Mathematical Modelling for Estimating the Entrance Surface Dose (ESD) of Patients Exposed to Diagnostic X-ray


M.K. Al-Motawakel

Physics Department, Faculty of Science, Sana’a University-Sana’a

  1. AL-Sharabi, Z. Eadan, N.A. AL-Sowaidi

National Atomic Energy Commission of Yemen (NATEC)-Sana’a


This research presents a mathematical simulation to calculate the Entrance Surface Dose (ESD) received by the adult patients during the radiological diagnosis examinations of chest, abdomen and lumbar spine, and it was carried out at five centers in the Capital City of Sana’a. The x-ray devices were calibrated, measuring the Radiation output factor of each device used for calculating the (ESD). The radiation output factor varied among  the x-ray devices and ranged from 2 x 10-9 to 2 x 10-5 mGy/(mAs.KVp)), which the minimum value was listed in the  second center’s device. In addition, the results of calculated ESD by using mathematical model showed that the ESD for the chest, lumbar spine, and abdominal examinations were in the range of (0.0342 to 1.095 mGy), (0.3667 to 11.613 mGy) and (0.3667 to 11.613 mGy), with an average of 0.3299, 3.575 and 3.45 mGy, respectively. The lowest calculated ESD values ​​of the three examinations were in the second center, because the x-ray tube of the device has largely consumed and its output factor is very low by five thousand two hundred and fifty (5250 times) compared to the average output factor of the remaining four x-ray devices, so in the 2nd  center, it is applied the CR system to clarify the imaging. The results of the study shows an increase of the ESD compared to the IAEA guidance levels. The increases were 42%, 35%, and 23% of the total studied cases of chest, lumbar spine, and abdomen examination respectively, due to the elevating mAs exposure parameters and reducing the distance (FSD) between the x-ray tube and the patient’s body.

Keywords: X-Ray devices, ESD, Radiation Output Factor, Guidance Levels, Mathematical Model

1-01072022-1-11 SJ of NATEC

Leave A Reply

Your email address will not be published.