Effects of scanning parameters reduction in dental radiographs on image quality and diagnostic performance: A randomised controlled trial

Objectives: To investigate the effect of reducing scanning parameters of digital dental panoramic tomogram (DPT) and lateral cephalometric (LC) radiographs on quality and diagnostic performance of the images. Design: Single-centre prospective two-arm parallel randomised controlled trial. Setting: Orthodontic Clinic, Faculty of Dentistry, Universiti Teknologi MARA, Selangor, Malaysia. Participants: Adult orthodontic patients aged 18-35 years, indicated for DPT and LC, who were fit and healthy with a body mass index of 18.5-25.0, not contraindicated to radiographic examination, not pregnant, and did not have a history of facial or skeletal abnormalities or bone diseases were included. Methods: Thirty-eight adult orthodontic patients were randomised into control and intervention groups. DPT and LC radiographs in the control group were obtained using standard scanning parameters as prescribed by the manufacturer using Orthopantomograph (R) OP300 by Instrumentarium. Scanning parameters in the intervention group were reduced by 60% for DPT (60 kV, 3.2 mA) and 30% for LC (85 kV, 8 mA). A five-point rating scale was used for the assessment of image quality. Images were evaluated for diagnostic performance by detection of anatomical landmarks. Mann-Whitney test was performed to compare the quality and diagnostic performance of the images and the observer agreement was assessed using the intraclass correlation coefficient (ICC). Results: For image quality, the control group produced slightly lower median scores (DPT 2.0, LC 2.0) compared to the intervention group (DPT 2.0, LC 3.0). For diagnostic performance, both groups showed similar median scores (DPT 21.0, LC 32.0). The differences between control and intervention groups for both modalities were not statistically significant. The average scores for intra-observer agreement were excellent (ICC 0.917) and inter-observer agreement was good (ICC 0.822). Conclusion: Minimising radiation exposure by reducing scanning parameters on digital DPT by 60% and LC by 30% on Intsrumentarium 300 OP did not affect the quality and diagnostic performance of the images. Thus, scanning parameters on digital DPT and LC should be reduced when taking radiographs.