J A Mulvaney | PubMed Health

PubMed1982

Problems with contrast-detail curves for CT performance evaluation.

Contrast-detail curves have been used frequently to describe the low contrast performance characteristics of computed tomography (CT) scanners. However, such curves can produce misleading conclusions if the effects of all variables influencing CT images are not considered. As shown in this experimental study, improperly designed contrast-detail curves disguise differences in CT performance when the same object is imaged with different x-ray spectra. These problems arise because contrast is defined as the difference in system-dependent CT numbers rather than the actual difference in the object. An alternate approach to CT performance evaluation using "difference-detail" curves is offered.

Humans↗

PubMed1981

X-ray equipment performance: a 3.5 year case history.

The continuing performance of radiographic imaging systems has become increasingly important as the complexity and cost of these systems continue to escalate, as replacement funding becomes more difficult to obtain, and as advisory and regulatory agencies place increasing emphasis on equipment-oriented quality control procedures. As a guide to the continuing performance of these imaging systems, selected performance indicators for two general-purpose radiographic-fluoroscopic units have been monitored for a 3.5 year period. The observations suggest that with inspection and adjustment at 6 month intervals for generator, x-ray tube, and beam restriction systems, and at 2 month intervals for the intensified fluoroscopic imaging system, the overall performance of the imaging systems can be maintained at a high level of consistency equivalent to the performance achieved when the equipment was initially installed.

Fluoroscopy↗