Radiation safety programSatendra kumar

Medical physicist

Radiation Safety Program

The objective of the Radiation Safety Program is to provide a place of employment as free as possible from any radiation hazards

What is Radiation ?

Radiation: Energy in the form of particles or electromagnetic waves

Survey meter

Detection of Radiation

Radiation protection The aim of radiation protection is to ensure that radiation

is used safely.The system of radiation protection was proposed by

International Commission of Radiological Protection(ICRP)

Radiation protection is based on the following principles:

A: Justification

B: Optimization

C: Dose limit

• JUSTIFICATION

• All exposure either diagnostic or therapeutic shall be

under taken only if the benefit gained out of the

detriment.

• No practice shall be adopted unless it produces a net

positive benefit.

• OPTIMIZATION

• All exposures which are justified shall be under taken

with a minimum possible dose.

• Every effort shall be taken to reduce the dose to As

Low As Reasonable Achievable (ALARA), taking

into account the economic and social considerations.

• Dose limit

• Exposure of radiation worker and individuals of public

must not exceed dose limit.

ALARA Principles

Distance

ShieldingTime

Factors which influence radiation exposure:

. Time

. Lower the time of exposure, lower the dose to patient and radiation worker.

. For a given shielding and distance from the source, exposure is directly proportional to time.

Distance

Effective & EasyInverse Square Law

Doubling distance from source, decreases dose by factor of four Tripling it decreases dose nine-fold

More Distance = Less Radiation Exposure

Shielding

Materials “absorb” radiationProper shielding = Less Radiation

Exposure

Public dose limits

.Whole body : 1mSv/yr averaged over any 5 year period.

. Lens of the eye : 15mSv/yr

. Skin : 50mSv/yr

. Hands & feet : no limit specified

Occupational dose limits

.Whole body : 20mSv/yr averaged over any 5 year period. (for pregnant radiation worker it is 5mSv/yr .)

. Lens of the eye : 150mSv/yr.

. Skin : 500mSv/yr.

. Hands & feet : 500 mSv/yr.

Radiation and Pregnancy

The pregnant woman who is a radiation worker can be considered as an occupationally exposed individual, but the foetus cannot. The total dose equivalent limit to an embryo-foetus is 5mSv, with the added recommendation that exposure to the foetus should not exceed 0.5 mSv in any one month.

Pregnant radiation worker should wear a second badge at the waist level (under the lead apron)

Biological effectsgenerally a threshold level exist (1Gy)greater the dose, greater the effect.e.g. : cataract, sterility.

generally without a threshold level of dose.higher the dose, higher risk of the effect.Genetic (damage in DNA/genes)Somatic (damage in cells/body/cancer)Teratogenic (damage in fetus)

Deterministic Effects:

Stochastic Effects

Relative penetrating ability of ionizing radiation in tissue

Alpha

Beta

Gamma

Neutron

(Several layers of skin)

102-12

Low energy gamma or x-ray

High energy gamma or x-ray

Shielding for gamma emitting material

External Exposure

1. Cosmic radiation Extremely energetic particles (protons) On interaction in atmosphere produces low energy particles Mainly muons, gamma, neutrons, electrons at sea level Range is 0.3 to 1 mSv (0.4 mSv)

2. Terrestrial gamma radiation

K-40, U-238, Th-232 are available in earth’s crust These nuclides and daughter products found in soil, building materials Range is 0.3 to 0.6 mSv (0.5) High in some areas (1.0 mSv)

NATURAL RADIATION EXPOSURES

1. Fluoroscopy2. Computed Tomography (CT)3. Chest Examinations4. Mammography

Important Radiological Examinations

Medical radiation exposures Diagnostic Radiology

Radiotherapy

Nuclear Medicine

Interventional Radiology

Types of Radiation use at Batra Hospital

Types of Radiation use at Batra Hospital

Radiation is used for diagnosis and therapeutic treatment

OT & Dental X-Ray , CT Machines, Fluoroscopy- Diagnostic, Deptt …. Radioactive Materials imaging – Nuclear

MedicineTherapeutic – Radiation Oncology

• Large quantities are used for patient therapy.• Smaller quantities are used for diagnostic

procedures and medical research• Special training and monitoring are required in

areas where personnel use radiation.

Protection from External Radiation Exposure

Protective DevicesLead ApronLead collar Lead Gonad ShieldLead gloves,proper monitoring

0.25 mm lead

60 kV; 100% 2 - 3 %

100 kV; 100% 8 - 15 %

Attenuation measured with lead aprons

X ray beam filtration has a great influence!!Measurements at San Carlos Hospital, Madrid

0.50 mm lead

60 kV; 100% < 1 %

100 kV; 100% 3 - 7 %

Attenuation measured with lead aprons

X ray beam filtration has a great influence!!Measurements at San Carlos Hospital, Madrid

Examination Dose to patient

CT Head 2mSv

CT Abdomen 9mSv

CXR 0.05mSv

Dental X-ray 0.005mSv

Lumber spine 2mSv

Dose from X-ray Procedures:-

Responsibilities of X-ray Technologist . Repeat X-ray must be avoided in order to reduce patient dose.

. Records of all radiological examination should be maintained.

. Personnel monitoring devices shall be used by all radiation worker.

. Each equipment must have separate log book which provide information about equipment manufacturer, model, serial no., max kV & max mA.

Radiation safety in Diagnostic Radiology The radiation safety of radiatin worker :

. Use of protective clothing, lead aprons, lead lined viewing windows, protective barriers, organ shields. . Use of suitable imaging parameter(kV & mA) so that repeat of same examination for a patient can be avoided. . Use of radiation monitoring and survey instruments. . Training of operator.

Radiation safety in Diagnostic Radiology The radiation safety of patient :

. Justification of the practice.

. Use of standard procedure and imaging parameter.

. Use of screen-film combinations, use of fast film.

. Limiting the field size to region of interest.

. Use of organ shield.

. Proper communication with patient.

Personal monitoring device

TLD Badge

Guidelines for Using TLD Badge:-

1.TLD badges are to be used only by persons directly

working in the radiation. Administrators, dark room

assistant , sweepers etc., need not be provided with

TLD badges .

2. TLD badge is used to measure the radiation dose it

does not protect the user from the radiation .

3. The name, personnel number, period of use, location

on the body ( chest or wrist ) etc, should be written in

the block letters on the front side of the badge.

4. A TLD badge once issued to a person should not be

used by another person.

5. TLD badge should be worn compulsorily at the chest

level. It represent the whole body dose equivalent. If

lead apron is used, TLD badge should be worn under

the lead apron.

6. A badge without filter or damaged filter should not

be used . It is replaced by a new holder.

7. Every radiation worker must ensure that the badge is

not left in the radiation field or near hot plates, ovens,

burners etc.

8.Loss or accidental exposure to the TLD badges

should immediately reported to the RSO.

9. Every new radiation worker has to fill up the

personnel data form, and should be sent to

Radiological safety officer of their respective

department.

Radiation Safety-Laboratory Rules-

1. Smoking, eating, and drinking are not permitted in radionuclide laboratories.

2. Food and food containers are not permitted in the laboratory. - Do not use refrigerators for common storage of food and radioactive materials. - Do not heat food or beverages in microwaves used to conduct research.