Madan M. Rehani, Pedro Ortiz López International Atomic Energy Agency Vienna, Austria

Keynote Lecture IRPA12, TS II.2.4 Protection of Patients in Medical Exposures Madan M. Rehani, Pedro Ortiz López International Atomic Energy Agency Vienna, Austria M.Rehani@iaea.org

Topics What is patient protection in medical exposure Magnitude of the problem How to achieve patient protection IAEA Resources

What is meant by Radiation Protection of Patients Diagnostic X ray & nuclear medicine examinations Interventional Procedures Purpose is not to give radiation exposure but to achieve diagnosis or specific clinical purpose- thus reduction of dose is the AIM, without compromising on quality -------------------------- Radiotherapy: Radiation is deliberately given to kill cells or achieve pain relief- So reduction of dose in NOT the aim But unnecessary dose reduction- Yes

What we want to achieve in Patient Protection Overall objective: Benefits outweighing the risks Specific objectives: 1. Radiation exposure should be no more than necessary for getting the desired clinical information or the outcome of the procedure; and 2. Deterministic injuries in interventional procedures and accidental exposures in radiotherapy should be avoided. 3. Communication with the patient and assurance to the patient that the patient is getting radiation exposure no more than necessary and that at this level of radiation exposure, the risks are much smaller than the benefits

Topics What is patient protection in medical exposure Magnitude of the problem How to achieve patient protection IAEA Resources

The size of the issue- Global (UNSCEAR)* Annually About 3.6 billion diagnostic X-ray examinations About 35 million nuclear medicine examinations About 5 million patients radiotherapy treatments * Report yet to be released

Then & Now Previously: I have to work whole life with radiation, whereas the patient may undergo procedure only few times Now 200 1

Then & Now Staff Patients

Long fluoroscopy times and/or thick body masses Coronary Angioplasty 6 1 230 lbs; 63 min FT Radiofrequency Ablation 17 yo; ~90 120 min FT TIPS placement 5 11 250 lb Coronary angioplasty 350 lb; 50 min FT Courtesy L. Wagner Coronary angioplasty 75 yo woman; 42 min FT Uterine Embolization 270 lb, 5 2 ; ~34 cm thick

A patient may get more radiation exposure in 5 CT scans than a staff working in X ray department for full working life with adequate protection

Cataract in the eye of interventional radiologist- 1990 s Staff protection in some situations is still important

TOTAL ~ 0.6101 msv Nuclear power < 0.002 msv Occupational 0.005 Chernobyl 0.002 Atmospheric testing 0.005 Medical 0.61 msv > 99.97% Global annual per caput dose from man-made sources (1997-2007) UNSCEAR 2008 Unpublished

A word of history Before the 70 s patient protection, not an issue, excluded from safety standards 1973 First national survey in the USA ( NEXT programme) Early 80 s surveys in UK, 1984 EC- Medical Directive 1991 first Agency s CRP on dose reduction 1996 BSS includes patient protection 2001 First International Conference, Unit on the Radiological Protection of Patients established 2002, Approval of International Action Plan (IAEA)

Topics What is patient protection in medical exposure Magnitude of the problem How to achieve patient protection IAEA Resources

Diagnostic Radiology Patient Protection in

Specific situations: Radiography TWO MAIN things that have helped immensely in patient protection: 1.Introduction of better intensifying screens (rare earth) resulting in halving of radiation dose to patient 2.Diagnostic Reference Levels (DRL)

Trends in average effective doses for medical examinations (UNSCEAR 2008) Average effective dose per examination (msv) Examination Health care level I 1970 1979 1980 1990 1991 1996 1997 2007 Chest radiography 0.25 0.14 0.14 0.07 Abdomen X-ray 1.9 1.1 0.53 0.82 Mammography 1.8 1.0 0.51 0.26

Are there further challenges in Radiography? Some developing countries are where developed countries were 30 years ago (e.g.next, NRPB ) There are number of countries that are still using calcium tungstate screens and manual film processing They need to go through the exercise Going through the PROCESS is: Educative Build capability in dose assessment and dose management

Are there further challenges in Radiography? Many countries have shifted or are shifting to digital radiography Easy to delete images and not know what happened Use of improper field size- common Diagnostic image can be obtained at 50% of dose but generally doses have increased by 2 times Unclear where problems really is in the data stream Popularity and ease is making for increased frequency Result: Patients getting MORE DOSE than necessary

Are there further challenges in Radiography? How often have studies shown patient doses higher than DRL, including in developing countries?

AJR June 2008

Are there further challenges in Radiography? DRLs need to be reduced Most people do not take into account higher screen speed Advice: Look for bigger fish

Global CT data (2000-2007) Wide variation in equipment among well developed countries (~ 10 fold): 93 scanners per million population in Japan 32 in the US 14 in Germany, Finland and Spain and 7-8 in U.K and France ~40,000 CT scanners worldwide ~180-200 million CT scans done annually Globally CT scans are about 5% of x-ray procedures and account for 35-40% of collective effective dose (~0.8 of 2.3 million person-sv)

Collective effective population doses: Comparison ~ 2,000 person-sv annually from occupational exposure ~2,300,000 person-sv annually from radiology. ~800,000 person-sv annually from CT ~400,000 person-sv worldwide over all time from entire Chernobyl release* * UNSCEAR 2007

Patient dose management in CT Reference dose quantities have been agreed upon (CTDI, DLP) There are people who argue death of CTDI Most modern machines now provide dose value (CTDIv, DLP) DRLs for adult are well established Dose/exam can be but in actual practice Collective dose by few 100% (600%)

Is there a cancer risk from CT? 1.4 Relative risk 1.3 1.2 1 CT scan sequence 3-phase CT liver scan 1.1 1.0 4-5% of CT scan patients A-bomb data show 50 a 100 200 300 400 statistically significant increase at > 50 msv Organ dose (msv)

Pediatric CT DRL for children not yet widely agreed upon, but UK & some other countries values available for different age groups Issue of pediatric phantom

Arch & Frush. Pediatric body MDCT: A 5-year follow-up survey AJR August 2008 Web-based survey, comparing data w.r.t to 2001 337 pediatric radiologists in 61 responses Significant reduction in kvp, mas 98% use weight-based adjustment in tube current Awareness main factor

Wallace et al. IRPA12, 2008 8 pediatric hospitals in Australia Dose reduction through MDCT optimization seminar DLP & Effective dose >50% reduction Role of training

DLP for chest CT > DRL Estonia Czech Republic Bosnia & HerzegovinaBulgaria (Republic of Srpska) Serbia Morocco MaltaMacedonia Tunisia Syria Kuwait Algeria Japan Ghana Sudan Kenya Tanzania Thailand

Computed Tomography In a number of countries adult exposure factors are being used for CT examinations of Children

Automatic Exposure Control Quite a large number of reports documenting benefits Personal interactions- many places find it impracticable- reason: image quality Academic centres with expertise in use of AEC find that claims as in research papers are valid

Automatic Exposure Control Dose increases if one does not select factors properly e.g. Noise index or image quality parameter If one selects High noise index- poor image quality, low dose Low noise index- good quality, high dose Example: Kidney for stones: unlikely to be missed even in low dose scan, but for appendicitis- higher dose scan is needed Heavy patient- upper value may reach

Patient Doses in CT- Future aspects Are there reports of patient dose changes in any department with time? Practically No Are there reports of holistic look? e.g. reduction by AEC ) say 30%, shielding (say 30%), centring of patient properly (say X%). No Total dose reduction?--no

Learning from Success Stories Occupational radiation protection Dose limits have been continuously brought down (1930 s- 500 msv to 20 msv/year now, Actual doses are 1 msv/yr for 95% of staff

Patient dose management in CT What is the single most important carry home point? Appeal to our distinguished colleagues sitting here to develop mechanism to be able to say that my patient was getting..x.. dose in (say) 2002 and gets..y.. dose now?

Use of DRLs We can ALL tell that the Car was costing X.. in (say) 2002, now it costs Y, Same about the salary.the house rent etc. Keep a regular record of patient dose for individual study (say abdomen, CTA ) in DRL quantities and show how it has changed with time.

Patient Protection in interventional procedures using X rays

Interventional Procedures The focus shifts from stochastic risk to deterministic injuries Earlier lack of awareness Equipment were not geared to measure dose Now KAP meters (stochastic risk) and new equipment with cumulative air kerma (for deterministic risk) Gaf chromic dosimtery films

Patient protection in Interventional Procedures DRLs for some procedures e.g. PTCA Initial reaction to DRL- not positive Complexity index

Udine- Cardiac Interventions Number of procedures per patient 1 2 3 4 5 6 7 >7 Number of patients 1967 940 194 138 41 29 14 9 Number of Patients Mean DAP Number of patients with DAP>300Gycm 2 3332 78.6 Gycm 2 2.6 % Nearly 6% of patients had 3 or more interventions

PTCA values exceeding Reference levels (KAP) Out of 20 countries for which data is available, 11 >Ref levels Slovenia Croatia Bulgaria Tunisia Algeria Lebanon Syria UAE Pakistan Thailand Kenya

Patients PSD >2 Gy. Lithuania Slovenia Croatia Bosnia & Herz. Armenia Tunisia Algeria Lebanon Syria Pakistan Thailand

Patient Protection Results from IAEA project in Latin American Countries (RLA9057): Please see the IRPA12 Abstract Book for papers in Interventional CT Mammography Radiography

Topics What is patient protection in medical exposure Magnitude of the problem How to achieve patient protection IAEA Resources

http://rpop.iaea.org

Approved Training Package IAEA Training Material on Radiation Protection in Diagnostic and Interventional Radiology Dose Area Product (DAP) Transm ission ionization cham ber in collaboration with Version: January 2005

Approved Training Package IAEA Training Material on Radiation Protection in Radiotherapy Accidental exposure Transport Use a m obile safe this can double up as em ergency container Treating 4 blocks as one Computer calculates correct treatment tim e Catheters indexed to avoid mixing up Lessons learned from accidental exposures in radiotherapy Inappropriate use of treatm ent planning C onsequences of accidents in collaboration with Version: January 2005

Approved Training Package IAEA Training Material on Radiation Protection in Nuclear Medicine READY FOR A NEW PATIENT A Radiation Safe sign is posted at the door after decontamination and clearing of room King Faisal Specialist Hospital and Research Center, Riyadh Shall the patient be hospitalized? Can the patient leave? Any restrictions? PREGNANCY AFTER THERAPY Radiopharmaceutical All activities Avoid pregnancy up to (MBq) (months) Au-198 colloid 10000 2 I-131 iodide (thyroid ca) 5000 4 I-131 iodide (thyrotoxicosis) 800 4 I-131 MIBG 5000 4 P-32 phosphate 200 3 Sr-89 chloride 150 24 Y-90 colloid (arthritic joints) 400 0 Y-90 colloid (malignancy) 4000 1 BREASTFEEDING SAFE ADMINISTRATION PATIENT SURVEY Typical Graph of the Exposure Rate at 1 m from the Patient Administered with of 5.5 GBq I-131 14 12 Exposure Rate (mr/hr) 10 8 6 4 Avoid mis-administration 2 0 1 2 3 4 5 Days of Isolation Abdalla Al-Haj in collaboration with Version: January 2005

Draft Training Package IAEA Training Material on Radiation Protection in PET/CT in collaboration with Version: September 2008

Dissemination CD is sent to anyone who requests to patient.protection@iaea.org or to anyone in the Unit Professional societies are given permission to make copies of CDs and distribute to members Conference organizers also given permission

Training courses- Medical Since 2002 46 regional training courses have been organized and 35 national training courses have been supported

IAEA Regional Projects Projects on patient dose management in radiography, interventional procedures, mammography and CT Latin America: RLA 9057 Europe: RER 9093 Asia: RAS 9047 Africa: RAF 9033 http://rpop.iaea.org

Patient Protection in Radiotherapy

Summary There is definite progress in radiological protection of patient Doses in radiography have reduced Patient doses in CT have increased Interventional procedures require attention Multiple procedures on same patient is becoming a BIG issue

Working towards making medical exposure a Safer practice