Rapid evaluation of weekly scintillation camera resolution and linearity using the orthogonal tri-hole phantom

Abstract

Objective: Both state and federal regulations require weekly monitoring of the resolution and linearity of the scintillation camera. Several phantoms are available to perform this quality control function. These include the quadrant bar. Bureau of Radiological Health (BRH), and orthogonal-hole (OH) phantoms. Each of these phantoms has either functional or temporal limitations on its use. The orthogonal tri-hole phantom (OTHP) was designed to overcome these limitations.

Methods: The OTHP consists of a precision-drilled lead plate sandwiched between two plastic plates. The OTHP has an active area of 15 in. x 20 in. which contains an orthogonal array of three-hole (2.5-mm, 3.0-mm, and 4.0-mm) clusters. Intrinsic and extrinsic images were acquired for the OTHP, OH phantom, BRH phantom and quadrant bar phantom.

Results: The OTHP test pattern allows resolution, linearity, object shape, and contrast to be evaluated simultaneously, either intrinsically or extrinsically, in a single image over the entire useful field-of-view.

Conclusion: The OTHP provides a more quantitative evaluation of the quality control parameters than any other phantom currently available. The use of the OTHP results in cost savings since both camera and technologist time are reduced because only one image is required instead of the two or four needed for other phantoms.