Appropriateness of high kVp technique for digital chest radiography : a phantom study

Abstract

Purpose: This study aimed to evaluate the appropriateness of using the high kVp technique in planar chest radiography (CXR) with modern direct digital detectors, focusing on patient dose, image quality, and Exposure Index (EI). The goal was to enhance understanding and provide recommendations for future research in the local medical imaging department. Methodology: The research design was an experimental prospective study that collected quantitative data. The study was divided into two phases. In phase 1, an anthropomorphic chest phantom was imaged using a range of kVp values, with and without an anti-scatter grid (ASG). For each imaging variation, the dose area product, mAs, mA, and EI were recorded. In phase 2, subjective and objective evaluations of image quality were conducted using region of interest equations and visual grading analysis, respectively. Results: The results indicated that using 109 kVp without an ASG is the most optimised experimental protocol. This approach reduced the radiation dose to the patient by up to 46.98% while maintaining equivalent image quality and optimal EI compared to the current standard high kVp technique (125 kVp with an ASG). Conclusions: The significant dose reduction achieved with the 109 kVp without an ASG protocol aligns with the ALARA principle, warranting further investigation. Although this study used a phantom, which does not reflect the diversity of patients undergoing CXR, the phantom represented a standard-sized patient. Therefore, the findings may be applicable to similar patient categories. However, further clinical research involving actual patients and larger data sets is necessary before this optimised protocol can be implemented in clinical practice. Implications for practice The use of higher kVp in planar chest radiography may require further consideration with modern digital systems, which may not need an ASG, significantly reducing radiation dose to patients while maintaining diagnostic image quality.