Radiation Protection of Patients Unit IAEA, the BSS and DRLs Regional Meeting on the Establishment and Utilization of Diagnostic Reference Levels Kampala, Uganda, 14-18 February, 2013 John Le Heron Radiation Protection of Patients Unit Radiation Safety and Monitoring Section Division for Radiation, Transport and Waste Safety

Outline Background & current issues The BSS and radiation protection in medical exposures IAEA activities & resources in TSA 3 DRLs and the BSS

Nuclear medicine procedure Radiotherapy procedure Medical exposures – current usage Every year, throughout the world, ionizing radiation is used in*: 4.000.000.000 diagnostic procedures 35.000.000 nuclear medicine procedures 8.000.000 radiotherapy treatment courses * An expanding activity worldwide These bring huge benefit to healthcare Diagnostic procedure Nuclear medicine procedure Radiotherapy procedure *UNSCEAR 2008

Increasing use of radiation in medicine More machines, etc New technologies and techniques New roles Increasing complexity in the planning & delivery of the radiation Single slice CT → Multi-Detector CT Film → Computed & Digital Radiography Hybrid imaging, PET-CT Image-guided interventional procedures Virtual procedures E.g. Changes in the role of imaging: First “port of call” A move towards “screening”, in all its guises These changes since the early 1990s provide a backdrop to the current use of radiation in medical applications. The reality is that the use of radiation in medical applications is increasing worldwide – more hardware, and more techniques and uses. This is accompanied by an increasing complexity in how the radiation is delivered. Computer control is becoming the default, with a consequent de-coupling between the operator and the amount of radiation being used. Accidental medical exposures can and do occur. All of these issues must be addressed in the revised BSS. E.g. IMRT, IGRT, etc.

Is this increasing use of radiation in medicine cause for concern? What are some of the current issues in imaging?

Patient doses – a perspective Depends on the radiological procedure E.g. Radiology: Radiography A few μSv to a few mSv, per procedure CT A few mSv to tens of mSv Image-guided interventional procedures Skin doses up to several 1000 mSv Radiation therapy Many tens of Gy (but only to target vol) NBR, 2.4 mSv LD50 3000 - 5000 mSv Whole body dose X ray exams

Radiography Doses to the patient are typically low Effective dose – a few μSv to a few mSv But variation by a factor of 20 more Many exams lack proper justification and/or optimization

Image-Guided Interventional Procedures Increase continues, in some countries doubling every 2 - 4 years Doses can be high Effective doses Can exceed 20 mSv Peak skin doses Can exceed several Gy Repeat procedures – not insignificant Health professionals involved may not have had radiation protection training Optimization often lacking

CT Usage increasing But issues with: More scanners Quicker to use Can do more with them But issues with: Justification Unnecessary exams Self-referral Pressure for “screening” Optimization Children Multiple follow-up examinations

A need for radiation protection of the patient Radiation dose Achieve clinical purpose ICRP principles of radiation protection Justification Net benefit for the patient Optimization Achieve clinical purpose with appropriate dose management

RP regulatory framework for medical exposure The old BSS and the new BSS The BSS sets out the requirements for Medical Exposure Medical Exposure often called “TSA 3” in IAEA projects Thematic Safety Area 3

IAEA projects and TSA 3 Directed at end-users – medical radiation facilities All hospitals and medical centres in a Member State where radiation is used in medical applications i.e. From large teaching hospitals to small rural units All modalities, as applicable Diagnostic radiology Radiography, fluoroscopy, CT, mammography, dental, DEXA Image guided interventional procedures Nuclear medicine Radiation therapy

TSA 3 – for each medical radiation facility: Appropriate persons are in place to take the relevant responsibilities Radiological medical practitioners Medical radiation technologists Medical physicists

TSA 3 – for each medical radiation facility: The radiation protection principle of justification is being applied In particular, “Level 3” for individual justification

TSA 3 – for each medical radiation facility: The principle of optimization of protection is being applied to every exposure Design considerations for equipment Operational considerations Calibration Dosimetry of patients DRLs Quality assurance for medical exposures Dose constraints

TSA 3 – for each medical radiation facility: Unintended and accidental medical exposures are being addressed Means for minimizing their likelihood If they occur: Appropriate investigations Appropriate corrective actions Written records

Some IAEA activities to help Member States with radiation protection of the patient

Dedicated website

Dedicated website – rpop.iaea.org Updated monthly Information for Health professionals Member States Patients Additional resources Publications Safety Standards Training material

Developing Standards

The new BSS Basis for RP in medical exposures Safety Guide RP in medical facilities (being developed) Safety Report Series Newer medical imaging techniques Guidelines for the release of patients after radionuclide therapy Establishing guidance levels in X ray guided medical interventional procedures

All available from RPoP website

Promoting Education and Training

Promoting Education and Training Development of standard packages for training in the application of the safety standards Approved training packages on: Radiation protection in: Diagnostic and interventional radiology Nuclear medicine Radiotherapy Cardiology PET/CT Paediatric radiology Prevention of accidental exposure in radiotherapy Dissemination of training material Downloadable from RPoP website or available as CD Organization of training courses

Technical Assistance

Technical Cooperation Through regional and national projects: Procurement for Member States QC kits, phantoms, dosimeters, publications, etc Fellowships & Scientific Visits Expert missions Regional & national training courses

Diagnostic Reference Levels & the BSS

The advent of DRLs Abdomen AP – NZ, 1983 Large variations in patient doses for the same exam have been long documented Many factors influence patient dose and image quality The need for improvement long recognized Various approaches advocated in 70s, 80s E.g. Patient exposure guides (USA) International recommendations ICRP first mentioned “DRLs” in Publication 60, 1990 Elaborated in Publication 73, 1996

The IAEA and DRLs The International BSS, 1996 Introduced Guidance Levels for medical exposure Concept same as DRLs Revised International BSS, 2011 DRLs continue as an important tool for optimization of patient radiation protection in imaging

What does the new BSS require? 2 aspects Establishing (national) DRLs Using the DRLs

Establishing national DRLs - BSS Who? Government as the facilitator Health Authority Professional Bodies Regulatory Body

Establishing national DRLs - BSS For what procedures? Medical imaging Including image guided interventional procedures

Using national DRLs - BSS The (radiation protection) Regulatory Body mandates the use of the nationally established DRLs

Using national DRLs - BSS At each medical radiation facility Local assessments of typical doses for common procedures Results compared with relevant DRLs, and if: Exceed the relevant DRLs; or Substantially below the relevant DRL and images not of diagnostic quality Review of adequacy of optimization of patient radiation protection Corrective action, if indicated

How DRLs work – a trigger for review National DRLs have been established Typical doses at a facility are periodically compared with the relevant DRLs If exceeds DRL, or If significantly below DRL and there are IQ problems Investigate and if needed improve optimization DRL based on 75th percentile Average ESD Room AA = 4.4 mGy Average ESD Room BB = 6.9 mGy Note: if below DRL, still may not be optimized

What are the features of DRLs? Applicable to a country or region within a country Values established, in consultation, by Professional bodies, Health Authority, RP Regulatory Body For common examinations In setting values, the following must be considered Clinical requirements – general or specific Adequate image quality Use of easily measured dose quantities Data from wide-spread surveys Standardised patient or phantom Need for revision as technology and techniques improve All of these will be discussed many times this week

In setting DRLs Adequate image quality

Example – Image Quality & Mammography 1990s, MGD increased Image quality demands, including Need for higher contrast New film developed, higher density needed Clinical requirements must be the driver DRLs must not be an impediment to such developments * D Spelic, et al. Biomed Imaging and Interv 2007; 3(2):e35

Setting a DRL value for a procedure performed with different technologies and techniques

Example – Dental intra-oral radiography Most common dental exam is the posterior “bitewing” view Direct exposure film D-speed E/F-speed Digital imaging DR (mainly) CR www.michigan.gov/mdch/0,1607,7-132-27417_35791_35798-46657--,00.htm M Alcaraz et al. Radiation Protection Dosimetry (2010) 140(4),391-5

Dental doses – intra-oral Depends on the image receptor Depends on the kVp, etc. Factor of 5 in the example Should the setting of DRLs accommodate all current practice or be technology specific? National DRLs are based on wide-spread surveys Blunt instrument In parallel, the professional bodies must take the initiative e.g. American Dental Association Dentists should use E/F-speed film In time, DRLs would reflect this professional body guidance http://www.michigan.gov/mdch/0,1607,7-132-27417_35791_35798-46657--,00.html

DRLs reflect immediate-past practice in a given country, “warts and all”, applied prospectively Therefore, the periodic review of DRLs is very important

Patient size The concept of a DRL is based on a typical patient, either: A phantom, or Patients selected on basis of some criteria Does “looking after” this standardised patient ensure that all patients are ok? Does an adult DRL help ensure optimization for a child? Experience has shown that the answer is “No” There is a need for a range of “standardised patients” E.g. several paediatric sizes

Setting DRL values – not all exams are equal DRLs for projection radiography are relatively easy But with other modalities it is more difficult Image Guided Interventional Procedures (IGIPs) Factors include Operator skill and experience Patient size and anatomy Complexity of the task Equipment Routine versus emergency DRLs for IGIPs need to reflect the overall system DRLs for IGIPs are not appropriate for deterministic effects DRLs are not used for individual patients

DRL values and the new BSS The new BSS gives no values The old BSS did (Schedule III) The new Safety Guide will discuss values of DRLs in use Preference is for each country (or region in a country) to have their own Based on the practice in their country

Do DRLs work – Trends with time UK has > 20 years of experience with DRLs Reviews in 1995, 2000, 2005 and 2010 2010 review showed for radiography: On average about 16% lower than 2000 review Typically less than 50% of original DRLs Trend due to better optimization, including regular monitoring of patient doses HPA-CRCE-034, Health Protection Agency, UK, 2012

Implementation around the world Still a long way to go Many countries have introduced DRLs, but the level of utilization varies widely Between countries, and within countries IAEA regional projects in patient protection Developing Member States in: Africa, Asia, Europe, Latin America Includes setting up DRLs Level of achievement to date is low At RAF9044 RCM, DRLs were identified as the number 1 priority

Regional meeting, Kampala, 18-22 Feb Aim To describe, using teaching, practical work and group discussion, the concepts and methodologies that will enable participants to facilitate in their own countries the: Establishment (and periodic review) of national DRLs, and Application and use of DRLs in their country’s hospitals

Summary BSS sets out the requirements for patient radiation protection Optimization of protection is a cornerstone of patient radiation protection DRLs are an important tool for optimization Need to be established Need to be used Need to be reviewed periodically