HEAPHY 1 & 2 PLENARY Tony COTTERILL

1. ABSTRACT This presentation will be in two parts: Under the Radiation Protection Act 1965 practitioners require a license to use irradiating apparatus and/or radioactive materials for medical imaging. Through a license condition licensees are required to report to the regulatory authority specified radiation incidents involving the exposure of patients. In diagnostic radiology notified radiation incidents are generally of low dose and consequently minimal risk. However, a significant proportion of notified incidents involve computerized tomography scans where patient doses are more significant. Also, on rare occasions incidents have included procedures involving the injection of patients with contrast media or radiopharmaceuticals. Causes of incidents include clerical errors, failure of staff to follow the so-called three-point check (e.g. name, date of birth and address), and referral errors such as the mislabeling of a request form. This presentation will give a summary of reported incidents in diagnostic radiology between July 2009 and the end of November 2011. The National Radiation Laboratory (NRL) has surveyed the use of conventional plain radiography in New Zealand since 1983. Since NRL's last supplemental survey in 1992 there have been improvements in technology, particularly with the widespread transition from film to digital imaging indicating the need for a new survey. The most recent survey was carried out by NRL in 2010 and involved collecting data nationally. This presentation reports the findings for this latest survey and presents national diagnostic reference levels HEAPHY 1 & 2 PLENARY Tony COTTERILL Fri 30th Aug 2013 Session 3 / Talk 4 14:30 – 14:50

2. Diagnostic Radiology: 1/ A Summary Of Reported Radiation Incidents2/ The Results of a National Survey Of Patient Doses In Conventional Plain Film Radiography Tony Cotterill, Glenn Stirling National Centre for Radiation Science (formally the National Radiation Laboratory)

3. ESR - a Crown Research Institute • Established July 1992 • Government owned • One of eight CRIs • Covered by CRI Act (1992)

4. NCRS (formally NRL) provision of services • National training centre • RPS course • RPO course (non-medical) • Regulatory Core of Knowledge • Bespoke training courses • Radiation Protection Advisor (RPA) • corporate RPA • senior medical/health physicist as the portfolio manager • simplicity of a single contract for the provision of all required radiation protection advice and services • comprehensive and flexible and cost effective

5. Incident reporting • To Ministry of Health’s ORS • A radiation incident involving the exposure of a patient to a radiation dose much greater than intended • ‘much greater than intended’ guideline multiplying factors • high dose eg, CT 2 • medium dose eg, AP abdomen 10 • low dose eg, chest 20 • A radiation exposure of a patient where none was intended, as in the case of mistaken identity • A radiation exposure of the embryo/foetus where the exposure had not been included in the justification process • An unexpected skin injury to a patient resulting from a prolonged radiation exposure in an interventional procedure Tony Cotteril 5

6. Reported main cause of incidents:July 2009 to December 2011 171 reported ~ 6 per month 63 major centres Tony Cotteril 6

7. Analysis of causes (1) Tony Cotteril 7

8. Analysis of causes (2) Tony Cotteril 8

9. Incidents involving: July 2009 to December 2011 Tony Cotteril 9

10. Modalities of incidents; July 2009 to December 2011 Tony Cotteril 10

11. Patient dose of incidents; July 2009 to December 2011 Tony Cotteril 11

12. 2/ Results of a National Survey Of Patient Doses In Conventional Plain Film Radiography Tony Cotteril 12

13. Number of conventional radiographyprocedures (excluding theatre mobiles) • ~ 13% increase per capita • an average a person will be x-rayed once every two years • Approximately 90% digital Tony Cotteril 13

14. Numbers of conventional radiographyprocedures for different age groups • Marked increase in the number x-rays of older adults with less paediatric x-rays • Demographics (eg, ageing population) alone doesnot account for this shift. Tony Cotteril 14

15. Relative frequency of the main types ofconventional radiography procedures • The contribution of conventional plain radiography procedures to the diagnostic radiology population dose per capita has dropped (243 to 99 µSv per capita per annum) This is probably because of a shift of higher dose procedures to other modalities such as CT Tony Cotteril 15

16. U.S. population exposure 2006 ~ 6 mSv per person 62 million CT examinations National Council on Radiation Protection and Measurement. Report No. 160. Tony Cotteril 16

17. Diagnostic Reference Levels (DRL) in termsof ESD (mGy) compared with other studies • Little change in DRL Tony Cotteril 17

18. Conclusions • There has been a small increase in the number of conventional plain radiography procedures being performed compared to 1983/84 • The age distribution of patients undergoing conventional plain radiography procedures, since NRL’s survey in 1983-84, shows a marked increase in the x-raying of older adults withless paediatric x-rays. Demographics alone do not account for this shift • The contribution of conventional plain radiography procedures to the diagnostic radiology population dose per capita has dropped. This is because of a shift of procedures to modalities such as CT. • Little change in the DRL Tony Cotteril 18