Organ dose and effective dose with the EOS scanner in spine deformity surgery: A study on anthropomorphic phantoms describing patient radiation exposure in full spine examinations

Organ dose and effective dose with the EOS scanner in spine deformity surgery. A study on anthropomorphic phantoms describing patient radiation exposure in full spine examinations.
Authors: Peter Heide Pedersen, Asger Greval Petersen, Søren Peter Eiskjær.

Background:
Ionizing radiation potentially leads to tissue damage. It has been documented in large cohort studies that radiographic imaging during childhood for spinal deformities eg. scoliosis, increases the lifetime risk of breast cancer.
The EOS biplane x-ray imaging system (EOS Imaging S.A, Paris France) has been developed to produce high quality images while at the same time reducing radiation dose. At our institution we use the EOS for pre- and postoperative full spine examinations.

Purpose:
The purpose of the study is to make first time organ dose and effective dose evaluations with micro-dose settings in full spine examinations. Our hypothesis is that organ dose and effective doses can be reduced 5-10 times compared to standard settings, without too high image-quality trade off, resulting in a theoretical reduction of radiation induced cancer.

Methods:
Patient dosimetry is performed on anthropomorphic child phantoms, representing a 5 year old and an adolescent. Thermoluminiscent detectors are used to measure organ dose. A first time measurement with micro-dose settings in both AP and PA will be performed in addition to standard settings in AP and PA positions. Effective dose is calculated using mean organ doses and tissue weighting factors. These findings and image quality will be compared to previously reported findings in standard settings and to conventional digital x-ray(CR)
Results:
Our preliminary studies have shown a significant reduction in absorbed organ dose. In AP position we found a mean liver organ dose of 0.03mSv as compared to 0.25mSv with standard dose settings, a dose reduction of 88%. As expected the liver dose was higher in PA position than AP position, 0.05mSv vs. 0.03mSv. Previously a 35% organ dose reduction compared to CR has been reported for the EOS in standard settings.