Application of Dose-Area Product compared with three other dosimetric quantities used to estimate patient effective dose in diagnostic radiology

Background: Application of Dose-area product (DAP) quantity has been increased in the clinical practice. DAP is relatively easy to measure. DAP has been shown to correlate well with the total energy imparted to the patient, which is related to the effective dose. Material and Methods: In this study, measurements of DAP were carried out in a sample of 421 adult patients who underwent conventional radiological examinations. Then, by using DAP some useful dosimetric quantities such as exposure area product (EAP), air kerma and entrance surface dose (ESD) were estimated. Furthermore, ESD was calculated by a Multi-O-Meter dosemeter. Effective doses were computed by measurement of DAP and corresponding conversion factors. Finally, the effective dose was determined using: i) ESD and data published by NRPB. ii) energy imparted derived from DAP, and iii) ODS-60 package. Results: The effective dose values derived from the four methods are in good agreement. The mean effective dose estimated from DAP measurement were 0.13, 0.42, 0.05, 0.59, 0.54 and 0.03 mSv/projection for chest, abdomen, cervical spine, lumbar spine, pelvis and skull examinations, respectively. Conclusion: Indirect effective dose determination using the NRPB dosimetric data and the measured value of DAP or ESD allows for reliable estimates of effective dose. The ODS-60 software was used in this study because it has the flexibility to manipulate the technical parameters of an examination and patient's parameters.