Justification and optimization

» Who decides which medical procedure is appropriate and whether it is justified?

The process of justification allows determining whether the medical exposure will take place or not. The goal of justification is to avoid unnecessary radiological procedure, which would result in patient being unnecessary exposed to ionizing radiation and its potential risks. 

First, a given radiological procedure shall be justified. This applies to the justification of new technologies and techniques as they evolve. This generic justification shall be carried out by the health authority in conjunction with appropriate professional bodies. 

The justification of medical exposure for an individual patient shall be carried out by means of consultation between the referring medical practitioner (who initiates the request for a radiological procedure) and the radiological medical practitioner (who is responsible for performing a procedure). A referral should be regarded as a request for a professional consultation or opinion rather than an instruction or order to perform. The referring medical practitioner brings the knowledge of the medical context and the patient’s history to the decision process, while the radiological medical practitioner has the specialist expertise on the radiological procedure. Therefore, the joint approach is required to justification and shared decision at the level of an individual patient considering:

  • The appropriateness of the request; 
  • The urgency of the procedure; 
  • The characteristics of the exposure and of the individual patient; 
  • The relevant information from any previous procedures; 
  • The relevant referral guidelines. 

» What guidance is available to help medical practitioners justify the individual patient exposure?

The process of determining appropriateness of a medical procedure is an evidence based approach to choosing the best test for a given clinical scenario, with account taken of the diagnostic efficacy of the proposed radiological procedure as well as of alternative procedures that do not use ionizing radiation, for example, ultrasound, magnetic resonance imaging (MRI) or endoscopy. 

Useful tools to support this decisionmaking process include national or international imaging referral guidelines developed by professional societies. Imaging referral guidelines can be disseminated or utilized through electronic requesting systems and clinical decision support tools or systems. It should be ensured that such systems correctly apply the regulatory requirements for justification, in particular with respect to roles and responsibilities. 

In determining the appropriateness of the radiological procedure for an individual patient, the following questions should be asked by the referring medical practitioner:

  • Has it been done already? 
  • Is it needed? 
  • Is it needed now? 
  • Is this the best investigation to answer the clinical question? 
  • Has the clinical problem been explained to the radiological medical practitioner? 

» Are there requirements to justify exposures for health screening of population or exposures of humans for research?

Justification for radiological procedures to be performed as part of a health screening programme for asymptomatic populations shall be carried out by the health authority in conjunction with appropriate professional bodies. 

Any radiological procedure on an asymptomatic individual that is intended to be performed for the early detection of disease, but not as part of an approved health screening programme, shall require specific justification for that individual by the radiological medical practitioner and the referring medical practitioner, in accordance with the guidelines of relevant professional bodies or the health authority. As part of this process, the individual shall be informed in advance of the expected benefits, risks and limitations of the radiological procedure. 

The medical exposure of volunteers as part of a programme of biomedical research is deemed to be not justified unless: 

(a) It is in accordance with the provisions of the Helsinki Declaration  and takes into account the guidelines published by the Council for International Organizations of Medical Sciences  , together with the recommendations of the International Commission on Radiological Protection (ICRP); (b) It is subject to approval by an ethics committee (or other institutional body that has been assigned functions similar to those of an ethics committee by the relevant authority), subject to any dose constraints that may be specified, and subject to applicable national regulations and local regulations.

» How optimization of medical exposure is ensured and who is responsible?

Once justified, the radiological procedure should be optimized and performed such that the exposure of the patient is managed in order to achieve the medical objective. 
Too low radiation dose could be as bad as too high radiation dose. As a  consequence, cancer is not cured or the images taken are not of a suitable diagnostic quality. The medical exposure should always lead to the required clinical outcome. 
Optimization is a prospective and iterative process that requires judgements to be made using both qualitative and quantitative information. The following aspects and tools have to be used to ensure optimization of protection and safety: 

  • Appropriate design of medical radiological equipment and software; 
  • Operational considerations specific to the modality and application; 
  • Calibration of sources and dosimeters; 
  • Quality assurance program implemented and independent audits made of this program; 
  • Dosimetry of patients to determine typical doses to patients for common diagnostic and image guided interventional procedures, and absorbed doses to the planning target volume and relevant organs for each patient in radiotherapy; 
  • Diagnostic reference levels established and used for most common diagnostic procedures (see more here); 
  • Dose constraints used in the optimization of protection and safety for persons acting as carers or comforters, or subject to exposure as part of a programme of biomedical research. 

Special considerations should be made for the optimization of protection and safety of patients who are: 

  • pregnant or breast-feeding (see more here
  • children (see more here)  

» What is required for prevention and investigation of accidental medical exposure?

Unintended and accidental medical exposures can occur from flaws in design and operational failures of medical radiological equipment, from failures of and errors in software, or as a result of human error. The hospital management has responsibility to ensure that all practicable measures are taken to prevent such exposures, and, if such an exposure does occur, that it is properly investigated and corrective actions are taken. Any of the following unintended or accidental medical exposures shall be promptly investigated and corrective actions implemented:

  • Any medical treatment delivered to the wrong individual or to the wrong tissue or organ of the patient, or using the wrong radiopharmaceutical, or with an activity, a dose or dose fractionation differing substantially from (over or under) the values prescribed by the radiological medical practitioner, or that could lead to unduly severe secondary effects; 
  • Any diagnostic radiological procedure or image guided interventional procedure in which the wrong individual or the wrong tissue or organ of the patient is subject to exposure; 
  • Any exposure for diagnostic purposes that is substantially greater than was intended; 
  • Any exposure arising from an image guided interventional procedure that is substantially greater than was intended; 
  • Any inadvertent exposure of the embryo or fetus in the course of performing a radiological procedure; 
  • Any failure of medical radiological equipment, failure of software or system failure, or accident, error, mishap or other unusual occurrence with the potential for subjecting the patient to a medical exposure that is substantially different from what was intended. 

Written records shall be kept of all unintended and accidental medical exposures. The more significant events are required to be reported to the regulatory body, according to the national requirements. In addition to mandatory reporting for regulatory purposes, anonymous and voluntary safety reporting and learning systems like the IAEA SAFRON and SAFRAD can significantly contribute to enhanced radiation safety and quality in health care.

Read more for: 

  • Accidents prevention in radiotherapy here 
  • Skin injuries from image guided interventional procedures here 

» Who has the primary responsibility for ensuring overall radiological protection of patients?

Because of the medical setting in which medical exposures occur, primary responsibility for radiation protection and safety for patients lies with the health professional responsible for the radiological procedure, who is referred to in GSR Part 3 as the ‘radiological medical practitioner’. The term radiological medical practitioner is the generic term that GSR Part 3 uses to refer to a health professional with specialist education and training in medical uses of radiation, who is competent to perform independently or to oversee procedures involving medical exposure in a given specialty. Health professionals that could take on the role of the radiological medical practitioner, depending on the particular use of radiation and on the laws and regulations in a State, include radiologists, nuclear medicine physicians, radiation oncologists, cardiologists, orthopaedic surgeons, other specialist physicians, dentists, chiropractors and podiatrists.

» Is involvement of medical physicist required and for what purpose?

GSR Part 3 requires involvement of medical physicist who provides specialist expertise with respect to radiation protection of the patient. Medical physicist is a health professional with specialist education and training in the concepts and techniques of applying physics in medicine, and competent to practice independently in one or more of the subfields (specialties) of medical physics (e.g. diagnostic radiology, radiation therapy, nuclear medicine).

The medical physicist has responsibilities in the optimization of radiation protection and safety in medical exposures, including source calibration, clinical dosimetry, image quality and patient dose assessment, and physical aspects of the quality assurance programme, including medical radiological equipment acceptance and commissioning. The medical physicist is also likely to have responsibilities in providing radiation protection and safety training for health professionals. In addition, he or she may also perform the role of the radiation protection officer, whose responsibilities are primarily in occupational and public radiation protection.