Radiation/Laser Safety - Exam 1 Flashcards
Types of Radiation
Electromagnetic:
- from motion of atoms
- combines electricity & magnetim
- electrons changing orbits
- ex: x-rays, light rays
Types of Radiation
Mechanical
- only travels through substances - not air
Types of Radiation
Nuclear (neutron)
- comes from unstable atom nuclei
- ex: nuclear plants
Types of Radiation
Cosmic (beta)
- involves electrons only
- ex: sun rays - travels @ speed of light almost
Non-ionizing radiation:
- stable form
- does not knock electrons off atoms
- does not break molecular bonds
- only harmful d/t heat energy (microwaves/radiowaves)
Ionizing Radiation:
- more harmful
- electrons are knocked off atoms
- they create ions
- the electrical charges cause intracellular chemical reactions
What are the 3 cellular risks w/ ionizing radiation?
- break DNA chains (cell death - apoptosis)
- mutate DNA chains - cancer
- Mutated sperm or egg cell - birth defects
Are x-rays or light rays stronger?
which one has more energy?
which one has longer wavelength?
- x-rays stronger
- x-rays more energy/shorter wavelength
- light rays have longer wavelength
X-rays are carried by particles called ________.
- photons (light particles)
How is light emitted w/ x-rays?
- electrons orbit the atom in a resting state
- they are heated and excited
- jump to higher energy orbit
- when they fall back down to the lower orbit - release photons (what we see as light)
Are small or large atoms more likely to absorb photons from x-ray?
large atoms
* greater energy differences b/w orbits
* lighter/brighter image on x-ray
* ex: bones, dense tissue
What are examples of tissue consisting of small atoms?
- soft tissue
- they don’t absorb as many photons on x-ray b/c smaller movement of electrons
- gray on x-ray
x-ray machine
What does the cathode do?
- heated filament in the middle
- heat causes electrons to fly off filament
x-ray machine
what does the anode do?
- made of tungsten (positively charged)
- attracts electrons across tube
x-ray machine
how do photons escape the machine through the window?
- as anode attracts the electrons - photons are released as energy
- makes the x-ray beam
x-ray machine
how is an image created?
chemical reaction on film
* tissue absorbs photons in a way that reflects the image
* small atoms vs. large atoms
x-ray machine
what 2 things can affect the image quality?
- ambient light can darken/lighten image
- intensity changes to beam
- over exposure: dark, obliterates structures
- under exposure: white, exaggerates structures
What are 4 Diagnostic uses for x-rays?
- radiography (bone fx, tube placement, foreign objects)
- mammography
- computed tomography (x-ray w/ computer processing)
- fluoroscopy - real time images, high radiation amounts
Diagnostics x-ray
Examples of Fluoroscopy uses:
- stent placement
- CBD stent
- aneurysm coils
- ortho/neurosurgery
What is a therapeutic use for radiation?
- radiation therapy
- damages cancer cell DNA
- creates ions w/ electrical charge - intracellular chemical reactions - breaks cancer cell DNA chains
Radiation Therapy SE
Hair loss:
anything above the waist
Radiation therapy SE
diarrhea/urinary changes:
anything below the chest (pelvis, rectum, abdomen)
Radiation SE:
n/v:
brain: chemoreceptor trigger zone
* pelvis, abdomen
radiation SE:
Sexual problems/infertility:
- pelvis/rectum
Radiation SE
Fatigue:
Brain, Breast, Chest, Head/neck, pelvis, rectum, abdomen
Radiation SE
dysphagia:
- chest
- Head/neck
radiation doses
what is a REM?
- radiation dose times a weighted factor
- nearly ~ to a Rad
- measured as millirem (mrem) 1/1000 of a Rem
Allowable yearly mrem doses
whole body:
- 5,000 mrem
Allowable yearly mrem doses
extremities:
50,000
Allowable yearly mrem doses
lens of eye:
15,000
allowable yearly mrem doses
pregnancy
- 500mrem after 2nd trimester
CXR mrem:
5-10mrem
* could be more w/ scatter and old machines
coronary angiogram mrem:
- 1,500 mrem
- done under fluoro
angioplasty mrem
- 5,700 mrem
CT mrem:
- 5,000 mrem
Indirect sources of Radiation
What is scatter?
- incidental radiation that projects across the room
- reflected off tables, patients, other surfaces
Scatter -
What is collimation?
how does it affect scatter?
- has to do w/ how wide the window is that photons are escaping through
- wider beam = more collimation/scatter
What things can increase scatter?
- wider beam window (increased collimation)
- obese pts
- bigger areas being x-rayed
- increased distance b/w pt and machine
What was the only symptom noticed in studies w/ 200,000 mrem exposure?
- transient erythema
- fetal doses < 10,000 mrem unlikely to cause effects after 20 weeks
Where are dosimeters worn?
- outside apron on collar
- inside apron on waist
Radiation Protection as low as Reasonably Achievable (ALARA)
What 4 things can providers do to decrease exposure to radiation?
- reduce time spent near beam entry
- distance: double distance from beam = cut exposure by 3/4
- scatter: be > 6ft from pt
- Shielding: lead aprons, portable shields, thyroid shield, lead glasses
What 3 things should we not do w/ our dosimeters?
- mix up inside vs. outside
- share w/ others
- don’t leave in car on dash/seat - absorbs heat from cosmic rays = higher reading
What form of radiation does MRI use?
non-ionizing
Principles of MRI:
________ ________ used to orient nuclei of ________ to north-south poles.
- magnetic field
- hydrogen molecules
- radiowave pulses change orientation of specific atoms which radiates energy
What generates the contrast in MRI?
- the time until tissue relaxation occurs when RF waves turn off
- affected by: densities of hydrogen nuclei in tissues, chemical & phys properties
T1 view:
Magnetic Vector relaxes
* fat bright, water dark
* gray-white matter contrast & normal anatomy
T2 View:
Axial spin relaxes
* Fat dark, water bright
* identifies tissue edema & pathology
MRI contrast
How does Gadolinium work?
- alters the magnetic properties of nearby water molecules = enhanced image
SE of Gadolinium
Clearance:
- itching, rash, warm skin sensation (benadryl)
- normal GFR - 24 hrs
Magnetic Field
What 2 things do ferromagnetic objects experience?
- attractive force
- high degree of Torque (line up w/ magnetic field)
- field always on
What are 4 risks of MRI?
- projectile risk
- RF energy causes tissue/device heating
- electromagnetic interference w/ EKG (artifact)
- Acoustic noise: 125dB (chainsaw) = hearing protection
What are 2 typical options for providing anesthesia in MRI?
What is our goal?
- Sevoflurane - MRI safe volatile
- TIVA - opioids not needed
- minimize movement
AANA Standards & MRI
- normal monitors: EKG, BP, pulse-ox, capnography
- have airway equip. available
- suction available
- MRI pumps or long tubing!
- laryngoscope handles, blades = induce in different room
MRI patient position concerns
- head/neck:
- abdominal scans:
- head/neck: airway inaccessible, stop scan if needed
- abdomen: brachial plexus injuries b/c arms over head (padding)
Provider Safety
What medical devices are not MRI safe?
- Pacemakers
- AICDs
- Implanted insulin pumps
Provider safety:
What medical devices are MRI safe?
- heart valves
- endovascular, biliary stents (8 weeks)
- coronary stents
- vascular ports, IVC filters
- ortho implants
Provider Safety
What can rapid movement toward the magnetic field cause?
(>1m/sec)
- dizziness
- HA
- light flashes
- nausea
What does LASER stand for?
How is the beam?
- Light Amplification by Stimulated Emission of Radiation
- focused narrow beam, high-intensity
What 5 types of surgery commonly use LASER?
- Cosmetic: minimal scarring
- LASIK
- dental
- general (condyloma, TURP)
- ENT: precise areas (sinuses, tracheal tumor)
How does the LASER work?
- electrons excited from energy source
- move to higher orbit
- return to ground state
- release photons of energy
electromagnetic radiation
more concentrated than x-ray
Properties of Laser Radiation
monochromatic:
- all photons in laser beam are same wavelength
Properties of Laser Radiation
Coherence:
- the travel of photons is synchronized in time and space
- no random movement
Properties of Laser Radiation
Collimation:
- laser beam photons are nearly parallel
- beam is focused on small area w/ no scatter
Properties of Laser Radiation
What are 6 advantages of using LASER?
- excellent precision
- good hemostasis
- rapid healing
- less scar formation
- less post-op edema/pain
- lower infection rates
Lasing Medium
What is argon LASER used for?
- modest tissue penetration (superficial)
- 0.05-2mm deep
- dermatology
Lasing Medium
What is Carbon Dioxide LASER used for?
- scatter minimal
- surrounding tissue damage negligible
- great for vocal cords/oropharynx
Lasing Medium
What is the Nd:YAG LASER used for?
- most powerful
- more heat
- deeper tissue penetration (2-6mm)
- tumor debulking
What are 5 Hazards of LASER?
- atmospheric contamination: lesion lasered - particles vaporized and breathed in/colonized (condyloma)
- perforation of vessel/structure
- embolism (entrain air if vessel perf)
- inappropriate energy transfer
- airway fire
What are the symptoms of inhaling particulate?
- HA, nausea (immediately)
- can cause: interstitial pneumonia, bronchiolitis, emphysema
- carcinogenic!
Generic Laser Safety:
- laser glasses for provider & pt w/ eyes taped
- windows covered
- laser plume masks
- suction
- water/saline irrigation - fire risk
- don’t tent drapes
What is the “fire triad”?
- ignition source: laser, ESU
- fuel: drapes, gauze dressings, ETT, gel mattress pads, facial/body hair
- oxidizer - keep O2 levels lower w/ laser (O2, nitrous, air)
What Airway Fire Safety things can we do?
- laser-resistant ETTs
- low FiO2 (21% if possible)
- wet pledgets around ETT
- methylene blue in ETT cuff - rupture sign (no fire prevention)
- use scissors to cut into trachea instead of bovie
- remove ETT during laser procedure and reinsert PRN sats