General introduction

6.2.1. General introduction

The goal of the diagnostic nuclear medicine procedure is to differentiate between normal and pathological conditions. The results of the procedure should therefore provide images and quantitative data that are suitable for classifying disease in a correct and reproducible way. From the instrumentation viewpoint, the clinical procedure is a combination of the scintillation camera and patient set-up, the data acquisition, the data processing and the final display of results. It is essential to realize that all aspects of the clinical procedure are linked. In order to achieve consistent and correct results, each part of the procedure must be carefully monitored and a standard clinical protocol must be adhered to.

This section more fully addresses quality assurance related to the clinical software (sometimes referred to as applications software) used to process the acquired images. Such software provides objective parameters of specific organ functions and generates functional diagnostic patterns, for example, for cardiac studies and for renal studies. The clinical software may be supplied as an integral part of the purchased scintillation camera–computer system, or it may

be a part of an independent nuclear medicine computer system.

The user expects that the clinical software has been developed to provide valid quantitative data for a well-defined objective and that this software has been well tested. The responsibility for this lies with the manufacturer or producer of the software. The software must have been carefully tested in clinical settings in a large number of studies in order to ascertain its validity for the objective. Some clinical studies must be supplied with the released clinical software as sample studies with known results for the user to test the software in their own environment. The software must also be accompanied with full documentation.

The clinical software requires acceptance testing and, thereafter, regular monitoring. The first responsibility of the user, therefore, is to perform quality assurance assessment on the clinical software before actually putting it into clinical use. This involves becoming fully familiar with the documentation and with all aspects of the clinical procedure. The objectives and assumptions of the software must be well understood. The software itself must then be tested with

a set of sample clinical studies, or a database of studies with known results, in order to ensure satisfactory results. In order to maintain quality assurance once the software is accepted and put into routine clinical use, the user is responsible for monitoring the software results. This requires user training, audits of results using the software, and inter- and intra-observer comparison tests.

The user must be aware at all times that the potential of a system to produce errors is almost unlimited. It is vital never to accept blindly the results from clinical software, but to remain open at all times to inconsistencies and errors, and to take care that results are reasonable. Owing to the diversity of clinical software, it is not possible to give exact protocols for quality assurance. The following guidelines are intended to help limit errors, to help check that the system is well behaved and to help the user gain confidence in the generated results.