title: An alignment ruler for computed tomography scanning.
abstract: This patient alignment ruler has been developed to deduce the position of high resolution CT scans relative to an anatomical marker. In addition, the ruler may be used to check the accuracy of the scan plane indicator lights and the consistency of the couch incrementation on any CT scanner. The ruler has been specifically designed for use with scanners employing a 13 mm slice width; however, it may easily be modified for other widths, by altering the hole pattern. An alignment device has been described in a previous publication (Nettle 1979) in which calculations using measurements made on the TV monitor were necessary. However, the ruler described here requires only visual interpretation. This ruler is both inexpensive and easy to manufacture.
mesh_terms: D006801:Humans; D012015:Reference Standards; D013122:Spinal Diseases / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed / Q000295:instrumentation*