Simplified patient positioning to reduce beam hardening in CT of the lower neck.

Certain regions of the body can be relatively difficult to image optimally by computed tomography (CT). The lower neck falls into this category. A routine transverse image at this level includes the shoulders, which can cause beam hardening [1] . Beam hardening reduces subject contrast and often produces streak artifacts between the shoulders [2, 3]. This image degradation is especially troublesome when searching for small soft-tissue masses in the neck, such as parathyroid adenomas [4]. Although software packages are available to compensate for beam hardening, the correction is only partial ; some deleterious effects on the interpretative value of lower neck scans persist [5]. We present a positioning technique that reduces the beam hardening encountered in CT evaluation of the lower neck. A commercially available cylindrical or triangular sponge about 15 cm in diameter and 35 cm long is placed between the scapulae of the supine patient while a second, smaller sponge is used to elevate the head (fig. 1). This allows for posterior positioning of the shoulders relative to the chest and neck, thus providing significant exclusion of the shoulders from the plane of interest and permitting transverse CT imaging of the lower neck without extensive beam hardening.