In 1928, the International Commission on Radiological Protection (ICRP) was formed to provide recommendations and guidance on protection against the risks associated with ionizing radiation.

The commission, determines safe practices involving radiation and offers dose-limit guidance for patients and employees commonly exposed to radiation.

Radiation dose per person from medical X-rays has increased almost 500 percent since 1982.

Nearly half of all medical X-ray exposures today come from CT equipment, and radiation doses from CT are higher than other X-ray studies.

The International Commission on Radiological Protection (ICRP) has a System of Radiological Protection based on three principles

1. Justification. No practice involving exposure to radiation should be adopted unless it produces a net benefit.
2. Optimisation. All exposures should be kept As Low As Reasonably Achievable (ALARA), economic and social factors being taken into account.
3. Limitation. The exposure of individuals should be subject to dose limits

·  X rays are a form of electromagnetic radiation that penetrates body tissue.

·       The body absorbs some of the X rays while the rest emerges on the other side to expose the film creating an image.

·       Belonging to the high end of the electromagnetic spectrum, they carry high frequency and a lot of energy.

Direct action

·       An X-ray track passing through a cell may directly disrupt the molecular bonds of cellular material such as DNA leading to abnormal cell replication and  initial event of carcinogenesis

Indirect action

·       The high energy of x-rays causes water molecules to be ionised into HO, HO2 free radicals or hydrogen peroxide H2O2 that have the ability to disrupt molecular bonds.

·       These free radicals cause breakage in DNA double bonds leading further to induction of mutations, chromosome aberrations and cell death.

·       Rapidly multiplying cells like those of gastrointestinal, skin or gonads are more affected.

The effects of radiation are classi?ed as stochastic (probabilistic) or non-stochastic (deterministic).

·       Stochastic effects are those where the probability of an effect occurring increases as the radiation dose increases and a lower threshold of dose is thought not to exist.

·       Non-stochastic effects are those where the severity of the effect increases with the dose and a threshold probably exists. The effects are specific to the tissue

• Radiography (e.g. Chest X rays)
• Fluoroscopy (e.g. angiogram)
• CT scan
• Nuclear medicine or isotope scan
• PET scan or PET CT
• DEXA scan
• Radiotherapy (non target tissue)

• Cataracts
• Cancer (small risk)
• Skin burns
• Risks in pregnancy (especially first trimester): stunted growth, brain abnormalities, and risk of cancer in later life.

This falls into 5 main areas

1. Minimisation of radiation use,
2. Maximizing the distance between the individual and the X-ray source, beam and scatter,
3. Use of lead screens,
4. Personal protective garment
5. Monitoring personal exposure dose.

·       Wherever possible, use ultrasound or an MRI scan

·       Extra care with young or pregnant patients.

·       Lead protective shielding for patients and healthcare staff.

·       Staying away from the fluoroscopy machine in theatre (radiation is significantly reduced at 2 meters or 6 feet)

·       Work quickly and efficiently to reduce time using X rays.

·       Use of personal dosimeter.

•  Ordering only the radiology tests essential for patient care
• Body parts known to be sensitive to radiation should be shielded whenever practical. These include the thyroid, gonads, and eyes
• Stop ordering repeat radiographic tests because the studies are not available for review or in our hospital

Table 1. FDA effective dose cumulative table