Radiation safety is important when using fluoroscopy for interventional pain procedures. The document discusses several principles of radiation safety including keeping fluoroscopy time brief, holding the x-ray tube low below the patient, and keeping staff away from radiation sources. Failure to follow radiation safety guidelines can put medical practitioners and patients at risk for radiation exposure and associated health effects like cancer.

1. Radiation Safety and Use of
Fluoroscopy During
Interventional Pain Procedures
DR MOHSEN ABAD
Pain specialist
IN THE NAME OF GOD

2. Overview
1) General concepts used in radiation safety
2) Basic concepts of radiation physics
3) Fluoroscopy device specific cations and settings
4) Fluoroscopy operating principles
5) The effects of radiation on biological systems
6) Radiation safety
7) Fundamental principles of radiation protection
8) Personal radiation measurement devices
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3. References
• Pain-Relieving Procedures : P. Prithvi Raj
• Atlas of Image-Guided Intervention in pain: James
P. Rathmell
• Chronic spinal pain: Laxmaiah Manchikanti
Total slide number: 76
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4. An early use of a
primitive x-ray
machine.
Note the lack of
attention to any form
of radiation
protection.
Courtesy American
College of Radiology.
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5. A. Hands of Mirhan Krikor Kassabian, MD, in early years after repeated
exposures of hands to x-rays, and in later years just before he died of
radiation-induced cancer
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6. General concepts used in radiation safety
• During the first half of the 20th century,
cancer incidence among physicians using
fluoroscopy was higher compared with
others
• Therefore, training was made mandatory
by the US FDA for physicians using
fluoroscopy in 1994
• Today almost all interventional procedures
are accompanied by fluoroscopy
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7. General concepts used in radiation safety
• Unfortunately, many physicians
performing interventional procedures
using fluoroscopy neglect the guidelines
of radiation safety
• Radiation is a serious risk factor
• Ideally, the fluoroscope should be used
personally by the physician
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8. Basic concepts of radiation physics
• Radiation is the dispersion of energy
through electromagnetic waves or
particles
• The radiation, ionizing the atom by
breaking off the electrons from their
orbits is called ionizing radiation.
• An X -ray is ionizing radiation, which
causes an atom to be ionized
• Electromagnetic energy is a type of
energy radiating at light speed in the
form of a sine wave, which is classified
by its wavelength
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9. Basic concepts of radiation physics
• Amplitude:
is the height of the wave
• Wavelength:
is the distance between two different
waves
• Frequency:
is the number of waves passing
through a specific point in a given time
period (measured in hertz, symbol Hz).
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10. Basic concepts of radiation physics
• Waves with longer wavelengths and
lower frequencies (e.g. radio waves,
visible light) have lower energy levels
• waves with shorter wavelengths and
higher frequencies (e.g. X –rays ,
gamma rays) have higher energy
levels, which means they are ionizing
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12. Basic concepts of radiation physics
• Radiation exposure is expressed as
roentgen or coulomb per kilogram
• whereas the energy absorbed from
radiation is expressed as radiation
absorbed dose (rad) or as gray (Gy)
• Because different types of radiation can
have different biologic effects, units of
exposure are converted from rad to
radiation equivalent in man (rem) or
sievert (Sv).
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1 roentgen (R) ≈ 1 rad ≈ 1 rem.

14. Fluoroscopy device specifications
and settings
1. Radiography tube.
2. Attached filter.
3. Collimator.
4. Antiscatter grid.
5. Image receptor.
6. Image intensifier.
7. Flat panel receptor
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17. 1. Radiography tube
• the source of energy to produce X –rays
• The amount, energy, and time of radiation
from the X -ray tube can be controlled
• Voltage is measured in kilovolts (peak
kilovoltage, kVp)
• In the clinic the voltage varies between 50 and
150 kVp
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18. 2. Attached filter
• metal disk attached to the edge of the X -ray
tube
• modify the X –ray energy spectrum.
• Without this piece, more rays would be used
• Ideally a filter would hold low -energy photons
while allowing the passage of high -energy
photons
• Aluminum and copper are generally used as
filters
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19. 3. Collimator
• A collimator is useful for restricting the area
X -rays focus on
• A collimator has two purposes:
1) to display the desired target organ
exposure to radiation and block the outside
body parts from the radiation
2) to improve image quality
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collimator

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Use of adjustable
(linear) collimator to
decrease radiation
exposure to the patient,
Use of adjustable (iris)
collimator to limit the
field and reduces
radiation exposure to
the patient

22. 4. Anti scatter grid
• It is placed between the patient and the image
sensor
• The purpose of this is to reduce the number of
photons scattering on the image receptor
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23. 5. Image receptor
• Digital technology is now used because of
advances in imaging sensor technology
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24. 6. Image intensifier
• Image-enhancing technology is a feature that
distinguishes a fluoroscopic device from a simple X -ray
machine
• Because of this, a live image can be taken.
• image enhancer consists of four parts:
– the photon and photocathode entrance
– the electrostatic focusing lenses
– The acceleration mode
– the photon exit
• the image quality is improved by 200 × 50 = 10,000
times
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25. 7. Flat panel receptor
• This is a piece that replaces the image
booster
• It was recently added to the fluoroscopy
device.
• X -rays convert it into an image.
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26. SCATTERED RADIATION
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27. Scattered radiation
There are three types of X –rays:
• primary X –rays : are released from the X -ray
tube
• scattered X –rays : are scattered from the
primary substance and occur as a result of
collision of electrons;
• residual radiation : is X -rays that pass
through the patient and strengthen the
image.
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29. Scattered radiation
• Primary scattering: occurs in all directions
from the patient.
• Secondary scattering: is at very low levels of
intensity during primary radiation
• Back scattering radiation: is a type of beam
that is scattered backwards from the surface
that it penetrates.
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32. Scattered radiation
• If the X -ray tube is on the patient and at eye level to
the physician performing the scanning, the physician ’s
face is relatively close to the X -ray tube and is
unprotected against radiation leaks scattered from the
tube.
• The image booster, if it is positioned above the
patient, also serves as a barrier to protect the
physician ’s face.
• in this position the tube is placed below the patient,
back scattering also occurs toward the ground
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34. Scattered radiation
• Fluoroscopy devices that automatically determine the
beam settings also automatically adjust the tube
potential (kV) with increasing thickness of the patient
’s body
• With an increase in tube potential, the force of the
primary beam increases and scattering radiation will
be more penetrating
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35. Fluoroscopy usage types
1. Continuous fluoroscopy:
– found in all the old machines, and is still a format that is used.
– Fluoroscopy continues as long as the pedal is held down.
– This format is used incorrectly by many physicians.
– From the aspect of radiation safety, this is very dangerous.
2. High-speed fluoroscopy:
– used in situations where normal fluoroscopy is inadequate.
– it is not recommended.
3. Pulsed fluoroscopy:
– The image speed and frames per second rate (fps) is selected.
– This is the most advantageous format.
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36. Effects of radiation on biological systems
Radiation effects on biological
systems are divided into two
Groups:
Determining
(direct, definitive)
effect
Cytocastic
(indirect,
nondefinitive)
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37. Determining (direct, definitive) effect
• the threshold of a certain dose of radiation should be
reached.
• The effects of the force of the radiation can be
determined beforehand
• As radiation doses increase, so does the ratio of dying
cells
• determining effects :
cataracts,
 infertility,
 hair loss,
 skin issues
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38. Cytocastic (indirect, nondefinitive) effect
• There is no threshold dose of radiation for cytocastic
effects
• The severity of the effect is unrelated to the dose of
radiation exposure
• “all or nothing law”
• cause mutagenic effects like cancer and leukemia
• The carcinogenic effects of ionizing radiation,
• caused either directly or as a result of ionization,
depend on the effect occurring on free radicals or other
chemical products.
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39. Cytocastic (indirect, nondefinitive) effect
• Damage to a cell ’s DNA is either immediately repaired
or eliminated through programmed cell death
(apoptosis)
• In the rare event that a mistake occurs in the repairing
mechanism or the repair is not made, part of the
chromosomes are changed (mutation) and tumor
induction will start.
• Despite all the protective measures that can be taken,
there is always the risk of cancer
• This risk is believed to be proportional to the total
exposure dose.
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40. Cytocastic (indirect, nondefinitive) effect
• The International Committee on Radiation
Safety Protection ICRP has produced
estimates of the maximum permissible
dose (MPD) of annual radiation to various
organs
• Exposure below these levels is unlikely to
lead to any significant effects
• the ICRP recommends that workers should
not receive more than 10% of the MPD
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41. Radiation exposure and dose units
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42. Yearly maximum radiation dosages
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43. Minimal pathological dose to target organ and effects
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44. Cytocastic (indirect, nondefinitive) effect
• In contrast, the typical entrance skin
exposure during fluoroscopy ranges from 1
to 10 R per minute.
• A typical single chest radiograph leads to a
skin entrance exposure of 15 mR
• 1 minute of continuous fluoroscopy at 2 R
per minute is equivalent to the exposure
during 130 chest radiographs.
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Comparative Radiation Doses for Common Diagnostic X-ray and Fluoroscopic Procedures

46. Radiation safety
• necessity for imaging or the procedure should be
assessed:
1. effectiveness of the procedure
2. personal dose limits
3. risk assessment
• radiation protection should take into account three basic
rules:
1. Time
2. Distance
3. use of protective materials (shielding)
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47. Radiation safety
• On many devices during fluoroscopy, the voltage and
current are adjusted automatically
• The physician only controls the X -ray exposure time
• The numbers of photons in the X -ray beam are
controlled by voltage (kV), tube current (mA), and
irradiation time in the tube.
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48. Fundamental principles of radiation protection
1. Hold the tube low.
2. Keep away from sources of radiation.
3. Consider the scattering profile.
4. Keep the beam time brief.
5. Set the appropriate geometry
6. Eliminate X -rays from the outside
7. The device should undergo technical checks
8. Wear protective clothing.
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49. Hold the tube low
• scattered radiation from the
patient, loses its energy
rapidly
• 985 times higher than
where the X -ray beam exits
• For this reason, the X -ray
tube should be kept under
the table or patient.
• the most appropriate
position is to move the
tube away from the patient
and the image amplifier
close to them.
• The severity of the
scattered radiation that
enters the patient is thus
minimized
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51. Hold the tube low
• protection to the physician ’s
body, head, and neck.
• routinely insert their hands
in the primary beam when
holding the X –ray tube on
the patient
• This causes epidermal
degeneration and browning
of the fingernails in the
hands
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52. If the primary beam passes close to the center, the exposure to
scattered radiation will be less.
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53. During routine use in the anterior-posterior plane, the x-ray tube
(source) should be positioned below the patient and the detector
above the patient to minimize radiation exposure to both the
patient and the practitioner.
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54. The oblique projection results in markedly increased exposure to
the practitioner
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55. 1. During use in the lateral projection, the practitioner should
step completely behind the x-ray tube (source) to minimize
radiation
exposure.
2. When it is necessary to work close to the patient during
lateral fluoroscopy, the practitioner should step away from the
x-ray tube and move to the side of the table opposite the x-
ray tube to minimize exposure
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56. Radiation exposure to both the patient and the practitioner is
dramatically increased when the x-ray tube (source) is inverted
above the patient.
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Some practitioners invert
the (-arm to
allow for more extreme
lateral angle (e.g.,
rotation beyond 35 to 45
degrees oblique to the
side opposite the (-arm is
not possible without
inverting the (-arm on
some units). Radiation
exposure can be reduced
by rotating the patient
on the table and keeping
the x-ray source below
the table.

57. Keep away from sources of radiation
• (power) is reduced in
inverse proportion to the
square of the distance.
• when distance from its
source is doubled, the
radiation density is
reduced by one -quarter
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58. Keep away from sources of radiation
what is a safe distance?
• stand 3 meters away from the table to reduce the beam
level that can be absorbed to an acceptable level.
• best place to stand for staff is where the X -ray scatters
twice before it reaches them
• radiation intensity decreases approximately 1000 times
with each scattering event
• in other words one -millionth of the original value
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59. Consider the scattering profile
• When the C -arm is angled, the scattered radiation is
also angled and the amount of radiation at the oblique
angle can be up to 4 times
• an unprotected head and neck will get more radiation.
• they should use thyroid protective lead and special lead -
sided protective glasses
• the amount of radiation scattered from the patient will
be very high near the table
• During scattering the wavelength and energy of photons
will change: For example, when a primary photon beam
of 110keV is scattered at an angle of 90 °, approximately
17% of the energy of the scattered photon beam is lost
and 91 keV
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60. 4. Keep the beam time brief
• use the scope intermittently to take a snapshot
• Take the final shot into memory,
• refrain from taking long , continuous images
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61. Every fluoroscopy operator should do
the following
1. Track the beam time:
– The C -arms of fluoroscopy devices have an irradiation
alarm that sounds for every 5 minutes of irradiation
2. Save the last image:
– Storing the last image in memory in this manner will
significantly reduce the radiation dose
– Pressing the pedal for a long time is not a factor in
increasing quality the image brightness, or contrast.
3. Use the pulse mode:
– two different modes, continuous and pulse.
– In pulse –mode imaging, intermittent versus continuous
radiation.
– This mode reduces the irradiation time by up to 2 to 4
times.
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62. Every fluoroscopy operator should do
the following
4. Limit the beam size (collimation)
– If possible, should restrict the irradiated area by reducing the
diaphragm or with the collimator.
– This process reduces the amount of scattered radiation and
improves the image quality
5. Set the appropriate geometry:
– If the X -ray tube is brought too close to the patient, it can
cause skin burns during long -term applications
– if the X-ray tube is too far from the patient, this can increase
the size of the image
– As a rule, doubling the focus distance increases the rate of
exposure to radiation fourfold.
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63. Every fluoroscopy operator should do
the following
6. Eliminate X -rays from the outside:
– Outside light barriers interacting with the fluoroscopy device
can block the image details from being seen.
– In such a case, the fluoroscopic image needs to be enlarged or
the amount of scattered light increased.
7. The device should undergo technical checks:
– Technical control is very important
– image intensifier ages
– automatic brightness control mode
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64. Every fluoroscopy operator should do
the following
8. Wear protective clothing
• Elastic protective clothing such as aprons, vests, shirts, skirts,
thyroid protectors, and gloves, glasses, are used in stationary or
moving environments without shielding
• they will never completely stop X-rays, only reduce them to an
acceptable level
• At 100 kV, 3.2% of the beam will pass through a 0.5 mm lead shirt,
and at 70 kV 0.36% will pass.
• if the physician wears a lead apron and gloves but stands in the
way of the primary radiation path, full security is not guaranteed
• A lead apron used correctly can offer 80% protection to active
blood -producing organs
• A well -chosen apron should start just below the manubrium
sternum to include the pubis symphysis index down to just above
the knee.
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65. Every fluoroscopy operator should do
the following
8. Wear protective clothing
• for the protection to be effective, the face of the person must be
turned toward the scattering source
• The physician who is implementing the fluoroscopy procedure
should not turn their back on the beam
• reinforced or equivalent materials that are filled with lead, copper,
barium, and tungsten
• These aprons should not be folded or wrinkled, and should not be
thrown around randomly
• addition, they should be checked every year, including vital areas to
ensure there are no cracks or breaks
• To protect against scattered radiation from the patient, two hanging
lead curtains next to the sides of the fluoroscopy tables can be used
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66. OPTIMAL
Lowest entrance dose
Large source to tabletop
distance
Small tabletop to detector
distance
Moderate entrance dose
Small source to tabletop
distance
Small tabletop to
detector distance
SUBOPTIMAL
Highest entrance dose
Smallest source to
tabletop distance
Large tabletop to
detector distance
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67. Personal radiation measurement devices
• Medical personnel who use a fluoroscopy device are exposed to
long -term chronic low -dose radiation
• The International Committee for Radiation Protection (ICRP) has
determined that the maximum tolerable radiation dose (the
permissible maximum dose) does not cause somatic and genetic
effects, and is the yearly permissible radiation dose.
• annual dose of total body radiation is 50 millisieverts (mSv)
• for a 5 –year average it should be a maximum of 20 mSv per
year
• annual dose for the lens is 150 mSv
• Annual dose for the skin is 500mSv
• In addition to the mutagenic effects from chronic radiation
exposure, immuno suppressant and atherosclerosis risks
increase.
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68. Dosimetry
• Dosimeters are devices carried by personnel who work
with radiation to determine radiation exposure
• To protect the dosimeter from the scattered beam, it must
be worn on the chest pocket under the iron apron.
• If the hand is exposed to radiation, a ring dosimeter
should be worn under the glove
• It is recommended that the CBC and biochemical values of
should regularly monitored
• an antioxidant diet followed including refraining from
tobacco and drugs that increase the oxidative burden.
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69. ring
dosimeter
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70. Dosimetry
• Film dosimeters measure 3 cm × 4cm.
They consist of a hard plastic protective
cover where the film is placed.
• Radiation density absorption is
measured with the help of the film
densitometer.
• The disadvantage of these dosimeters is
that X -rays of different energies can be
affected to varying degrees,
• and the dosimeter is sensitive to
changes in atmospheric temperature
and humidity
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71. Dosimetery
• Pen dosimeters are portable, pen
-shaped, pocket dosage -
measuring tools.
• They allow radiation levels to be
monitored by people who are
exposed to radiation doses daily
or weekly.
• Their disadvantages are they are
expensive and prone to vibration
and shock.
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72. Dose optimization rules for
fluoroscopy use
1. An increase in body mass in turn increases the amount
of scattered radiation, which also increases the doses
that staff receive.
2. The tube current (mA) values should be set as low
as possible.
3. The highest tube voltage (kV) should be selected to
give the best combination of the lowest possible dose
to the patient with the optimal image quality.
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73. Dose optimization rules for
fluoroscopy use
4. The space between the X -ray tube and the patient
should be the maximum distance possible. Also, this
maximum distance should not obstruct the
procedure that is being performed.
5. The space between the image magnifier and the
patient must be the minimum distance possible
6. The zoom mode should not be used unless
essential.
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74. Dose optimization rules for
fluoroscopy use
8. If possible, on anteroposterior imaging, place the
X –ray tube toward the lower part of the patient.
9. Lateral or oblique imaging should be avoided if possible;
if this is not possible, it should stand on the image booster side.
7. Always use the narrowest collimation.
10. All employees should have protective goggles, thyroid protectors,
wear uniforms, use a dosimeter, and position themselves in ways so
that they receive minimum doses from the system.
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75. Dose optimization rules for
fluoroscopy use
11. Irradiation should be kept within the minimum time
possible.
– the last image is stored
– snapshots are taken,
– the procedure of choice is pulsed fluoroscopy because it
reduces the time exposed to radiation
12. The person using the fluoroscopy device should be
trained on it for their own safety and that of the patient
13. Finally, the radiation risk should be assessed from the
standpoint of the benefit of the procedure that will be provided;
the planned intervention should be decided accordingly.
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