Introduction to Radiation Protection PDF

Summary Introduction to  Sources of radiation Radiation  Effects of radiation  Who are the advisory bodies?...

Summary Introduction to  Sources of radiation Radiation  Effects of radiation  Who are the advisory bodies? Protection  UK legislation  Principles of Radiation Protection  Ionising Radiation Regulations 2017 - IRR 2017  Ionising Radiations (Medical Exposures) Dr Stamatia Papathanasiou Regulations 2024 - IR(ME)R 2024 [email protected]  Discuss some of the relevant regulations and comment on where they fit into working practices 1 2 How do we quantify ionising radiation? When we are interested on the effects of ionizing radiation to living organisms, then the physical quantity of interest is the radiation Dose. Dose is measured in Gy (Grays). What is ionising radiation? E.g. a patient who has a chest X-ray will receive a dose of 0.02 mGy. 3 4 Sources of ionizing radiation Medical exposure  X-rays and Radioactive isotopes used for imaging and treatment  Radiotherapy doses are higher but diagnostic contributes more to population as a whole  Of the 15% of medical dose of entire population almost 90% is from diagnostic radiography CT = 7% of procedures CT = 47% of annual collective dose from diagnostic imaging 1 Health Professions Agency 2005 5 6  A full study of radiation protection requires covering:  Radiobiology  Genetics  Statistical analysis of risk  Methods of reducing radiation doses to workers How can we protect ourselves from  Rate and decay patterns of radioactivity released into radiation? the environment  Absorbing power of different materials to different radiations 7 8 Why do we need to have radiation Inherited radiation damage protection?  Does not introduce new, unique mutations  May increase the incidence of the same mutations that occur spontaneously 9 10 Discussions  A 22-year-old female patient was referred to imaging Deterministic effect department for abdomen x-ray with clinical indication from diagnostic bowel obstruction. How do you proceed with this imaging request? (Cardiac  Points to consider: Angiography)  Is patient’s age under important consideration before proceeding the x-ray?  Any radiation protection or safety issue to be considered?  Any screening method may involved? Dose Optimisation Justification Limitation 2 11 12  Lead Rubber Aprons Hazard Warnings  Thyroid collars required when primary beam is directed towards the thyroid  Prudent to use for female patients who are or maybe pregnant Must be able to identity that equipment is switched on at the mains power Equipment must be able to flash to demonstrate that an exposure has occurred 13 14 Practical Methods of Reducing Dose The aims of radiation protection are:  Stand at cables full length (2m) and never in  To prevent deterministic effects by keeping doses ‘controlled area’ during exposure below the thresholds for those effects  Personal monitoring dosimeters for staff  To reduce the risk of stochastic effects to levels  Good technique means not having to repeat which are considered acceptable procedure  Correctly identify the patient and obtain their consent for the X-ray 15 16 What does the IRCP do? International Commission on Radiological Protection (ICRP)  Non-government body - Used worldwide as a common basis for expert advisers (200 volunteer scientists)  Radiation protection standards, guidelines and  They make legislation recommendations either Prevents broad or detailed based cancer caused International by ionising on research radiation  These are not mandatory but influential Protects Independent environment  Differences between from ionising radiation countries are found in ICRP methods of enforcement 3 17 18  New Regulations UK Radiation Legislation Ionising Radiations Ionising Radiation  The Euratom/European Union Directive Basic Safety Regulations (Medical Standards Directive 2013 (BSSD) stipulated that all IRR 2017 Exposure) EU member states must have new radiation safety Regulations regulations in place by 6 February 2018 (Deals with equipment and workers) IR(ME)R 2024 UK legislation  Ionising Radiations Regulations 2017 (enforced by HSE, Health and Safety Executive)  Ionising Radiations (Medical Exposures) Regulations 2017 (enforced by the CQC, Care Quality Commission) 19 20 Principles of Radiation Radiation Legislation Protection  Justification – The benefits of the use of radiation must outweigh the associated risks and hazards  IRR 2017  Optimisation – ALARP (As Low As Reasonably  Dose limits – Limits of radiation which should not be Practicable) exceeded by workers and the public.  Dose Limitation – staff and general public (not patients) 21 22 IRR 2017 Dose Limits IRR 2017 Dose Limits  If you reach 3 tenths of any dose limit e.g. Whole body (20mSv) that is 6 mSv an investigation is 20 needed and you become a classified worker  relevant employees will be made subject to medical surveillance and have their doses appropriately assessed and recorded 4 23 24  Radiation Legislation  All members of the public have a dose limit of 1 mSv In terms of dose limitations, who do  Pregnant employees are not to exceed 1 mSv for the you think has higher dose limit? a) The general public remainder of the pregnancy i.e. from when they notify b) The radiation workers the RPS/RPA 25 26 IRR 2017 Controlled and Supervised areas Controlled Areas (17) Any area where radiation doses could exceed 6mSv a year Entry into this area must be restricted Physical demarcation of controlled area 1 Supervised Areas (17) Any area not designated as a controlled area but under review Likely to receive 1mSv a year 2 27 28 Controlled Areas Controlled Areas 2m  A controlled area is an area around a patient and x- Primary Beam ray set prohibiting normal access during 2m radiography and exist whilst the x-ray machine is….. Wall - sufficiently attenuating 5 29 30  Controlled Areas Monitoring  The area extends 2m from the patient, tube and film in any direction until it has been sufficiently attenuated by a primary barrier.  Prohibit normal access during radiography  You are monitored  Operate in accordance with Local Rules – film badges and  In a controlled area you could receive 3/10ths of a dose TLD limit  Also referred to as ‘Designated Area’ 31 32 RPA and RPS  Radiation Protection Advisor Someone who advices on implementation of designated areas, installation and acceptance of new equipment, testing engineering controls, staff training.  Conducts investigation following a radiation incident 33 34 RPA and RPS Over-exposure  What to do in the event of an over-exposure?  Contingency plans (stated in Local Rules)  Radiation Protection Supervisor  What would you do if the x-ray tube continued to produce radiation after the exposure button was  Someone appointed by the LEGAL PERSON to help released? ensure compliance with the regulations and supervise arrangements set out in the local rules  They must receive appropriate training. 6 35 36  Who do you notify if there has been an Routine Inspection and testing of equipment over exposure?  RPA without delay – this person will commence an  Necessary for confirm no changes to description investigation of equipment and the ongoing acceptability of the  RPS location  ? Patient  Health and Safety Executive (HSE)  Quality Assurance (QA) Tests to identify and  Medicines and Healthcare products Regulatory Agency investigate trends that suggest possible (MHRA) - online deterioration 37 38 Ionising Radiation (Medical Exposure) Regulations IR(ME)R 2024 IR(ME)R 2024  Deals with radiation protection for patients 39 40 Ionising Radiation (Medical Exposure) Regulations IR(ME)R 2024 Responsible for auxillary Responsible for equipment every X-ray unit associated with radiation safety Takes legal Staff who are or  Four levels of Responsibility responsibility for maybe pregnant implementing must inform the  Employer (Legal Person) IRR17 & employer in IR(ME)R 2024 Employer writing ASAP  Referrer (Legal  Practitioner Person)  Operator 7 41 42  Usually a Usually a medical doctor, medical doctor, dentist, or other dentist, or other health care health care professional professional Takes Primary Is permitted to Refer to the function is to responsibility refer individuals IR(ME)R for an individual justify the for medical X- practitioner individual medical ray exposure exposure exposure Referrer Practitioner 43 44 IR(ME)R 2024 Position patient, film and X-ray tube Setting  Came into force in 6 Feb 2018 parameters for Correctly identify the patient!! and delivering  To protect the patient the X-ray exposure  Covers duties of employers and employees in ensuring that x-ray equipment, shielding and standard operating procedures meet adequate Performs the standards of radiation protection practical aspects Processing  Care Quality Commission oversees compliance associated with a Operator films, QA testing  https://www.cqc.org.uk/guidance-providers/ionising- radiographic examination radiation/enforcing-irmer 45 46 Application (3) Interpretation (2) The regulations apply to following medical Carers and comforters exposures: In medical diagnosis or treatment Individuals who are knowingly and willingly exposed to ionising radiation through support and comfort of those As part of occupational health surveillance undergoing exposure As part of health screening programmes  Consider: In medical or biomedical, diagnostic or therapeutic research programmes Dose constraint Dose optimisation As part of medico-legal procedures Recording / reviewing 8 47 48  Specified Duty Holders Interpretation (2)  Employer Employer  Referrer Any natural or legal person, in the course of trade,  Practitioner business or other undertaking, carries out (other than an employee), or engages others to carry out  Operator medical exposures at a given radiological installation In NHS the hospital trust is the employer 49 50 Duties of Employer (4) Duties of Employer (4)  Written procedures for medical exposures (6)  Ensures adequate training of staff  Written protocols for every type of standard  Ensures adverse incidents involving radiation other radiological practice for each equipment (6) than defective equipment are investigated - accidental or unintended exposure  Referral criteria for medical exposure (6)  Review why reference dose levels are exceeded and  QA programmes (6) take action (e.g. individual training)  Clinical audit (7) 51 52 Written procedures Interpretation (2)  Advice obtained from other colleagues in radiology, radiotherapy and NM etc. Referrer  Practitioner may write them but employer is still A registered medical or dental practitioner, or responsible other health professional who is entitled in accordance with the employer’s procedures to  E.g. refer individuals for medical exposure to a  Positive ID procedure practitioner  Procedure for enquiries of females of child bearing age  Procedures for giving information and written instructions  Specific to each machine, room and examination 9 53 54  Referrer Interpretation (2)  Agreement at local level between employer and health care professional Practitioner  e.g. certain health care professionals may refer A registered medical or dental practitioner, or patients for extremities but not CT other health professional who is entitled in accordance with the employer’s procedures to  Screening programmes exclude referrer take responsibility for an individual medical exposure. 55 56 Practitioner Interpretation (2)  Agreed locally between employer and health care professionals Operator  e.g. can act as practitioner for extremities, but not Any person who is entitled in accordance with the interventional procedures employer’s procedures to carry out any practical aspect associated with the procedure of a medical exposure  Requires full knowledge of potential benefit and therefore adequately trained 57 58 Operator Interpretation (2)  Responsibilities must be clearly defined in written Practical aspect procedures The physical conduct of any of the exposure and any  e.g. by profession, grade, or individual name (Job supporting aspects including handling and use of descriptions) radiological equipment, and the assessment of  Operators include doctors, medical physicists, technical and physical parameters including radiation medical physics technicians, nurses, radiographers, doses, calibration and maintenance of equipment, radiopharmacists and assistant practitioners preparation and administration of radioactive medicinal  Physicists employed by Trust check equipment prior products and the post processing of medical images. to use 10 59 60  Practical aspect Interpretation (2) Medical physics expert (14) E.g. Certificate of competence  Calibration of equipment that emits ionising radiation Demonstrate underpinning knowledge, competence  Preparation of radioactive medicinal products requires demonstration of practical experience in the following areas:  Computer planning  Compliance with IR(ME)R 2017  Equipment management / Dosimetry -Technical  Calculation of monitor units used in radiotherapy specs.  Optimisation - QA, acceptance testing, DRLs,  Performing the exposure incidents  May need applications training  Could also be RPA 61 62 Duties of practitioner, Operator and Duties of practitioner, Operator and Referrer (5) Referrer (5)  Practitioner and Operator shall comply with  Operator will be responsible for each and every employer’s written procedures practical aspect which he/she carries out  Practitioner responsible for justification of medical  Referrer shall provide practitioner with sufficient exposure medical data to enable the practitioner to decide on whether there is sufficient net benefit of such an  Practical aspects may be allocated to specific exposure i.e. justification individuals (by employer or practitioner) who are then responsible 63 64 Duties of practitioner, Operator and Interpretation (2) Referrer  Practitioner and Operator shall cooperate, regarding Diagnostic Reference Levels practical aspects, with other specialists and staff involved in a medical exposure Dose levels in medical radiodiagnostic practices or, in  Any person who acts as employer, referrer, the case of radioactive medicinal products levels of practitioner or operator must comply with the above activity, for typical examinations for groups of standard- duties sized patients for broadly defined types of equipment 11 65 66  Medical Exposure National DRLs  Dose limits do not apply to medical imaging  Reviewed at five-yearly intervals exposures  Medical physics to contribute patient dosimetry data  Diagnostic reference levels are recommended to National Patient Dose Database (NPDD)  DRLs are published for Dose Area Product (DAP)  List of examinations for which there are National and Entrance Surface Dose (ESD) values for DRLs are being extended when sufficient data on UK common examinations and projections practice has accrued  Departments are expected to survey their own doses  Investigations should be undertaken in X-ray There are now reference levels for more examinations departments where doses are found to exceed these National Diagnostic Reference Levels (NDRLs) Updated 19 August 2019) levels https://www.gov.uk/government/publications/diagnostic-radiology- national-diagnostic-reference-levels-ndrls/ndrl 67 68 National DRLs Exam 1995 2000 review review review 2005 2010 review Local DRLs ESD per radiograph (mGy) Skull AP/PA 4 3 2 1.8 Skull LAT 2 1.6 1.3 1.1  Reference doses set at this Chest PA 0.2 0.2 0.15 0.15  Employers are responsible for setting local DRLs level are intended to be an Chest LAT 0.7 1 0.6 0.5  DRLs should be reviewed annually indication of abnormally high T/Spine AP 5 3.5 4 3.5 doses. T/Spine LAT 16 10 7 7  Provides a formal mechanism for revision of locally L/Spine AP 7 6 5 5.7 adopted DRL values which may follow revised or new  When compared with local L/Spine LAT 20 14 11 10 national DRLs, or additions to local patient dose data measurements they identify L/Spine  Where examination protocols have been changed, examinations or rooms in L5/S1 35 26 26 most urgent need of Abdomen AP 7 6 4 4 the effect on the locally adopted DRLs should be investigation and corrective Pelvis AP 5 4 4 4 considered action. DAP per examination (Gy.cm2) IVU 25 16 14 14 Barium meal 17 13 14 12 Barium enema 35 31 24 21 69 70 Dose regularly exceeded Justification of Individual Medical Exposure (11)  Investigation by Radiology manager and Medical Special attention shall be paid to: Physics Expert (MPE)  Specific objectives of exposure and characteristics of the individual  Performance of X-ray equipment  Exposures that have no direct benefit for individuals  Exposure protocols undergoing the exposure  Potential detriment to the individual  Technique and training of operator  Available alternative techniques  Look at level at which DRL has been set  The urgency of the procedure 12 71 72  Optimisation (12) Optimisation (12) ‘involves ensuring that doses arising from exposures ALARP principle, operator must pay attention to the are kept as low as reasonably practicable, but following when selecting equipment and techniques: consistent with the intended purpose’  QA In practice, optimisation is a process which relies  Assessment of patient dose heavily on professional competence and skill  Adherence to diagnostic reference levels (must be monitored) 73 74 Optimisation (12) Other employer responsibilities Practitioner and operator must pay attention to:  Clinical Audit  Expert Advice  Medico-legal exposures  Medical exposures of children  Equipment  Medical exposures in health screening programmes  Training  Medical exposures where pregnancy cannot be excluded  In NM, breast feeding females undergoing medical exposures 75 76 Web addresses City, University of London Northampton Square London EC1V 0HB United Kingdom  http://www.radiation.org.uk/ - Useful Radiation T: +44 (0)20 7040 5060 E: [email protected] Safety References & Web Sites www.city.ac.uk/department  http://www.hse.gov.uk/radiation/ionising/index.ht m - Health and Safety Executive  https://www.gov.uk/government/publications/diag nostic-radiology-national-diagnostic-reference- Thank you! levels-ndrls/ndrl - National Diagnostic Levels  http://www.cqc.org.uk – Care Quality Commission 13 77 78