wall thickening (greater than 2 mm), periappendiceal fatstranding, appendiceal wall thickening, and/or an appendicolith(Fig. 30-1). While there remains a concern of ionizing radia-tion exposure with a CT scan, typical low-dose CT scans resultin exposure of 2 to 4 mSv, which is not significantly higherthan background radiation (3.1 mSv).18 Recent trials have alsosuggested that although low-dose CT scans of 2 mSv do notgenerate high-resolution images, using these lower resolutionimages does not affect clinical outcomes. 19 Intravenous contrastis generally preferred in these studies, but it can be avoided inpatients with allergies or low estimated glomerular filtration rate(less than 30 mL/minute for 1.73 m 2 ). Several meta-analyseshave suggested that CT scan is more sensitive and specific thanultrasound in diagnosing appendicitis.Ultrasound. Ultrasonography has a sensitivity of 0.85 (95%CI 0.79–0.90) and a specificity of 0.90 (95% CI 0.83–0.95).20Graded compression ultrasonography is used to identify theanteroposterior diameter of the appendix. An easily compressibleappendix <5 mm in diameter generally rules out appendicitis.Features on an ultrasound that suggest appendicitis includea diameter of greater than 6 mm, pain with compression,presence of an appendicolith, increased echogenicity of the fat,and periappendiceal fluid. 21 Ultrasound is cheaper and morereadily available than CT scan, and it does not expose patients toionizing radiation, but it is user-dependent and has limited util-ity in obese patients. In addition, graded compression is usually

Pediatric radiation exposure during medical imaging procedures has been a topic of increasing concern due to the potential long-term health implications associated with ionizing radiation. Previous studies have highlighted the heightened sensitivity of pediatric patients to radiation due to their developing tissues and longer life expectancy, necessitating a critical evaluation of radiation doses in pediatric imaging procedures (Sabarudin & Sun, 2013; BEIR VII Phase 2, 2006).In the context of computed tomography angiography (CTA), several studies have emphasized the need for optimizing imaging protocols to minimize radiation exposure while maintaining diagnostic quality. For instance, research by Xu and Zhang (2010) demonstrated the importance of dose optimization measures in reducing radiation exposure during CTA procedures. Similarly, Westra et al. (2014) highlighted the significance of entrance skin dose reduction in pediatric CT examinations.Furthermore, the American College of Radiology (ACR) has provided guidelines for quality control and radiation safety in computed tomography, emphasizing the ALARA principle and the use of protective shielding to minimize radiation exposure (ACR, 2017). These guidelines serve as a benchmark for evaluating the adherence to radiation safety measures in pediatric CTA procedures.Studies by Ali et al. (2019) and Hollingsworth et al. (2007) have provided valuable insights into radiation dose reduction initiatives and effective strategies for minimizing radiation exposure in cardiac CT and other imaging modalities. These initiatives underscore the importance of continuous improvement in imaging protocols to ensure patient safety.In summary, the existing literature underscores the critical need for optimizing imaging protocols, standardizing radiation doses, and adhering to radiation safety measures to minimize pediatric radiation exposure during CTA procedures. This literature review provides a foundation for the current study, which aims to comprehensively evaluate pediatric radiation exposure and imaging protocols in the context of CTA procedures.

The scientific unit of measurement used to measure the dose received from radiations, such as X-rays or background radiation, is the millisievert (mSv). The table shows the X-ray dose resulting from CT scans of various parts of the body. The table also frequencywavelengthfrequency = wave speed / 1500(3.0*10^8)/1500 = 2*10^5Hz2*10^5can cause burnscan cause skin cancerradiographythe ability to penetrate the skin and tissue but not the bone allowing for an imageof the bones to be createdPage 18 shows the time it would take to get the same dose from background radiation. Part of the body X-ray dose in mSv Time it would take to get the same dose from background radiation Abdomen 9.0 3 years Sinuses 0.5 2 months Spine 4.0 16 months A student suggests that the X-ray dose and the time it would take to get the same dose from background radiation are directly proportional. Use calculations to test this suggestion and state your conclusion.

In which of these radiological examinations ionizing radiation is used?Question 33Select one:Digital subtraction angiographyUltrasoundMagnetic resonance imaging

In a round trip to Mars, calculate how much more radiation would astronauts be exposed to compared to an average CT scan. About 7 times moreAbout 70 times moreAbout 700 times moreI'm not sure

ainful for patients with peritonitis. A comparison of the effi-cacy of ultrasound v. CT scan is found in Table 30-2.MRI. MRI of the abdomen has a sensitivity of 0.95 (95% CI0.88–0.98) and specificity of 0.92 (95% CI 0.87–0.95) for iden-tification of acute appendicitis. 22 MRI is an expensive test thatrequires significant expertise to perform and interpret and isusually recommended in patients for whom the risk of ionizingradiation outweighs the relative ease of obtaining a contrastCT scan, i.e., pregnant or pediatric patients