Radiation safety precaution. General Principles of Radiation Safety. Aspects of shielding in diagnostic radiology. Nuclear Power Plant Safety. Specific Handling Precautions For Various Radionuclides.

1. Sabir Rasheed
Radiation Safety Precautions

2. General
Principles of
Radiation Safety
1. Reduce Time
2. Increase the distance between source
and personnel.
3. Use of protective barriers.
4. Reduction of exposure factors and
unnecessary radiography.
5. Use of radiation monitoring devices.
6. X-ray beam filtration and proper
shielding of tube head.
7. Age and sex of involved personnel.

3. Time
• The exposure time is related to radiation
exposure and exposure rate (exposure per unit
time) as follows :
Exposure time= Exposure
Exposure rate
Or
Exposure = Exposure rate x Time
• The algebraic expressions simply imply that if
the exposure time is kept short, then the resulting
dose to the individual is small

6. Shielding
Shielding implies that certain materials
(concrete, lead) will attenuate radiation
(reduce its intensity) when they are placed
between the source of radiation and the
exposed individual.

7. - Lead aprons: cut exposure by factor of 20
0.25 mm Pb eq
0.5 mm Pb
Alpha

 
Beta
Gamma and X-rays
Neutron
distant scatter:
direct involvement:
Paper Lead
Plastic Concrete


n



 

8. Four aspects of
shielding in
diagnostic
radiology
1.X-ray
tube
shielding
Room
shielding
Personnel
shielding
Patient
shielding

9. 1- X-ray tube shielding (Source Shielding)
• The x-ray tube housing is lined with thin sheets of lead because x-rays produced in the tube are scattered
in all directions.
• This shielding is intended to protect both patients and personnel from leakage radiation.
• Leakage radiation is that created at the X-ray tube anode but not emitted through the x-ray tube portal.
• Rather, leakage radiation is transmitted through tube housing.
• According to AERB recommendations
manufacturers of x-ray devices are required to shield the tube housing to limit the leakage radiation
exposure rate to 0.1 R/ hr at a distance of 1 meter from the tube anode.

10. X-ray Tube
Image Intensifier
Position the X-ray tube under the
patient not above the patient.
The largest amount of scatter
radiation is produced where the x-
ray beam enters the patient.
By positioning the x-ray tube below
the patient, you decrease the
amount of scatter radiation that
reaches your upper body.
X-ray Tube Position

11. 2-Room shielding
Lead lined plaster board
Lead glass viewing window
Room should also be well coated with
lead along with free from any leakage.
The wall of room should be at least 22cm
thick and should be of concrete into which iron may be introduced.
Warning signs must be placed near X ray room regarding potential hazards.

12. 3-Personal Shielding
Gloves Glasses Overshoes
Apron

14. 4-Patient shielding
• Most radiology departments shield the worker and the attendant, paying little attention to the radiation pr
otection of the patient.
• It has been recommended that the thyroid, breast and gonads be shielded, to protect these organs esp
ecially in children and young adults

15. Age and Sex of involved Personnel
• Persons under 18 years of age should not be involved in radiograph because of the sensitivity of the g
rowing tissues.
• Pregnant females should not be involved because of extreme sensitivity of embryos at certain stages
of development.

16. Radioactive Waste
Disposal
• Radioactive waste includes anything that
contains or is contaminated with
radioactive material.
• Collect radioactive waste in proper
containers.
• Keep containers closed and secured
unless you are adding waste.
• Report the proper information on the
radioactive waste tag when material is put in
the waste container.
• Keep a tag on the waste container at all
times.

17. Always practice ALARA

18. Why Practice ALARA?

19. Any type of ionizing radiation poses some risk. As exposure
increases, so does risk.
Research shows that some people’s DNA is more resistant or
susceptible to damage, and some people have an increased risk
of cancer after exposure to ionizing radiation.
Limit your exposure whenever possible.

21. Nuclear safety is the safety of operating personnel, general public and the minimum impact on the
environment.
Three levels of nuclear safety
1. First level: It addresses the prevention of accidents by virtue of design, construction and surveillance
of the plant.
2. Second level: It provides safety systems to protect operators and general public and to minimize or
prevent damage.
3. Third level: It supplements the first two by adding margin of safety in the event of extremely
unlikely or unforeseen events.
Nuclear Power Plant Safety

22.  Safety should be ensured in all stages, from the inception of the plant to its full-fledged commissioning and
finally decommissioning.
 Human beings working inside the power plant need to be constantly monitored for any over exposure of
radiation as a result of their routine job operations. The standards laid down in this regard should be
strictly adhered to and the working environment should be regularly checked for radiation levels.
 The most challenging task is the proper disposal of waste materials from the nuclear power plant. These
waste materials come in different forms such as solid, liquid and gaseous. All these types of wastes have their
own methods of disposal and the main idea is to dispose off these wastes in a manner which is least harmful
for human beings, flora, fauna and the natural environment.
 Proper Emergency Response Plans. The best thing is to be prepared for such a situation and have properly
trained personnel as well as the requisite equipment in order to deal effectively with such situations.
Nuclear Power Plant Safety

23. Posting Warning Signs
CAUTION:
Radioactive
Material

25. SPECIFIC HANDLING
PRECAUTIONS FOR
VARIOUS
RADIONUCLIDES
H-3 C-14 P-32 P-33 S-35 Cr-51 I-125

26. Tritium (H-3)
Precautions
1. Follow General Safety Precautions for all isotopes.
2. Monitor surfaces routinely and keep record of the results. Geiger counters (survey meters) are not sensitive to
tritium radiation and therefore wipe tests and a liquid scintillation counter are necessary to determine levels of
contamination.
3. Radiation badges are not issued to individuals using only tritium because the radiation emitted by tritium is not of
sufficient strength to penetrate the badge.
4. Submit urine samples for analysis if requested to do so by the Radiation Safety. MCG’s current GDNR license
requires an individual to submit a urine sample when working with 100 mCi or more of tritium at one time.
5. Due to the long half-life of tritium, tritiated waste must be segregated from short-lived waste. H-3 and C-14 waste
may be combined, but must be kept separate from P-32, S-35, I-125 and other radioactive waste.

27. Carbon (C-14)
1. Monitor surfaces routinely and keep records of the results.
2. Geiger counters are sensitive to the beta radiation from C-14 if the probe is used within a 1/2 inch of the surface
and the proper probe is used.
3. Radiation Safety recommends a pancake type probe and a meter with a linear scale. With such a probe very low
amounts of C-14 may be detected on a surface. Average efficiency with a pancake probe is approximately 3%.
4. Do not cover the pancake probe with saran wrap® or parafilm®, etc. when using the probe to monitor for C-14.
This practice will decrease the efficiency of detection.
5. Wipe tests should be taken and counted in a liquid scintillation counter for the most sensitivity when detecting
removable surface contamination.
6. Radiation badges are not issued for individuals using 14 C as the badge is very unlikely to detect any radiation
because of the short beta range in air.
Precautions

28. Phosphorus ( P-32)
1. Perform dry runs and practice routine operations to improve dexterity and speed before using P-32.
2. Avoid skin exposure by using tools to indirectly handle unshielded sources and potentially contaminated vessels.
3. Traps may be necessary to collect P-32 if large gas or vapor releases are anticipated. This is to reduce the release
to the environment.
4. Monitor surfaces routinely and keep records of the results. Geiger counters with a pancake probe should be used
for P-32 radiation. Average efficiency for detecting P-32 with a pancake probe is 30%. Use wipe tests and a
Liquid Scintillation Counter to determine levels of removable P-32 contamination.
5. Do not work over open containers of P-32 without shielding. Work with plexi-glass shields (1/4-to-1/2-inch
thickness).
6. Shield all stock vials of P-32.
7. Do not use thin sheets of lead to shield P-32.
Precautions

29. Sulphur (S-35)
1. Traps may be necessary if large gas or vapor releases are anticipated. This is to reduce the release to the environment.
It may be necessary to incorporate activated charcoal into experiments involving volatile forms of S-35.
2. Monitor surfaces routinely and keep record of the results. Geiger counters are sensitive to the beta radiation from S-35
if the probe is used within a 1/2 inch of the surface and the proper probe is used.
3. The Radiation Safety Section recommends a pancake type probe and a meter with a linear scale. With such a probe
very low amounts of S-35 may be detected on the surface. Average efficiency for S-35 with a pancake probe is
approximately 8%.
4. Do not cover the pancake probe with saran wrap® or parafilm®, etc. when using themprobe to monitor for S-35.
5. Wipe tests should be taken and counted in a Liquid Scintillation Counter for the most sensitivity when detecting
removable surface contamination.
6. Proper tubes should be used for storage of single use aliquots of volatile S-35 material. Screw top tubes with rubber
seals are recommended.
Precautions

30. Iodine (I-125)
1. Use forceps fitted with rubber sleeves to ensure a secure grip on containers.
2. Radiation badges should be worn by all personnel involved in performing iodinations.
3. Radiation Safety approved hoods must always be used when performing iodinations.
4. Never remove the rubber vial septum on containers of volatile iodine! Remove all NaI-125 aliquots with
hypodermic syringes inserted through the vial’s rubber septum.
5. Store NaI-125 solutions at room temperature in an approved hood, do not freeze and avoid heating Na I-125 as
this will result in subsequent volatilization.
6. Maintain a pH greater than 7 in NaI-125 solutions in order to reduce volatilization.
7. In the event of a spill involving volatile NaI-125 hold your breath and vacate the iodination area closing the doors
behind you. Do not permit anyone to enter the spill area and contact Radiation Safety immediately.
8. More information pertaining to thyroid counts may be obtained by calling Radiation Safety.
Precautions

31. Conclusions
Dose reduction = time, distance, shielding. ALARA
principle must be followed for the optimization of
radiation dose. Reduction on patient dose similarly
reduces the personnel dose in case of fluoroscopy
Modern medicine would be impossible without ionizing
radiation. The committee recognizes both the
tremendous benefits derived from the use of ionizing
radiation in medicine and its potential for harm.