I ntegrated M anagement & E ducational C onsultancy S ervices “Radiology Update Seminar for The Dental Team” Dr. Richard DeCann & Mr. Tim Reynolds IMECS Radiography Consultants Tel:

What do dentists need to know? UK radiation dose distributions Nature and effects of radiation Clinical implications of IRR1999 and IR(ME)R 2000 Patient safety and selection criteria Optimisation of radiographic techniques Quality assurance and record keeping

What do nurses need to know? Principle foundations of dental radiographic techniques Equipment used Methods of processing films and the practice of digital radiography Hazards of exposure to ionising radiations Have an understanding of the regulatory requirements

What must nurses be able to do? Prepare the equipment and materials Prepare and care for patients Process radiographs Properly mount radiographs Undertake quality assurance measures in processing

The Discovery of X-Rays Prof. W. Roentgen November

UK Dose Distribution Comparison between dose sources in the UK

Man Made Dose Distribution Medical dose compared with other man made sources

Comparing Medical Doses General medical dose compared with dental

Radiological Examinations in the UK Number of general medical examinations compared with dental

Potential for Dose Saving Up to 50% of the medical dose delivered in the UK is unnecessary

Workshop List the characteristics of x-rays e.g. travels in straight lines

Nature of Ionising Radiation Travels in straight lines at the speed of light Obeys the inverse square law Penetrates, excites and ionises matter Chemical and biological effect Photographic and fluoroscopic effect Unaffected by magnetic or electric fields

Electromagnetic Spectrum low high Energy radio waves visible light cosmic rays micro waves X & gamma rays

X-Ray Tube anodecathode target X-ray beam electron beam

Workshop What units are used to measure radiation exposure and dose ?

Units of Radiation Measurement Exposure = COULOMBS PER KILOGRAM Kinetic Energy Released per unit Mass (KERMA) Absorbed Dose = GRAY Joules per Kilogram

Dose Reference Levels PA DRLsDOH 4Mgy HPA 2mGy Recommended 1 – 1.5mGy OPG DRLsDOH 66mGy HPA 20mGy Recommended 10 – 15mGy

Units of Radiation Measurement Exposure = COULOMBS PER KILOGRAM Kinetic Energy Released per unit Mass (KERMA) Absorbed Dose = GRAY Joules per Kilogram Dose Equivalent = SIEVERT Gray x Q (x-rays=1, protons=10, alpha=20) Effective Dose = SIEVERT Biological Effect (dose equivalent x tissue sensitivity)

Dose Reference Levels PA DRLsDOH 4Mgy HPA 2mGy Recommended 1 – 1.5mGy (Effective dose 0.002mSv) OPG DRLsDOH 66mGy HPA 20mGy Recommended 10 – 15mGy (Effective dose 0.007mSv)

Units of Radiation Measurement Exposure = COULOMBS PER KILOGRAM Kinetic Energy Released per unit Mass (KERMA) Absorbed Dose = GRAY Joules per Kilogram Dose Equivalent = SIEVERT Gray x Q (x-rays=1, protons=10, alpha=20) Effective Dose = SIEVERT Biological Effect (dose equivalent x tissue sensitivity)

Round collimator at 6cms diameter = 29cm

DRL = mGy/cm2

Thyroid collars

Effective Dose and Kilo-voltage 60 kV 70kV

Excitation and Ionisation

X-ray photon

Excitation and Ionisation X-ray photon Ionised electron

Excitation and Ionisation

Radiobiology Random interactions causing direct and indirect tissue damage Critical body macromolecules: protein, DNA (damage with incomplete or misrepair) H 2 O affected because of large size and content Ionised water becomes chemically reactive and can affect DNA by indirect action Formation of free radicals: HO 2 (peroxyls) H 2 O 2 (peroxides)

Ionisation and free radicals RH + Radiation = RH + + electron R H H 2 O HO H

Radiobiology The exposure of a cell to radiation may result in: The premature death of the cell Prevention or delay in cell division Changes in cell structure and/or functions which may be passed on to daughter cells

What is damaged? DNA Any of the cytoplasmic organelles I bet they say MITOCHONDRIA

What Type of Damage Can Occur? Stochastic Deterministic

Who is Affected? Somatic Genetic

Variations with Age at Exposure

I ntegrated M anagement & E ducational C onsultancy S ervices “Radiology Update Seminar for The Dental Team” Dr. Richard DeCann & Mr. Tim Reynolds IMECS Radiography Consultants Tel:

Legislative Framework Two sets of regulations have been introduced in the UK in the last 13 years Ionising Radiations Regulations 1999 (IRR 99) Ionising Radiations (Medical Exposures) Regulations 2000 (IR(ME)R 2000)

IRR 1999 Is about: –Environment –Workers –Members of the public

Public Protection

IRR 1999 Is about: –Environment –Workers –Members of the public –Management of radiationm protection

IRR 1999 HSE notification Risk assessment

Risk Assessment Window Exposure Switch Mains isolator 4M Surgery 2 Waiting room

Staff Risk Assessment

IRR 1999 HSE notification Risk assessment Contingency plans Dose restriction/limitation Training RPS/RPA Controlled areas

Controlled areas

?Fire regulations

How MUCH Lead ?

IR(ME)R 2000 Is about: Patient protection

Ionising Radiation (Medical Exposures) Regulations 2000 Summary Justification –Patient examination, identify clinical reason, written report Optimisation –Maximum yield with minimal dose Entitlement –Anyone can do anything as long as they are trained and it is agreed and monitored

Selection (Referral)Criteria SELECTIVE –Symptomatic to confirm or refute ROUTINE –Circumstantial evidence SCREENING –No evidence

Optimisation Patient ID Patient care Check history, area Admin Justification 70kV DC Film holders Rectangular collimators Film speed Viewing Maintenance & QA –Equipment –Processor Audit Training

Digital Dental Radiography Direct –Charge Coupled Devices / CMOS –(wired systems) Indirect –Photo phosphor plates

Digital Image Processing Analysis –Collect numeric information based on the image Enhancement –Improve appearance of image Encoding –Reduce information required to describe the image

Ionising Radiation (Medical Exposures) Regulations 2000 Conceptual Framework Clinical audit –Radiographic and Radiological Expert advice –Medical Physics Expert Equipment inventory –Radiation Protection File Training –What, how and assessed Enforcement –Health & Work

Justification of an individual medical exposure No person shall carry out a medical exposure unless: –It has been justified by a practitioner as showing sufficient net benefit. –It has been authorised by a practitioner (where appropriate the operator) –Has been authorised by the local research/ethics committee –It is a part of an agreed medico-legal procedure –In the case of a female of childbearing age, he has enquired whether she is pregnant, if relevant.

Ionising Radiation (Medical Exposures) Regulations 2000 Employer Referrer/Prescriber Practitioner Operator

Duty of Role Holders Employer: to provide a framework for radiation protection of the patient through provision of standard operating procedures. Referrer/Prescriber: to provide sufficient relevant clinical information on the patient to enable the justification of the medical exposure. Practitioner: to justify each individual medical exposure. Operator: to undertake practical aspects of the medical exposure.

Employer Any natural or legal person who, in the course of a trade, business or other undertaking, carries out (other than as an employee), or engages others to carry out, medical exposures or practical aspects, at a given radiological installation.

Employer Procedures for Dentists Protocols and/or guidelines for: –Patient identification –Competencies of practitioners & operators –Medico-legal exposures –Women of childbearing age – Reduce accidental exposure to ALARP Expected doses and dose recording Quality assurance

Referrer A registered medical or dental practitioner, or other health care professional who is entitled in accordance with the employer’s procedures to refer individuals for a medical exposure to a practitioner.

Practitioner A registered medical or dental practitioner, or other health professional who is entitled, in accordance with the employer’s procedures, to take responsibility for an individual medical exposure.

Operator Any person who is entitled, in accordance with the employer’s procedures, to carry out practical aspects (including those to whom practical aspects have been allocated) except, when training, where they do so under the direct supervision of a person who is adequately trained.

Adequate Training Practitioners and operators shall have successfully completed training, including theoretical knowledge and practical experience (in radiation protection and diagnostic or therapeutic techniques involving ionising radiation) appropriate to their specific area of practice.

Quality Assurance Primary Functions Consistently high quality images Doses to staff and patients are as low as reasonably practicable Key Elements Darkroom, film and processing X-ray equipment Working procedures Audits & Quality Targets

Darkroom Film storage and stock rotation Light tight integrity (visual) Safelight (coin test)

Quality Control: Equipment Monitoring Weekly clean with spirit based solution and checks for: Electrical: sockets, plugs, earthing, insulation, leads (mains, exposure), tube head (leaks).

Quality Control: Equipment Monitoring Weekly clean with spirit based solution and checks for: Electrical: sockets, plugs, earthing, insulation, leads (mains, exposure), tube head (leaks). Mechanical: mountings, support, brakes, stability, fixtures and fittings (collimators). Radiation: output checks (annual), tube head (dents), mains isolation switch

Trophy 70 Room 2 June Electrical Socket Plug Leads Tubes leaks Mechanical Security Wall support Tube arm Tube head Cone/collimators Radiation Tube dents Mains isolation Signature Date

Quality Control: Processor Monitoring Weekly clean with checks for: Electrical: sockets, plugs, leads, earthing and insulation. Lightproof: lid, feed cover, light screen (coin test) Transport: rollers and screens, daily cleaner. Image quality: temperature (heater, thermostat), activity (replenishment), wash, drainage, cleanliness, stepped wedge test.

Velopex June Electrical Socket Plug Leads Lightproof Lid Sleeves Daily Cleaner Daily water drain Stepped wedge Signature Date

Stepped Wedge This is what the wedge looks like This is what a picture of it should look like

Accessory Equipment Cassettes Screens Viewing boxes Film holders

Quality rating and quality standards for radiographs Rating/Quality Basis 1. Excellent:No errors of exposure, positioning or processing. Not less than 70%. 2. AcceptableSome errors which do not detract from the diagnostic use. Not greater than 20%. 3. UnacceptableErrors which render the radiograph diagnostically unacceptable. Not greater than 10%.

Guidelines for Image Critiques Area: film position and orientation (axis, border, blip) Projection: beam centring and angulation

Critique Projection: beam centring and angulation (no cone cut, crowns in profile/3mm border, no interproximal overlap, bite block in profile) 3 mm

Guidelines for Image Critiques Area: film position and orientation (axis, border, blip) Projection: beam centring and angulation Density: level of blackness Contrast: difference in density for a range of structures Sharpness: level of detail Artifacts: something on the film that shouldn’t be there

Orthopantomography

Plain Radiography

Scanography

Plain Radiography

Tomography

Focal Trough Focal trough Pivotal Plane

Principles of Radiation Protection Justification of the exposure Positive identification of the patient Reference to existing radiological records Shielding: primary & secondary barriers Distance Beam restriction Minimum number of personnel in the examination room Quality assurance of all equipment and audit of activities Choice of x-ray and imaging equipment

Richard Tim