Chest Radiography Optimization: Identifying the Optimal kV for Image Quality in a Phantom Study

TL;DR

This study uses a phantom to find the best kV settings for chest X-rays to balance image quality and radiation dose.

Contribution

The study introduces a quantitative phantom-based evaluation of optimal kV settings for chest radiography.

Findings

Intermediate tube voltages improved dose-normalized image quality for slim and average thickness phantoms.

Higher voltages were needed for obese-equivalent phantoms to maintain image quality.

Image quality and dose depend on tube voltage and phantom thickness combinations.

Abstract

Chest radiography remains one of the most frequently performed imaging examinations, highlighting the need for optimization of acquisition parameters to balance image quality and radiation dose. This study presents a phantom-based quantitative evaluation of chest radiography acquisition settings using a digital radiography system (AGFA DR 600). Measurements were performed at three tube voltage levels across simulated patient-equivalent thicknesses generated using PMMA slabs, with a Leeds TOR 15FG image quality phantom positioned centrally in the imaging setup. Image quality was quantitatively assessed using signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR), which were calculated from mean pixel values obtained from repeated acquisitions. Radiation exposure was evaluated through estimation of entrance surface dose (ESD). The analysis demonstrated that dose-normalized performance metrics favored intermediate tube voltages for slim and average patient-equivalent thicknesses, while higher voltages were required to maintain image quality in obese-equivalent conditions. Overall, image quality and dose were found to be strongly dependent on the combined selection of tube voltage and phantom thickness. These findings indicate that modest adjustments to tube voltage selection may improve the balance between image quality and radiation dose in chest radiography. Nevertheless, as the present work is based on phantom measurements, further validation using clinical images and observer-based studies is required before any modification of routine radiographic practice.

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