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Description
The primary radiation source contributing to total population exposure is medical imaging, particularly various modalities based on CT scans. On the other hand, radon gas is the most significant natural contributor, but its percentage contribution to total exposure has been decreasing over the last few decades. Optimisation strategies for reducing the medical radiation burden include ensuring that procedures are medically justified and using the lowest possible optimal radiation dose. Radiation dose optimisation in radiology is a critical aspect of modern healthcare, aimed at balancing the necessity of diagnostic imaging with the imperative of patient safety. The paper explores the fundamental principles, techniques, and considerations in optimising radiation dose to safeguard patients while preserving image fidelity. Some reasons behind the excessive and in some cases avoidable, exposure of patients are also discussed. The spectacular growth in the diagnostic applications of ionising radiation in medicine over the past several decades has been associated with numerous benefits. At the same time, however, the related increase in exposure of patients to radiation from these procedures has generated considerable concern due to the potential attributable risks of cancer. The emphasis will be on assessing the population’s exposure at a relatively low level, where only stochastic effects are expected. Stochastic effects of radiation represent potential future health problems, primarily cancer (leukaemia and malignant tumours) and adverse genetic effects, which occur randomly at any low level of exposure, with the probability of the effect increasing with the effective dose. However, the severity of the effect remains unchanged (it is independent of the dose initially received). Unlike deterministic effects, which only occur above a specific threshold dose and worsen with dose, stochastic effects have no minimum threshold. They can manifest themselves after a particular period of exposure, often with a long latency period, even many years after irradiation 1. On the other hand, deterministic effects are caused by severe damage or death of cells. These effects are short-term, adverse tissue reactions resulting from a dose high enough to damage living tissue. The severity of the deterministic effect increases with radiation dose above a threshold, below
which no detectable tissue reactions are observed. Reflecting on the present situation, the process of raising the medical burden in developing countries is much lower. Medical imaging has many important clinical uses and can provide significant benefits. However, CT, fluoroscopy, and nuclear medicine imaging procedures also present risks. A balanced public health approach seeks to support the benefits of medical imaging while reducing the risks. Despite universal consensus that computed tomography (CT) overwhelmingly benefits patients when used for appropriate indications, concerns have been raised regarding the potential risk of cancer induction from CT due to the exponentially increased use of CT in medicine. In addition to the possibility of using alternative methods such as ultrasound or MRI, which do not use ionising radiation, the most crucial strategy for reducing this potential risk remains keeping the radiation dose as low as reasonably achievable, consistent with the diagnostic task. Here, an important role is played by selecting patients who meet specific needs for such examinations and by appropriately training all staff involved in radiation protection. Medical doctors should also be trained, including the criteria for selecting patients for CT examinations.
| Preferovaná sekcia | Biologické účinky žiarenia a odhad rizika z ožiarenia |
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