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.