Radiation Risk of X-ray Examinations

Radiation Risk of X-ray Examinations

• Radiation risk refers to the damage caused by ionising radiation through energy deposition in tissues, leading to ionisation within tissues.
• There are two types of radiation interactions with tissue: direct and indirect.
• Direct interaction: radiation energy is directly transferred to DNA, causing structural changes in its molecules.
• Indirect interaction: radiation energy is absorbed by water molecules, forming free radicals that damage DNA molecules.

Adverse Health Effects of Radiation

• There are two types of adverse health effects: deterministic and stochastic effects.
• Deterministic effects: high radiation doses, resulting in immediate damage (within minutes, hours, days, or weeks).
• Stochastic effects: low radiation doses, potentially leading to cancer development, with a lag period of at least 5 years, and up to 10 or 20 years.

Fluoroscopy

• Fluoroscopy: continuous acquisition of a sequence of X-ray images over time (real-time X-ray movie of the patient).
• Fluoroscopic systems use X-ray detector systems capable of producing images in rapid sequence.
• Applications of fluoroscopy: positioning catheters in arteries, visualising contrast agents, invasive therapeutic procedures (surgery), and making X-ray movies of anatomic motion (e.g., heart or oesophagus).