Nuclear cardiology practices and radiation exposure in Africa: results from the IAEA Nuclear Cardiology Protocols Study (INCAPS).

OBJECTIVE: While nuclear myocardial perfusion imaging (MPI) offers many benefits to patients with known or suspected cardiovascular disease, concerns exist regarding radiation-associated health effects. Little is known regarding MPI practice in Africa. We sought to characterise radiation doses and the use of MPI best practices that could minimise radiation in African nuclear cardiology laboratories, and compare these to practice worldwide. METHODS: Demographics and clinical characteristics were collected for a consecutive sample of 348 patients from 12 laboratories in six African countries over a one-week period from March to April 2013. Radiation effective dose (ED) was estimated for each patient. A quality index (QI) enumerating adherence to eight best practices, identified a priori by an IAEA expert panel, was calculated for each laboratory. We compared these metrics with those from 7 563 patients from 296 laboratories outside Africa. RESULTS: Median (interquartile range) patient ED in Africa was similar to that of the rest of the world [9.1 (5.1-15.6) vs 10.3 mSv (6.8-12.6), p = 0.14], although a larger proportion of African patients received a low ED, ≤ 9 mSv targeted in societal recommendations (49.7 vs 38.2%, p < 0.001). Bestpractice adherence was higher among African laboratories (QI score: 6.3 ± 1.2 vs 5.4 ± 1.3, p = 0.013). However, median ED varied significantly among African laboratories (range: 2.0-16.3 mSv; p < 0.0001) and QI range was 4-8. CONCLUSION: Patient radiation dose from MPI in Africa was similar to that in the rest of the world, and adherence to best practices was relatively high in African laboratories. Nevertheless there remain opportunities to further reduce radiation exposure to African patients from MPI.

Nuclear Cardiology Practice in Asia: Analysis of Radiation Exposure and Best Practice for Myocardial Perfusion Imaging　- Results From the IAEA Nuclear Cardiology Protocols Cross-Sectional Study (INCAPS).

BACKGROUND: This paper examines the current status of radiation exposure to patients in myocardial perfusion imaging (MPI) in Asia.Methods and Results:Laboratories voluntarily provided information on MPI performed over a 1-week period. Eight best practice criteria regarding MPI were predefined by an expert panel. Implementation of ≥6 best practices (quality index [QI] ≥6) was pre-specified as a desirable goal for keeping radiation exposure at a low level. Radiation effective dose (ED) in 1,469 patients and QI of 69 laboratories in Asia were compared against data from 239 laboratories in the rest of the world (RoW). Mean ED was significantly higher in Asia (11.4 vs. 9.6 mSv; P<0.0001), with significantly lower doses in South-East vs. East Asia (9.7 vs. 12.7 mSv; P<0.0001). QI in Asia was lower than in RoW. In comparison with RoW, Asian laboratories used thallium more frequently, used weight-based technetium dosing less frequently, and trended towards a lower rate of stress-only imaging. CONCLUSIONS: MPI radiation dose in Asia is higher than that in the RoW and linked to less consistent use of laboratory best practices such as avoidance of thallium, weight-based dosing, and use of stress-only imaging. Given that MPI is performed in Asia within a diverse array of medical contexts, laboratory-specific adoption of best practices offers numerous opportunities to improve quality of care.

Opportunities for improvement on current nuclear cardiology practices and radiation exposure in Latin America: Findings from the 65-country IAEA Nuclear Cardiology Protocols cross-sectional Study (INCAPS).

BACKGROUND: Comparison of Latin American (LA) nuclear cardiology (NC) practice with that in the rest of the world (RoW) will identify areas for improvement and lead to educational activities to reduce radiation exposure from NC. METHODS AND RESULTS: INCAPS collected data on all SPECT and PET procedures performed during a single week in March-April 2013 in 36 laboratories in 10 LA countries (n = 1139), and 272 laboratories in 55 countries in RoW (n = 6772). Eight "best practices" were identified a priori and a radiation-related Quality Index (QI) was devised indicating the number used. Mean radiation effective dose (ED) in LA was higher than in RoW (11.8 vs 9.1 mSv, p < 0.001). Within a populous country like Brazil, a wide variation in laboratory mean ED was found, ranging from 8.4 to 17.8 mSv. Only 11% of LA laboratories achieved median ED <9 mSv, compared to 32% in RoW (p < 0.001). QIs ranged from 2 in a laboratory in Mexico to 7 in a laboratory in Cuba. Three major opportunities to reduce ED for LA patients were identified: (1) more laboratories could implement stress-only imaging, (2) camera-based methods of ED reduction, including prone imaging, could be more frequently used, and (3) injected activity of 99mTc could be adjusted reflecting patient weight/habitus. CONCLUSIONS: On average, radiation dose from NC is higher in LA compared to RoW, with median laboratory ED <9 mSv achieved only one third as frequently as in RoW. Opportunities to reduce radiation exposure in LA have been identified and guideline-based recommendations made to optimize protocols and adhere to the "as low as reasonably achievable" (ALARA) principle.

Nuclear Cardiology Practices and Radiation Exposure in the Oceania Region: Results From the IAEA Nuclear Cardiology Protocols Study (INCAPS).

BACKGROUND: There is concern about radiation exposure with radionuclide myocardial perfusion imaging (MPI). This sub-study of the International Atomic Energy Agency (IAEA) Nuclear Cardiology Protocols Study reports radiation doses from MPI, and use of dose-optimisation protocols in Australia and New Zealand (ANZ), and compares them with data from the rest of the world. METHODS: Data were collected from 7911 MPI studies performed in 308 laboratories worldwide in one week in 2013, including 439 MPI studies from 34 ANZ laboratories. For each laboratory, effective radiation dose (ED) and a quality index (QI) score (out of 8) based on pre-specified "best practices" was determined. RESULTS: In ANZ patients, ED ranged from 0.9-17.9 milliSievert (mSv). Median ED was similar in ANZ compared with the rest of the world (10.0 (IQR: 6.5-11.7) vs. 10.0 (IQR 6.4-12.6, P=0.15), as were mean QI scores (5.5±0.7 vs. 5.4±1.3, P=0.84). Use of stress-only imaging (17.6% vs. 31.8% of labs, P=0.09) and weight-based dosing of technetium-99m (14.7% vs. 30.3%, P=0.07) was lower in ANZ compared with the rest of the world but this difference was not statistically significant. Median ED was significantly lower in metropolitan versus non-metropolitan laboratories (10.1 mSv vs. 11.6 mSv, P<0.01), although mean QI scores were similar (5.4±0.8 vs. 5.5±0.7, P=0.75). CONCLUSION: Across ANZ, there is variability in ED from MPI, and use of radiation safety practices, particularly between metropolitan and non-metropolitan laboratories. Overall, ANZ laboratories have a similar median ED to laboratories in the rest of the world.

Functional compared to anatomical imaging in the initial evaluation of patients with suspected coronary artery disease: An international, multi-center, randomized controlled trial (IAEA-SPECT/CTA study).

OBJECTIVE: To test the hypothesis that, in the initial evaluation of patients with suspected coronary artery disease (CAD), stress myocardial perfusion imaging (MPI) would result in less downstream testing than coronary computed tomographic angiography (CCTA). METHODS: In this international, randomized trial, mildly symptomatic patients with an intermediate likelihood of having CAD, and asymptomatic patients at intermediate risk of cardiac events, underwent either initial stress-rest MPI or CCTA. The primary outcome was downstream noninvasive or invasive testing at 6 months. Secondary outcomes included cumulative effective radiation dose (ERD) and costs at 12 months. RESULTS: We recruited 303 patients (151 MPI and 152 CTA) from 6 centers in 6 countries. The initial MPI was abnormal in 29% (41/143) and CCTA in 56% (79/141) of patients. Fewer patients undergoing initial stress-rest MPI had further downstream testing at 6 months (adjusted OR 0.51, 95% CI 0.28-0.91, P = 0.023). There was a small increase in the median cumulative ERD with MPI (9.6 vs. 8.8 mSv, P = 0.04), but no difference in costs between the two strategies at 12 months. CONCLUSION: In the management of patients with suspected CAD, a strategy of initial stress MPI is substantially less likely to require further downstream testing than initial testing with CCTA. TRIAL REGISTRATION: clinicaltrials.gov identification number NCT01368770.

Gender Differences in Radiation Dose From Nuclear Cardiology Studies Across the World: Findings From the INCAPS Registry.

OBJECTIVES: The aim of this study was to investigate gender-based differences in nuclear cardiology practice globally, with a particular focus on laboratory volume, radiation dose, protocols, and best practices. BACKGROUND: It is unclear whether gender-based differences exist in radiation exposure for nuclear cardiology procedures. METHODS: In a large, multicenter, observational, cross-sectional study encompassing 7,911 patients in 65 countries, radiation effective dose was estimated for each examination. Patient-level best practices relating to radiation exposure were compared between genders. Analysis of covariance was used to determine any difference in radiation exposure according to gender, region, and the interaction between gender and region. Linear, logistic, and hierarchical regression models were developed to evaluate gender-based differences in radiation exposure and laboratory adherence to best practices. The study also included the United Nations Gender Inequality Index and Human Development Index as covariates in multivariable models. RESULTS: The proportion of myocardial perfusion imaging studies performed in women varied among countries; however, there was no significant correlation with the Gender Inequality Index. Globally, mean effective dose for nuclear cardiology procedures was only slightly lower in women (9.6 ± 4.5 mSv) than in men (10.3 ± 4.5 mSv; p < 0.001), with a difference of only 0.3 mSv in a multivariable model adjusting for patients' age and weight. Stress-only imaging was performed more frequently in women (12.5% vs. 8.4%; p < 0.001); however, camera-based dose reduction strategies were used less frequently in women (58.6% vs. 65.5%; p < 0.001). CONCLUSIONS: Despite significant worldwide variation in best practice use and radiation doses from nuclear cardiology procedures, only small differences were observed between genders worldwide. Regional variations noted in myocardial perfusion imaging use and radiation dose offer potential opportunities to address gender-related differences in delivery of nuclear cardiology care.

Nuclear cardiology practice and associated radiation doses in Europe: results of the IAEA Nuclear Cardiology Protocols Study (INCAPS) for the 27 European countries.

PURPOSE: Nuclear cardiology is widely used to diagnose coronary artery disease and to guide patient management, but data on current practices, radiation dose-related best practices, and radiation doses are scarce. To address these issues, the IAEA conducted a worldwide study of nuclear cardiology practice. We present the European subanalysis. METHODS: In March 2013, the IAEA invited laboratories across the world to document all SPECT and PET studies performed in one week. The data included age, gender, weight, radiopharmaceuticals, injected activities, camera type, positioning, hardware and software. Radiation effective dose was calculated for each patient. A quality score was defined for each laboratory as the number followed of eight predefined best practices with a bearing on radiation exposure (range of quality score 0 - 8). The participating European countries were assigned to regions (North, East, South, and West). Comparisons were performed between the four European regions and between Europe and the rest-of-the-world (RoW). RESULTS: Data on 2,381 European patients undergoing nuclear cardiology procedures in 102 laboratories in 27 countries were collected. A cardiac SPECT study was performed in 97.9 % of the patients, and a PET study in 2.1 %. The average effective dose of SPECT was 8.0 ± 3.4 mSv (RoW 11.4 ± 4.3 mSv; P < 0.001) and of PET was 2.6 ± 1.5 mSv (RoW 3.8 ± 2.5 mSv; P < 0.001). The mean effective doses of SPECT and PET differed between European regions (P < 0.001 and P = 0.002, respectively). The mean quality score was 6.2 ± 1.2, which was higher than the RoW score (5.0 ± 1.1; P < 0.001). Adherence to best practices did not differ significantly among the European regions (range 6 to 6.4; P = 0.73). Of the best practices, stress-only imaging and weight-adjusted dosing were the least commonly used. CONCLUSION: In Europe, the mean effective dose from nuclear cardiology is lower and the average quality score is higher than in the RoW. There is regional variation in effective dose in relation to the best practice quality score. A possible reason for the differences between Europe and the RoW could be the safety culture fostered by actions under the Euratom directives and the implementation of diagnostic reference levels. Stress-only imaging and weight-adjusted activity might be targets for optimization of European nuclear cardiology practice.

Current worldwide nuclear cardiology practices and radiation exposure: results from the 65 country IAEA Nuclear Cardiology Protocols Cross-Sectional Study (INCAPS).

AIMS: To characterize patient radiation doses from nuclear myocardial perfusion imaging (MPI) and the use of radiation-optimizing 'best practices' worldwide, and to evaluate the relationship between laboratory use of best practices and patient radiation dose. METHODS AND RESULTS: We conducted an observational cross-sectional study of protocols used for all 7911 MPI studies performed in 308 nuclear cardiology laboratories in 65 countries for a single week in March-April 2013. Eight 'best practices' relating to radiation exposure were identified a priori by an expert committee, and a radiation-related quality index (QI) devised indicating the number of best practices used by a laboratory. Patient radiation effective dose (ED) ranged between 0.8 and 35.6 mSv (median 10.0 mSv). Average laboratory ED ranged from 2.2 to 24.4 mSv (median 10.4 mSv); only 91 (30%) laboratories achieved the median ED ≤ 9 mSv recommended by guidelines. Laboratory QIs ranged from 2 to 8 (median 5). Both ED and QI differed significantly between laboratories, countries, and world regions. The lowest median ED (8.0 mSv), in Europe, coincided with high best-practice adherence (mean laboratory QI 6.2). The highest doses (median 12.1 mSv) and low QI (4.9) occurred in Latin America. In hierarchical regression modelling, patients undergoing MPI at laboratories following more 'best practices' had lower EDs. CONCLUSION: Marked worldwide variation exists in radiation safety practices pertaining to MPI, with targeted EDs currently achieved in a minority of laboratories. The significant relationship between best-practice implementation and lower doses indicates numerous opportunities to reduce radiation exposure from MPI globally.

IAEA programs in empowering the nuclear medicine profession through online educational resources.

The International Atomic Energy Agency's (IAEA) programme in human health aims to enhance the capabilities in Member States to address needs related to the prevention, diagnosis, and treatment of diseases through the application of nuclear techniques. It has the specific mission of fostering the application of nuclear medicine techniques as part of the clinical management of certain types of diseases. Attuned to the continuous evolution of this specialty as well as to the advancement and diversity of methods in delivering capacity building efforts in this digital age, the section of nuclear medicine of the IAEA has enhanced its program by incorporating online educational resources for nuclear medicine professionals into its repertoire of projects to further its commitment in addressing the needs of its Member States in the field of nuclear medicine. Through online educational resources such as the Human Health Campus website, e-learning modules, and scheduled interactive webinars, a validation of the commitment by the IAEA in addressing the needs of its Member States in the field of nuclear medicine is strengthened while utilizing the advanced internet and communications technology which is progressively becoming available worldwide. The Human Health Campus (www.humanhealth.iaea.org) is the online educational resources initiative of the Division of Human Health of the IAEA geared toward enhancing professional knowledge of health professionals in radiation medicine (nuclear medicine and diagnostic imaging, radiation oncology, and medical radiation physics), and nutrition. E-learning modules provide an interactive learning environment to its users while providing immediate feedback for each task accomplished. Webinars, unlike webcasts, offer the opportunity of enhanced interaction with the learners facilitated through slide shows where the presenter guides and engages the audience using video and live streaming. This paper explores the IAEA's available online educational resources programs geared toward the enhancement of the nuclear medicine profession as delivered by the section of nuclear medicine of the IAEA.

Quality management in nuclear medicine for better patient care: the IAEA program.

The International Atomic Energy Agency promotes the practice of nuclear medicine among its Member States with a focus on quality and safety. It considers quality culture as a part of the educational process and as a tool to reduce heterogeneity in the practice of nuclear medicine, and in turn, patient care. Sensitization about quality is incorporated in all its delivery mechanisms. The Agency has developed a structured peer-review process called quality management (QM) audits in nuclear medicine practices to help nuclear medicine facilities improve their quality through this voluntary comprehensive audit process. The process is multidisciplinary, covering all aspects of nuclear medicine practice with a focus on the patient. It complements other QM and accreditation approaches developed by professional societies or accreditation agencies. The Agency is committed to propagate its utility and assist in the implementation process. Similar auditing programs for practice in diagnostic radiology and radiotherapy, called QUADRIL and QUATRO, respectively, are also in place. Necessary amendments in the auditing process and content are incorporated based on technological and practice changes with time. The reader will become familiar with the approach of the Agency on QM in nuclear medicine and its implementation process to improve patient care.

Role of 99mTc-Tetrofosmin delayed scintigraphy and color Doppler sonography in characterization of solitary thyroid nodules.

OBJECTIVES: A study was undertaken to evaluate the diagnostic efficiency of Tc-Tetrofosmin scan and color Doppler in the characterization of benign and malignant solitary thyroid nodules. METHODS: Fifty-two patients found to have a cold solitary thyroid nodule on Tc-pertechnetate scintigraphy were included in this study. All patients underwent a single-injection dual-phase (30 min and 120 min) Tc-Tetrofosmin scan. The intranodular vascularity was measured using color Doppler sonography. Fine-needle aspiration cytology was performed on all the patients. In the following days and weeks all patients underwent surgery. RESULTS: Thirteen out of 15 patients with thyroid cancer showed delayed retention of radiotracer (on 120 min images as compared to the initial 30 min image). Thirty-six out of 37 patients harboring benign solitary nodules showed significant washout of tracer on delayed images. Sensitivity, specificity, positive predictive value and negative predictive value of delayed Tc-Tetrofosmin scintigraphy were found to be 86.6, 97.2, 92.8 and 94.7%, respectively. The Doppler study was able to demonstrate increased vascularity in the center of 8 of the 15 malignant nodules. Thirty-two patients harboring a benign solitary nodule showed normal or increased peripheral vascularity on Doppler study. Sensitivity, specificity, positive predictive value and negative predictive value of color Doppler were found to be 53.5, 86.4, 61.5 and 82%, respectively. CONCLUSION: Delayed Tc-Tetrofosmin scintigraphy is a highly sensitive and specific method for characterizing solitary thyroid nodules, while color Doppler has a low sensitivity but relatively high specificity in differentiating benign from malignant thyroid lesions.

Anti-inflammatory activity of Seabuckthorn (Hippophae rhamnoides) leaves.

Immunomodulatory activity of Seabuckthorn (SBT) leaf extract was evaluated in adjuvant induced arthritis (AIA) rat model. Inflammation was induced by injecting Complete Freund's Adjuvant (CFA) in the right hind paw of rats. SBT extract was administered intraperitoneally to treat the inflammation. The extent of inflammation and treatment response was evaluated by clinical analysis, scintigraphic visualization using technitium-99m-glutathione (Tc99m-GSH) and lymphocyte proliferation. Serial evaluation was carried out on days 1, 7, 14, 21 and 28 after creation of inflammation. The Tc99m-GSH uptake in the inflamed leg was compared with the normal contralateral leg of the same animal. The measurements were done by obtaining scintigraphic images using gamma camera and an online computer. Both qualitative and quantitative evaluation of radiotracer accumulation was considered to evaluate the anti-inflammatory response. The lymphocyte proliferation study revealed cellular immunosuppression during the early phase of the disease. Administration of SBT extract on the same day or 5 days prior to inflammatory insult into the joint, significantly reduced the inflammation as compared to the untreated animals in a dose dependent manner. These observations suggest that the SBT leaf extract has a significant anti-inflammatory activity and has the potential for the treatment of arthritis.

Differentiation of malignant and benign solitary thyroid nodules using 30- and 120-minute tc-99m MIBI scans.

Technetium-99m methoxy isobutylisonitrate (MIBI) has been found to be taken up by various tumors, including thyroid cancer. We prospectively evaluated 77 patients with cold thyroid solitary nodules on Tc-99m pertechnetate scintigraphy to evaluate the diagnostic value of Tc-99m MIBI scintigraphy. The aim of this study was to find out if thyroid nodules can be characterized on the basis of retention of MIBI and whether preoperative evaluation of malignancy is possible using this method. Single injection, dual-phase (30 and 120 minutes) thyroid scintigraphy using Tc-99m MIBI was performed in all these patients. In the following days and weeks, all patients underwent surgery. Using the 120/30-minute thyroid lesion to background radiouptake ratio (RUR), malignant and benign thyroid nodules could be separated with a sensitivity, specificity, and positive predictive value of 84.4%, 95.45%, and 93.33%, respectively. The mean RUR for malignant thyroid lesions was found to be 1.57+/-0.32, whereas for benign lesions, the ratio was significantly lower, 0.32+/-0.19. In conclusion, fine needle aspiration cytology along with the 120/30 minutes Tc-99m MIBI scintigraphy ratio appears to be useful in the preoperative assessment of solitary thyroid nodules.

Unusual widespread metastatic presentation of mixed medullary-follicular thyroid carcinoma.

Mixed medullary-follicular thyroid carcinoma (MMFTC) is a rare tumor with a metastatic behavior that has not been fully appreciated. Scintigraphy and radioiodine entrapment propensity of its metastases remains largely undescribed. The authors present a case of MMFTC with widespread bone and soft-tissue metastases, where every known site of metastases concentrated radioiodine intensely. The patient responded well to radioiodine therapy. The report suggests that the tumor may have a propensity to metastasize to the skeleton, and the metastases retain the ability to accumulate radioiodine.

Detecting protein losing enteropathy by Tc-99m dextran scintigraphy: a novel experience.

OBJECTIVE: To evaluate protien using enteropathy by Tc-99m dextran scintigraphy. METHODS: Methods for detecting protein loss from the intestine revolve around fecal nitrogen excretion, the clearance of alpha-1 antitrypsin in stools and by endoscopic biopsy. RESULT: The diagnosis of protein-losing enteropathy (PLE) can also be established by a scintigraphic method that is noninvasive, simple and requires no patient preparation or motivation. This diagnostic modality can also delineate the site of protein loss, thereby offering a targeted approach, and if need be, surgery. Radiolabelling of a non-protein, noncolloidal, nonparticulate and biofriendly molecule like dextran with Technetium-99m for imaging enteric protein loss was utilized in imaging eight children with PLE. CONCLUSION: The results were encouraging. The authors advocate the use of this diagnostic tool in identifying patients with PLE, particularly in the pediatric age group.

Etiology and clinical predictors of intractable epilepsy.

To determine the etiology and clinical predictors of intractable epilepsy, a case-control study comprising 50 patients and 50 control subjects was performed. Patients included children who had more than one seizure per month over at least 6 months. Control subjects included children with epilepsy who had been seizure-free for more than 6 months. Patients were evaluated with special reference to birth history and development. Clinical examination and neurodevelopmental assessment were performed in all the patients. Drug monitoring was performed to exclude pseudointractability. Epilepsy in the study group was caused by perinatal problems (48%) and sequelae of central nervous system infection (24%) and was idiopathic in 20%. In the control group, epilepsy was idiopathic in 72%, a result of calcified granuloma in 22%, and perinatal problems comprised 6% of the subjects. On univariate analysis, strong association was evident between intractable epilepsy and several factors, including age at onset of seizure, remote symptomatic epilepsy, initial seizure type, history of neonatal seizure, high initial seizure frequency, microcephaly, and neurologic impairment. On multivariate analysis, neurologic impairment (odds ratio [OR] 12.25; 95% confidence interval [CI] 3.58-41.89), age at onset of seizure less than 1 year (OR 11.70; 95% CI 2.95-46.43), myoclonic seizure/infantile spasm (OR 10.36; 95% CI 2.39-44.93), and remote symptomatic epilepsy (OR 2.9; 95% CI 1.13-7.43), were independent predictors of intractability.