Investigation of X-Ray Attenuation Properties of Organs Within the Body and Head of Cadaveric Subjects Vs. Living Patients for the Validation of CT Organ Dose Measurements
A Mench1*, L Sinclair1, T Griglock2, B Cormack1, J Sirera1, M Arreola1, (1) University of Florida, Gainesville, FL, (2) Oregon Health and Science University, Portland, OR,MO-B-Salon EF-4 Monday 10:00:00 AM - 12:00:00 PM Room: Salon EF
Purpose: To investigate how postmortem changes observed in human tissue affect x-ray attenuation characteristics and confirm the validity of using cadaveric subjects for direct organ dose studies in Computed Tomography (CT).
Methods:In order to assess the effects of postmortem changes on the x-ray attenuation properties of human tissue, and consequently on absorbed dose, seven cadaveric subjects and five living patients spanning a range of Body Mass Indices (BMIs) from 17 to 49 were analyzed in this study. Head and body CT scans were used to delineate regions of interest (ROIs) encompassing various organs and to obtain average Hounsfield Units (HUs) for each region. The calculated effective x-ray energy was used to determine attenuation coefficients based on these HUs and to draw comparisons between those from organs of cadavers and living patients.
Results:Most organs showed attenuation coefficients differing by less than 1% between cadaveric subjects and living patients. Breast tissue differed by 2.02% and lungs without the presence of fluid differed from living patients by 2.77%. More significant differences in attenuation were found where fluid had infiltrated the cadaveric lungs and caused a discrepancy of 10.54%. The use of cadavers with minimally fluid-filled lungs is still clinically relevant as they represent patients with pleural effusions or pneumonia. The results remained consistent with those found in other literature.
Conclusion:The findings show excellent agreement in attenuation properties between the organs of cadaveric subjects and those of live patients with the exception of lungs with high levels of fluid retention. This confirms the accuracy of using cadavers for measurement of average organ doses delivered to patients during routing CT examinations.