Somatostatin-receptor avidity of pancreatic neuroendocrine tumor thrombus in porto-caval venous systems on 99mTc-Octreotide and posttherapeutic 177Lu-DOTA-TATE scans.

A 62-year-old woman with a history of abdominal pain presented with multiple hepatic lesions and dilatation of portal, splenic and superior mesenteric veins on the magnetic resonance imaging referred for a 99mTc-octreotide scan. Accordingly, similar octreotide-avid lesions were found as well as an uptake in the epigastric region conforming to the anatomy of the portocaval venous system, compatible with a tumor thrombosis. Then, the patient underwent two cycles of therapy with 177Lu-DOTA-TATE, on that the same appearance was observed. The uptake in the tumor thrombus remained somewhat unchanged, but clinically, a significant improvement of the intractable ascites was achieved.

"Picture-in-Picture" Artifact: Introduction and Characterization of a Hitherto Unrecognized Imaging Artifact in Creating Perfusion Defects in Myocardial Perfusion Single-Photon Emission Computed Tomography.

Following a moving hot spot in the projections of raw images and profound perfusion defects in myocardial perfusion single-photon emission computed tomography (SPECT) imaging of a patient, a hypothesis was postulated that the perfusion defects were artifactual, and the high activity concentration of the gallbladder may be a culprit for this phenomenon, owing to flawed event positioning function of the gamma camera due to a malfunctioning digital event processor electronics board. To depict the characteristics of this artifact, a point source containing an activity of 3 mCi of pertechnetate is placed on the scanning table with the detector facing the table (at a distance of 30 cm), and then, in other detector positions and 1-min static images are acquired accordingly. The ratio is calculated as follows: count of the artifactual focus: 1860, count of the index focus: 705,727, and artifactual-to-index focus ratio: 0.003. In testing the uniformity of gamma camera based on the National Electrical Manufacturers Association protocol, a nonuniform response was detected, seemingly, a smaller field of view (FOV) is reproduced in the main FOV causing nonuniformity more than the acceptable level. The smaller flood image lies in the upper right corner of the main flood image. In essence, the extremely bright gallbladder was the source of error, and its image was reproduced in the FOV, which was superimposed on the left ventricular myocardium in some of the projections and was propagated to SPECT images.

Comparison of radioiodine ablation rates between low versus high dose, and according to the surgeon's expertise in the low-risk group of differentiated thyroid cancer.

Radioiodine ablation following surgery is the accepted treatment for patients with differentiated thyroid cancer (DTC). Since that surgical volume and radioiodine dose can have impact on treatment outcome, we aimed to evaluate them on the treatment outcome of low-risk DTC patients. Low-risk DTC patients were classified into four groups, including (1) thyroidectomy was performed by thyroid surgeon and low-dose (1850 MBq [30 mCi]) radioiodine was administered (n = 17), (2) thyroidectomy was performed by thyroid surgeon and high-dose (3700 MBq [100 mCi]) radioiodine was administered (n = 10), (3) thyroidectomy was performed by general surgeon and low-dose radioiodine was administered (n = 22), and (4) thyroidectomy was performed by general surgeon and high-dose radioiodine was administered (n = 29). All patients were followed at least for 6 months and also for evaluation of treatment success, neck sonography, thyroid-stimulating hormone-off, thyroglobulin (Tg)-off, and anti-Tg-off tests were performed. Furthermore, two common radioiodine treatment-associated side effects, including dry mouth, and nausea/vomiting were assessed for all patients. Seventy-eight low-risk DTC patients (female: 70 [89.7%]; male: 8 [10.3%]) aged from 18 to 78 years old with mean of 41.96 ± 13.42 years were enrolled in this study. In total, the treatment was successful in 96.2% of patients. There was no significant difference in treatment success among groups (P > 0.05), while there was a significant association among administered activity and side effects. In low dose patients, only one patient complained from dry mouth; however, 11/39 patients who received high dose of iodine complained from dry mouth (P = 0.002). In addition, 9/39 high dose patients suffered from vomiting/nausea, while none of low-dose patients suffered from vomiting/nausea (P = 0.001). In low-risk DTC patients, surgical volume and amounts of radioiodine had no significant impact on treatment results; therefore, low dose radioiodine following thyroidectomy may be preferable to low-risk DTC patients to avoid side effects.

Technical and patient-related sources of error and artifacts in bone mineral densitometry using dual-energy X-ray absorptiometry: A pictorial review.

Dual-energy X-ray absorptiometry is currently the standard and validated tool for measurement of bone mineral density and for the evaluation of osteoporosis. Current densitometry scanners based on dual-energy X-ray absorptiometry method produce two X-ray beams with different energies to differentiate the overlapped soft tissue and bony structures, by creating two different attenuation profiles. Procedural guidelines are available to technicians and physicians to guarantee the best practice, including consistent positioning during scanning and standard reporting. However, similar to other imaging modalities, dual-energy X-ray absorptiometry may be influenced by technical errors, and thus, imaging artifacts may arise and accuracy and precision of the results may be influenced. This issue may, in turn, affect the final result and interpretation. Hence, the article is arranged with the intention of presenting some less common and rare technical and patient-related sources of error and resultant artifacts, from poor patient preparation to acquisition and data processing. Where appropriate, the corresponding tables of densitometric results (bone mineral density) and statistical parameters (T- and Z-scores) are provided.

Less influence of body mass index on bone mineral density of radius as compared to proximal femur: Possible role in the diagnosis of osteoporosis.

It has been shown that body mass index (BMI) and obesity may affect the mineral density of bones, regionally on weight-bearing bones or systemically through hormones and cytokines. The objective of this study was to evaluate the effect of BMI on bone mineral density (BMD) of the radius. In this cross-sectional study, 260 patients, 233 postmenopausal women and 27 men over 50, were included who underwent a bone densitometry scanning using dual-energy X-ray absorptiometry after obtaining an informed consent. The scanning was performed in three areas (i.e., spine, proximal femur, and radius), then densitometric data (BMD, T- and Z-score) were extracted. Regression analysis was performed to evaluate the effect of independent variables of age, gender, and BMI on the BMD of the above regions. By grouping the patients in two categories (BMI <25 as normal or underweight and BMI >25 as overweight and obese), the discordance in the diagnosis following the inclusion of radius into interpretation (diagnosis based on 2 vs. 3 areas), was assessed by an agreement test. The study is approved by the ethics committee of the university. Of 260 participants in the present study, mean and standard deviation for age were 61.48 ± 8.95 for all patients, 65.81 ± 10.59 for male and 60.98 ± 8.62 for women. An increasing effect of BMI was found to be statistically significant in weight-bearing areas (total femur and femoral neck) and BMI increase was not associated with increased BMD of radius. An agreement test between two diagnoses is used that showed a discordance of 28.5% in diagnosis (diagnosis based on 2 vs. 3 areas) with a kappa coefficient of 0.547 (P = 0.001). In total, 25.4% was minor discordance and 3.1% was major discordance. Based on the results of this study, it is concluded that the BMI is not associated with increased BMD in bones that are not weight bearing, such as radius. Therefore, it may be preferred to include the densitometric data of radius into the diagnosis.

The impact of nonstandard hip rotation on densitometric results of hip regions and potential misclassification of diagnosis.

The present study is intended to investigate the degree to which insufficient internal rotation could impact the densitometric results and change the diagnosis. A significant difference was found between the results in nonstandard compared with standard rotation and an increase in the BMD and T- and Z-scores from nonstandard to standard rotation. Likewise, a change in diagnosis was observed in a significant proportion of patients. PURPOSE: To investigate the impact of nonstandard rotation of hip on the densitometric results of femoral neck and total femur region as well as the amount of change in diagnosis (i.e., misclassification of diagnosis) based on hip region. METHODS: Ninety-seven patients (88 females and 9 males) were included in the study. After receiving informed consent, each subject underwent a densitometric scanning in two modes, one with standard rotation of the leg and the other with nonstandard rotation (i.e., the leg in relaxed position without applying the positioner to strap the foot to) of the same leg. All data were analyzed using the auto-analysis option of the HOLOGIC® software. Bone densitometric results, T- and Z-scores, rate of change in diagnosis, and also the agreement between the diagnoses in the two modes are calculated and compared by using a paired-sample t test and cross-tabulation. RESULTS: The mean age of 97 patients was 56.91 ± 11.70 years. A significant difference was found in the BMDs, T-scores, and Z-scores of the neck and total femur regions of interest in standard and nonstandard rotations. We found an increase in the BMD of the femoral neck and total femur of 0.020 and 0.010 g/cm2, respectively, from standard to nonstandard leg rotation and that this, in turn, led to a 0.4 and a 0.13 increases in T-scores of the neck and total femur, respectively, from standard to nonstandard rotation. In the diagnosis based on femoral neck only, the diagnosis changed in 17 (17.5%) patients, i.e., 12 (12.4%) from osteopenia to normal, 3 (3.1%) from osteoporosis to osteopenia, and 2 (2.0%) from below the expected range for age to within the expected range for age. There was only a change of one level in diagnosis. DISCUSSION AND CONCLUSIONS: According to the results, the changes in the BMD and T- and Z-scores can be interpreted as underdiagnosis or, in simple terms, not finding the disease or underestimating the level of disease. Therefore, proper rotation of the leg is an important factor during densitometry. Any deviation from standard rotation changes the BMD of those regions, and thereby the T- and Z-scores accordingly, and thus the diagnosis.

Shifting paradigms in the management of pediatric differentiated thyroid cancer from static to dynamic risk stratification: a step forward toward precision medicine.

INTRODUCTION: This study aimed to assess the usefulness of a risk-adopted management system known as dynamic risk stratification (DRS) in comparison with the American (ATA) and European Thyroid Associations' (ETA) risk classifications in the management of pediatric patients with differentiated thyroid cancer (DTC). MATERIALS AND METHODS: The current study included 50 pediatric patients with DTC who were treated with total or near total thyroidectomy and radioiodine ablation whose risk assessment was initially defined according to the ATA and ETA guidelines. During the two years after initial treatment, patients were reclassified according to their DRS. RESULTS: The study showed that the ability of the DRS system to predict the final outcome was superior to that of the ATA and ETA guidelines. The observed variance in predicting final outcome was 2.3 % for ETA, 14.8 % for ATA, and 83.4 % for DRS. In intermediate/high-risk patients, according to the ATA/ETA guidelines, an excellent response to initial therapy resulted in a noteworthy reduction (about 40 %) for detection of structural disease at the time of final follow-up. The risk of structural disease at the time of final follow-up was significantly higher in the structural incomplete response group (HR = 23.34, P = 0.00) and biochemical incomplete response group (HR = 13.83, P = 0.03) than in the excellent response group. CONCLUSION: The data documented the significance of re-stratifying pediatric patients with DTC on the basis of the findings obtained at the time of or after their initial therapy (total thyroidectomy and radioiodine ablation), predominantly in the intermediate/high-risk patients. In addition, DRS helped to better modulate the later follow-up, excluding a large number of intermediate/high risk patients from needless intensive workups, allowing personalization of follow-up management.

Jaffe-Campanacci syndrome: Any role for 99mTc-methylene diphosphonate bone and 99mTc-octreotide scans for evaluation of the disorder?

Jaffe-Campanacci syndrome (JCS) is a rare clinical disorder with almost unknown etiology. The main feature of this syndrome is skeletal involvement as nonossifying fibroma which may cause severe morbidity to these patients. X-ray imaging is the widely available modality for evaluation of skeleton, but radionuclide imaging modalities may have a role in workup. Herein, we present a case of JCS evaluated with 99mTc-methylene diphosphonate bone and 99mTc-octreotide scans for the extent of skeletal involvement. To the best of our knowledge, from over than 30 cases reported in the literature, no evaluation with radionuclide imaging has been done.

Coexisting Sources of False-Positive Reflux on a Direct Radionuclide Cystography Scan.

Direct radionuclide cystography is currently a popular method for evaluation of vesicoureteral reflux, despite its pitfalls and drawbacks in producing false-positive results. In this article, we present a case with 2 sources of false-positive reflux on a direct radionuclide cystography scan.

Evaluation of Prognostic Factors Associated With Differentiated Thyroid Carcinoma With Pulmonary Metastasis.

BACKGROUND: Because one of the major sites for metastasis of thyroid cancers is the lung, studying the pattern of pulmonary metastasis may provide useful information for the effective treatment of these patients. In this study, by assessing the metastasis pattern, we aimed to identify the factors that may affect prognosis and response to treatment in patients with differentiated thyroid carcinoma (DTC) with pulmonary metastasis. METHODS: This retrospective study included 75 patients with DTC with pulmonary metastasis who were referred to our nuclear medicine section over a period of 10 years. The data obtained were analyzed with regard to response to treatment to assess the effects of the included factors on prognosis. RESULTS: Of the 1746 patients referred to our section, 75 (4.3%) had pulmonary metastasis. According to the pattern of pulmonary metastasis, they were divided into 4 groups: nodular, diffuse, combined, and other. The mean age of the patients was 43.8 ± 18.5 years. After the follow-up, 58 patients survived, 14 of whom responded to the treatment. The mean number of radioiodine therapy sessions that the patients received was 3.2 ± 2, and the mean cumulative dose was 554.7 ± 387.8 mCi. Statistical analysis of the data revealed that there was no significant difference in the response to treatment between patients with different patterns of pulmonary metastasis (P > 0.3). However, significant differences were reported in the response to treatment between patients with papillary thyroid carcinoma and those with follicular thyroid carcinoma (P < 0.03). The 1-, 5-, and 9-year survival rates were reported as 98%, 76%, and 51%, respectively. CONCLUSIONS: Patients with DTC with pulmonary metastasis have a relatively favorable prognosis and response rate, as well as longer survival. The type of DTC is the only factor that affects the response to treatment.

One size does not fit all: the merit of absorbed doses to the blood in 131I therapy for differentiated thyroid carcinoma.

The amount of 131I necessary for successful ablation in patients with differentiated thyroid cancer (DTC) is still subject to debate. This study investigates the relationship of the absorbed dose of radiation to the blood while administering 131I activity with several other parameters in DTC patients. This prospective study included 90 DTC patients who were classified into three groups according to their level of dosage: 3.7 GBq (38.9%), 5.55 GBq (55.6%), and 7.4 GBq (5.5%). Blood dosimetry of treated patients was performed using external whole-body counting with a Geiger Muller dosimeter located 2 m away from the patients. Dose rate was measured at 2, 4, 5, 24, and 48 h after the administration of radioiodine. Based on the results of whole-body dose rate measurements, 48 h after administration of 3.7, 5.55, and 7.4 GBq of radioiodine, absorbed doses to patients' blood were estimated at 0.49 ± 0.12, 0.71 ± 0.21, and 0.76 ± 0.11 Gy, respectively. Increasing radioiodine dosage from 3.7 GBq to 5.55 GBq significantly increased blood dose, while there was no significant difference in blood dose between radioiodine dosages of 5.55 GBq and 7.4 GBq. The absorbed dose to the blood was significantly correlated to the patients' gender and the presence of lymph node metastases, but it was not significantly correlated to the type of pathology and regional or distant metastases. Ablation activities exceeding 5.55 GBq produce no further increase in the accumulated activity per volume of blood. The literature regarding this issue is scarce, and further studies are required to verify these preliminary results.

Phase 2 study of a high dose of 186Re-HEDP for bone pain palliation in patients with widespread skeletal metastases.

UNLABELLED: (186)Re-1-hydroxyethylidene-1,1-diphosphonate (HEDP) is an attractive radiopharmaceutical for the treatment of bone pain arising from skeletal metastatic lesions. Currently, (186)Re-HEDP is most commonly used in European countries. The aim of this study was to investigate the palliative efficacy and adverse effects of (186)Re-HEDP in patients with different types of cancers and skeletal bone pain. METHODS: Nineteen (8 male, 11 female) patients with various cancers (breast, prostate, renal cell carcinoma, colon, and neuroendocrine tumors) and painful bone metastases were included in the study. A dose of 1,480-3,330 MBq (40-90 mCi) of (186)Re-HEDP was administered intravenously. The patients' level of pain relief was assessed by the Visual Analog Scale for 8 wk after treatment and by a weekly blood cell count to evaluate for hematologic toxicity. RESULTS: The overall response rate was 89.5%, and the mean pain score assessed by the Visual Analog Scale was reduced from 9.1 to 5.3 after 1 wk (P = 0.003). No adverse effects were reported by patients during intravenous administration or for up to 24 h after administration. A flare reaction was seen in 63.2% of patients, mainly during days 1-3, and lasted for 2-4 d. There was no significant correlation between the response to therapy and the flare reactions (P > 0.05). The nadir of platelet reduction occurred at the fourth or fifth week and led to platelet infusion in only 4 patients with a low baseline platelet count and diffuse skeletal metastases. Bone marrow suppression occurred in patients receiving higher doses, but no clinical problems were seen except in 2 patients who required packed cell transfusion similar to their prior transfusions. CONCLUSION: (186)Re-HEDP is an effective radiopharmaceutical for the palliative treatment of metastatic bone pain and has minimal adverse effects.

A study of the time of hospital discharge of differentiated thyroid cancer patients after receiving iodine-131 for thyroid remnant ablation treatment.

The aim of this study was to measure the radiation exposure rate from differentiated thyroid carcinoma (DTC) patients who had received iodine-131 ((131)I) treatment, and to evaluate hospital discharge planning in relation to three different sets of regulations. We studied 100 patients, 78 females and 22 males, aged 13 to 79 years (mean 44.40±15.83 years) with DTC, in three Groups who were treated with 3.7, 5.5 or 7.4GBq of (131)I, respectively. The external whole-body dose rates following oral administration of (131)I were measured after each one of the first three hospitalization days. A multivariant linear analysis was performed, considering exposure rates as dependent variables to the administered dose for treatment, age, gender, regional and/or distant metastases, thyroglobulin (Tg), antibodies to Tg and thyroid remnant in the three dose groups. We found that the exposure rates after each of the three first days of hospitalization were 30, 50 and 70µSvh-1 at 1m. All our DTC patients had an acceptable dose rate on days 2 and 3 that allowed their hospital discharge. After only 1 day of hospitalization, just 3/11 cases showed not permissible exposure rates above 70µSvh-1. In conclusion, it is the opinion of the authors that after measuring the exposure rates, most treated, DTC patients could be discharged after only one day of hospitalization, even some of those treated with high doses of (131)I (7.4GBq). Patients, who received the higher doses of (131)I, should not be released before their individual exposure rate is measured.

Population radiation dose from diagnostic nuclear medicine procedures in the Tehran population in 1999-2003: striking changes in only one decade.

Use of unsealed radiopharmaceuticals in Iran's nuclear medicine centers has expanded rapidly in the last decade. As part of a nationwide survey, this study was undertaken to estimate the radiation risk due to the diagnostic nuclear medicine procedures performed in Tehran in 1999-2003. During the five years of the study, the data of 101,540 yearly examinations of diagnostic nuclear medicine were obtained for 34 (out of 40) active nuclear medicine centers in Tehran. The patients studied were aged 1 y, 5 y, 10 y, 15 y, and adults (>15 y). Compared to an earlier investigation in 1989 (which was published in 1995), striking changes were found to be occurring in the trends of nuclear medicine in Tehran in a matter of a decade. The frequency of cardiac examinations increased from less than 1% in 1989 to 43.2% (mean of 5 y) in 2003; thyroid examinations, with the relative frequency of higher than 80% in 1989, decreased to 26.7% in the current investigation (averaged for 2001); and the number of overall examinations per 1,000 population of Tehran increased from 1.9 in 1989 to 8.8 in this study (about fourfold). The decrease in relative frequency of thyroid examinations could be attributed to the lower referral policy (mainly by specialists), decreased incidence of goiter due to implementation of programs for iodine enrichment diets, introduction of fine needle aspiration (FNA), and sonography techniques for diagnosis of thyroid disease. The large increase in relative frequency of cardiac examinations could be due to the increase in the number of single photon emission computerized tomography (SPECT) systems in recent years as compared to 1989 in Tehran. The collective effective dose increased from 400 (person-Sv) in 1999 to 529 (person-Sv) in 2003, and the effective dose per capita increased from 34.80 µSv in 1999 to 44.06 µSv in 2003 (average, 35.60 µSv).

The diagnostic value of (99m)Tc-IgG scintigraphy in the diabetic foot and comparison with (99m)Tc-MDP scintigraphy.

UNLABELLED: Diabetic foot infection is the most common etiology of nontraumatic amputation of the lower extremities, and early diagnosis is of great importance in its management. The aim of this prospective study was to evaluate the strength of (99m)Tc-IgG scintigraphy in diagnosis of osteomyelitis of the diabetic foot and to compare (99m)Tc-IgG scintigraphy with (99m)Tc-methylene diphosphonate (MDP) scintigraphy. METHODS: A prospective university hospital-based study was performed over 24 mo. Eighteen patients with type II diabetes and foot ulcers (15 men and 3 women; age range, 45-80 y) were referred for imaging because of clinically suspected osteomyelitis. Early (5-h) and late (24-h) (99m)Tc-IgG scanning and 3-phase skeletal scintigraphy were completed for all patients at a 3- to 4-d interval. Regions of interest over the involved bony sites and the contralateral normal sites were drawn, and the abnormal-to-normal ratios were acquired for both (99m)Tc-IgG and (99m)Tc-MDP studies. RESULTS: From a total of 23 lesions, we observed 10 sites of osteomyelitis, 10 sites of cellulitis, and 3 sites of aseptic inflammation confirmed by MRI, clinical presentation, histopathologic examination, and follow-up evaluation as a gold standard. Both (99m)Tc-IgG and (99m)Tc-MDP scanning showed excellent sensitivity for diagnosis of osteomyelitis, but the specificity was significantly lower (69.2% and 53.8%, respectively). Sensitivity, specificity, and accuracy in the diagnosis of osteomyelitis were, respectively, 100%, 53.8%, 73.9% for (99m)Tc-MDP scanning; 100%, 69.2%, 82.6% for 5-h (99m)Tc-IgG scanning; and 60%, 76.9%, 69.5% for 24-h (99m)Tc-IgG scanning. There was no significant difference between the semiquantitative indices of 5-h and 24-h (99m)Tc-IgG scanning for inflammation, cellulitis, and osteomyelitis. CONCLUSION: Although both (99m)Tc-IgG and (99m)Tc-MDP scintigraphy have high sensitivity for the diagnosis of osteomyelitis, the specificity of these studies is poor. For (99m)Tc-IgG scintigraphy, 5-h images appear to be adequate, and there is little benefit to performing additional imaging at 24 h.

Role of 99mTc-ubiquicidin 29-41 scintigraphy to monitor antibiotic therapy in patients with orthopedic infection: a preliminary study.

INTRODUCTION: Ubiquicidin (UBI) 29-41 is a cationic synthetic antimicrobial peptide fragment that binds preferentially with anionic microbial cell membranes at the site of infection. This study evaluated the potential ability of Tc-UBI 29-41 to assess response to antibiotic therapy in orthopedic infection. METHODS: A total of 12 patients, 10 men and two women (mean age, 41.6 years; range, 23-75 years), with suspected orthopedic infection (bone, soft tissue, or prosthesis) and positive Tc-UBI scan for infection were included in the study. One day after the Tc-UBI scan, a bone scan was performed as well. After this evaluation, eight of the nine treated cases responded to the treatment. Then, one nonresponder patient and two nontreated patients of three cases underwent antibiotic therapy and were evaluated again 10-14 days later. After this, one of the two patients not treated the first time responded to therapy and two patients did not. Moreover, one patient refused to undergo therapy both the first and second time. Thus, 11 treated cases were analyzed in this study and divided in two groups: (a) nine treated responders and (b) two treated nonresponders. In all patients, erythrocyte sedimentation rate and C-reactive protein were measured and also wound cultures were assessed. RESULTS: Quantitative analysis of erythrocyte sedimentation rate, C-reactive protein, and bone scan before and after the 10-14-day interval showed no significant change in either group, but a quantitative Tc-UBI scan at 30, 60, and 120 min after tracer injection indicated significant reduction in radiotracer uptake after the 10-14-day interval compared with the Tc-UBI scan before this interval in the responder group, and no significant change in the nonresponder group. CONCLUSION: The Tc-UBI scan can determine response to antibiotic therapy in orthopedic infection in humans.