Retrospective Patient Dose Analysis of Ghana’s First Direct Digital Radiography System

Abstract

The log file generated in the flat panel detector of a direct digital x-ray machine (General Electric, Haulun Medical Systems, Serial Number 8M0392) after x-ray exposure was used to acquire data regarding the entrance surface air kerma (ESAK) for some routine x-ray examinations. The data were collected for a minimum of 10 standard adult patients undergoing each examination considered. The mean ESAK were found to be 0.25, 0.33, 0.14, 7.33, 9.76, 7.38, and 6.86 mGy for skull AP and LAT, chest AP, lumbar spine AP and LAT, pelvis AP and abdomen AP series, respectively. The mean ESAK values recorded from this study show wide variations but were below diagnostic reference levels (DRLs) of the Commission of European Communities and also compare with other recommendations. The comparisons of this study's dose levels with DRLs were undertaken as an approach to dose optimization. The study revealed that a dose audit of digital radiography systems is necessary because of the potential high doses one is likely to receive. Continuous dose evaluation in digital radiography is therefore encouraged in order to optimize doses to patients.

Review of the current status of radiation protection in diagnostic radiology in Africa

“…Examples of such applications in some African countries show that patient doses are in the range of 0.18 mGy (chest PA) to 10.8 mGy (lumbar spine lateral) for some common CR x-ray examinations, which were different from the doses in film-screen systems as they were lower than 0.3 mGy (chest PA) but higher in the case of lumbar spine Lateral of 5.9 mGy. 14,15 Literature data in DR show that patient doses are in the range of 0.14 (chest PA) to 9.76 (lumbar spine lateral) mGy 15,16 and, therefore, are relatively lower than in film-screen systems as expected. The potential for patient "dose creeps" was observed both in CR and DR due to the nature of the techniques.…”

“…In some countries, even calcium tungstate screens with emission in the blue range and a screen speed of 200 have been used rather than rare earth screen with emission in the green range and a screen speed of 400 in x-ray cassettes. [9][10][11][12][13][14][15][16] Accordingly, actions have been taken by the IAEA in the past to motivate and support the change of calcium tungstate screens to rare earth screens. It must be noted that this single action results in patient dose reduction by about half, and the results are definitive.…”

“…Second, basic information on radiation protection in diagnostic radiology, including patient dose and image quality, is now available. [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] Third, the potential for optimization of radiation protection using simple and inexpensive techniques has been demonstrated, upon which further developments can be made. 5,28,29,33,34 Fourth, a number of staff have been trained in radiation protection principles, justification of medical procedures, and medical exposure control.…”

“…5,8 This is evidenced in studies undertaken in African countries in general radiography, fluoroscopy, mammography, CT scanning, and interventional procedures. [9][10][11][12][13][14][15][16][17][18][19][20][21][22]29,33,34 As a result of the mentioned achievements, there is a potential for improved outreach of radiation protection in diagnostic radiology that can contribute to related sustainable programs. 36 Despite the aforementioned achievements, some challenges have been discussed in this paper.…”

“…5,8 For African region, in the early 2000s, there was a lack of information on radiation doses to patients in various diagnostic and interventional procedures, but, in recent years, there have been a series of publications. [9][10][11][12][13][14][15][16][17][18][19][20][21][22] The aim of this paper is to consolidate information to understand the current status of radiation protection in diagnostic and interventional procedures in African countries and identify challenges and possible strategies for improvement. The paper separately reviews situations for radiography, interventional procedures, computed tomography (CT), mammography, justification, optimization, and awareness on radiation protection.…”