Patterns and trends of population radiation exposure and projected the risk of exposure-induced death from gamma camera examinations in Yazd Province.

INTRODUCTION: The use of nuclear medicine examinations as imaging modalities has recently increased. This study aimed to assess the radiation dose delivered to patients from common diagnostic nuclear medicine examinations and estimate the risk of exposure-induced death (REID). In addition, the frequency of nuclear medicine procedures were evaluated from 2015-2018. MATERIALS AND METHODS: The data were collected from adult patients who had undergone cardiac, skeletal, renal, lacrimal, and thyroid imaging. For each patient, the effective dose was calculated using dose conversion factors, and REID was estimated using PCXMC. The frequency of examinations between 2015 and 2018 was obtained from the hospital information system (HIS). RESULTS: The highest estimated effective dose was attributed to the scans of myocardial stress (8.09 ± 1.28 mSv), myocardial rest (5.59 ± 1.27 mSv), and thyroid imaging (3.93 ± 0.55 mSv). In addition, cardiac stress examination had the highest REID values for solid cancers (212.5 ± 67.5) and bone scans had the highest REID values for leukemia (11.5 ± 2.5). A large increase in the number of myocardial perfusion scans was a significant contributor to an increase in collective effective dose from 23.37 man-Sv in 2015 to 49.47 man-Sv in 2018, a compound annual growth rate (CAGR) of 26%. CONCLUSION: Although the annual frequency and per capita effective dose of nuclear medicine procedures in Yazd Province increased continuously, they were comparably lower than those reported for other countries. Despite this, the cancer risks of nuclear medicine scans at the individual level are negligible (around 0.01% excess fatal cancer risk), yet the increasing tendency for these examinations could be of concern.

Could heart rate recovery and exercise capacity predict abnormal 99mTc-MIBI myocardial perfusion scan findings?

Background and aim: Ischemic heart diseases lead to numerous deaths worldwide. Prevention, rapid diagnosis and treatment are principal strategies in controlling mortality due to coronary artery diseases (CAD). Considering variety of options, finding suitable diagnostic modality for each patient has been controversial for long times. Exercise treadmill test (ETT) is a well-known and old modality compared to radionuclide scintigraphy. In this study we aimed to assess if heart rate recovery (HRR) and exercise capacity (EC) in ETT can predict perfusion defects in 99mTc-MIBI SPECT myocardial perfusion imaging (MPI). Materials and methods: In this cross-sectional, descriptive-analytic study, we enrolled 254 patients referred for MPI to nuclear medicine department of Afshar or Shahid Sadoughi Hospital, Yazd, Iran. All patients underwent ETT and MPI. HRR and EC in ETT plus abnormal perfusion findings in MPI along with patient's history and demographic information were recorded in a questionnaire. Finally, all data were analyzed using SPSS ver.22 software. Results: Based on our results, 161 (63.4%) of patients were men. Half of patients were diagnosed with hypertension. 45% were diagnosed with diabetes, 41% had hyperlipidemia and 8.3% were smokers. Based on our findings, 18.1% of patients had abnormal MPI results. Our analytic results indicated that there is no statistically significant association between transient RV visualization, transient ischemic dilation or lung to heart ratio with 1st and 2nd minute HRR and EC. Conclusion: Considering lack of association between ETT indices and MPI findings, it seems that ETT is not adequately sensitive in predicting perfusion defects in MPI. Thus, it seems logical in some cases to ignore expenses of MPI and suggest it to patients before ETT based on clinical judgement.

European trends in radiology: investigating factors affecting the number of examinations and the effective dose.

The advances in technology have led to a growing trend in population exposure to radiation emerging from the invention of high-dose procedures. It is, for example, estimated that annually 1.2% of cancers are induced by radiological scans in Norway. This study aims to investigate and discuss the frequency and dose trends of radiological examinations in Europe. European Commission (EC) launched projects to gain information for medical exposures in 2004 and 2011. In this study, the European Commission Radiation Protection (RP) reports No. 154 and 180 have been reviewed. The RP 154 countries' data were extracted from both reports, and the average variation trend of the number of examinations and effective doses were studied. According to the results, plain radiography and fluoroscopy witnessed a reduction in the frequency and effective dose per examination. Nevertheless, European collective dose encountered an average increase of 23%, which resulted from a growing tendency for implementation of high-dose procedures such as CT scans and interventional examinations. It is worth noting that most of the CT procedures have undergone an increase in effective dose per examination. Although demand and dose per examination in some radiological procedures (such as intravenous urography (IVU) have been reduced, population collective dose is still rising due to the increasing demand for CT scan procedures. Even though the individual risks are not considerable, it can, in a large scale, threaten the health of the people at the present time. Due to this fact, better justification should be addressed so as to reduce population exposure.

CT Scan Incidental Findings in Head Trauma Patients - Yazd Shahid Rahnemoun Hospital, 2005-2015.

BACKGROUND: Incidental findings are presented in radiology reports. Many of these findings do not require further investigation; however, some require further investigation and repeated imaging. The aim of this study was to determine the frequency of incidental findings on CT scans of patients with head trauma from 2005 to 2015. METHODS: This analytical cross-sectional study was conducted in years on 5,193 CT scan reports referred to Shahid Rahnemoun hospital in Yazd, Iran. The images were evaluated by consensus agreement of two radiologists. The relationship between age, sex and incidental findings was analyzed using the SPSS 20 software. RESULTS: A total of 5,193 subjects with a mean age of 34.16 ± 21.17 were examined. About 64% of cases were male. The frequency of incidental findings was 10.9%. The most common finding was calcification with a frequency of 3.3% and the least was Dandy Walker finding at 0.02%. There was no relationship between age, sex and the frequency of incidental findings. No significant trend was found between IFs frequency during ten years. CONCLUSION: The results of this study indicated that most incidental findings were related to benign findings, but also malignant findings were diagnosed.

Monte Carlo evaluation of the potential benefits of flattening filter free beams from the Oncor® clinical linear accelerator.

OBJECTIVES: To evaluate the potential privileges of flattening filter-free (FFF) photon beams from Oncor® linac for 6 MV and 18 MV energies. METHODS: A Monte Carlo (MC) model of Oncor® linac was built using BEAMnrc MCCode and verified by the measured data using 6 MV and 18 MV energies. A comprehensive set of data was also characterized for MC model of Oncor® machine running with and without flattening filter (FF) for 6 MV and 18 MV beams in six field sizes. The investigated characteristics included mean energy, energy spectrum, photon spatial fluence, superficial dose, percent depth dose (PDD), dose output, and out-of-field dose with two indexes of lateral dose profile and isodose curve at three depths. RESULTS: Using FFF enhanced the energy uniformity 3.4±0.11% (6 MV) and 2.05±0.09% (18 MV) times and improved dose output by factor of 2.91 (6 MV) and 4.2 (18 MV) on the central axis, respectively. Using FFF also reduced the PDD dependencies by 9.1% (6 MV) and 5.57% (18 MV). In addition, using FFF had a lower out-of-field dose due to the reduced head scatter and softer spectra. CONCLUSIONS: The findings in this study suggested that using FFF, Oncor® machine could achieve better treatment results with lower dose toxicity and a shorter beam-on time.

PATIENT-SPECIFIC DOSIMETRY FOR PEDIATRIC IMAGING OF 99mTc-DIMERCAPTOSUCCINIC ACID WITH GATE MONTE CARLO CODE.

In this study, radiation absorbed dose of 99mTc-dimercaptosuccinic acid (DMSA) in critical organs was calculated using Monte Carlo simulation. Ten child patients with genitourinary abnormalities were imaged using a series of planar, SPECT and MRI, after injection with 99mTc-DMSA. Patient-specific organ segmentation was performed on MRI and used as input in GATE. Organs with substantial uptake included kidneys, bladder and liver. The mean organ absorbed dose coefficients (mGy/MBq) were 0.063, 0.058, 0.018, 0.016, 0.013 and 0.010 for the right kidney, left kidney, bones, urinary bladder wall, liver and gonads, respectively. The absorbed dose coefficients in the remainder of the body was 0.012 mGy/MBq. The authors implemented an image-based Monte Carlo method for patient-specific 3D absorbed dose calculation. This study also demonstrates the possibility to obtain patient-specific attenuation map from MRI to be used for the simulations of radiation transport and energy deposition in phantom using Monte Carlo methods.

The Normal Value of Tibial Tubercle Trochlear Groove Distance in Patients With Normal Knee Examinations Using MRI.

Patellar instability is a multifactorial common knee pathology that has a high recurrence rate, and the symptoms continue and ultimately predispose the patient to chondromalacia and osteoarthritis. Tibial tuberosity-trochlear groove distance (TTTG) is very important in the assessment of patellofemoral joint instability. The purpose of this study was to report the normal value of TTTG in males and females in different age groups and to assess the reliability of MRI in measuring TTTG. All patients presenting with knee pain and normal examinations of the knee joint, with a normal MRI report, referring to Shahid Sadoughi hospital of Yazd, Iran, from April 2014 to September 2014, were included in the study. MR images were studied once by two radiologists and for the second time by one radiologist. Mean value of TTTG was reported for males and females and in three age groups. Intra- and inter-observer reliability was calculated. A total of 98 patients were eligible to evaluate during 6 months (68 male and 30 female). Mean TTTG was 10.9±2.5 mm in total, which was 10.8±2.8 mm and 11.3±2.3 mm in males and females, respectively (P>0.05). Mean TTTG in males ≤30 years, 30-50 years and, ≥51-year-old were 10.8±2.6 mm, 10.8±2.7 mm, and 10.8±2.6 mm, respectively; that was 12.1±3.4 mm, 11.4±1.9 mm, and 10.5±1.7 mm in females ≤30 years, 31-50 years and, ≥51-year-old, respectively (95% CI). The coefficient of variation was <10% for both intra- and interobserver analysis. The results of the present study showed no significant difference in TTTG value between males and females in different age groups. In addition, it demonstrated that MRI is a reliable method in assessment of TTTG and identified normal value for TTTG at 10.9±2.5 mm.

Comparative Diagnostic Performance of Ultrasonography and 99mTc-Sestamibi Scintigraphy for Parathyroid Adenoma in Primary Hyperparathyroidism; Systematic Review and Meta- Analysis

Objective: Ultrasonography (US) and parathyroid scintigraphy (PS) with 99mTc-MIBI are common methods for preoperative localization of parathyroid adenomas but there discrepancies exist with regard to diagnostic accuracy. The aim of the study was to compare PS and US for localization of parathyroid adenoma with a systematic review and meta-analysis of the literature. Methods: Pub Med, Scopus (EMbase), Web of Science and the reference lists of all included studies were searched up to 1st January 2016. The search strategy was according PICO characteristics. Heterogeneity between the studies was accounted by P < 0.1. Point estimates were pooled estimate of sensitivity, specificity and positive predictive value of SPECT and ultrasonography with 99% confidence intervals (CIs) by pooling available data. Data analysis was performed using Meta-DiSc software (version 1.4). Results: Among 188 studies and after deletion of duplicated studies (75), a total of 113 titles and abstracts were studied. From these, 12 studies were selected. The meta-analysis determined a pooled sensitivity for scintigraphy of 83% [99% confidence interval (CI) 96.358 -97.412] and for ultra-sonography of 80% [99% confidence interval (CI) 76-83]. Similar results for specificity were also obtained for both approache. Conclusion: According this meta- analysis, there were no significant differences between the two methods in terms of sensitivity and specificity. There were overlaps in 99% confidence intervals. Also features of the two methods are similar.

Risk factors of breast cancer in the Eastern Mediterranean Region: a systematic review and meta-analysis.

BACKGROUND: Identifying risk factors of breast cancer is a key point for preventive strategies to reduce the incidence. The aim of current study was to determine most important risk factors for breast cancer in the Eastern Mediterranean Region (EMR) using a systematic review. MATERIALS AND METHODS: PubMed, Scopus, Web of Science till August 24, 2012 and the reference lists of all included studies were searched. Analytic studies which had reported odds ratios (OR), relative risk (RR) or required data to calculate them were included. A total of 343 studies were critically appraised and finally 30 studies were meta-analyzed. Heterogeneity between the studies was assessed by I2 and Cochran's Q. Egger's test was used to assess publication bias. RESULTS: Twenty five case- control studies, one nested case-control and four cohort studies were included. The largest ORs were obtained for history of no live birth (2.25; 95%CI: 1.58-3.18), body mass index (BMI) more than 30 (2.21; 95%CI: 1.71-2.36), age at first pregnancy more than 30 years old (1.52; 95%CI: 1.30-1.77) and meat consumption more than three times per week (1.39; 95%CI: 1.03-1.87). The other important predictors were higher education and smoking as risk factors, physical activity and ovulatory stimulating medication as protective factors. CONCLUSIONS: The most important predictors of breast cancer in EMR were history of no live birth, BMI more than 30, age at first pregnancy more than 30 years old, physical inactivity and smoking. Almost all these risk factors are consistent with known risk factors for this cancer in other parts of the world.

Factors Associated with Breast Cancer Screening Decision Stage among Women in Tehran, Iran.

BACKGROUND: Early detection through screening is the best method to reduce death due to breast cancer. It has been shown, having knowledge and generating positive attitudes, influences the decision of women to participate in the screening programs. The aim of this study was to identify the factors associated with breast cancer screening (BCS) and with an intention to have screening among women in Tehran, Iran. METHODS: A cross-sectional study was carried out from January to July 2011, among women who had attended to primary health-care centers in West Tehran using multi-stage sampling method. We invited 1,240 women sequentially to complete a self-administered survey questionnaire at the beginning of their visit; and 1,012 (82%) completed the survey. The questionnaire included, items drawn from the Preventive Health Model that assess socio-demographic background and perceptions about BCS. Multiple logistic regression analysis was performed to identify factors associated with screening and intention to do screening in the future. RESULTS: The mean age of subjects was 38.2 years. Women who perceived more screening efficacy (odd ratio [OR] =1.63; confidence interval [CI] 95%: 1.12-2.37) and fewer performance barriers (OR = 0.82; CI 95%: 0.68-0.97) were more likely to perform clinical breast exam in the future. The women who reported higher clinical breast exam self-efficacy (OR = 1.82; CI 95%: 1.39-2.37), mammography self-efficacy (OR = 1.31; CI 95%: 1.04-1.65), screening efficacy (OR = 1.53; CI 95%: 1.18-1.97), and family influence (OR = 1.27; CI 95%: 1.05-1.54), and those who reported fewer screening performance barriers (OR = 0.56; CI 95%: 0.48-0.67) were more likely to decide for carried out mammography in the future. Most respondents indicated that they intended to do clinical breast exam and mammography in the future (75.8% and 72.1% respectively). About 65% of women reported they would do both. CONCLUSIONS: We found that women's intention to do BCS was very high and a comprehensive national program is needed to guide their intention. Among different demographic factors, the impact of education level on doing BCS was significant.

Management of pelvic organ prolapse and quality of life: a systematic review and meta-analysis.

INTRODUCTION AND HYPOTHESIS: One of the main outcomes in the assessment of the treatment of pelvic organ prolapse in women is quality of life. Using quality of life as an outcome measure is increasing in the majority of clinical trials. The aim of current study was to determine the effects of the treatment of pelvic organ prolapse on patients' quality of life using systematic review and meta-analysis. METHODS: A systematic search for finding randomized controlled studies on pelvic organ prolapse published before October 2012 was conducted. The JAMA users' guide to the medical literature quality assessment scales for randomized clinical trials was used to assess the quality of included articles. The mean difference in total quality of life score between before and after intervention (surgical or pelvic floor training) with 95 % confidence interval (CI) was considered as a primary summary measure. Egger's test was used to evaluate the publication bias. Heterogeneity was assessed using I(2) Index. RESULTS: Fifty-seven RCT were critically appraised. Thirty-two articles were eligible after critical evaluation. Mean difference in change in the total quality of life score with 95 % CI for surgical treatment was 74.03 (66.3-81.6) by PFDI-20 and was 44.57 (22.53-66.65) by PFIQ-7. The mean difference in changed in the total quality of life score with 95 % CI was 1.32 (-2.8-5.4) for pelvic floor training (PFT). CONCLUSION: We found that surgical interventions on prolapse can improve the quality of life of women. There was a relative effect of PFT on the quality of life of women with prolapse in systematic review. This effect was not seen in meta-analysis, probably because of finding few eligible studies to pool the effect size.

Depression and general anxiety in the prisoner of war's children: a cross sectional study.

BACKGROUND: The main aim of this study was to assess the prevalence of depression and general anxiety of the prisoners of war (POW) children. The study was also designed to compare the prevalence of depression and general anxiety amongst the POW's children and normal adults, 20 years after the Iraq-Iran war. METHOD: An analytic cross-sectional study carried out in June 2009 in Yazd (the centre of Yazd province in Iran). The target and sampled population were the children of the Iranian POW who lived in Yazd. One hundred and twenty six POW's children, who were born before 1990 (date of father's freedom) were assessed. The duration of father's captivation was between 29-119 months. Ninety-five subjects accepted to participate. General anxiety and major depression were assessed by Persian version of Hamilton Scale for anxiety and Beck depression Inventory. This study was a combination of the psychological interview and questionnaire. Ninety five of normal adult group were also paired matched and assessed. RESULT: Among 126 POW's children who fulfilled the inclusion criteria, the responsive rate was 75.3% (95 participants). The mean age of participants was 28.3 (SD: 5.34).The father's captivation duration were 29-119 months (mean: 79.2, SD: 21.6). The prevalence of depression and general anxiety amongst the POW's children were 48.4% and 79%. The prevalence of depression and general anxiety among the paired group were 21.1% and 63.2%.The differences between two groups were significant (p =0.000). CONCLUSION: In this study we have demonstrated the prevalence of major depression and general anxiety in POW's children and a normal adult sample. The differences of major depression and general anxiety among the two groups were significant.