Justification in protection of patients
Justification in radiological protection of patients is different from justification of other radiation applications, in that generally the very same person enjoys the benefits and suffers the risks associated with a procedure. Dose limits are not directly relevant, since ionising radiation, used for medically indicated purpose and at the appropriate level of dose, is an essential tool that will cause more good than harm. (ICRP Publication 105 Radiological Protection in Medicine)
There are three levels of justification of a radiological practice in medicine: (1) At the first and most general level, the proper use of radiation in medicine is accepted as doing more good than harm to the society. This general level of justification is now taken for granted; (2) At the second level, a specified procedure with a specified objective is defined and justified (e.g. chest x rays for patients showing relevant symptoms). The aim of the second level of justification is to judge whether the radiological procedure will improve the diagnosis or treatment, or will provide necessary information about the exposed individuals. The total benefits from a medical procedure include not only the direct health benefits to the patient, but also the benefits to the patient’s family and to the society; (3) At the third level, the application of the procedure to an individual patient should be justified (i.e. the particular application should be judged to do more good than harm to the individual patient).
Hence all individual medical exposures should be justified in advance, taking into account the specific objectives of the exposure and the characteristics of the individual involved. Usually, no additional justification is needed for the application of a simple diagnostic procedure to an individual patient with the symptoms or indications for which the procedure has already been justified in general. For high-dose examinations, such as complex diagnostic and interventional procedures, individual justification by the practitioner is particularly important and should take account of all the available information. This includes the details of the proposed procedure, the characteristics of the individual patient, the expected dose to the patient, and the availability of information on previous or expected examinations or treatment. In addition, alternative procedures should always be considered regardless an examination involves high-dose or low-dose exposure. (ICRP Publication 85 Avoidance of Radiation Injuries from Medical Interventional Procedures; ICRP Publication 117 Radiological Protection in Fluoroscopically Guided Procedures outside the Imaging Department; ICRP Publication 121 Radiological Protection in Paediatric Diagnostic and Interventional Radiology)