Justification and Optimization Principles of ALARA in Pediatric CT at a Teaching Hospital in Ethiopia

Abstract

BACKGROUND: Radiation from CT (computerized tomography), poses risk of radiation associated cancer. Studies indicate a cumulative dose of 50mGy triples the risk of leukemia and a dose of 60mGy triples the risk of brain tumors in children. This study aimed to assess the application of “Justification and Optimization Principles of ALARA (As Low As Reasonably Achievable)” in pediatric CT.METHOD: A prospective cross-sectional study was conducted from December 2017 to July 2018 G.C at Tikur Anbessa Specialized Hospital. CT request forms were reviewed. All pediatric patients listed for CT were included. The collected data were analyzed using SPSS version 25.RESULTS: Four hundred and twenty nine CT requests were reviewed, 246 (57.3%) were males and 183(42.7%) were females; 52(12.1%) were less than 1 year old, 153(35.7%) between 1 to 5 years, 113(26.3%) between 5 to 10 years and 111(25.8%) 10 to 14 years old. On the other hand, 28(6.5%) scan requests were rejected based on the ALARA justification principle, and from these, in 11(39.2%) MRI was recommended instead of CT, in 6(21.42%) US was recommended. Review of previous CT helped to reject 4(14.28%). Review of prior chest radiographs helped in rejecting 2(7.14%) requests. For 5(17.8%) and 19(4.4%), requests were optimized by applying principles of optimization to reduce received dose from CT.CONCLUSION: Overall, 47(11%) patients were protected from unnecessary radiation exposure by applying the principles of ALARA. The use of other alternating imaging modalities is vital in pediatric patients who are more radiosensitive and have longer time to manifest radiation induced injury.

Optimization of routine pediatric CT examination in Hawassa city, Sidama region Ethiopia

“…The ndings of this study also showed the DLP per scan (55.9, 109.4, 145, and 258.9) mGy cm for pediatric chest CT were comparable with the reports of Japan [19] ( 70, 95, 175, and 230) mGy cm and higher than the reports of US [16], Belgium [17], Germany [18] in all age groups. On the contrary, the DLP per scan (38.1, 96.3, 136.1, and 242.5) mGy cm of this study for abdominal CT examinations were lower than international reports of the US [16], Belgium [17], Germany [18], and Japan [19] for all age groups (≤ 1, (1-5], (5-10] and (10)(11)(12)(13)(14)(15)) years respectively.…”

“…However, the ndings for abdominal CT examinations were lower than DRL reports of the US [16], Belgium [17], Germany [18], and Japan [19]. The established LDRLs of this study in terms of DLP per scan (mGy cm) showed that higher DLP per scan values (723.4, 1032.7, 1037.4, and 1126.7) mGy cm were used during pediatric head CT examinations for all age groups (≤ 1, (1-5], (5-10] and (10)(11)(12)(13)(14)(15)) years respectively compared to the international DRLs where the maximum DLP per scan was 1000 mGy cm used in Japan for age group (10)(11)(12)(13)(14)(15) years [19]. This difference could be due to the selection mode of acquisition axial or helical scanning, CT scanning parameter settings, and different manufacturers of the CT scanners used [20].…”

“…Another study that evaluated the frequency of pediatrics CT exams for patients under the age of 15 in 128 CT facilities in 28 developing countries of Africa, Asia, and Eastern Europe found that the frequency of pediatric CT exams was higher in Africa than in Asia and Eastern Europe [9]. According to a study done in Ethiopia, the Tikur Anbessa teaching hospital was able to use optimization and justi cation procedures to protect 11% of pediatric patients from unnecessary radiation doses [10]. However, the study mainly focused on the justi cation of CT request forms and rarely addresses individual patient scan parameters and CT dose quantities.…”

Ultra‐low dose CT scanning for PET/CT

“…Furthermore, in various conditions, patients may benefit tremendously by receiving multiple CT and PET/CT scans frequently for monitoring treatment, thereby mostly covering the whole‐body 9,10 . Therefore, the globally adopted radiation protection framework follows the well‐known ‘‘As Low As Reasonably Achievableʺ (ALARA) principle to ensure a careful balance between the benefits and risks of using radiation in diagnostic imaging 11,12 . Advanced image reconstruction methods 13–15 and improved detectors have contributed to PET/CT images of much higher spatial resolution and signal‐to‐noise ratio even at substantially lower injected radiotracer dosages.…”

“…9,10 Therefore, the globally adopted radiation protection framework follows the well-known ''As Low As Reasonably Achievableʺ (ALARA) principle to ensure a careful balance between the benefits and risks of using radiation in diagnostic imaging. 11,12 Advanced image reconstruction methods [13][14][15] and improved detectors have contributed to PET/CT images of much higher spatial resolution and signal-to-noise ratio even at substantially lower injected radiotracer dosages. In addition, new CT hardware and software has been proposed to minimize radiation exposure due to the CT component.…”