Test 1 Flashcards by Courtney W

Radiation that has the ability to make an atom a charged particle (remove an electron)

Ionizing radiation

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Radiation in which electric and magnetic fields vary simultaneously (ex: x-ray, gamma rays, etc)

Electromagnetic radiation

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What is the difference between x-rays and gamma rays?

X-rays come from Brems interactions (manmade); gamma from nucleus (natural)

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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

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2 forms of ionizing radiation

Electromagnetic radiation

Particulate radiation

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Plank’s equation

E=hv or E=hc/λ

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Plank’s constant (h)

6.62 x 10^-34

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6 types of electromagnetic radiation (from highest to lowest frequency)

Gamma rays
Ultraviolet light
Visible light
Infrared light
Microwaves
Radio and television

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7 types of visible light (from low to high frequency)

Red
Orange
Yellow
Green
Blue
Indigo
Violet (ROYGBIV)

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Average wavelength (λ) (m) and frequency (v) (Hz) of gamma rays

λ = 10^-12 m
v = 10^20 Hz

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Average wavelength (λ) (m) and frequency (v) (Hz) of ultraviolet light

λ = 10^-8 m
v = 10^17 Hz

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Average wavelength (λ) (m) and frequency (v) (Hz) of visible light

λ = 10^-6 m
v = 10^14 Hz

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Average wavelength (λ) (m) and frequency (v) (Hz) of infrared light

λ = 10^-5 m
v = 10^13 Hz

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Average wavelength (λ) (m) and frequency (v) (Hz) of microwaves

λ = 10^-2 m
v = 10^10 Hz

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Average wavelength (λ) (m) and frequency (v) (Hz) of radio and television waves

λ = 10^2 m
v = 10^6 Hz

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Energy and frequency are ___________; energy and wavelength are _____________________

Proportional; inversely proportional

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2 major groups of radiation in a therapy department

External beam

Brachytherapy sources

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2 types of external beams

Linear accelerators (linacs)
Cobalt-60

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Machines that produce x-ray, gamma rays, and electrons; most popular
Ex: SRS/SBRT

External beams

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Machines that emit gamma rays, x-rays, alpha, and beta particles
Ex: 137Cs, 192Ir, 125I

Brachytherapy sources

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2 types of beams made by linacs based on what is being treated

Photon

Electron

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3 categories of linacs based on types of energies (want different energies for different part thicknesses)

Low
High
Dual-energy (most common)

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Cobalt-60 delivers gamma rays with dual-energies of what MeV, averaging what MeV?

1.7 and 1.33 MeV

Average = 1.25 MeV

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Amount of energy delivered to tissue (keV/um)

Linear energy transfer (LET)

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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?

What is the quality factor (QF) of protons other than recoil protons and energy greater than 2 MeV?

What is the quality factor (QF) of thermal neutrons (slower)?

What is the quality factor (QF) of fast neutrons, alpha particles, and fission fragments other than heavy nuclei?

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?

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?

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

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

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

Test 1 Flashcards

(384 cards)