Contribution of medicine to population exposure
Medical procedures serve as a massive artificial source of ionizing radiation (IR). It is in this field that there is a real opportunity to reduce the radiation load on people. Hygienists focus primarily on diagnostic X-ray examinations, as radiation therapy is used predominantly in elderly patients with severe neoplasms and does not contribute significantly to the genetically significant dose (the risk of new tumors is minimal due to the long latent period).
Foreign experience shows that in developed countries (USA, Japan, France, England, Sweden), the radiation load on citizens is 2–3 times lower than in Russia. Causes of high dose loads in Russia:
- A huge number of unjustified and repeated examinations.
- Lack of continuity between healthcare facilities.
- Defects in patient dose load accounting.
- Medical errors (refusal to use personal protective equipment, unjustified prescription).
- Technical errors (poor quality of radiographs, incorrect patient positioning).
Among X-ray methods, fluoroscopy delivers the highest load (0.98 mSv/year), fluorography delivers a moderate load (0.35 mSv/year), and radiography delivers the lowest and safest load (0.22 mSv/year).
Regulation under NRB-99 and protection principles
Radiation Safety Standards (NRB-99) do not establish rigid limits for medical radiation procedures. Instead, control levels based on international standards are used. A strict limit of 1 mSv/year applies only to screening examinations and scientific experiments involving healthy volunteers.
The goals of the radiation protection system are divided into two categories:
- Complete elimination of deterministic (threshold) effects — compliance with standards guarantees that the patient will not develop radiation sickness, cataracts, or radiation burns.
- Limitation of the risk of stochastic (non-threshold) effects. These include tumors and genetic mutations. They lack specificity, have a long latent period, and are assessed using the linear no-threshold concept (any dose, even the smallest, increases the risk).
To minimize risks, the principle of justification is applied. The use of ionizing radiation sources is prohibited if the benefit does not outweigh the potential harm. The physician is obliged to prioritize alternative methods (ultrasound, MRI, thermography, immunology) and prescribe X-rays strictly according to clinical indications.
Legal regulation and dose accounting
Radiation safety is established by the Federal Law "On Radiation Safety of the Population" of 1996. For violating requirements, officials bear administrative, civil, and criminal liability. Medical personnel are obliged to maintain a culture of radiation safety to protect themselves and patients.
Key patient rights:
- Unobstructed receipt of information about the received dose.
- The right to refuse X-ray procedures. Exception: screening examinations for epidemiologically dangerous diseases (e.g., pulmonary tuberculosis), provided there are no contraindications.
To ensure continuity of care, the "X-ray Examination Dose Accounting Sheet" must be pasted into the medical record. Similar control is maintained for personnel — an "Individual Radiation Dose Accounting Card" is opened for each employee.
Briefly: answers to topical questions
Which categories of exposed individuals (A, B, C) are established by the Radiation Safety Standards (NRB-99)?
The Radiation Safety Standards establish three main categories of exposed individuals:
- Personnel (Group A) — individuals directly working with ionizing radiation sources.
- Personnel (Group B) — individuals who, due to working conditions, are within the sphere of influence of ionizing radiation sources.
- Population — in the source document, this category is designated as "Population", without the letter "C".
What is the essence of the three main principles of radiation safety: standardization, justification, and optimization (ALARA)?
The essence of the main principles of radiation safety lies in strict control and minimization of radiation exposure.
- Principle of standardization — establishment and strict compliance with hygienic standards (permissible dose limits) of irradiation.
- Principle of justification — prohibition of any activities using radiation sources unless the expected benefit to the individual and society outweighs the risk of potential harm.
- Principle of optimization (ALARA) — maintaining radiation doses as low as reasonably achievable while ensuring the necessary volume and quality of diagnostic information or therapeutic effect.
Two main rules of safe X-ray imaging: Justification (the benefit of the scan definitely outweighs the risk) and Optimization (maximum protection for the patient and staff).
Class and exam questions
Are there rigid dose limits for patients in radiology?
There are no rigid limits for therapeutic and diagnostic procedures; control levels are applied instead. However, for preventive examinations and screening of healthy individuals, a strict limit is established—no more than 1 mSv per year.
Can a patient refuse to undergo fluorography?
By law, a patient has the right to refuse medical examination. The only exceptions are preventive examinations aimed at detecting epidemiologically hazardous diseases (e.g., tuberculosis) in the absence of medical contraindications.
Why is radiation therapy not taken into account when assessing the genetically significant dose of the population?
Radiation therapy is used for severe malignant neoplasms, most commonly in elderly patients. Due to the severity of the underlying disease and the long latent period of radiation-induced tumors, the risk of developing new genetic or oncological consequences is considered negligible.
What else to study on this topic
- Linear non-threshold dose-response concept
- Specifics of deterministic and stochastic radiation effects
- Alternative non-radiation diagnostic methods (ultrasound, MRI, thermography)
- Legal liability of medical workers regarding radiation safety
Master the entire topic in the "Hygiene" course
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Other topics in "Chapter 7. Basics of radiation hygiene"
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