Test 1 Flashcards
Radiation that has the ability to make an atom a charged particle (remove an electron)
Ionizing radiation
Radiation in which electric and magnetic fields vary simultaneously (ex: x-ray, gamma rays, etc)
Electromagnetic radiation
What is the difference between x-rays and gamma rays?
X-rays come from Brems interactions (manmade); gamma from nucleus (natural)
A stream of atomic or subatomic particles that may be charged positively (ex: alpha particles), negatively (ex: beta) or not at all
Electrons don’t go as far as photons (superficial treatment); short travel range and don’t penetrate wall so don’t have to worry about shielding)
Particulate radiation
2 forms of ionizing radiation
Electromagnetic radiation
Particulate radiation
Plank’s equation
E=hv or E=hc/λ
Plank’s constant (h)
6.62 x 10^-34
6 types of electromagnetic radiation (from highest to lowest frequency)
Gamma rays Ultraviolet light Visible light Infrared light Microwaves Radio and television
7 types of visible light (from low to high frequency)
Red Orange Yellow Green Blue Indigo Violet (ROYGBIV)
Average wavelength (λ) (m) and frequency (v) (Hz) of gamma rays
λ = 10^-12 m v = 10^20 Hz
Average wavelength (λ) (m) and frequency (v) (Hz) of ultraviolet light
λ = 10^-8 m v = 10^17 Hz
Average wavelength (λ) (m) and frequency (v) (Hz) of visible light
λ = 10^-6 m v = 10^14 Hz
Average wavelength (λ) (m) and frequency (v) (Hz) of infrared light
λ = 10^-5 m v = 10^13 Hz
Average wavelength (λ) (m) and frequency (v) (Hz) of microwaves
λ = 10^-2 m v = 10^10 Hz
Average wavelength (λ) (m) and frequency (v) (Hz) of radio and television waves
λ = 10^2 m v = 10^6 Hz
Energy and frequency are ___________; energy and wavelength are _____________________
Proportional; inversely proportional
2 major groups of radiation in a therapy department
External beam
Brachytherapy sources
2 types of external beams
Linear accelerators (linacs) Cobalt-60
Machines that produce x-ray, gamma rays, and electrons; most popular
Ex: SRS/SBRT
External beams
Machines that emit gamma rays, x-rays, alpha, and beta particles
Ex: 137Cs, 192Ir, 125I
Brachytherapy sources
2 types of beams made by linacs based on what is being treated
Photon
Electron
3 categories of linacs based on types of energies (want different energies for different part thicknesses)
Low
High
Dual-energy (most common)
Cobalt-60 delivers gamma rays with dual-energies of what MeV, averaging what MeV?
1.7 and 1.33 MeV
Average = 1.25 MeV
Amount of energy delivered to tissue (keV/um)
Linear energy transfer (LET)
What is the charge, atomic mass number, and origin of alpha particles (a)?
Charge = +2
Atomic mass number = 4
Origin = nucleus
What is the charge, atomic mass number, and origin of negatrons (B-) (beta particles)?
Charge = -1
Atomic mass number = 0
Origin = nucleus
What is the charge, atomic mass number, and origin of positrons (B+) (beta particles)?
Charge = +1
Atomic mass number = 0
Origin = nucleus
What is the charge, atomic mass number, and origin of neutrinos (v)?
Charge = 0
Atomic mass number = 0
Origin = nucleus
What is the charge, atomic mass number, and origin of x-rays?
Charge = 0
Atomic mass number = 0
Origin = electron shells
What is the charge, atomic mass number, and origin of gamma rays (y)?
Charge = 0
Atomic mass number = 0
Origin = nucleus
Basically a helium nuclei that has been stripped of its two electrons
Emitted by heaviest nuclides/large unstable atoms that have a large amount of excess energy
Damage done with ingestion
Can be stopped by paper
Ex: uranium decays to produce daughters radium and radon
Alpha particles (a)
How many protons and neutrons do alpha particles have?
2 protons
2 neutrons
Alpha particles have a very _____ LET because it distributes all its energy when it hits
High
Can be positively or negatively charged Emitted from the nucleus; not natural, created through decay Have the rest mass of an electron Shielded best with plastics or glass Dependent on Z^2/mass^2 Greater Z = more photon production, small mass = more Brems Energy range = energy/2 In range = dissipated, 90% = shallow
Beta particles (B- or B+)
Rest mass of electrons and beta particles (B- or B+)
0.511 MeV
1 MeV beta particle has a range of _______ centimeters of tissue
2 cm
Similar to electrons but carry no charge; not affected by electromagnetic forces but by a “weak” subatomic force of much shorter range and are therefore able to pass through great distances in matter
Neutrino
No mass and no charge; manmade by Brems (85%) or characteristic (15%) interactions
X-rays
No mass and no charge; natural from nucleus
Gamma rays
What are photoelectric interactions dependent on?
Z^3/E^3
What are Compton interactions dependent on?
Electron density (why we can treat with radiation therapy; if it was photoelectric they’d all be absorbed by bone)
3 types of natural background radiation
Cosmic
Terrestrial
Internal exposure
What percent of human-absorbed radiation doses arise from natural background radiation?
82%
Radiation that reaches our planet from high-energy photon emissions beyond our atmosphere (sun/stars)
Atmosphere absorbs some of the emitted radiation before they reach the planet’s surface
Depends on location/height on earth
Cosmic radiation
What is the dose per year of natural background radiation?
1 mSv/yr + 2 mSv/yr radon = 3 mSv/yr
What is the dose per year of cosmic radiation?
26 mrem/yr = 0.26 mSv/yr
Radiation from earth; naturally occurring radioactive materials
Terrestrial radiation
What is the cosmic radiation dose in Denver compared to at sea level?
2 times as much in Denver than at sea level = 5mrem/0.5 mSv
What is the terrestrial radiation dose in the Rocky Mountains?
0.63 mSv
Accounts for 2/3 of natural background radiation
Second cause of lung cancer in the US
Can be found in cement in basements
Radon
What is the dose per year of terrestrial radiation (not including radon)?
16 mrem/yr = 0.16 mSv/yr
What is the dose per year from radon?
200 mrem/yr = 2 mSv
Naturally occurring radiation in the body
Internal exposure
What is the dose per year from internal exposure?
20 mrem/yr = 0.2 mSv
What is the radiation dose from man-made sources?
0.6 mSv
What is the radiation dose from medical sources?
0.5 mSv
What is the radiation dose from consumer products?
0.11 mSv
2 types of man-made sources of radiation
Medical
Consumer products
Amount of ionization produced by photons in air per unit mass of air, only applicable to photons while they interact with air
Exposure
Traditional and SI units of exposure
Traditional: Roentgen (R)
SI: Coulomb/kg of air
Unit of charge
Coulomb (C)
1 R = ? C per gram of air
2.48x10^-4 C per gram of air
The use of exposure is limited to photons with energies below what MeV?
3 MeV
Amount of energy absorbed per mass of any material while radiation interacts in the material
Absorbed dose
Traditional and SI units of absorbed dose
Traditional: rad
SI: gray (Gy)
2 units of energy
Erg
Joule (J)
1 rad = ? erg per gram of material
100 erg per gram of material
1 Gy = ? J per kg of material = ? rad
1 J per kg of material = 100 rad
1 Gy = ? rad = ? cGy
100 rad = 1 cGy
Product of absorbed dose and a quality factor, which takes into account the biological effects of different types of radiation
Dose equivalent
Traditional and SI units of dose equivalent
Traditional: rem
SI: Sievert (Sv)
Radiation weighting factor, specific to specific types of radiation; accounts for the biological effectiveness of the specific radiation
Quality factor (QF)
Rad x QF
rem
Gray x QF
Sievert (Sv)
1 Sv = ? rem
100 rem
Number of radioactive disintegrations (transformations) per unit of time; how quickly isotopes decay
Activity
Traditional and SI units of of activity
Traditional: curie (Ci)
SI: becquerel (Bq)
curie = ? disintegrations/second
3.7 x 10^10 disintegrations/second
1 Bq = ? disintegrations/second
1 disintegrations/second
1 Ci = ? Bq
3.7 x 10^10 Bq
What is the quality factor (QF) of x-rays and gamma rays (y), beta particles, positrons, and muons, and high energy external protons?
1
What is the quality factor (QF) of protons other than recoil protons and energy greater than 2 MeV?
2
What is the quality factor (QF) of thermal neutrons (slower)?
5
What is the quality factor (QF) of fast neutrons, alpha particles, and fission fragments other than heavy nuclei?
20
Higher quality factor = ________ dose
Higher
Detects the ionizations produced by the interactions in a gas, simplest measurement device
Sensitivity depends on the mass of the gas
Voltage affects ion saturation; if not enough voltage ions will reassemble and readings will be innacurate
Used for QA on linacs
Ionization chambers
What is the calibration of ionization chambers?
2%
What is the average voltage of ionization chambers?
200-300 V
2 types of gas-filled detectors
Ionization chamber
Geiger-Muller (GM) detector
Very sensitive to radiation, doesn’t measure dose
High voltage
Used for detection of contamination (detecting the presence of radioactive materials in areas or on surfaces where they aren’t wanted)
Geiger-Muller (GM) detector
Consists of crystal substance that when irradiated has electrons displaced in its crystal lattice
When the crystal is heated, the electrons return to their normal location (original energy states/valence bands) with the emission of characteristic energy that can be seen as light by using a detector
Dose stored for days or weeks, good personal monitor
More responsive than film, mimics tissue
Dose received is proportional to the radiation damage in the crystal
Thermoluminescent dosimeter (TLD)
3 materials TLDs may be made of
Lithium fluoride (Lif)
Lithium borate
Calcium fluoride
TLDs are accurate within what percent?
5%
What is the annealing process of TLDs?
Preheat TLD for 1 hour at 400 °C and at 24 hours at 80 °C to get rid of glow peaks
Inexpensive personnel monitor with different filters for different doses, depths, and radiation energy (ex: lead, tin, no filter)
Film badge
What is the deep and shallow dose of film badges in centimeters?
Deep = 1 cm Shallow = 0.0007 cm
What is the accuracy of dose readings of film badges?
+/-20 (inaccurate)
Film badges are more responsive to low energy with no response for ____ MeV or greater
10 MeV
Initially expensive, gas-filled dosimeter
Offers immediate readout
Used for infrequently exposed people
Have to charge it to zero it out or you could get false readings
Pocket dosimeter
2 neutron detectors
Rascal
Bubble counter
3 materials a rascal detector can be made of
Boron trifluoride (BF3)
Argon
Propane
How do you read a bubble counter?
5 bubble/mrem
Radiation is stored in this dosimter, then scanned by a laser and emits light
More sensitive than film
Uses filters to distinguish dose (deep, eye, etc.)
Personnel monitoring device commonly used today
Optically stimulated luminescence (OSL)
What is the OSL made of?
Aluminum oxide detector
What energy range do linacs use and at what energy are neutrons emitted?
Linacs use 8-18 MeV and neutrons are emitted at greater than 10 MeV
What shielding material is used for neutrons?
Borated polyethylene
Set standards; agencies authorized by congress to establish mandates and regulations that explain the technical, operational, and legal details necessary to implement laws
Regulatory agencies
Set exposure levels, voluntary regulatory agency
Reports cover all radiation-associated industries
National Council on Radiation Protection and Measurement (NCRP)
Regulatory agency that sets exposure levels
International Commission on Radiation Protection
2 regulatory agency that set exposure levels
National Council on Radiation Protection and Measurement (NCRP)
International Commission on Radiation Protection
Independent agency of the US government that’s charged with overseeing reactor safety, security, licensing, and renewal, radioactive material safety, and spent fuel management; responsible for isotope usage (need license for brachytherapy)
Nuclear Regulatory Commission (NRC)
Federal regulatory agency that licenses and okays linacs
Reviews radiopharmaceuticals and radiation-producing equipment (Title 21)
Food and Drug Administration (FDA)
Federal regulatory agency that governs shipment of radioactive materials (Title 49)
Department of Transportation
Administrative regulatory agency requiring employers to ensure safety of workers
Workplace safety and health
Regulations that relate to the use of radiation in regards to employees
Occupational Safety and Health Administration (OSHA)
Have a threshold for induction and severity increases with dose (ex: erythema, epilation, cataracts)
Have to reach threshold to see certain effects
Nonstochastic/deterministic effects
No induction threshold and are proportional to the dose received (ex: cancer, genetic effects, teratogenic effects)
Probability increases with dose, sensitivity doesn’t
Stochastic effects
Embryologic malformations; developmental effects
Effects on kids exposed in utero/fetus
Correlation: earlier trimester = greatest effect from radiation exposure
Teratogenic effects
Lethal effect of acute whole-body exposure in which 50% of the total population exposed is affected in 30 days
LD 50/30
What is the LD 50/30?
4.5 Gy (450 rads)
3 effects of radiation
Somatic/carcinogenesis
Genetic/mutagenesis
Developmental/teratogenesis
Effects that take place in the exposed individual
Somatic effects/carcinogenesis
Abnormalities occurring in future kids/subsequent generations
Exposure to gonads, usually presents as cancer
Genetic effects/mutagenesis
What is the chance of the exposed individual developing fatal cancer per rem due to low level exposure?
1 chance in 2500 of developing fatal cancer per rem due to low level exposure
There is no known threshold for genetic effects but models predict what occurance?
1 in 10,000 per rem occurrence
What can happen in the 1st 3 weeks if a fetus is exposed and what can happen after?
1st 3 weeks = failure to implant
After = different types of childhood cancers
Comparisons for radiation workers are made with workers in “safe” industries in which risk of injury is about 1 in 10,000 per year; because radiation-induced effects may exhibit a latent period, these comparisons are difficult
Comparable risk
Measure of the genetic risk to the population as a whole from exposure to ionizing radiation to some or all members of the population
Dose that, if received by every member of the population, would be expected to result in the same total genetic effect on the population as the sum of the individual doses
Gives measurement of what general risk can take place from exposure in a population
Takes natural and manmade radiation into account
Genetically significant dose (GSD)
Lifetime cancer rise for acute whole body exposure to low LET radiation
8 in 10,000 per rem (8 per 10,000 people per rem)
Effective dose equivalent limit (stochastic effects) of annual occupational exposures
50 mSv (5 rem)
Dose equivalent limits for tissues and organs (nonstochastic effects) of lens of the eye of annual occupational exposures
150 mSv (15 rem)
Dose equivalent limits for tissues and organs (nonstochastic effects) of all others (ex: red bone marrow, breast, lung, gonads, skin, and extremities) of annual occupational exposures
500 mSv (50 rem)
Cumulative exposure
10 mSv x age in years (1 rem x age in years)
Planned special occupational exposure, effective dose equivalent limit and guidance for emergency occupational exposure
50 mSv (5 rem)/year
Annual public exposure effective dose equivalent limit, continuous or frequent exposure
1 mSv (0.1 rem)
Annual public exposure effective dose equivalent limit, infrequent exposure
5 mSv (0.5 rem)
Effective dose equivalent when remedial action is recommended
> 5 mSv (>0.5 rem)
Remedial action recommended exposure to radon and its decay products
> 0.007 Jhm^-3 (>2 WLM)
Annual public exposure dose equivalent limits for lens of eye, skin, and extremeties
50 mSv (5 rem)
Effective dose equivalent limit for annual education and training exposure
1 mSv (0.1 rem)
Dose equivalent limit for lens of eye skin, and extremities for annual education and training exposure
50 mSv (5 rem)
Total dose equivalent limit for embryo-fetus exposures
5 mSv (0.5 rem)
Dose equivalent in a month for embryo-fetus exposures
0.5 mSv (0.05 rem)
Negligible individual risk level (annual) effective dose equivalent per source or practice
0.01 mSv (0.001 rem)
3 major rules
Time (Cobalt-60 machine examples)
Distance (inverse square law)
Shielding (HVL)
Exposure from a Cobalt-60 machine must be less than ____ mR/hr at any point one meter from the source; if the average exceeds ____ mR/hr it’s outside of limit (shielding not working)
10 mR/hr; 2 mR/hr
Thickness of absorbing material necessary to reduce the x-ray intensity to half its original value
Half-value layer (HVL)
Most dense shielding material (written in mm versus others in cm)
Lead
Number of patients per week times the amount of radiation for each (cGy/week or rad/wk)
Time interval of the absorbed dose rate (cGy/min or rad/min) determined at the depth of the maximum absorbed dose, 1 meter from the “source”
Workload (W)
Fraction of time the primary beam is aimed at a particular wall
Use factor (U)
Fraction of time the shielded space is occupied
Occupancy factor (T)
Percent of radiation transmitted through the wall, ceiling, etc. Helps determine HVL
Transmission factor (B)
Permissible dose (P) of a controlled area
0.1 cGy/wk
Permissible dose (P) of an uncontrolled area (don’t control who is going in and out of space)
0.01 cGy/wk
Distance from the source of radiation to occupied area; inverse sqaure
Distance (d)
Limit for occupied area; radiation worker equivalent or general public
Effective dose
Use factor (U) 0 degree (down on IEC)
31%
Use factor (U) 90 and 270 degrees
21.3%
Use factor (U) 180 degrees
26.3%
Occupancy factor (T) of full occupancy areas
1
Areas occupied full-time by an individual, same people in there everyday; ex: work offices treatment planning areas, nurses stations, attended waiting areas, occupied space in nearby building
Full occupancy area
Occupancy factor (T) of adjacent treatment room, patient examination room adjacent to shielded vault
1/2
Occupancy factor (T) of corridors, employee lounges, staff rest rooms
1/5
Occupancy factor (T) of treatment vault doors
1/8
Occupancy factor (T) of public toilets, unattended vending rooms, storage areas, outdoor areas with seating, unattended waiting rooms, patient holding areas, attics, janitors’ closets
1/20
Occupancy factor (T) of outdoor areas only transient pedestrian or vehicular traffic, unattended parking lots, vehicular drop-off areas (unattended), stairways, unattended elevators
1/40
Portions of the floor, ceiling, and wall that generally receive the primary beam
Primary barrier
Formula for transmission factor
B=Pd^2/WUT
What do room warning signs with doses greater than 1 mSv or 0.1 rem in an hour read?
Caution: high radiation area
What do room warning signs with doses greater than 5 Gy read?
Grave danger: very high radiation area
How often should the “beam on” indicator lights be checked?
Daily
Turn off radiation when the circuit is interrupted
Door interlocks
Hear and see inside room while at control booth
Visual and aural communication
Independant system with a backup batter that kills machine, cuts power
Beam on monitors
Where should you go if the beam on monitors don’t work?
Circuit breaker
How often should you log sources in/out of brachytherapy?
Weekly
4 restrictions for visitors and staff post brachytherapy
Nobody under 18 or pregnant can enter
Visitors only allowed for about 20 minutes
Personal monitors for people in room
Keep a certain distance from the patient and/or behind a shield
Rooms adjacent to brachytherapy rooms must be less than ____mR/hr
2 mR/hr
How often should a leak test be done for a double-sealed isotope (ex: cesium)?
About every 3 years (less often because it is more sealed)
How often should a leak test be done for a single-sealed isotope (ex: Ir, cobalt, etc.)?
Every 6 months
What is the limit of the results after a wipe test (done with damp wet cloth and placed in scintillation chamber)?
Less than or equal to 0.05 microCi
Treatment at a dose rate of less than 2 Gy/hr; source stays in patient for a long time (handled with tongs, lead gloves, etc.)
Low dose rate (LDR)
Treatment at a dose rate that exceeds 12 Gy/hr; high activity can be as much as 10 Ci (ex: Ir)
Not handled manually, remote afterloader
High dose rate (HDR)
Connect cathodes and machine administers dose; afterloading using a treatment unit controlled from outside the treatment vault
Remote afterloader
About how many runs can off a HDR source can you get (can get brittle and break off in patient)?
1,000 runs
Permanent implant must be less than ____mR/hr at 1 meter to be released (ex: prostate treatment takes a couple days, then read patient; patient must be monitored, sleep alone, no one on lap, etc.)
5 mR/hr
3 steps for removing isotope inventory
Take inventory
Sources removed (patient room; who removed, time and date)
Sources remaining
2 steps for returning isotope inventory
Sources remaining (who removed from patient, time/date returned) Complete inventory
Implements radiation protection program
Radiation safety officer (RSO)
Oversees use of byproduct material
Radiation safety committee (RSC)
4 members of a radiation safety committee
RSO
Authorized used (doctor)
Nurse
Management representative
What is the usual dose per fraction?
180-200 cGy
2 segregations for disposal of radioactive waste
Half-life less than 90 days must decay 10 half-lives
Half life greater than 90 days must be sent off-site if they can’t house them (can get expensive)
Tissues in organs that can only be affected by the incapacitation of only one element; ex: spinal cord (if there’s a break in the spine, it stops working below break)
Serial structure/response tissues
If organ gets damaged, everything around it still works; ex: lungs
Parallel structure/response tissues
Dose of radiation that’s expected to produce a 5% complication rate within 5 years; want to stay at or below dose
Tolerance dose 5/5 (TD5/5)
Outline organ to reduce and track dose; reproduction of an external body shape, usually taken through the transverse plane of the treatment beam
Contour
Pelvis contains ____% of bone marrow in adults
25%
Bone death
Osteonecrosis
Osteonecrosis of femoral head at _____ Gy (_______ cGy)
60 Gy (6000 cGy)
If _____% of bone marrow treated, WBC and platelet counts can be lowered
25%
Treating kids bones can cause orthopedic problems; treat epiphyseal/growth plate ______ or it can ______ kids growth
Evenly, disrupt
Striated muscle not as radiosensitive but radiation to this muscle can ______ growth in kids
Retard
Permanent sterility is unavoidable at low doses around ______-______ cGy
1500-2000 cGy
Treatment can cause _________ in women due to disruption in the normal production of female hormones; ________ can happen in males due to radiation
Menopause; impedance
Ovaries can be relocated ________, _________, or _______ along uterus based on treatment field
Superiorly, laterally, or midline
How is testicular disease usually treated?
Testes less often exposed, not commonly in primary beam; when treating testicular disease usually remove affected testicle and treat surrounding tissue
As much as _____% of dose to testes from internal scatter; can be reduced to _____% by using testicular clam/shield
10%, 3%
Testes known to house __________ cells; more common in childhood cancer, may be treated if cells found in biopsy
Leukemia
After mucosal doses at _______ cGy (ex: gynecological brachytherapy) can cause scar tissue or adhesions that can destroy upper vagina
Lose vaginal patency/flexibility which can be resumed by vaginal dilator, sex, etc.
10,000 cGy
Normal bladder capacity
Greater than or equal to 400 cc’s
At greater than or equal to _____ cGy can cause dysuria which raises concern of bladder infection
2500 cGy
Mucosal inflammation, difficult or painful inflammation
Dysuria
At ______ cGy, bladder fibrosis may occur and permanently reduce capacity
5000 cGy
Abnormal connection between two hollow spaces may form in the urinary tract at high doses especially if surgery or tumor is involved
Fistulas
Men should avoid irradiation ____-____ weeks post-op before radiation to avoid stenosis; rare in females, usually from tumor not radiation
6-8 weeks
Stenosis
Narrowing
Severe inflammation of intestines
Radiation induced severe acute causes interruption of eating; stop oral intake to IV
Enteritis
Symptoms of small intestine start appearing at ____-____ Gy
20-25 Gy
2 things small intestine can develop from radiation
Obstruction
Fistula
3 symptoms of small intestine radiation
Diarrhea
Nausea
Vomiting
Abnormal formation of fibrous tissue caused by alterations in the structure and function of blood vessels
Obstruction of the small intestine due to this may require surgery if severe
Fibrosis
Doses to the small intestine greater than ______ cGy may induce severe symptoms
4500 cGy
3 ways small bowel can be manipulated from the treatment field
Prone with pillow under stomach
False tabletop with hole for stomach to drop through
Full bladder elevates small bowel
Inflammation of rectum
Proctitis
At about ______ cGy acute injuries/side effects to the rectum and anus appear
2500 cGy
2 symptoms of rectum and anus irradiation
Tenesmus
Mucoid diarrhea
Feeling need to defecate, ineffective and painful straining during bowel movement
Tenesmus
Increased dose of ___-___ cGy increases side effects to the rectum and anus
65-70 cGy
Rectovaginal fistulas appear with high doses, especially with _______________
High beam/brachytherapy
Anus should be avoided at all costs unless tumor is very low because it affects the ________
Sphincter
Anus skin breakdown at _____-_____ Gy (less with IMRT)
25-30 Gy
3 late results from tumoricidal dose to the rectum and anus
Chronic ulcers
Infection
Stenosis to the point where normal defection is impossible (may need colostomy)
Dose high enough to eradicate tumor
Tumoricidal dose
_______-______ cGy will cause decrease in hydrochloric acid in the stomach
1500-2000 cGy
Stomach can tolerate _____ Gy
40 Gy
2 symptoms high fractional doses to the stomach can cause
Nausea
Vomiting
________ cGy threshold for danger for the liver, substantial increase at _______ cGy
2500 cGy, 3500 cGy
In kids, abnormal liver scans at midplane doses of ______-______ cGy
1200-2500 cGy
If 75% or more of liver receives ______-_____ cGy, at great risk for liver failure or death
3000-3500 cGy
Doses to the liver can cause acute ________ and can become chronic like ________
Hepatitis, cirrhosis
4 symptoms with radiation injury to liver
Jaundice
Anorexia
Fatigue
Weight loss
Yellowing of the skin caused by obstruction of bile ducts, liver disease, or excessive breakdown of RBC’s
Jaundice
Enlarged liver
Hepatomegaly
Inflammation of the kidneys
Nephritis
Adult kidney threshold
2000 cGy
2 ways to fix severe bilateral kidney failure
Chronic dialysis
Transplant
Kidney problems: increased BP, may need to remove destroyed kidney if it increases BP but if not patient can keep it
Radiation-induced nephrectomy
Have two kidneys so may go over TD5/5 if other is functional
Never take both kidneys to _______ cGy; if one is receiving high dose keep other low to none at all
2000 cGy
Kidney disease or damage
Unilateral radiation __________ doesn’t result in uremia; won’t see reduction in output if only one kidney is injured
Nephropathy
Reduced urine output
Uremia
Located on superior pole of kidneys
TD5/5 unknown because kidney tolerance dose so low
Adrenal glands
Nickname for pancreatic cancer because once we see signs and symptoms it’s usually too late; rising incidence
Silent killer
Not a dose limiting structure because stomach and liver reduce dose so much we don’t reach high enough doses to see effects
Pancreas
2 complications caused by irradiation of the spleen
Alteration in blood count
Alteration in immune function
Area that receives a lot of treatment (breast and lung)
Thorax
Makes everything more sensitive to radiation, symptoms happen earlies and more severe; may force patient to take breaks between treatments
Concurrent radiation and chemotherapy
Don’t want to start treatment and take break because of __________; won’t have effect on cancer cells
Rad-bio effect
RT treatments given in daily segments over an extended period of time, what makes RT work
Fractionization
8 organs of the respiratory system
Nose Pharynx Larynx Trachea Lungs Bronchi Hilum Lung parenchyma
Portion of lung involved in gas exchange; most susceptible to radiation and what gives low TD5/5
Lung parenchyma
3 organs of the lung parenchyma
Alveoli
Alveolar ducts
Respiratory bronchioles
___-___ Gy threshold of pneumonitis in lower tissue density in lungs 1-3 months after radiation
20-25 Gy
Inflammation of lung tissue, clinical manifestation of vascular, epithelial, and interstitial injuries
Pneumonitis
6 symptoms of pneumonitis
SOB on exertion Dry cough Dyspnea Fevers (if patient develops SOB and fever, indicative of greater lung injury) Night sweats Cyanosis
Pneumonitis can be treated with _______ to alleviate symptoms but doesn’t stop development
Steroids
If pneumonitis not treated, patient can develop long-term radiation ________ 2-4 months after treatment which affects/prevents expansion and interrupts gas transfer; this and pneumonitis increases risk of infection
Fibrosis
Abnormal narrowing of body passage; severe inflammation of esophagus may make this permenant (lose elasticity)
Stricture
Inflammation of esophagus
Esophagitis
Pain with swallowing and swelling develops ____-____ days after esophagus treatment starts; pain usually subsides about ____ week after treatment
Pain increases with dose
10-12 days; 1 week
Higher dose per fraction because more dose = less fractions needed
Hypofractionization
Fractional doses smaller than conventional, delivered two or three times daily to achieve an increase in the total dose in the same overall time
Hyperfractionation
Inflammation of the pericardium
Pericarditis
Membrane enclosing the heart, consisting of an outer fibrous layer and an inner double layer of serous membrane
Pericardium
Can see acute pericarditis appear the ____ year post treatment
1st
3 symptoms of pericarditis
Anterior chest pain
SOB
Low-grade fever
Pericarditis can develop at ____ Gy
20 Gy
3 ways pericarditis can be treated
Aspirin
NSAIDs
Steroids
Several years later if whole pericardium receives ___ Gy or more; can impede filling and reduce cardiac output (surgery only option to help)
50 Gy
Myocardium can develop _________________ after RT, which reduces function and is often related to a _______________
Interstitial fibrosis Myocardial infarction (heart attack)
Heart muscle
Myocardium
Young people may develop hardening of arteries after radiation of heart and pericardium
Coronary arteriosclerosis
Chemo drugs, cardiotoxicity (heart toxicity) along with RT can cause CHF
Doxorubicin/adriamycin
Prepuberty radiation will hinder development of the breast at ______-_____ cGy dose and can also induce malignant changes within breast many years after exposure (patient considered high risk)
1000-1500 cGy
2 symptoms of the breast at 2000 cGy
Erythema can develop to dry desquamation
Mild tenderness of breast
Shedding of the epidermis
Desquamation
3 symptoms of the breast at 4500 cGy
Most desquamation
Mild firmness
Edema
______ cGy can cause obvious fibrotic changes; smaller and harder breast and persistent changes after treatment (spider veins)
6000 cGy
Bundle/network of nerves from neck to armpit
Brachial plexus
Cervical nerves begin at ______________
Base of the skull
Doses greater than _____ Gy to the brachial plexus can cause damage; loss of motor function and sensory deprivation in ipsilateral arm that takes _____ year(s) or more to show
55 Gy; 1 year
3 treatments brachial plexus is contoured for
Head and neck
Breast (axillary nodes)
Lung
Within a few weeks of spinal cord treatment, patient may experience electrical shock/sensation down the back and into the limbs due to desheathing of myelin sheath; not permanent
Lhermitte’s sign/phenomenon
Spinal cord injury comes ___-____ months post treatment
8-48 months
2 spinal cord injuries from radiation therapy
Characterized motor deficit below treatment (circuit)
Para- or quadriplegia (higher damage = quad)
With head and neck treatments, swallowing becomes an issue that affects nutritional intake and leads to increased ________
Morbidity
Dose at which mandible can develop osteonecrosis
About 50-60 Gy
Xerostomia seen at this dose; little recovery once salivary glands are suppressed (artificial saliva, water)
About 2000 cGy
Xerostomia
Drymouth
Radiation causes _______ decay because of bacterial proliferation since saliva not going through; fluoride treatments, pre-dental work if patient has history of teeth issues
Dental
Squamous cells that for lips, mouth, pharynx, and larynx
Mucosa
Erythema of mucosa at ______ cGy
2000 cGy
Mouth can get thrush (whitening) at about ______ cGy; antifungal therapies
3000 cGy
Soft palate vulnerable and site where radiation _________ appears first
Mucotitis
Can shield teeth with _____ when treating mucosa of lip but beam can scatter off high Z material leading to more skin breakdown; add low Z material (_____) to outside of shield
Lead; wax
Negative pressure and fluid in middle ear caused by obstruction of eustachian tube
Serous otitis
Dose that causes serous otitis due to obstruction (lack of drainage); decongestants
4000 cGy
3 organs that become red and inflamed during treatment of the ears
Ear canals
Drains
Eustachian tubes
3 sound conducting bones of the ears that can develop fibrosis later due to higher radiation doses
Incus
Stapes
Malleus
Clouding of lens; non-stochastic (increases with dose)
Cataracts
Cataracts can develop at _____ cGy over a period of years of low dose
500 cGy
Irradiation of this gland can lead to loss of tear creation and chronic dry eyes (artificial tears)
Lacrimal gland
Drains conjunctiva
Punctum lacrimal
Tear duct can develop fibrosis and cause obstruction leading to this
Watery eyes
Develops when anterior chamber of eye is irradiated
Glaucoma
Dose at which retina, optic nerve and chiasma can experience vision loss
5000 cGy
X-shaped structure formed at the point below the brain where the two optic nerves cross
Chiasma
Muscle that opens and closes mouth; more vulnerable to radiation and develops fibrosis before other muscles
Pterygoid muscle
Spasm of jaw muscles causing the mouth to remain tightly closes; can lead to nutritional and dental care problems (exercise jaw, open and close mouth)
Trismus/lockjaw
Trismus gradually develops over doses of ________ cGy or greater
6000 cGy
3 symptoms that develop around doses of 5000 cGy due to swelling of supraglottic larynx
Hoarseness
Dysphagia
Airway obstruction
Difficulty swallowing
Dysphagia
Whole larynx being treated at ______ cGy = can start seeing chronic laryngeal inflammation
6500 cGy
Death or disintegration of a cell or tissue caused by disease or injury
Cartilage necrosis
After cartilage necrosis, removal of the larynx and separation of the airway from the mouth, nose, and esophagus
Laryngectomy
Endocrine gland, non-dosing structure
Thyroid gland
Underactivity of the thyroid, decreased function/hormones
Hypothyroidism
5 symptoms of hypothyroidism
Fatigue Weakness Hair loss Depression Memory loss
Disorder from hypothyroidism that causes the eyes to bulge; treat muscles with radiation to relax them back
Graves disease
Normal function of pituitary gland drops around ___-___ Gy; insufficiencies happen when treating nasopharynx and base of skull because gland is in sella turcica (2 cm superior and anterior to EAM)
55-60 Gy
3 organs radiation of pituitary gland impairs
Gonads
Thyroid
Adrenal function (hormone replacement, surgery through nose)
After we administer so much radiation to a tumor, the tumor can be seen better; can change treatment plan
Tumoritis
Dose at which tumor borders are visible
Around 1000 cGy
Obstruction of the blood supply to an organ or region of tissue, causing local death of the tissue
Infarction
Mental retardation in kids is a risk with midplane whole brain doses of about ______ cGy in _____ fractions over 2.5 weeks with injections of methotrexate (chemo) into CSF (whole brains usually treated with about 3000 cGy in adults)
2400 cGy; 12 fractions
2 abnormalities that show up on kids CT scans during/after brain treatment that cause medical problems
Dilated ventricles
Calcifications throughout brain
Infants/kids are more susceptible to chronic brain injury during treatment because their ______ cells are still proliferating
Mitotic
Brain tumors rare in first _____ years of life
2
Moderate to severe neurological handicaps will follow in about _____% or _____ of kids dosed/treated in brain
33% or 1/3
Why is palliative treatment delivered with high doses per fraction?
It gets rid of symptoms faster
____ of those treated who receive _____ cGy of midplane dose in low fractions with concurrent systemic chemo can develop memory impairment, poor judgement, and other intellectual defects within a few months of brain treatment
33%; 3000 cGy
Vision loss can start to occur at _____ cGy or greater to the optic nerves and chiasm
4500 cGy
Temporary hair loss occurs at about _____ cGy usually around the first two weeks of treatment (____-____ fractions)
1000 cGy; 10-12 fractions
Hair regrowth will usually occur as long as we don’t hit doses of ___-___ Gy where it can be permanent
40-45 Gy
Skull radionecrosis _____ unless doses are high
Rare
Usually don’t treat whole extremity if at least ___-___ cm of soft tissue not treated, lymphedema can occur at around ____ Gy (subcutaneous fibrosis stops lymph drainage)
1-3 cm, 40 Gy
Doses to foot greater than ___-___ Gy should be avoided in elderly because of slowed healing process
35-40 Gy
Avoid irradiating epiphysis in kids, ____ Gy can affect growth
20 Gy
Radiotherapy of a surgically dissected axilla and supraclavicular region leads to this
Lymphedema
Halves of body, less toxic
Hemibody
Radiation given in a way to cover whole body
Total body irradiation (TBI)
2 forms of TBI
Low dose
High dose
2 reasons TBI is done
Suppress patient’s immune system
Prevent rejection of donor bone marrow after a bone marrow transplant
10-15 cGy per treatment 1-3 times weekly until TD of 150 cGy for chronic lymphocytic leukemia (CLL) and some favorable types and non-Hodgkins lymphoma (systemic diseases); chemo works better though
Palliative
Low dose TBI
Used to be done in single application of 1000 cGy Cobalt-60 at 5 cGy/min
Increase distance to 300-400 cm to fit whole body which lowers dose, longer treatment
Single high dose TBI
2 types of high dose TBI
Single
Fractionated
6-8 single fractions BID usually in the morning and afternoon with at least 6 hours between them at 1200-1400 cGy
Less toxicity and reduces risk of pneumonitis and pneumonia
Fractionated high dose TBI
6 symptoms patient can experience from fracionated high dose TBI
Radiation induced enteritis Xerostomia Diffuse (spread-out) skin erythema Temporary hair loss Sterilization Cataracts
TD5/5 (3/3 volume) and side effect of kidney
2300 cGy - clinical nephritis
TD5/5 (3/3 volume) and side effect of symptomatic bladder contracture and volume loss
6500 cGy - symptomatic bladder contracture and volume loss
TD5/5 (3/3 volume) and side effect of femoral head
5200 cGy - necrosis
TD5/5 (3/3 volume) and side effect of TMJ mandible
6000 cGy - marked limitation of joint function
TD5/5 (3/3 volume) and side effect of rib cage
5000 cGy - pathologic fracture
TD5/5 (3/3 volume) and side effect of brain
4500 cGy - necrosis, infarction
TD5/5 (3/3 volume) and side effect of brain stem
5000 cGy - necrosis, infarction
TD5/5 (3/3 volume) and side effect of optic nerve I & II
5000 cGy - blindness
TD5/5 (3/3 volume) and side effect of chiasma
5000 cGy - blindness
TD5/5 (3/3 volume), rule of thumb, what doctor’s may go up to and side effect of spinal cord
TD5/5: every 20 cm, 4700 cGy
Rule of thumb: 4500 cGy
What doctor’s may go up to: 5000 cGy
Side effect: myelitis necrosis
TD5/5 (3/3 volume) and side effect of brachial plexus
6000 cGy - clinically apparent nerve damage
TD5/5 (3/3 volume) and side effect of eye lens I & II
1000 cGy - cataract requiring intervention
TD5/5 (3/3 volume) and side effect of eye retina I & II
4500 cGy - blindness
TD5/5 (3/3 volume) of ear mid/external that causes acute serous otitis
3000 cGy
TD5/5 (3/3 volume) of ear mid/external that causes chronic serous otitis
5500 cGy
TD5/5 (3/3 volume) and side effect of parotid I & II
3200 cGy - xerostomia
TD5/5 (3/3 volume) of larynx that causes cartilage necrosis
7000 cGy
TD5/5 (3/3 volume) of larynx that causes laryngeal edema
4500 cGy
TD5/5 (3/3 volume) and side effect of lung I
1750 cGy - pneumonitis
TD5/5 (3/3 volume) and side effect of heart
4000 cGy - pericarditis
TD5/5 (3/3 volume) and side effect of esophagus
5500 cGy - clinical stricture/perforation
TD5/5 (3/3 volume) and side effect of stomach
5000 cGy - ulceration perforation
TD5/5 (3/3 volume) and side effect of small intestine
4000 cGy - obstruction perforation/fistula
TD5/5 (3/3 volume) and side effect of colon
4500 cGy - obstruction perforation/ulceration/fistula
TD5/5 (3/3 volume) and side effect of rectum
6000 cGy - severe proctitis/necrosis/fistula, stenosi
TD5/5 (3/3 volume) and side effect of liver
3000 cGy - liver failure/damage
TD5/5 (3/3 volume) and side effect of spleen
3000-4000 cGy - hypofunction
