Collimation and Exposure Parameter Influence Image Quality and Potential Radiation Dose to the Eye Lens of Personnel in Computed Radiography of the Canine Pelvis.

Malene Bisgaard,Stine Pedersen,Signe N Meyer,Dorte Hald Nielsen,Signe Timm,Line Marie Johansen,Clara Allberg,Fintan J Mcevoy,Helle Precht,Anna V Müller

doi:10.3389/fvets.2021.684064

Abstract

Introduction: The purpose of this study was to evaluate the effect of collimation on image quality and radiation dose to the eye lenses of the personnel involved in computed radiography of the canine pelvis.Materials and Methods: A retrospective study of canine pelvic radiographs (N = 54) was undertaken to evaluate the relationship between image quality and the degree of field the collimation used. This was followed by a prospective cadaver study (N = 18) that assessed the effects on image quality and on scattered radiation dose of different collimation field areas and exposure parameters. All radiographs were analyzed for image quality using a Visual Grading Analysis (VGA) with three observers. Finally, the potential scattered radiation dose to the eye lens of personnel restraining a dog for pelvic radiographs was measured.Results: The retrospective study showed a slightly better (statistically non-significant) VGA score for the radiographs with optimal collimation. Spatial and contrast resolution and image sharpness showed the greatest improvement in response to minimizing the collimation field. The prospective study showed slightly better VGA scores (improved image quality) with the optimal collimation. Increasing the exposure factors especially the tube current and exposure time (mAs) resulted in improved low contrast resolution and less noise in the radiographs. The potential eye lens radiation dose increased by 14, 28, and 40% [default exposures, increased the tube peak potential (kVp), increased mAs, respectively] as a result of reduced collimation (increased beam size).Conclusion: The degree of collimation has no statistically significant on image quality in canine pelvic radiology for the range of collimation used but does have an impact on potential radiation dose to personnel in the x-ray room. With regard to radiation safety, increases in kVp are associated with less potential scatter radiation exposure compared to comparable increases in mAs.

Highlights

The purpose of this study was to evaluate the effect of collimation on image quality and radiation dose to the eye lenses of the personnel involved in computed radiography of the canine pelvis
A Kruskal–Wallis test was conducted to determine whether the image quality grades (VGA) differed according to three collimation groups: small, medium, and large
It showed no significant difference between the collimation size groups for either the VGA score (VGAS) or the individual Visual Grading Analysis (VGA) image criteria scores (Crit 1–5), see Table 3

Summary

Introduction

The purpose of this study was to evaluate the effect of collimation on image quality and radiation dose to the eye lenses of the personnel involved in computed radiography of the canine pelvis. Radiology-based imaging diagnosis is constantly evolving, and it remains a valuable tool in diagnosis and clinical decision-making in veterinary medicine. High image quality radiographs are required for clinical diagnosis. Image quality is a collective term, which covers various factors that individually affect visualization of anatomical structures in the radiograph [1,2,3]. Important parameters for image quality are spatial resolution (i.e., visualization of small details), contrast resolution (i.e., discrimination of structures with different radiopacities), sharpness, and homogeneity. All parameters mentioned will influence the radiograph and the process of making the diagnosis [4]

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Discussion

Conclusion