Patient radiation dose and image quality in simple radiographic projections using computed radiography (CR) system : comparison the results between before and after the training

Abstract

The purpose of this study is to determine the patient dose in clinical setting from the CR system while maintaining the image quality and the retake rate reduction. The data were collected from patients examined at two X-ray rooms, No.4 and EMS, in five routine types of seven projections. Those were chest (PA), abdomen (AP), cervical spine (AP), lumbar spine (AP/LAT), and skull (PA/LAT) at Rajavithi Hospital, Ministry of Public Health, Bangkok Thailand. 458 digital images were collected for the purpose of the dose determination and image quality over a period of one month. The entrance surface dose (ESD) was calculated using the data of the entrance surface air kerma, ESAK, the radiographic technique data, the patient data and back scatter factor for a selected group of patients in the period of before and after the training program. Image quality was evaluated by two radiologists as Grade A (clearly accept), B (accept with some remarks) and C (reject). The results show that the mean ESD of before and after training in mGy, from Room No.4 of chest (PA) was 0.23/0.17, abdomen (AP) 3.34/3.03, cervical-spine (AP) 0.32/0.29, lumbar-spine (AP/LAT) 3.02/2.72, 8.93/8.32 and skull (PA/LAT) 1.94/1.74, 1.71/1.49 respectively. From Room EMS of chest (PA) was 0.36/0.25, abdomen (AP) 2.84/2.81, cervical-spine (AP) 0.34/0.33, lumbar-spine (AP/LAT) 2.20/1.96, 8.79/7.90 and skull (PA/LAT) 1.57/1.26, 1.58/1.20 respectively. The mean ESD of all projections is less than the international guidance level. For Room No.4, there was no statistically significant in patient dose after training for abdomen (AP), cervical spine (AP) lumbar spine (AP/LAT), and skull (PA/LAT) examinations (p>0.05).Whereas for chest (PA) has statistically significant improvement (p<0.05). For Room EMS, there was no statistically significant in patient dose after training for abdomen (AP), lumbar spine (AP), and skull (PA/LAT) examinations (p>0.05).Whereas for chest (PA), cervical spine (AP) and lumbar spine (LAT) show statistically significant to patient dose (p<0.05). The poor image quality caused by the patient positioning, over-under exposure, and image artifact. The reject analysis before and after training was 51/1,488 images or 3.4% and 66/2,668 images or 2.5% from Room No.4, and 75/2,751 images or 2.7% and 72/ 2,905 images or 2.5% from Room EMS. The cause of retake was mainly from patient positioning. The data are useful for the formation of national guidance levels as recommended by IAEA.