iaea human health series publications - SEDIM

4. BASIC PRINCIPLES OF QUALITY ASSURANCEIN MAMMOGRAPHY4.1. QUALITY ASSURANCE ACTIVITIESA QA programme for diagnostic radiology, as defined by the World Health Organization (WHO) [39], is anorganized effort by the staff operating a facility to ensure that the diagnostic images produced are of a sufficientlyhigh quality to reliably provide adequate diagnostic information at the lowest possible cost and with the leastpossible exposure of the patient to radiation consistent with the requisite level of image quality. This requires theestablishment of a comprehensive QA programme for medical diagnosis, whose technical aspects are under thesupervision of an appropriate medical physicist.QA programmes for medical exposures should include:(1) Measurements of the physical parameters of the radiation generators and imaging devices at the time ofcommissioning and periodically thereafter.(2) Verification of the appropriate physical and clinical factors used in patient diagnosis.(3) Written records of relevant procedures and results. This includes a manual that defines clear lines ofresponsibility, outlines the individual QC tests performed, gives the test frequencies, is useful for stafftraining, facilitates audit of a service and helps to keep a record of information within the facility.(4) Verification of the appropriate calibration and conditions of operation of dosimetry and monitoringequipment.(5) Optimization of clinical protocols and equipment operation to achieve the QA aims as stated above.(6) Regular and independent quality audit reviews of the QA programme.QA programmes are designed to ensure that the radiology equipment and staff procedures can yield thedesired information. They include:(1) Administrative procedures or management actions designed to verify that:— The QC tests are performed properly and according to a planned timetable.— Results of these tests are evaluated promptly and accurately.— The necessary corrective measures are taken in response to these results.— Responsibility for QA actions is appropriately assigned.— Quality standards for equipment in the facility are established.— Adequate training is provided.— Appropriate equipment is selected for each examination, including the writing of adequate equipmentspecifications.(2) Acceptance and commissioning testing (Fig. 6):— Acceptance tests are those tests performed to verify that the vendor has met the purchase specifications.Preferably the tests will be performed independently by the medical physicist, but they are often performedby the company installing the equipment under the supervision of the medical physicist [40].— In addition, if a digital PSP image receptor is installed to be used with an older X ray system and gantry, theacceptance tests should be conducted on the entire system to assess whether the performance is acceptable.— Commissioning tests are those tests performed by the medical physicist at the time the equipment is putinto service that are used to establish baseline levels of performance. These tests include all the tests thatare required to be performed annually.— To a large extent, acceptance and commissioning tests overlap. This publication primarily describes teststhat form a comprehensive, ongoing QC programme for mammography, but it is recognized that it isnecessary to ensure that the equipment as delivered conforms to specified standards, and that appropriateinitial baseline values are established and used to ensure proper maintenance for the quality of theequipment throughout its service life. During acceptance testing, a qualified person should check theelectrical and mechanical safety of any new installation.21