Lumbar spine radiology: analysis of the posteroanterior projection

The use of the posteroanterior (PA) technique as a means of dose reduction has been used effectively in radiology departments for chest and abdominal The aim of this investigation was to establish if the PA lumbar spine proje ction offers any advantages over the traditional anteroposterior (AP) view in terms of radiation dose and image quality. The contribution of tissue di splacement to any dose reduction was also evaluated. The first part of: Vie study involved the use of an anthropological phantom where entrance surfac e and an internal dose were measured for both the PA and AP projections. En trance surface doses for both projections were then measured on randomly al located female patients. Resultant image quality was assessed using CEC qua lity criteria. Anterior to posterior patient diameter was also recorded. Th e results demonstrated that with the PA compared with the AP projection, re ductions of 38.6% (p = 0.016) and 38.9% (p = 0.02) in patient entrance surf ace dose and internal phantom dose, respectively. No significant difference s in image quality were noted between the two projections. Patient diameter decreased by 1.8 cm with the PA view. The authors conclude that tissue dis placement is the main factor for the patient dose reduction and recommend e mployment of the PA procedure for routine lumbar spine examinations.