METHOD: We simulate the CT head examination using a water phantom with a standard protocol (120 kVp/180 mAs) and a low dose protocol (100 kVp/142 mAs). The table height was adjusted to simulate miscentering by 5 cm from the isocenter, where the height was miscentered superiorly (MCS) at 109, 114, 119, and 124 cm, and miscentered inferiorly (MCI) at 99, 94, 89, and 84 cm. Seven circular regions of interest were used, with one drawn at the center, four at the peripheral area of the phantom, and two at the background area of the image.
RESULTS: For the standard protocol, the mean CNR decreased uniformly as table height increased and significantly differed (p
Materials and Methods: A total of 8,030 intraoral images were retrospectively collected from 3 groups of undergraduate clinical dental students. The type of examination, stage of the procedure, and reasons for repetition were analysed and recorded. The repeat rate was calculated as the total number of repeated images divided by the total number of examinations. The weighted Cohen's kappa for inter- and intra-observer agreement was used after calibration and prior to image analysis.
Results: The overall repeat rate on intraoral periapical images was 34.4%. A total of 1,978 repeated periapical images were from endodontic assessment, which included working length estimation (WLE), trial gutta-percha (tGP), obturation, and removal of gutta-percha (rGP). In the endodontic imaging, the highest repeat rate was from WLE (51.9%) followed by tGP (48.5%), obturation (42.2%), and rGP (35.6%). In bitewing images, the repeat rate was 15.1% and poor angulation was identified as the most common cause of error. A substantial level of intra- and interobserver agreement was achieved.
Conclusion: The repeat rates in this study were relatively high, especially for certain clinical procedures, warranting training in optimization techniques and radiation protection. Repeat analysis should be performed from time to time to enhance quality assurance and hence deliver high-quality health services to patients.
Objectives: We explored the perceptions and practices related to the use of radioprotective garments among medical radiation workers in public hospitals, and sought to understand the reasons for non-adherence.
Design and setting: A qualitative approach was applied by conducting face-to-face in-depth interviews with 18 medical radiation workers from three university hospitals using a semi-structured interview guide.
Results: Five themes emerged with respect to perceptions on the use of radioprotective garments: (i) the dilemmas in practising radiation protection, (ii) indication of workers' credibility, (iii) physical appearance of radioprotective garments, (iv) practicality of radioprotective garment use, and (v) impact on workflow. Actual lack of radioprotective garment use was attributed to inadequate number of thyroid shield and other garments, radioprotective garments' unsightly appearance including being dirty and defective, impracticality of using radioprotective garments for some nuclear medicine procedures, disruption of workflow because of workers' limited movements, attitudes of workers, and organisational influences.
Conclusion: Medical radiation workers demonstrated a definitive practice of using radioprotective aprons, but often neglected to use thyroid shields and other garments. Availability and hygiene are reported as the core issues, while unclear guidelines on practical use of radioprotective garments appear to lead to confusion among medical radiation workers. To the best of our knowledge, this is the first qualitative study of its kind from a middle-income Asian setting.