This document discusses radiation protection in nuclear medicine. It defines radiation and its types, as well as the effects of radiation exposure including death, cancer, genetic effects, infertility and skin burns. The goals of radiation protection are to prevent deterministic effects and reduce stochastic effects. Key principles for protecting patients, workers and the public include justification, optimization and dose limitation. Specific guidelines are provided for diagnostic and therapeutic procedures, as well as protecting pregnant individuals, families and workers. General facility layout and classification of areas are also reviewed along with guidelines for working in a nuclear medicine department.

1. Blessy Sara Philip
NM Technologist

2. I have no conflict of interest
to disclose with respect to
this presentation.

3. What is radiation?
• Radiation is energy that comes from a source and travels
through space and may be able to penetrate various
materials.
• Two types- Ionizing- Radiation that has sufficient energy to
dislodge orbital electrons.
Eg: α particles, β particles, neutrons, gamma rays, and x-rays.
Non ionizing- Radiation that does not have sufficient energy to
dislodge orbital electrons.
Eg: microwaves, ultraviolet.

5. What are the effects of
radiation?
• Death
• Cancer
• Genetic effects
• Infertility
• Cataracts
• Skin burns

6. The aim of radiation protection is to prevent reliably the deterministic effects
and to reduce the risk of stochastic effects to a reasonably achievable level.
The dose limit values are set so that deterministic effects are ruled out.
Cancer
Genetic effects
Death
Skin burns
Cataract
infertility

7. Measuring Radiation
• Radioactivity - amount of ionizing radiation released by a material.
how many atoms in the material decay in a given time period
Curie (Ci) and Becquerel (Bq)
• Exposure - amount of radiation traveling through the air.
radiation monitors measure exposure.
Roentgen (R) and Coulomb/kilogram (C/kg)
• Absorbed dose - amount of radiation absorbed by an object or person
(that is, the amount of energy that radioactive sources deposit in materials
through which they pass).
rad and gray (Gy)
• Dose equivalent - combines the amount of radiation absorbed and the
medical effects of that type of radiation.
rem and Sv
• Effective Dose- Measure of the radiation and the type of the tissue
affected.

8. Who should be protected in
NM?
• Patient
• Members of patient’s family
• Workers
• General public

9. How to protect?
• In order to keep the risk of stochastic damage as low
as possible(ALARA), there are 3 general principles
based on recommendations from the ICRP
• Justification
• Optimization
• Dose limitation

10. Protection of patients in
Nuclear medicine- Diagnostic
• In medical exposures no ‘dose limit’
• Justification and optimization.
• Justification plays the role of gatekeeper, as it
will determine whether the exposure will take
place or not.
• The radiological procedure should be performed
in such a way that the radiation protection and
safety is optimized.

11. Pregnant & Breast feeding
patients
• Pregnancy is contraindication- Justification
• The administered activity shall be in
proportion to body weight using 70% of the
normal adult activity for the required
examination
• Breast feeding- cessation times
depending on RPs used.

12. Radiopharmaceutical
Administered Activity MBq
(mCi)
Cessation Period
99m
Tc MAA 150 (4) 12.6 hours
99m
Tc Pertechnetate 1,100 (30) 24 hours
440 (10) 12 hours
99m
Tc Sulphur colloid 440 (12) 6 hours
67
Ga Citrate 7 (0.2) 1 week
50 (1.3) 2 weeks
150 (4) 1 month
111
In White blood cells 20 (0.5) 1 week
131
I NaI Any Complete cessation
201
Tl Chloride 110 (3) 2 weeks

13. Patients protection-
Therapeutic dose
• To be accommodated in a separate room with toilet with
restricted entry.
• When radio iodinated compounds are to be administered for
conditions other than thyroid disease use thyroid blocking
agent in order to reduce the radiation dose to the thyroid.
• Justification for breastfeeding patients- try to delay if possible.
• Pregnancy is absolute contraindication.
• After therapy delay pregnancy depending on the RP & dose.

14. Protection of the family
• Short effective half-life of most diagnostic RPs
-very little radiation hazard to the patient's
family.
• Even the very small doses that might be
received could be avoided by minimizing
prolonged intimate contact between a patient
and members of the family during the first few
hours after administration of a diagnostic
radiopharmaceutical.
• Therapy Patients – to be released from the
hospital only when its sure that effective dose
to family wont exceed 5 mGy.

15. • Education upon discharge-
Flushing toilets twice
No close physical contact
Washing clothes and utensils separately
Maintaining distance from pregnant women
and children

16. Protection of workers
• Time: Directly proportional to radiation exposure
• Distance: inverse square law- intensity is inversely
proportional to the square of the distance from the source.
• Shielding: As ionizing radiation passes through matter,
the intensity of the radiation is diminished. Shielding is the
placement of an “absorber” between you and the radiation
source.
Alpha, beta, or gamma radiation can all be stopped by
different thicknesses of absorbers.

17. The Three Cardinal Rules of
Radiation Protection

18. Lead box
Vial & syringe
shields L- Bench
Lead bin

19. Dose Employees (18+
years)
Trainees (<18
years)
Whole body effective
dose
20 mSv
NMT 50mSv in a
single year
6 mSv
Equivalent dose for
eye
150mSv 50 mSv
Equivalent dose for
skin
500mSv 150 mSv
Equivalent dose for
extemities
500mSv 150 mSv
Annual dose limits for employees and trainees

20. Pregnant staff
• Declare pregnancy in writing
• Foetus considered as general public.
• Dose to foetus not to exceed 5mSv during
the entire pregnancy.
• Additional dosimeter is issued to the
employee to wear in the abdominal region.

21. Layout of a NM department- Diagnostic Studies
Total area = 150‐160 SQ. M.
All the walls should be made of 9” brick or 6” concrete. Fume Hood -if required
Low High

22. Classification of areas in an
NM department
• Controlled areas: radiation ˃ 7.5μSv /hr.
Hot lab, injection room, storage room,
imaging rooms
Restricted entry
Individual and area monitoring
• Supervised areas: ˃ 2.5 μSv /hr to 7.5
μSv/hr All supervised area must be regularly
monitored.
Area monitoring

23. • All radioactive packages that arrive in the Nuclear
Medicine Dept. must be monitored and wipe
tested for possible contamination.
• Radioactive solid waste with half life less than 65
days to be stored till 10 physical half live is over
and then to be disposed as normal waste.
• Low level liquid waste can be diluted until their
activities drop below acceptable levels, and then
disposed as normal waste.
• For Iodine therapy – delay tank

24. General guidelines for working in a NM
• Keep inventory of all radioactive materials, radioactive waste and personnel dose
readings.
• Quality control procedures and records for all equipment used to measure radioactivity
and obtain images from radionuclide studies.
• Verify the patient’s name, radionuclide, activity, and administration site prior to the
administration of radiopharmaceutical doses.
• Use syringe shields and vial shields during preparation and administration
• Wear appropriate PPE and use remote handling tools as necessary .
• Wear assigned personal dosimeters while working in areas where radioactive materials
are used and stored.
• Do not eat, drink, apply cosmetics or store personal effects in areas where radioactive
materials are used or stored.
• Use spill trays and absorbent paper to prevent/control contamination from radioactive
materials.
• Perform and document radiation contamination and ambient surveys as required by
regulation.
• Notify OHS of spills and incidents of personnel contamination.
• Notify OHS of any suspected error in a radiopharmaceutical administration.