive disease (PD) in three patients. With ⁹⁰ Y-DOTATOC therapy, SD was found in all 10 patients. During the re-evaluation period (4-27 months), one patient had to be shifted from ⁹⁰ Y-DOTALAN to ⁹⁰ Y-DOTATOC therapy due to reduced ¹¹¹ In-DOTALAN uptake after 5.5 GBq. In the first 6 months after PRRT with DOTATOC, SD was found in nine of 10 patients and PD in one patient. Thereafter, SD was observed in two patients and PD in eight patients. Nine of 13 patients after PRRT with either DOTALAN or DOTATOC died. None of the patients had experienced severe acute hematological side-effects. Transient thrombocytopenia or lymphocytopenia was seen in 10 patients after 3.7 GBq, and a skin reaction in one patient. Total accumulated kidney dose ranged between 4 and 64 Gy, with reduced creatinine clearance in two patients. Pain relief was achieved in three of three patients after ~3.7 GBq ERT within 4-6 months. Appetite, weight, Karnofsky score and general well-being had improved in patients with SD during and after therapy. Based on the results of this study conducted on a small group of patients, we conclude that PRRT may offer an alternative treatment option for SSTR-positive tumors, with only mild transient side-effects and a marked improvement in the quality of life.

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