B Pearlin*, R Livingstone, Christian Medical College, Vellore, Tamil NaduIN,

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  B Pearlin

PO-GePV-I-25 (Sunday, 7/25/2021)   [Eastern Time (GMT-4)]

Purpose: To evaluate the impact of radiation dose on image quality in six different flat panel detectors (FPD) and optimize radiation dose by altering exposure factors in low and high kVp chest radiography.

Methods: Radiographic images of a semi-anatomical chest phantom were acquired from 6 FPDs from 4 different digital radiography (DR) manufacturers. Dose-area-product (DAP) was measured for three different protocols (Standard, AEC and low radiation dose) utilising 70 and 110 kVp. To normalize measurements across all FPDs, a standard DAP value of 51.05 µGym² obtained at 70 kVp and 9.43 µGym² at 110 kVp was used. The lowest possible radiation dose to provide acceptable image quality was achieved by manually adjusting mAs for both tube potentials. While selecting AEC exposure parameters, density, dose level or exposure (speed) classes were altered to obtain optimal radiation dose and image quality. Contrast to noise ratio (CNR), signal to noise ratio (SNR), figure of merit (FOM), contrast detail of the lung, heart and diaphragm regions and spatial resolution were quantified using a workstation.

Results: In comparison with standard protocol, radiation dose reduction of 21%, 21.6%, 59.5%, 60.7%, 62.2% and 67.6% was achieved in GE Definium8k, Siemens Fusion, Fujifilm FGX, Fujifilm FGXR, Philips Digital Diagnost and Siemens Aristos with low dose protocol at 70 kVp. However, at 110 kVp, radiation dose could be reduced by 15.7%, 34.8% for Philips Digital Diagnost and Siemens Aristos alone.

Conclusion: This study demonstrates the feasibility of using a semi-anatomical chest phantom in the optimisation of radiation dose and image quality for different FPDs. The FOM was a good indicator in assessing image quality between different detectors.

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