Investigation of Organ and Effective Doses with Increasing Weight Percentiles

3^rd International Conference on Medical Physics & Biomedical Engineering

November 07-08, 2016 Barcelona, Spain

Keyhandokht Karimi-Shahri, Mohammad Mehdi Firoozabadi,Zahra Sharifi

Physics Department, School of Sciences, University of Birjand, Iran

Posters & Accepted Abstracts: J Bioengineer & Biomedical Sci

Abstract :

Workers and patients who are exposed to ionizing radiation in various occupational and medical environments are in the different weight percentile even in the same age group. In this study this effect investigates on organ-absorbed dose and effective dose(ED). For this reason, the ORNL modified adult phantom (50th weight percentile) and the Monte Carlo N-Particle Transport Code (MCNP) were used for external photon energies (10 keV�10 MeV) in Anterior-Posterior (AP), Posterior-Anterior (PA), Left- Lateral (LLAT) and Right-Lateral (RLAT) irradiation geometries. To create percentile-specific phantoms from base phantom (50th percentile phantom), the volume of internal organs was kept constant and an increase in body weight to achieve the desired weight percentile (65th, 75th, 85th and 95th) was done by adding layers of adipose and soft tissues on the phantom. For example, torso was changed as follow (The ORNL torso is a cylinder with an elliptical cross-section): the radius along the major and minor axes of the elliptic section was increased by adding adipose and muscle tissues. The muscle layer was placed and then the adipose layer covered it. By appending these layers, the positions of the skin and breasts were altered. Skin was transferred forward by considering the thickness of the external layers added. Radial changing for breasts was also considered. The results indicate that increasing the weight percentile decreases ED and the organ absorbed doses for all energies and irradiation geometries. For instance, the ratio of ED in 95th to 50th percentile (E95/E50) is 0.78, 0.79, 0.81 and 0.80 at 1 MeV photon beams for AP, PA, LLAT and RLAT geometries, respectively. In fact, there is a notable decreasing in doses that should be considered in the protection and treatment aims.

Biography :

Email: k.karimi@birjand.ac.ir