Population Dose

The HSE has a legal obligation under Statutory Instrument 478 (2002) on medical exposures to collect and publish statistics on population dose levels from the use of medical ionising radiation on an annual basis.  A survey will be conducted each year on a particular modality.  The first of the surveys were conducted in 2010 and related to the calculation of the total collective dose contributed from the use of Computed Tomography (CT) in Ireland and from the use of dental radiation. 

Report on CT Population Dose, 2009

The baseline study, Population Dose from CT Scanning: 2009, undertaken in 2010, has estimated that about 67 per cent of the annual radiation dose from all medical radiation arose from Computed Tomography (CT) scans. This is in line with the most recent UK survey reporting an estimated 68 per cent of the annual dose from medical radiation due to CT.

Advancements in technology and in the improved diagnostic capability of CTs have increased their use and improved the clinical diagnostic information available to clinicians.  The increased dose attributable to CT is in keeping with international trends of increasing use and collective effective dose from CT over time. 

The new study reveals that the average annual radiation dose to each member of the public from CT scans has been estimated as 0.48millisieverts (mSv).  This compares with the recent UK report of 0.4mSv per person from CT scans, and the most recent figure from the USA of 1.5mSv per person.  The average annual background radiation for each member of the public in Ireland is approximately 3.4 mSv (report by the Radiological Protection Institute of Ireland, 2008).

Report on Dental Radiation Population Dose, 2010

The second modality chosen for survey of population dose was Dental Radiology, to coincide  with the  2010 Review of Compliance with Patient Radiation Protection Legislation.

The report, Population Dose from Dental Radiology: 2010 reveals that the annual radiation dose to the population from dental radiology was found to be less than 1 per cent of the annual radiation dose from all medical radiation.

The study reveals that the average annual radiation dose to each member of the public from dental radiology was found to be 0.0013milliSieverts(mSv). This can be compared with international reports of 0.0018mSv dose in the UK and 0.0064mSv in the USA.

Report on Population Dose from General X Ray and Nuclear Medicine 2010.

The baseline study Population Dose from General X Ray and Nuclear Medicine 2010, undertaken in 2011, included data from all X-ray and Nuclear Medicine holders, both public and private.

An estimate of 2,575,180 x-rays for 2010 was extrapolated from the information returned.  The collective dose (total dose to the population) from General X-ray was found to be 255manSv with a dose per caput (dose per head of population) of 0.056mSv per annum. The comparable dose per caput for other countries recently surveyed ranges from 0.08mSv in the UK (2008) to 0.3mSv in France (2007)

There were 29,993 nuclear medicine scans performed in the year. The collective dose from Nuclear Medicine scans was found to be 112manSv, with a dose per caput of 0.02mSv per annum. The comparable dose per caput for other countries recently surveyed ranges from 0.03mSv in the UK (2003) to 0.11mSv in Germany (2002).

These results can be compared to that of CT where a Collective Dose of 1368manSv was reported by the HSE in 2010. The collective dose from all diagnostic ionising radiation procedures equates to a total annual dose per caput of 0.5mSv.  This compares to an estimate of 0.54mSv in RPII 2006 data for Ireland and to the dose per caput in the UK (2008) of 0.4msv (excluding Nuclear Medicine), the USA where the dose per caput is 2.2mSv (NCRP 2009) and France where the dose per caput is 1.3mSv (2007).

Publications:

Population Dose from CT Scanning: 2009

Population Dose from Dental Radiology: 2010

European Guidance on Estimating Population Dose from Medical X-ray Exposures

Report on Population Dose from General X Ray and Nuclear Medicine 2010. |

Dose Tracking Systems and their Role in Population Position Paper Dose Monitoring and Optimisation in Ireland 2014.

The HSE plans to conduct further studies to measure the annual radiation dose from all medical radiation.  In a separate study, the HSE plans to conduct a national clinical audit of radiation protection in Ireland.