Radiation Exposure from Medical Imaging Procedures

The growing use of imaging procedures in the United States has raised concerns about exposure to low-dose ionizing radiation in the general population. We identified 952,420 nonelderly adults (between 18 and 64 years of age) in five health care markets across the United States between January 1, 2005, and December 31, 2007. Utilization data were used to estimate cumulative effective doses of radiation from imaging procedures and to calculate population-based rates of exposure, with annual effective doses defined as low (< or = 3 mSv), moderate (> 3 to 20 mSv), high (> 20 to 50 mSv), or very high (> 50 mSv). During the study period, 655,613 enrollees (68.8%) underwent at least one imaging procedure associated with radiation exposure. The mean (+/-SD) cumulative effective dose from imaging procedures was 2.4+/-6.0 mSv per enrollee per year; however, a wide distribution was noted, with a median effective dose of 0.1 mSv per enrollee per year (interquartile range, 0.0 to 1.7). Overall, moderate effective doses of radiation were incurred in 193.8 enrollees per 1000 per year, whereas high and very high doses were incurred in 18.6 and 1.9 enrollees per 1000 per year, respectively. In general, cumulative effective doses of radiation from imaging procedures increased with advancing age and were higher in women than in men. Computed tomographic and nuclear imaging accounted for 75.4% of the cumulative effective dose, with 81.8% of the total administered in outpatient settings. Imaging procedures are an important source of exposure to ionizing radiation in the United States and can result in high cumulative effective doses of radiation.

Introduction: Computed tomography (CT) is a medical imaging modality that produces 3-D cross-sectional images of tissues using several X-ray projections at different angles. Since its introduction in the 1970s, CT usage has been on the increase for both adults and pediatrics. A major challenge of this modality is the high doses of radiation exposure to patients, especially in pediatrics, who are more radiosensitive compared to adults. Hence, the need to ensure that radiation safety standards are adhered to. This will go a long way in reducing the adverse effects of radiation. The aim of this study was to assess the level of compliance to international dose reference levels (DRLs) in terms of effective doses in pediatric CT scans conducted in three Iraqi hospitals. Materials and Methods: CT brain and abdomen/pelvis examinations were conducted for pediatric patients aged between few months and 15 years in three Iraqi hospitals (Al Wasiti, Neuroscience and Al Omara). All scans were performed on a Somatom Sensation® 16 multidetector CT (MDCT) scanner with a Straton® X-ray tube (Siemens, Erlangen, Germany) utilising automatic tube current modulation (CARE Dose4DTM; Siemens, Erlangen, Germany). Volumetric CT dose index (CTDIvol) and dose length product (DLP) were collected for 180 patients (60 in each hospital). Afterwards, their effective doses were estimated from DLP values and compared with international DRLs. Results: Brain CT: The DLP values obtained for Al Wasiti, Neuroscience and Al Omara hospitals were in the range; 789-918.8 mGy.cm, 833-874.6 mGy.cm and 627.6-810 mGy.cm respectively, while their corresponding effective doses were in the range; 1.8-2.09 mSv, 1.9- 2.06 mSv and 1.43-1.83 mSv. Abdomen/Pelvis: The DLP values obtained for Al Wasiti, Neuroscience and Al Omara hospitals were in the range; 392.9-425.8 mGy.cm, 355-395 mGy.cm and 314.8-383.6 mGy.cm respectively, while their corresponding effective doses were in the range; 6.65-7.22 mSv, 6- 6.7 mSv and 5.34-6.51 mSv. Using the International Commission on Radiological Protection (ICRP) publication 103 as basis for assessing compliance level, for brain CT we observe slightly higher values in Al Wasiti and Neuroscience hospitals while Al Omara was similar to the international DRLs. However, for abdomen/pelvis CT examinations, the effective doses in all three hospitals were within the acceptable limits of international DRLs. Conclusion: This study has shown an encouraging level of compliance towards adequate radiation protection management in pediatric CT examinations among the three hospitals. Although, the best compliance level was observed in Al Omara hospital. Regular monitoring should be enforced to ensure that CT doses delivered to pediatric patients are as low as reasonably achievable without compromising diagnostic quality.

Estimates of individual patient risk, and epidemiologic studies assessing potential late effects, must use patient size–specific dose estimates—they cannot use only scanner output (volume CT dose index or dose-length product).

Analysis of Radiation Exposure in Trauma Patients at a Level I Trauma Center

2183 ULTRA-LOW DOSE CT COMPARABLE TO STANDARD CT IN PATIENTS WITH SUSPECTED RENAL COLIC

Diagnostic Imaging: State of the Art or Science?

Background: Peritonsillar abscess (PTA) is a common occurrence in adult patients, and an important question in such often-seen disease processes is whether we are treating these patients effectively, efficiently, and economically. We sought to determine if a diagnostic computed tomography (CT) scan was associated with a difference in clinical intervention in adult patients with PTA and if CT was associated with delaying this intervention.Methods: We conducted a retrospective case-control study examining therapeutic interventions in adults with PTA. Patients were divided into a control group (those diagnosed without CT, n=159) and a case group (those diagnosed with CT, n=203). Patients were examined for 3 outcomes: admission, bedside procedure (needle aspiration, incision/drainage), and surgical procedure (incision/drainage, tonsillectomy). In addition, we calculated times to admission, otolaryngology consultation, bedside procedure, and surgical procedure.Results: We found a significant association between CT and intervention, with the CT group more likely to be admitted (P< 0.001), the non-CT group more likely to undergo a bedside procedure (P<0.001), and the CT group more likely to undergo operative intervention (P=0.02). Mean times to otolaryngology consultation, admission, and bedside procedure were significantly longer in the CT group than in the non-CT group, determined by calculating the difference of the means with 95% confidence intervals for each comparison (P<0.001).Conclusion: We found that CT scans appear to be useful in the workup and treatment of adult patients with PTA, evidenced by significant differences in interventions between groups with and without CT scans. We also found that CT scans have the potential to delay these interventions, as the time to each intervention examined was significantly longer in patients who had a CT scan. Given the need to reduce cost, enhance efficiency, and eliminate harmful side effects (in this case, radiation exposure and delays in care), we question whether CT is the gold standard imaging method for diagnostic work up of PTA.

Objective To evaluate the uncertainty of the small bowel dose-volume and the normal tissue complication probability (NTCP) during intensity-modulated radiotherapy (IMRT) for rectal cancer, and to provide a reference for the dose limit and protection of the small bowel during IMRT for rectal cancer. Methods A total of 20 patients with rectal cancer who received postoperative adjuvant radiotherapy from March 2014 to August 2015 were enrolled in this study, including 10 patients receiving CT scan in the supine position and 10 patients in the prone position. All patients received computed tomography (CT) scan before the treatment and at weeks 1, 2, 3, and 4 of treatment, and they were defined as Plan, 1W, 2W, 3W, and 4W CT groups, respectively. The small bowel loop (BL) and peritoneal space (PS) were delineated on the images. The IMRT plan based on the Plan CT was copied to the 1W, 2W, 3W, and 4W CT groups, and then the small bowel dose-volume and NTCP were assessed for all CT groups. The paired t-test was used for comparison between groups. The Pearson method was used to analyze the correlation between NTCPC (chronic NTCP) and dose-volume. Results A total of 89 CT images of 20 patients were obtained. In all the patients, the volumes of BL and PS were 251.21 cm3 and 1324.16 cm3, respectively, and the shift% was 23.15% and 11.34%, respectively. The V15 of BL and PS was 184.86 cm3 and 792.45 cm3, respectively, and the shift% was 31.69% and 3.70%, respectively. The V30 of BL and PS was 88.01 cm3 and 645.73 cm3, respectively, and the shift% was 37.66% and 10.49%, respectively. The V15 of BL in 35% of patients and V15 of PS in 20% of patients, the Dmax of BL in 50% of patients, and the NTCP of 15% of patients in the course of treatment exceeded the safety limits. The 1-4W CT groups had a significantly higher NTCPC than the Plan CT group (4.02% vs. 3.20%, P=0.104), and their SD% was 41.68%. There was a significant correlation between NTCPC and V30-V50 of BL (R>0.400, P=0.000). The NTCPA (acute NTCP) and NTCPC in the supine position were significantly higher than those in the prone position (62.30% vs. 56.74%, P=0.061; 4.88% vs. 3.22%, P=0.145). Conclusions Small bowel motility leads to an uncertainty of the adverse event assessment during IMRT for rectal cancer. The change in BL is significantly larger than that in PS and the change in BL and PS in the supine position is significantly larger than that in the prone position. Using the prone position and minimizing V15 and V30 when designing the treatment plan can reduce the NTCPA and NTCPC in the small bowel. Key words: Rectal neoplasms/intensity-modulated radiotherapy; Small bowel; Normal tissue complication probability

Computed Tomography (CT) Scan is a diagnostic imaging procedure that combines X-ray technology and computer processing to produce detailed cross-sectional images of the human body. Despite its diagnostic benefits, undergoing a CT Scan can provoke anxiety in patients, often due to limited understanding of the procedure, concerns about radiation exposure, and uncertainty regarding the examination results. Elevated anxiety levels may compromise patient comfort and interfere with the examination process. This study aimed to examine the relationship between patients’ knowledge about the CT Scan procedure and their anxiety levels during examinations at the Radiology Department of RUMKIT TK II Prof. Dr. J.A. Latumeten. A quantitative research design with a cross-sectional approach was employed. Total sampling was used, involving 30 patients who underwent CT Scan examinations. Data were collected using structured questionnaires and analyzed using the Chi-Square statistical test to determine the association between knowledge and anxiety levels. The results indicated that there was no significant relationship between patients’ level of knowledge and their anxiety during CT Scan examinations, as evidenced by a significance value of 0.674, which is greater than the 0.05 threshold. This finding suggests that patients’ knowledge alone does not significantly influence anxiety levels during the procedure. Other factors, such as prior experiences with medical imaging, current health conditions, and environmental or staff support, may also play a role in shaping patients’ anxiety. In conclusion, while knowledge about the CT Scan procedure is important, it does not appear to directly reduce patient anxiety. Health practitioners should consider a holistic approach, addressing psychological, environmental, and experiential factors to minimize anxiety and improve patient comfort and cooperation during CT Scan examinations.

Simple SummaryLung cancer is the leading cause of cancer mortality worldwide. In recent years, numerous technologies have been used to perform image-guided percutaneous thermal ablation, mainly including radiofrequency ablation, microwave ablation, and cryoablation. These image-guided ablation techniques have emerged as a safe, cost-effective, minimally invasive treatment alternative for patients who do not require surgery. Procedural planning, monitoring, and lesion targeting are generally performed with the help of computed tomography; navigation systems are emerging as valid tool to reduce procedural time and radiation dose administration. In the present paper, we investigate the efficacy of an optical-based navigation system (SIRIO) to perform lung thermal ablation. SIRIO proved to be a reliable and effective tool when performing CT-guided LTA, displaying a significant decrease in the number of required CT scans, procedure time, and radiation doses administered to patients.(1) Background: The aim of this retrospective study is to assess safety and efficacy of lung radiofrequency (RFA) and microwave ablation (MWA) using an augmented reality computed tomography (CT) navigation system (SIRIO) and to compare it with the standard CT-guided technique. (2) Methods: Lung RFA and MWA were performed with an augmented reality CT 3D navigation system (SIRIO) in 52 patients. A comparison was then performed with a group of 49 patients undergoing the standard CT-guided technique. All the procedures were divided into four groups based on the lesion diameter (>2 cm or ≤2 cm), and procedural time, the number of CT scans, radiation dose administered, and complications rate were evaluated. Technical success was defined as the presence of a “ground glass” area completely covering the target lesion at the immediate post-procedural CT. (3) Results: Full technical success was achieved in all treated malignant lesions for all the considered groups. SIRIO-guided lung thermo-ablations (LTA) displayed a significant decrease in the number of CT scans, procedure time, and patients’ radiation exposure (p < 0.001). This also resulted in a dosage reduction in hypnotics and opioids administrated for sedation during LTA. No significant differences were observed between the SIRIO and non-SIRIO group in terms of complications incidence. (4) Conclusions: SIRIO is an efficient tool to perform CT-guided LTA, displaying a significant reduction (p < 0.001) in the number of required CT scans, procedure time, and patients’ radiation exposure.

DO YOU AGREE?○ That our nation’s children deserve safe and appropriate medical imaging.○ That when used properly, medical imaging is lifesaving.○ That there are risks to almost every aspect of health care. For medical imaging, one of the risks includes exposing children to radiation.○ That parents m

COMPUTED TOMOGRAPHY (CT) SCANNING, WHICH WAS introduced for imaging the head in 1972 and became widely available for imaging the rest of the body by the early 1980s, has revolutionized the practice of medicine and surgery. This technology, for which the Nobel Prize was awarded in 1979, has been used to diagnose and guide the management of diseases affecting every part of the body, improving quality of life and saving countless lives. Two articles in this issue of JAMA, however, point out the complexities involved in deciding whether to extend the use of CT scanning from diagnosis to screening and in determining whether the current use of CT scanning is appropriate or excessive. As the value of CT scanning as a diagnostic tool became clear, it was natural to consider a potential role for this technology to screen for subclinical disease amenable to early intervention. The potential benefits of such screening must, of course, be weighed against the risks and costs. The risk that the ionizing radiation exposure from medical diagnostic tests will cause cancer appears to be small but not zero. Ionizing radiation causes DNA double-strand breaks that are repaired imperfectly, potentially leading to mutations and consequent cancers. An analysis of data from 15 countries has led to the estimate that from 0.6% to 3.2% of cancer diagnosed to age 75 years may be attributable to diagnostic x-rays, including CT scans, although these calculations involved assumptions subject to considerable uncertainty. Another risk of screening is the occurrence of falsepositive findings that may lead to adverse psychological effects on patients as well as physical harm caused by diagnostic procedures undertaken to investigate the findings. Moreover, CT scans are expensive, as are the diagnostic procedures performed to evaluate abnormalities detected. In this issue of JAMA, Bach and colleagues report the results of their systematic review of randomized clinical trials (RCTs) and cohort studies addressing the benefits and risks of screening for early-stage lung cancer using low-dose CT (LDCT) scans. The authors focus on lung cancer–specific and all-cause mortality outcomes in RCTs, avoiding the mistaken inferences that can result from lead-time bias, lengthbiased sampling, and overdiagnosis with other outcomes and designs. Their review yielded only 3 RCTs from which valid inferences can be drawn concerning the effect of LDCT screening for lung cancer among current or former smokers aged 50 years or older. Of these 3 studies, the National Cancer Institute’s National Lung Screening Trial (NLST) was by far the largest and most persuasive, driving the authors’ conclusion that lung cancer mortality is reduced by LDCT screening of adults meeting the NLST entry criteria: age 55 to 74 years, current or former smokers, 30 or more pack-years, and still smoking or having done so within the past 15 years. The good news of a mortality benefit is tempered by some of the specifics. In the NLST, the number needed to screen to prevent 1 lung cancer death was 320 persons undergoing 3 annual LDCTs. Across all studies reviewed, the average rate of detecting nodules per round of screening was 20%, and more than 90% of these nodules turned out to be benign, leading to substantial follow-up testing including invasive procedures. Combining screening and follow-up diagnostic scans, the estimated mean 3-year radiation exposure of NLST participants in the screening group was 8 mSv, which Bach et al estimate would cause 1 cancer death per 2500 persons screened, although this death would likely occur many years later. The heterogeneity in nodule detection rate both among NLST sites and among the other studies reviewed by Bach et al, and the inconsistent mortality results of the 2 smaller RCTs, add a measure of uncertainty to the estimated benefit that would be obtained from broad application of LDCT screening. Nevertheless, the estimates of the benefits and risks of LDCT screening for lung cancer derived from the NLST are the best information currently available. The American College of Chest Physicians, the American Society of Clinical Oncology, and the American Thoracic Society have endorsed an evidence-based practice guideline, included as an online appendix to the article by Bach et al, rec-

Lung Cancer in today’s world is one of the major widespread dangerous diseases which is the subject of maximum deaths every year. Accurate detection of lung cancer could boost the endurance rate. Medical image processing has a significant impact on the recognition of lung tumors using Computer Tomography (CT) scan images. Images from a CT scan are widely used because they provide comprehensive imaging of tumor progression inside the lungs. Although different types of noise might be experienced while doing CT scans, producing it a monotonous task for recognizing tumors in the lung. Elimination of noise in CT images is a challenging task for medical diagnoses. The presence of noise in an image is inevitable. Hence reducing noise from the CT scan image is critical for further analysis. Hence various filtering techniques have been used that denoise and enhance the image and help in further evaluation of CT images for accurate lung cancer detection. This paper analyses the noises of different kinds in the CT images and different noise removal techniques which help in improving the accuracy of segmentation and feature extraction as they remove unwanted noise and contribute to the accurate detection of lung cancer. The various filtering methods are analyzed with salt along with pepper noise and speckle noise. The performances of different filters are computed in terms of metrics for evaluation like PSNR, SSIM, MSE, and SNR. The experimental results show that the median filter is more efficient in comparison to other filtering methods in eliminating noises that exist in lung CT images by owning fewer MSE values of 214.8522, high SNR value of 19.36304, SSIM value 0.595997, and high PSNR value of 24.80941.

Objective: In situations where computed tomography (CT) scans are necessary for pregnant patients, such as in cases of trauma or other conditions that provide clinical benefit, accurately estimating the radiation dose to which the fetus is exposed is crucial. However, current methods are not sufficiently practical or feasible for routine clinical use. This study aims to assess and calculate the fetal dose and associated organ doses resulting from CT scans in pregnant patients using the Monte Carlo Simulation Method. Methods: Monte Carlo (MC) simulations and related calculations were conducted on pregnant patient phantoms for different gestational periods (8-15 weeks) using a 64-slice CT scanner (Discovery CT750 HD GE Healthcare) to estimate fetal doses. Organ dose calculations were also carried out. The MC code simulating dose distributions was validated with measurements from the CT Dose Index (CTDI) following AAPM protocols. Volumetric CTDI values from the MC simulations were normalized, enabling the development of a calculation algorithm for fetal dose assessments across different body regions and exposure settings. The algorithm, approved by the institutional review board, was validated through patient-specific MC simulations on CT data from pregnant patients (with gestational ages of 8-15 weeks) who had undergone CT scans. Results: Based on the data, it can be concluded that the fetus was exposed to low radiation doses, which do not present significant risk to fetal development. The doses observed in the study fell within acceptable clinical limits, indicating that fetal radiation exposure during CT scans can be managed safely with appropriate protocols. However, minimizing radiation exposure during pregnancy is essential. The use of low-dose protocols, as demonstrated in this study, is especially important for these patients. Moreover, the study’s findings highlight the importance of optimizing CT scan parameters and adopting radiation reduction strategies in routine clinical practice. Alternative imaging methods that utilize non-ionizing radiation, such as ultrasound or MRI, should also be considered when clinically appropriate. Conclusions: This study provides a clinically applicable approach to calculating fetal radiation doses during CT scans. The developed algorithm can help reduce fetal exposure and ensure patient safety. Future studies could expand on this research by validating the algorithm in larger patient cohorts and different gestational stages. The findings emphasize the need for radiology technologists to use the lowest possible dose protocols and explore non-ionizing imaging alternatives whenever feasible. .

Value of technetium 99m sestamibi iodine 123 imaging in reoperative parathyroid surgery.