The Evaluation of the Correlation between Radiographic Exposure Technique and Entrance Surface Air Kerma using Exposure Index from Computed Radiography

Authors

  • Paowarin Khayaiwong Radiological Department, Faculty of Science, Ramkhamhaeng University
  • Pichan Keawpookum

Keywords:

Computed Radiography, Entrance surface air kerma, Exposure index, Exposure techniques

Abstract

Analog imaging system like Film-screen Radiography had been gradually replaced by Digital imaging system. Computed Radiography (CR) is the most common filmless system in Thailand. However, an adjustable digital image may induce unnecessary radiation exposure to patient. The KAP-meter, real time transmitted dosimeter, is quite expensive when consider as the radiographic examination cost. An Exposure Index (EI), a quantity derived from pixel value, is actually the indicator for image quality assessment used for patient dose monitoring. Objective:The aim of this study is to evaluate the correlation between Radiographic Exposure Technique and Entrance Surface Air KERMA (ESAK) using EI from CR. Methods: EI, ESAK, kVp, mAs of common radiographic procedures such as skull, chest, abdomen and pelvis were performed in anthropomorphic phantom and their correlations were analyzed by R(statistical data analysis software). Result: All procedures had strong correlation between EI and ESAK (p-value less than 0.01). The Pearson’s correlation (R) were 0.873, 0.901, 0.857, and 0.859 for skull, chest, abdomen, and pelvis respectively. Discussion and Conclusion:There was poor correlation between EI and kVp in this study. Hence kVp can affected x-ray beam quality this may alter the detective quantum efficiency (DQE) and conversion efficiency (CE) of CR. Further study ofextremities radiography should be performed. The comparison between our imaging system and that of the other system may encourage dose optimization.

References

A.M.Costa, M.S.Pelegrino (2014). Evaluation of entrance surface air kerma from exposure index in computed radiography. Radiation Physics and Chemistry 104:198-200

Agung N S,Suryono, Suharyo H, A. Gunawan S, Bedjo S, Sugiyanto, Gatot M W(2017). Exposure Index and Entrance Surface Dose of ANSI Chest Phantom with Computed Radiography. Int. J. of Allied Med. Sci. and Clin. Research 5(4) :947-953

Internal Atomic Energy Agency (2004). Optimization of the radiological protection of patients undergoing radiography, fluoroscopy and computed tomography. IAEA-TECDOC-1423

P Kaewpookum, Napapong P, Supakajee (2013). Correlations among Entrance Surface Air KERMA, KERMA-Area Product and Exposure Index in Chest Digital Radiography at Phramongkutklao Hospital. Royal Thai Army Medical Journal 66:103-109

Downloads

Published

2021-04-30

Issue

Section

Original Articles