radiation and catheterization lab safety l.
Skip this Video
Loading SlideShow in 5 Seconds..
Radiation and Catheterization Lab Safety PowerPoint Presentation
Download Presentation
Radiation and Catheterization Lab Safety

Loading in 2 Seconds...

play fullscreen
1 / 44

Radiation and Catheterization Lab Safety - PowerPoint PPT Presentation

  • Uploaded on

Radiation and Catheterization Lab Safety. Joan E. Homan, M.D. Cardiology Fellow . Catheterization Lab Safety Objectives. Definitions Basic science Safety. Radiation - Terms. Dose Exposure and exposure rate Absolute dose Dose equivalent. Radiation - Terms. Exposure –

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
Download Presentation

PowerPoint Slideshow about 'Radiation and Catheterization Lab Safety' - lorant

Download Now An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
radiation and catheterization lab safety

Radiation and Catheterization Lab Safety

Joan E. Homan, M.D.

Cardiology Fellow

catheterization lab safety objectives
Catheterization Lab SafetyObjectives
  • Definitions
  • Basic science
  • Safety
radiation terms
Radiation - Terms
  • Dose
    • Exposure and exposure rate
    • Absolute dose
    • Dose equivalent
radiation terms4
Radiation - Terms
  • Exposure –
    • the amount of ionizing radiation a person is exposed to
    • expressed as roentgens (R)
    • Can be directly measured and is expressed as R/minute or milli-R/hour
radiation terms5
Radiation - Terms
  • Absorbed Dose –
    • The amount of energy deposited in tissue, (the amount of radiation needed to transfer a certain amount of energy (1 joule/kg)).
    • Expressed as gray (Gy) or rad (1 gray = 100 rad)
    • Absorbed dose varies with type of tissue:
      • i.e. bone = 5.0 ; soft tissue = 0.95
radiation terms6
Radiation - Terms
  • Dose Equivalent
    • The absorbed dose multiplied a quality factor allowing for different tissue sensitivities
    • Expressed as sievert (Sv) or rem (1 sievert = 100 rem)
    • Used to account for different biological effects of radiation
    • Rad, rem and roentgen have approximate numerical equivalence in the x-ray energy range used in the cardiac catheterization lab.
  • Production
    • Current is applied to a filament
      • Electrons are released and accelerated towards a target by a high-voltage electrical potential
    • X-rays are produced when:
      • Electrons collide and are completely stopped by the target (characteristic x-rays)
      • Electrons are rapidly decelerated after striking the target (braking x-rays)
x ray tube assembly
X-Ray Tube Assembly

transmitted radiation

Absorbed radiation

Target (ie patient)

Scattered radiaion





High voltage lead

image acquisition
Image Acquisition
  • Fluoroscopy – type of x-ray examination used for dynamic imaging
  • Image intensifiers - amplify the brightness of the image to improve visibility
  • X-rays transmitted through patient, enter the input phosphor which emits light that is then converted to electrical energy
  • The electrical energy is amplified and converted back into light at the output phosphor
  • Output phosphor of the image intensifier is coupled to a television pickup tube which converts the light pattern into an electrical signal which forms the image on the monitor


TV Monitor

Video camera

Video Recorder

Image intensifier



Fluoroscopy Imaging System

X-ray tube

cine angiography
Cine Angiography
  • Light exiting the output phosphor is divided, diverting part of the beam to TV monitor and the rest to the cine camera lens – refocuses light onto cine film
  • Standard cameras use 35mm film at frame rates of 15-60frames/sec (15-30fps for angiography and 60fps for ventriculography)
environmental radiation exposure mrem year
Environmental Radiation Exposure (mrem/year)
  • Natural Background
      • Cosmic rays 30-70
      • External terrestrial 10-100
      • Internal 10-20
      • Radon 200
  • Medical sources
      • X-rays 39
      • Radiopharmaceuticals 14
  • Man-made Sources
      • Fallout 3
      • Nuclear industry <1
      • Consumer products 3-4
      • Airline travel 0.6
  • Total 360
radiation dose and dynamics
Radiation Dose and Dynamics
  • Limit of 10 R/minute
  • Patient radiation dose dependent on several factors:
    • X-ray tube factors
    • Image intensifier factors
    • Distance factors
    • Patient factors
x ray tube factors
X-ray tube factors
  • Operator independent:
    • kVp – voltage across the x-ray tube, the energy that accelerates the electrons
    • Intensity of x-rays and image brightness directly related to the current passing through the filament
    • Increasing the kVp produces higher energy x-rays which have greater penetrating power for larger patients
    • Optimal setting for adults – 70-80kVp
    • Copper or aluminum filters placed between x-ray tube and patient to absorb low energy x-rays that are inadequate for imaging purposes
image quality
Image quality
  • Automatic brightness control –automatically adjusted to maintain brightness
  • Collimation
    • restrict the size of the x-ray field
  • Field Size and Magnification
    • Field size decreases with magnification, therefore, the local patient radiation dose must increase to compensate for the loss of brightness
    • Low magnification (9-11 inch)
    • Intermediate magnification(6-7 inch)
    • High magnification (4-5 inch)
image intensifier factors
Image intensifier factors
  • Skin exposure
    • 1-2R/min in 9 inch mode
    • 2-5R/min for smaller magnification modes
    • For 10 minutes of fluoroscopy, patient’s skin exposure is 10-50R (10-50rads)
image intensifier magnification modes
Image Intensifier Magnification Modes

Same area

Output phosphor

Input Phosphor

9 inch field

6.5 inch field

  • Skin radiation increases with decreasing distance
  • Table height (height of operator) affects patient dose
  • Standard is to maintain 18” between x-ray tube and patient
  • Image intensifier should be as close to patient as possible
exposure factors
Exposure factors
  • Prolonged or repeated cine runs
  • Longer fluoroscopy times
  • Higher frame rates

All increase radiation exposure to the patient

patient factors
Patient Factors
  • Age
  • Health of patient
  • Skin site
recommended dose limits for occupational exposure to ionizing radiation
Recommended Dose Limits for Occupational Exposure to Ionizing Radiation
  • Effective Dose Limits - Occupational
    • Annual 5000 millirem
    • Cummulative 1000 millirem x age
  • Annual Dose Limits for Tissues – Occupational
    • Lens of eye 15,000 millirem
    • Skin, hands, feet 50,000 millirem
    • Embryo fetus, total 500 millirem
    • Embryo fetus, monthly 50 millirem
  • Annual Public Exposure – Nonoccupational
    • Annual effective dose 100-500 millirem
    • Lens of the eye 1500 millirem
    • Skin, hands, feet 5000 millirem
radiation biology
Radiation Biology
  • Radiation Injury
    • Damage and repair
    • Somatic effects
    • Effects on developing embryo and fetus
damage and repair
Damage and Repair
  • Injury produced by large amounts of energy transferred to individual molecules
    • Causes ejection of electrons
    • Initiates physical and chemical effects on tissues especially DNA
    • Failure of repair mechanism leads to:
      • Cell death or
      • Mutation
radiation damage and repair
Radiation Damage and Repair
  • Effects to tissue depend on:
    • Amount of energy imparted
    • Location and extent of region of body exposed
    • Time interval over which energy is imparted
radiation biology26
Radiation Biology
  • Deterministic effects – those in which the number of cells lost in an organ or tissue is so great that there is a loss of tissue function
    • IE skin erythema and ulceration
  • Stochastic effects– occur if an irradiated cell is modified rather than killed and then goes on to reproduce
    • Do not appear to have a threshold and the probability of the effect occurring is related to the radiation dose
somatic effects
Somatic Effects
  • Observed early (days to weeks)
    • Early effects develop in proliferating cell systems (most radiosensitive skin, ocular lens, testes, intestines, esophagus)


  • Observed late (months to years)
    • Carcinogenesis is the most important delayed somatic effect
    • Delayed effects often seen in nerves, muscles and other radioresistant tissues
groups at increased risk
Groups at Increased Risk
  • Five groups of patients known to have genetic or chromosomal defects and an increased sensitivity to various types of ionizing radiation:
    • Xeroderma pigmentosum
    • Ataxia-telangiectasia
    • Fanconi’s anemia
    • Bloom Syndrome
    • Cockayne’s syndrome
direct radiation effects
Direct Radiation Effects
  • Determined by dose
    • Bone marrow depression with whole body radiation > 500 rad
  • Skin erythema occurs if a single dose of 6 – 8 Gy (600-800 rad) is given, and it is not identified until 1-2 days after irradiation
  • The higher the irradiation dose, the more quickly the erythema may be identified
skin erythema
Skin Erythema
  • Characterized by a blue or mauve discoloration of the skin
  • Increases during the first week
  • Usually fades during the second week
  • May return 2-3 weeks after the initial insult and last for 20-30 days
  • Acute doses in excess of 8 Gy will produce exudative and erosive changes in the skin
  • Penetrating doses in excess of 20 Gy: there is usually a nonhealing ulceration
skin edema
Skin Edema
  • May appear in a few hours or a few weeks
  • The higher the dose, the shorter the period for appearance
skin injury by type
Skin Injury by Type
  • Type I injury – damage limited to the epidermis and dermis without much damage to the subcutaneous tissues
    • Initial erythema
    • A 3-wk latency period
    • A secondary erythema followed by
    • An exudative epidermatitis and recovery in 3-6 months
skin injury by type33
Skin Injury by Type
  • Type II Injury
    • A vascular endothelitis
    • At least 6-8 months post exposure the acute reactions are renewed with necrosis and ulceration usually requiring surgery
    • A result of damage below the basal layer of the epidermis
type iii injury
Type III Injury
  • Necrosis within a few weeks of the acute exposure
radiation safety and protection
Radiation Safety and Protection
  • Lab specific
    • Constructed with 1.5mm of lead or equivalent shielding to protect individuals in the control room and adjacent areas
radiation safety and protection36
Radiation Safety and Protection
  • Personal protection
    • Time
    • Distance
    • Shielding
radiation safety and protection37
Radiation Safety and Protection
  • Time
    • Radiation dose is proportional to exposure duration
  • Distance
    • Radiation dose is inversely proportional to the square root of the distance from the patient (or staff)
radiation safety
Radiation Safety
  • Shielding
    • Lead is the most common material used
    • A lead apron with an equivalent of 0.5mm of lead in front panel is mandatory
    • Lead in the back panel provides additional protection
    • Thyroid shield (0.5mm equivalence) is recommended to shield the sternum, upper breast and thyroid gland
radiation safety39
Radiation Safety
  • Shielding continued
    • Leaded eyeglasses with the side shields reduce the exposure to the eyes and may improve visual acuity
    • Recommended for staff with collar-badge doses approaching 15rem per year and for interventionalist’s in training
radiation safety40
Radiation Safety
  • Shielding continued
    • Hands receive the highest radiation dose, but are relatively insensitive to radiation
    • Supplemental lead shielding to reduce exposure to scatter is available in the form of table mounted lead drapes, ceiling mounted lead acrylic shields and rolling lead acrylic shields
personnel dosimetry
Personnel Dosimetry
  • Interventionalists commonly assigned 2 radiation badges
    • One on collar
    • Second underneath lead apron
      • Lead apron reduces the radiation dose at the waist to 10% of dose at collar at 75kVp.
      • Effective dose equivalent best estimated by averaging the 2 dosimeters
    • Mean dose equivalent per procedure 4 +/- 2 millirem, highest doses were delivered to physicians in training (5 rem per year)*
radiation safety42
Radiation Safety
  • Women of child-bearing age should receive a pregnancy test prior to procedure
  • Current regulations restrict radiation dose to the embryo and fetus to 500millirem for the entire gestation and a monthly dose < 50 millirem
  • Pregnancy does not exclude working in the cardiac catheterization lab
  • Highest danger of fetal abnormalities is in the first trimester
  • Maturity lead aprons provide an additional 1mm of lead equivalence
  • Use of properly fitting wrap-around apron provides same protection to the fetus
  • Fetal radiation badge should be worn on the abdomen under the apron to record monthly fetal exposure
  • Braunwald, et al. Heart Disease, A textbook of Cardiovascular Medicine, 6th Edition, WB Saunders Company, 2001.
  • Mettler,FA, Upton, AC. Medical Effects of Ionizing Radiation, 2nd Edition, WB Saunders Company, 1995.
  • Mettler, FA, Voelz, GL. Current Concepts: Major Radiation Exposure – What to Expect and How to Respond. NEJM 2002; 346(20):1554-1561.
  • Safian, RD; Freed, MS. The Manual of Interventional Cardiology, 3rd Edition, Physician’s Press, 2001.
  • Shapiro, J. Radiation Protection, A Guide for Scientists, Regulators and Physicians, 4th Edition, Harvard University Press, 2002
  • Wilde, P; Pitcher, EM; Slack, K. Radiation hazards for the patient in cardiological procedures. Heart 2001; 85(2): 127-130