Effect Of Beam Overlapping On Entrance Surface Dose In Whole Spine Radiography Using The Eos

Abstract

Background/Objectives: This study examines the effect of overlapping beams on the patient's dose in the simultaneous acquisition method by comparing the dose difference between the simultaneous acquisition of the front and lateral images and the individual acquisition methods during spine examination using EOS. Therefore, I would like to suggest the best test method with the minimum dose.

Methods: This study was aimed at the anthropomorphic phantom. The posture was taken as posteroanterior (PA), and the mid sagittal plane (MSP) and mid coronal plane (MCP) of the phantom were positioned in line with the positioning guide lines in the EOS. The device for the entrance surface dose measurement was attached to the front and side surfaces, respectively, at the height of the 6th cervical and thoracic vertebrae. The X-ray irradiation range was set from the external auditory canal of the phantom to the 8th thoracic vertebra. The scan condition was fixed to body shape ‘S’ and scan speed ‘3’, the coronal plane irradiation condition was set to 83 ㎸, 200 ㎃, DAP 59.62 m㏉*㎠ and the sagittal plane was set to 102 ㎸, 200 ㎃, DAP 84.86 m㏉*㎠.

Findings: Compared to the case of acquiring the PA and Lat. images at the same time compared to the case of acquiring the images separately, at the C 6 position, PA was 2.34 μ㏉ and Lat. was 4.22 μ㏉, and at the T 6 position, PA was 2.94 μ㏉ and Lat. was 0.19 μ㏉, it was found to be more affected. At the same time, it was found that the effect of the dose due to the overlapping of the beams when acquiring PA and Lat. images were very insignificant.

Improvements/Applications: In case of both testing, it is possible to receive a maximum dose of about 2.6% and a minimum of 0.1% more than when coronal and sagittal are tested individually. Most of the patients who come to our hospital due to spinal sagittal plane imbalance complain of a lot of pain in maintaining a standing posture with the back straight. The majority of these patients are the elderly. Taking this into consideration, doing two images at once rather than dividing the test in two and giving a smaller dose of about 2% will improve the efficiency of the test, prevent re-radiation and reduce the patient's pain post test. I think it's the right way to do it.