Radiation Dose Reduction and Cancer Risk Estimation Associated with Upper Limbs Radiographic Examination by using Optimal Projections: A Phantom Study

Abstract

Introduction: Ionising radiation used during medical imaging examinations should be monitored carefully to reduce the radiation harm and biological effects. In radiography, As Low As Reasonably Achievable (ALARA) principles should be applied during patient positioning by placing the patient sensitive organs away from the radiation beam. Aim: To determine the Entrance Skin Dose (ESD), effective dose and Lifetime Attribute Risk (LAR) of cancer in eye and gonad area when positioning the patient facing towards the primary radiation beam and facing away from it. Materials and Methods: An experimental study conducted using an X-ray phantom to simulate patient position during upper limb radiography. Radiation measurement was done by using TLD placed at the level of the eye and gonads and two different imaging orientations were used (standard and modified). The ESD, effective dose was calculated from TLD’s readings. The BEIRVII report was used to estimate the LAR of cancer. Results: Results showed significant ESD, effective dose, and LAR reduction when the patient was sitting beside the table and not facing the radiation beam. Results indicate that there were significant differences in ESD and ED to the eye and gonads between the different patient orientations. In terms of eye dose, there is a dose difference of 12% between the two projections. For gonad gland doses there is a dose difference of 50% with p-value <0.001. Conclusion: This study confirmed the relation between dose reduction and patient orientation and it aligns with the ALARA principle to ably all efforts to minimise unnecessary radiation exposure.

Keywords

• cancer risk
• radiation protection
• radiography