Bismuth shielding . Daniel .J.P , Radiology Technologist , Khorfakhan hospital . Sharjha , UAE
-
Upload
haijaypeedan -
Category
Education
-
view
1.049 -
download
3
description
Transcript of Bismuth shielding . Daniel .J.P , Radiology Technologist , Khorfakhan hospital . Sharjha , UAE
Bismuth Shielding:Helpful or Harmful
DANIEL.J
TECHNOLOGISTDEPT OF RADIOLOGYKHORFAKKAN HOSPITAL
INTRODUCTION
• Bismuth shielding has been used to reduce the dosefrom CT to superficial radiosensitive organs, such asthe breast, lens of the eye, and thyroid.• Concerns include an adverse effecton image quality and absorption ofphotons exiting the patient and ontheir way to the detector• Clinical studies did not control fornoise level; primarily assessedwhether “clinically acceptable”
Bismuth Eye Shielding
BISMUTH SHEILDS
MOTIVATION
• To quantitatively assess the dose reduction and image
quality in controlled experiments:– Standard clinical protocol– Bismuth shielding– Organ-based TCM– Globally decreasing the tube current to
achieve the samedose reduction as bismuth shielding
Scanning parameters
• Reference scan parameters were chosen from ourstandard spiral head scanning protocol– 120 kV, 1s rotation, 5 mm image thickness, 300 mm
FOV• Chose a reduced effective mAs [“Low-mAs”] to yieldthe same dose reduction to the eye as bismuth shield:Low-mAs = Ref-mAs * Bi_Dose / Ref_Dose• Bi_Dose and Ref_Dose are the doses measured at
theeye with and without bismuth shielding, respectively.
Organ-based Tube Current Modulation
EYE SCANNING PARAMETERS
DOSE REDUCTION TO EYE LENS
IMAGE QUALITY EVALUATION
IMAGE QUALITY EVALUATION
EYE IMAGE EVALUATION
THORAX IMAGE EVALUATION
THORAX IMAGE EVALUATION
ORGAN BASED TCM
THORAX IMAGE EVALUATION
THORAX IMAGE EVALUATION
THORAX IMAGE EVALUATION
THORAX IMAGE EVALUATION
BISMUTH vs OTHER TECHNIQUES
COMPARISON
SUMMARY
CONCLUSION