Which quality control procedures are used in the nuclear imaging for myocardial ischemia?

Updated: Aug 07, 2019
  • Author: Thomas F Heston, MD, FAAFP, FASNC, FACNM; Chief Editor: Eugene C Lin, MD  more...
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Answer

Quality control begins with proper equipment selection. Although single-head cameras are used widely and are probably the most popular system, dual-head cameras separated by 90° are gaining popularity. A circular or elliptical orbit may be used. Step-and-shoot acquisition is the most common method of imaging, although continuous acquisition cameras may provide greater sensitivity.

A procedure manual containing a step-by-step procedure for each examination should be on hand. The manual also must contain quality-control procedures for all instruments and radiation safety measures. The procedures manual should be updated and reviewed regularly.

Daily quality-control procedures for most cameras include energy peaking and a low-count intrinsic flood (3-10 million counts). An intrinsic resolution is performed weekly. An extrinsic high-count flood (30 million counts) and center-of-rotation analysis are performed at least monthly. Weekly center-of-rotation analysis is required on many cameras. These quality-control measures are only rough guidelines. Following the manufacturer's recommendations for each specific camera is important.

One must look for several sources of error on each patient study. Interstitial infiltration of the radiopharmaceutical can alter uptake and clearance kinetics. Patient motion artifacts and diaphragmatic creep can create artificial defects. Frequently, minor motion artifacts can be corrected by reprocessing the data.

Suboptimal stress decreases the sensitivity of the test; therefore, in the final report, stating the actual heart rate achieved as a percentage of the age-predicted and gender-predicted maximum heart rate is important. Study processing needs to be standardized.

Raw data need to be reviewed in a rotational cinematic format prior to the examination of reconstructed tomographic sections. The purpose of this is to identify attenuation artifacts (eg, breast shadows) or overlapping artifacts (eg, liver or bowel activity), motion, abnormal noncardiac uptake, increased lung uptake, or anything else unusual.


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