Medical exposure to radiation and XXXX .

@entity1 @entity259 @entity2073 @entity5
In 2008, the worldwide estimated age-standardised incidence rates for @entity259 incidence were 4.7 and 1.5 per 100,000 @entity1 and @entity1 , respectively. @entity259 's overall contribution to the worldwide @entity5 burden is relatively small, but incidence rates have increased over the last three decades throughout the world. This trend has been hypothesised to reflect a combination of technological advances enabling increased detection, but also changes in environmental factors, including population exposure to ionising radiation from fallout, diagnostic tests and treatment for benign and malignant conditions. Studies of the atomic bomb survivors and populations treated with radiotherapy have established radiation as a risk factor for @entity259 , particularly from early life exposure. About 0.62 @entity2073 (20%) of the global annual per caput effective radiation dose comes from diagnostic medical and dental radiation for the period of 1997-2007, increased from 0.4 @entity2073 for the years 1991-1996. This international trend of increasing population exposure to medical diagnostic sources of radiation, attributed in large part to the growing use of computed tomography scans, but also interventional radiology procedures, has raised concerns about exposure to radiosensitive organs such as the thyroid. Worldwide, medical and dental X-rays constitute the most common type of diagnostic medical exposures, but their contribution to the cumulative effective dose is relatively low, whereas computed tomography scans account for 7.9% of diagnostic radiology examinations but 47% of the collective effective dose from diagnostic radiation procedures in parts of the world. Although the radiation exposure from computed tomography scans is substantially lower than that from radiotherapy, multiple computed tomography scans could result in non-trivial cumulative doses to the thyroid. Studies are currently underway to assess the incidence of @entity5 in large cohorts of @entity1 who received computed tomography scans. National and international efforts have been developed to raise awareness and to standardise procedures for use of computed tomography and interventional radiology procedures in paediatric and general populations.
