Keywords:
Image verification, Physics, Conventional radiography, Radioprotection / Radiation dose
Authors:
B. A. Openy; Kampala, Uganda/UG
DOI:
10.26044/ecr2019/C-0728
Methods and materials
Study design: A cross sectional study.
Study setting: This study was conducted in eight x-ray units in Kampala.
These X-ray units included both Government and private units.
Study variables included: Patient’s factor: sex,
age,
and weight.
Machine factor: kVp,
mAs,
CR,
conventional/Analogue,
DR,
FSD.
Dependent variables were Incident Air Kerma and Entrance Skin Dose.
Outcome: DRL.
ESD calculation; IAK (Incident Air Kerma) and ESAK/ESD (Entrance Skin Dose) was calculated as below.
IAK = tube output at 1m (mGy/mAs) x mAs x 1/FSD.
Tube output values were obtained from the Table.
The FSD was calculated by subtracting the patient’s thickness from the FFD (film to focus distance).
ESD= IAK x BSF Where; BSF= Back Scatter Factor = 1.35.
The DRLs was calculated from ESDs by determining the 75% percentile third quartile of ESDs.
Positioning: anteroposterior and lateral.
Exposure was done on arrested expiration.
Post exposure; patient waited for their results in the designate waiting area.
Data analysis: Univariate analysis was used for general description of subjects studied and to answer objective 1&2.
Numerical characteristics were summarized as means,
median with standard deviation.
ESDs were summarized as means with standard deviations.
The DRLs were determined as the 75th percentiles of the ESD for each X-ray unit.
The ESDs were summarized as means to get the Local DRLs answering objective 2.
Then comparision made between X-ray rooms and International DRLs to answer objective 3 and 4.