Do not adjust your set

Radiation Safety Induction

for Radiology Registrars

John SaundersonRadiation Protection Adviser

TPRH ext 6690

Ionising radiations• x-rays gamma rays (-rays) beta particles () electron beams

Not ionising radiations

• lasers ultraviolet (UV) infrared (IR) ultrasound MRI

Ionising / Non-ionising

Part 1 Physics Lectures

• Basic Physics (4h)– Trevor Davies (Nuclear Medicine Physicist)– CHH ext 2119 / 2125 trevor.davies@hey.nhs.uk

• Radiation hazards and dosimetry (10h)– John Saunderson (Consultant Physicist/Radiation Protection Adviser)– PRH ext 6690 john.saunderson@hey.nhs.uk

• Diagnostic radiology (10h)– Jenny Wilson (Radiation Physicist)– PRH ext 6693 jenny.wilson@hey.nhs.uk

• CT (2h)– Craig Moore (Radiation Physicist)– PRH ext 6808 craig.moore@hey.nhs.uk

• Radionuclide Imaging (2h)– Graham Wright (Nuclear Medicine Physicist)– CHH 2125 / 2115 graham.wright@hey.nhs.uk

• + 9h radiographer sessions

Exam

11 Dec 2006

Wilhelm Roentgen

• Discovered X-rays on 8th November 1895 .

Frau Roentgen’s hand,

1895Colles’ fracture 1896 .

Mihran Kassabian (1870-1910)

Dose Reduction Precautions

• X-ray tubes shielded• Collimation• Aluminium filters• Weekly exposure limits

introduced

Radiation Effects

• Acute radiation syndrome• Including vomiting, diarrhea, reduction in the

number of blood cells, bleeding, epilation (hair loss), temporary sterility in males, and lens opacity (clouding )

• Late 1940’s Dr Takuso Yamawaki noted an increase in leukaemia

• 20% of radiation cancers were leukaemia (normal incidence 4%)

• Incidence peaked at 6-8 years• Solid cancers – excess seen from 10

years onwards.

• Early X-ray pioneers – Acute effects– Precautions introduced

• Atomic bomb survivors– Acute effects similar in nature to pioneers– Some increased cancer risk

• But what about radiology today?

Cancer Risk• 1 in 20,000 risk of fatal cancer per

millisievert– Chest x-ray: 0.02mSv ► 1 in a million risk– Abdomen x-ray: 1mSv ► 1 in 20,000– Barium meal: 3mSv ► 1 in 7,000– CT abdomen: 10mSv ► 1 in 2,000– (Typical interventional radiologist dose < 3 mSv/y)

• Small risk compared to natural cancer risk

• Why worry?

700 CANCER CASES CAUSED BY X-RAYS

X-RAYS used in everyday detection of diseases and broken bones are responsible for about 700 cases of cancer a year, according to the most detailed study to date.

 

The research showed that 0.6 per cent of the 124,000 patients found to have cancer each year can attribute the disease to X-ray exposure. Diagnostic X-rays, which are used in conventional radiography and imaging techniques such as CT scans, are the largest man-made source of radiation exposure to the

general population. Although such X-rays provide great benefits, it is generally accepted that their use is associated with very small increases in cancer risk.

 

30 January 2004

Average X-ray examination dose = 0.5mSv ► 1 in 40,000 risk

UK Radiology = 41.5 million X-rays per year

Basic Principals of Radiation Protection

• Justification– Benefit > risk

• Optimisation– Doses as low as reasonably achievable

• Limitation– Absolute legal limits for staff and public– Reference levels as guidance for patients.

Regulations

• Ionising Radiations Regulations 1999 (IRR99)– Local rules, radiation protection supervisors

• Ionising Radiation (Medical Exposures) Regulations 2000 (IRMER2000)– Referrers, practitioners, operators– Justification & optimisation

• Medicines (Administration of Radioactive Substances) Regs 1978 (ARSAC)– Nuclear medicine

Organising radiation safety

Controlled Areas

Local Rules

Radiation Protection Supervisor

Radiation Protection Adviser

Radiographer.

IRMERIonising Radiation (Medical Exposures) Regulations 2000

• Referrers – allowed to request medical exposure– Trust decides who can e.g. GP, consultant, etc.

• Practitioners– Justifies X-ray - decides there is net benefit– Trust decides who can e.g. radiologist

• Operator– Performs “practical aspects”– Trust decides who can e.g. radiographer, technician

.

19

Medicines (Administration of Radioactive Substances) Regs 1978

(“MARS” / “ARSAC”)

• “No person shall administer to a human being (otherwise than to himself) any radioactive medicinal product unless he is doctor or dentist holding a certificate issued by the Health Minister for the purposes of section 60 of the Act in respect of radioactive medicinal products (hereinafter referred to as a “certificate”) or a person acting in accordance with the directions of such a doctor or dentist.” .

Radiation in hospitals

• Radioactive substances– nuclear medicine– pathology– radiotherapy

• X-ray sources– Radiology– Radiotherapy– Pathology .

X-ray tube

Primary beam

Scattered radiation

Patient

Leakage

Basic Principles

Time

Distance

Shielding

Distance

•Double distance = 1/4 dose

•Triple distance = 1/9th dose.

Shielding

Shielding

Typical Transmission through Shielding (90 kV)

• 0.25 mm lead rubber apron 8.5%• 0.35 mm lead rubber apron 5%• 2 x 0.25 mm apron 2.5%• 2 x 0.35 mm apron 1.0%

•Double brick wall 0.003%•Plasterboard stud wall 32%•Solid wooden 1” door 81%•Code 3 lead (1.3 mm) 0.1%.

Lead Apron Storage

• Always return to hanger• Do not

– fold– dump on floor and run

trolleys over the top of them!!!

• X-ray will check annually• But if visibly damaged,

ask X-ray to check them.

First Physics lectures

• Tuesday 12 September• 2pm start (please be prompt)

• The Princess Royal Hospital, Saltshouse Road

The End