Test 1 Flashcards Preview

RAD 360 - Fundamentals of Radiation Therapy > Test 1 > Flashcards

Flashcards in Test 1 Deck (384)
Loading flashcards...
1

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

Ionizing radiation

2

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

Electromagnetic radiation

3

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

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

4

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

5

2 forms of ionizing radiation

Electromagnetic radiation
Particulate radiation

6

Plank's equation

E=hv or E=hc/λ

7

Plank's constant (h)

6.62 x 10^-34

8

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

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

9

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

Red
Orange
Yellow
Green
Blue
Indigo
Violet (ROYGBIV)

10

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

λ = 10^-12 m
v = 10^20 Hz

11

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

λ = 10^-8 m
v = 10^17 Hz

12

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

λ = 10^-6 m
v = 10^14 Hz

13

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

λ = 10^-5 m
v = 10^13 Hz

14

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

λ = 10^-2 m
v = 10^10 Hz

15

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

λ = 10^2 m
v = 10^6 Hz

16

Energy and frequency are ___________; energy and wavelength are _____________________

Proportional; inversely proportional

17

2 major groups of radiation in a therapy department

External beam
Brachytherapy sources

18

2 types of external beams

Linear accelerators (linacs)
Cobalt-60

19

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

External beams

20

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

Brachytherapy sources

21

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

Photon
Electron

22

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

Low
High
Dual-energy (most common)

23

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

1.7 and 1.33 MeV
Average = 1.25 MeV

24

Amount of energy delivered to tissue (keV/um)

Linear energy transfer (LET)

25

What is the charge, atomic mass number, and origin of alpha particles (a)?

Charge = +2
Atomic mass number = 4
Origin = nucleus

26

What is the charge, atomic mass number, and origin of negatrons (B-) (beta particles)?

Charge = -1
Atomic mass number = 0
Origin = nucleus

27

What is the charge, atomic mass number, and origin of positrons (B+) (beta particles)?

Charge = +1
Atomic mass number = 0
Origin = nucleus

28

What is the charge, atomic mass number, and origin of neutrinos (v)?

Charge = 0
Atomic mass number = 0
Origin = nucleus

29

What is the charge, atomic mass number, and origin of x-rays?

Charge = 0
Atomic mass number = 0
Origin = electron shells

30

What is the charge, atomic mass number, and origin of gamma rays (y)?

Charge = 0
Atomic mass number = 0
Origin = nucleus

31

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)

32

How many protons and neutrons do alpha particles have?

2 protons
2 neutrons

33

Alpha particles have a very _____ LET because it distributes all its energy when it hits

High

34

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+)

35

Rest mass of electrons and beta particles (B- or B+)

0.511 MeV

36

1 MeV beta particle has a range of _______ centimeters of tissue

2 cm

37

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

38

No mass and no charge; manmade by Brems (85%) or characteristic (15%) interactions

X-rays

39

No mass and no charge; natural from nucleus

Gamma rays

40

What are photoelectric interactions dependent on?

Z^3/E^3

41

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)

42

3 types of natural background radiation

Cosmic
Terrestrial
Internal exposure

43

What percent of human-absorbed radiation doses arise from natural background radiation?

82%

44

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

45

What is the dose per year of natural background radiation?

1 mSv/yr + 2 mSv/yr radon = 3 mSv/yr

46

What is the dose per year of cosmic radiation?

26 mrem/yr = 0.26 mSv/yr

47

Radiation from earth; naturally occurring radioactive materials

Terrestrial radiation

48

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

49

What is the terrestrial radiation dose in the Rocky Mountains?

0.63 mSv

50

Accounts for 2/3 of natural background radiation
Second cause of lung cancer in the US
Can be found in cement in basements

Radon

51

What is the dose per year of terrestrial radiation (not including radon)?

16 mrem/yr = 0.16 mSv/yr

52

What is the dose per year from radon?

200 mrem/yr = 2 mSv

53

Naturally occurring radiation in the body

Internal exposure

54

What is the dose per year from internal exposure?

20 mrem/yr = 0.2 mSv

55

What is the radiation dose from man-made sources?

0.6 mSv

56

What is the radiation dose from medical sources?

0.5 mSv

57

What is the radiation dose from consumer products?

0.11 mSv

58

2 types of man-made sources of radiation

Medical
Consumer products

59

Amount of ionization produced by photons in air per unit mass of air, only applicable to photons while they interact with air

Exposure

60

Traditional and SI units of exposure

Traditional: Roentgen (R)
SI: Coulomb/kg of air

61

Unit of charge

Coulomb (C)

62

1 R = ? C per gram of air

2.48x10^-4 C per gram of air

63

The use of exposure is limited to photons with energies below what MeV?

3 MeV

64

Amount of energy absorbed per mass of any material while radiation interacts in the material

Absorbed dose

65

Traditional and SI units of absorbed dose

Traditional: rad
SI: gray (Gy)

66

2 units of energy

Erg
Joule (J)

67

1 rad = ? erg per gram of material

100 erg per gram of material

68

1 Gy = ? J per kg of material = ? rad

1 J per kg of material = 100 rad

69

1 Gy = ? rad = ? cGy

100 rad = 1 cGy

70

Product of absorbed dose and a quality factor, which takes into account the biological effects of different types of radiation

Dose equivalent

71

Traditional and SI units of dose equivalent

Traditional: rem
SI: Sievert (Sv)

72

Radiation weighting factor, specific to specific types of radiation; accounts for the biological effectiveness of the specific radiation

Quality factor (QF)

73

Rad x QF

rem

74

Gray x QF

Sievert (Sv)

75

1 Sv = ? rem

100 rem

76

Number of radioactive disintegrations (transformations) per unit of time; how quickly isotopes decay

Activity

77

Traditional and SI units of of activity

Traditional: curie (Ci)
SI: becquerel (Bq)

78

curie = ? disintegrations/second

3.7 x 10^10 disintegrations/second

79

1 Bq = ? disintegrations/second

1 disintegrations/second

80

1 Ci = ? Bq

3.7 x 10^10 Bq

81

What is the quality factor (QF) of x-rays and gamma rays (y), beta particles, positrons, and muons, and high energy external protons?

1

82

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

2

83

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

5

84

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

20

85

Higher quality factor = ________ dose

Higher

86

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

87

What is the calibration of ionization chambers?

2%

88

What is the average voltage of ionization chambers?

200-300 V

89

2 types of gas-filled detectors

Ionization chamber
Geiger-Muller (GM) detector

90

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

91

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)

92

3 materials TLDs may be made of

Lithium fluoride (Lif)
Lithium borate
Calcium fluoride

93

TLDs are accurate within what percent?

5%

94

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

95

Inexpensive personnel monitor with different filters for different doses, depths, and radiation energy (ex: lead, tin, no filter)

Film badge

96

What is the deep and shallow dose of film badges in centimeters?

Deep = 1 cm
Shallow = 0.0007 cm

97

What is the accuracy of dose readings of film badges?

+/-20 (inaccurate)

98

Film badges are more responsive to low energy with no response for ____ MeV or greater

10 MeV

99

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

100

2 neutron detectors

Rascal
Bubble counter

101

3 materials a rascal detector can be made of

Boron trifluoride (BF3)
Argon
Propane

102

How do you read a bubble counter?

5 bubble/mrem

103

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)

104

What is the OSL made of?

Aluminum oxide detector

105

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

106

What shielding material is used for neutrons?

Borated polyethylene

107

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

108

Set exposure levels, voluntary regulatory agency
Reports cover all radiation-associated industries

National Council on Radiation Protection and Measurement (NCRP)

109

Regulatory agency that sets exposure levels

International Commission on Radiation Protection

110

2 regulatory agency that set exposure levels

National Council on Radiation Protection and Measurement (NCRP)
International Commission on Radiation Protection

111

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)

112

Federal regulatory agency that licenses and okays linacs
Reviews radiopharmaceuticals and radiation-producing equipment (Title 21)

Food and Drug Administration (FDA)

113

Federal regulatory agency that governs shipment of radioactive materials (Title 49)

Department of Transportation

114

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)

115

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

116

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

117

Embryologic malformations; developmental effects
Effects on kids exposed in utero/fetus
Correlation: earlier trimester = greatest effect from radiation exposure

Teratogenic effects

118

Lethal effect of acute whole-body exposure in which 50% of the total population exposed is affected in 30 days

LD 50/30

119

What is the LD 50/30?

4.5 Gy (450 rads)

120

3 effects of radiation

Somatic/carcinogenesis
Genetic/mutagenesis
Developmental/teratogenesis

121

Effects that take place in the exposed individual

Somatic effects/carcinogenesis

122

Abnormalities occurring in future kids/subsequent generations
Exposure to gonads, usually presents as cancer

Genetic effects/mutagenesis

123

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

124

There is no known threshold for genetic effects but models predict what occurance?

1 in 10,000 per rem occurrence

125

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

126

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

127

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)

128

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)

129

Effective dose equivalent limit (stochastic effects) of annual occupational exposures

50 mSv (5 rem)

130

Dose equivalent limits for tissues and organs (nonstochastic effects) of lens of the eye of annual occupational exposures

150 mSv (15 rem)

131

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)

132

Cumulative exposure

10 mSv x age in years (1 rem x age in years)

133

Planned special occupational exposure, effective dose equivalent limit and guidance for emergency occupational exposure

50 mSv (5 rem)/year

134

Annual public exposure effective dose equivalent limit, continuous or frequent exposure

1 mSv (0.1 rem)

135

Annual public exposure effective dose equivalent limit, infrequent exposure

5 mSv (0.5 rem)

136

Effective dose equivalent when remedial action is recommended

>5 mSv (>0.5 rem)

137

Remedial action recommended exposure to radon and its decay products

>0.007 Jhm^-3 (>2 WLM)

138

Annual public exposure dose equivalent limits for lens of eye, skin, and extremeties

50 mSv (5 rem)

139

Effective dose equivalent limit for annual education and training exposure

1 mSv (0.1 rem)

140

Dose equivalent limit for lens of eye skin, and extremities for annual education and training exposure

50 mSv (5 rem)

141

Total dose equivalent limit for embryo-fetus exposures

5 mSv (0.5 rem)

142

Dose equivalent in a month for embryo-fetus exposures

0.5 mSv (0.05 rem)

143

Negligible individual risk level (annual) effective dose equivalent per source or practice

0.01 mSv (0.001 rem)

144

3 major rules

Time (Cobalt-60 machine examples)
Distance (inverse square law)
Shielding (HVL)

145

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

146

Thickness of absorbing material necessary to reduce the x-ray intensity to half its original value

Half-value layer (HVL)

147

Most dense shielding material (written in mm versus others in cm)

Lead

148

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)

149

Fraction of time the primary beam is aimed at a particular wall

Use factor (U)

150

Fraction of time the shielded space is occupied

Occupancy factor (T)

151

Percent of radiation transmitted through the wall, ceiling, etc. Helps determine HVL

Transmission factor (B)

152

Permissible dose (P) of a controlled area

0.1 cGy/wk

153

Permissible dose (P) of an uncontrolled area (don't control who is going in and out of space)

0.01 cGy/wk

154

Distance from the source of radiation to occupied area; inverse sqaure

Distance (d)

155

Limit for occupied area; radiation worker equivalent or general public

Effective dose

156

Use factor (U) 0 degree (down on IEC)

31%

157

Use factor (U) 90 and 270 degrees

21.3%

158

Use factor (U) 180 degrees

26.3%

159

Occupancy factor (T) of full occupancy areas

1

160

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

161

Occupancy factor (T) of adjacent treatment room, patient examination room adjacent to shielded vault

1/2

162

Occupancy factor (T) of corridors, employee lounges, staff rest rooms

1/5

163

Occupancy factor (T) of treatment vault doors

1/8

164

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

165

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

166

Portions of the floor, ceiling, and wall that generally receive the primary beam

Primary barrier

167

Formula for transmission factor

B=Pd^2/WUT

168

What do room warning signs with doses greater than 1 mSv or 0.1 rem in an hour read?

Caution: high radiation area

169

What do room warning signs with doses greater than 5 Gy read?

Grave danger: very high radiation area

170

How often should the "beam on" indicator lights be checked?

Daily

171

Turn off radiation when the circuit is interrupted

Door interlocks

172

Hear and see inside room while at control booth

Visual and aural communication

173

Independant system with a backup batter that kills machine, cuts power

Beam on monitors

174

Where should you go if the beam on monitors don't work?

Circuit breaker

175

How often should you log sources in/out of brachytherapy?

Weekly

176

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

177

Rooms adjacent to brachytherapy rooms must be less than ____mR/hr

2 mR/hr

178

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)

179

How often should a leak test be done for a single-sealed isotope (ex: Ir, cobalt, etc.)?

Every 6 months

180

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

181

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)

182

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)

183

Connect cathodes and machine administers dose; afterloading using a treatment unit controlled from outside the treatment vault

Remote afterloader

184

About how many runs can off a HDR source can you get (can get brittle and break off in patient)?

1,000 runs

185

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

186

3 steps for removing isotope inventory

Take inventory
Sources removed (patient room; who removed, time and date)
Sources remaining

187

2 steps for returning isotope inventory

Sources remaining (who removed from patient, time/date returned)
Complete inventory

188

Implements radiation protection program

Radiation safety officer (RSO)

189

Oversees use of byproduct material

Radiation safety committee (RSC)

190

4 members of a radiation safety committee

RSO
Authorized used (doctor)
Nurse
Management representative

191

What is the usual dose per fraction?

180-200 cGy

192

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)

193

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

194

If organ gets damaged, everything around it still works; ex: lungs

Parallel structure/response tissues

195

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)

196

Outline organ to reduce and track dose; reproduction of an external body shape, usually taken through the transverse plane of the treatment beam

Contour

197

Pelvis contains ____% of bone marrow in adults

25%

198

Bone death

Osteonecrosis

199

Osteonecrosis of femoral head at _____ Gy (_______ cGy)

60 Gy (6000 cGy)

200

If _____% of bone marrow treated, WBC and platelet counts can be lowered

25%

201

Treating kids bones can cause orthopedic problems; treat epiphyseal/growth plate ______ or it can ______ kids growth

Evenly, disrupt

202

Striated muscle not as radiosensitive but radiation to this muscle can ______ growth in kids

Retard

203

Permanent sterility is unavoidable at low doses around ______-______ cGy

1500-2000 cGy

204

Treatment can cause _________ in women due to disruption in the normal production of female hormones; ________ can happen in males due to radiation

Menopause; impedance

205

Ovaries can be relocated ________, _________, or _______ along uterus based on treatment field

Superiorly, laterally, or midline

206

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

207

As much as _____% of dose to testes from internal scatter; can be reduced to _____% by using testicular clam/shield

10%, 3%

208

Testes known to house __________ cells; more common in childhood cancer, may be treated if cells found in biopsy

Leukemia

209

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

210

Normal bladder capacity

Greater than or equal to 400 cc's

211

At greater than or equal to _____ cGy can cause dysuria which raises concern of bladder infection

2500 cGy

212

Mucosal inflammation, difficult or painful inflammation

Dysuria

213

At ______ cGy, bladder fibrosis may occur and permanently reduce capacity

5000 cGy

214

Abnormal connection between two hollow spaces may form in the urinary tract at high doses especially if surgery or tumor is involved

Fistulas

215

Men should avoid irradiation ____-____ weeks post-op before radiation to avoid stenosis; rare in females, usually from tumor not radiation

6-8 weeks

216

Stenosis

Narrowing

217

Severe inflammation of intestines
Radiation induced severe acute causes interruption of eating; stop oral intake to IV

Enteritis

218

Symptoms of small intestine start appearing at ____-____ Gy

20-25 Gy

219

2 things small intestine can develop from radiation

Obstruction
Fistula

220

3 symptoms of small intestine radiation

Diarrhea
Nausea
Vomiting

221

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

222

Doses to the small intestine greater than ______ cGy may induce severe symptoms

4500 cGy

223

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

224

Inflammation of rectum

Proctitis

225

At about ______ cGy acute injuries/side effects to the rectum and anus appear

2500 cGy

226

2 symptoms of rectum and anus irradiation

Tenesmus
Mucoid diarrhea

227

Feeling need to defecate, ineffective and painful straining during bowel movement

Tenesmus

228

Increased dose of ___-___ cGy increases side effects to the rectum and anus

65-70 cGy

229

Rectovaginal fistulas appear with high doses, especially with _______________

High beam/brachytherapy

230

Anus should be avoided at all costs unless tumor is very low because it affects the ________

Sphincter

231

Anus skin breakdown at _____-_____ Gy (less with IMRT)

25-30 Gy

232

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)

233

Dose high enough to eradicate tumor

Tumoricidal dose

234

_______-______ cGy will cause decrease in hydrochloric acid in the stomach

1500-2000 cGy

235

Stomach can tolerate _____ Gy

40 Gy

236

2 symptoms high fractional doses to the stomach can cause

Nausea
Vomiting

237

________ cGy threshold for danger for the liver, substantial increase at _______ cGy

2500 cGy, 3500 cGy

238

In kids, abnormal liver scans at midplane doses of ______-______ cGy

1200-2500 cGy

239

If 75% or more of liver receives ______-_____ cGy, at great risk for liver failure or death

3000-3500 cGy

240

Doses to the liver can cause acute ________ and can become chronic like ________

Hepatitis, cirrhosis

241

4 symptoms with radiation injury to liver

Jaundice
Anorexia
Fatigue
Weight loss

242

Yellowing of the skin caused by obstruction of bile ducts, liver disease, or excessive breakdown of RBC's

Jaundice

243

Enlarged liver

Hepatomegaly

244

Inflammation of the kidneys

Nephritis

245

Adult kidney threshold

2000 cGy

246

2 ways to fix severe bilateral kidney failure

Chronic dialysis
Transplant

247

Kidney problems: increased BP, may need to remove destroyed kidney if it increases BP but if not patient can keep it

Radiation-induced nephrectomy

248

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

249

Kidney disease or damage
Unilateral radiation __________ doesn't result in uremia; won't see reduction in output if only one kidney is injured

Nephropathy

250

Reduced urine output

Uremia

251

Located on superior pole of kidneys
TD5/5 unknown because kidney tolerance dose so low

Adrenal glands

252

Nickname for pancreatic cancer because once we see signs and symptoms it's usually too late; rising incidence

Silent killer

253

Not a dose limiting structure because stomach and liver reduce dose so much we don't reach high enough doses to see effects

Pancreas

254

2 complications caused by irradiation of the spleen

Alteration in blood count
Alteration in immune function

255

Area that receives a lot of treatment (breast and lung)

Thorax

256

Makes everything more sensitive to radiation, symptoms happen earlies and more severe; may force patient to take breaks between treatments

Concurrent radiation and chemotherapy

257

Don't want to start treatment and take break because of __________; won't have effect on cancer cells

Rad-bio effect

258

RT treatments given in daily segments over an extended period of time, what makes RT work

Fractionization

259

8 organs of the respiratory system

Nose
Pharynx
Larynx
Trachea
Lungs
Bronchi
Hilum
Lung parenchyma

260

Portion of lung involved in gas exchange; most susceptible to radiation and what gives low TD5/5

Lung parenchyma

261

3 organs of the lung parenchyma

Alveoli
Alveolar ducts
Respiratory bronchioles

262

___-___ Gy threshold of pneumonitis in lower tissue density in lungs 1-3 months after radiation

20-25 Gy

263

Inflammation of lung tissue, clinical manifestation of vascular, epithelial, and interstitial injuries

Pneumonitis

264

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

265

Pneumonitis can be treated with _______ to alleviate symptoms but doesn't stop development

Steroids

266

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

267

Abnormal narrowing of body passage; severe inflammation of esophagus may make this permenant (lose elasticity)

Stricture

268

Inflammation of esophagus

Esophagitis

269

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

270

Higher dose per fraction because more dose = less fractions needed

Hypofractionization

271

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

272

Inflammation of the pericardium

Pericarditis

273

Membrane enclosing the heart, consisting of an outer fibrous layer and an inner double layer of serous membrane

Pericardium

274

Can see acute pericarditis appear the ____ year post treatment

1st

275

3 symptoms of pericarditis

Anterior chest pain
SOB
Low-grade fever

276

Pericarditis can develop at ____ Gy

20 Gy

277

3 ways pericarditis can be treated

Aspirin
NSAIDs
Steroids

278

Several years later if whole pericardium receives ___ Gy or more; can impede filling and reduce cardiac output (surgery only option to help)

50 Gy

279

Myocardium can develop _________________ after RT, which reduces function and is often related to a _______________

Interstitial fibrosis
Myocardial infarction (heart attack)

280

Heart muscle

Myocardium

281

Young people may develop hardening of arteries after radiation of heart and pericardium

Coronary arteriosclerosis

282

Chemo drugs, cardiotoxicity (heart toxicity) along with RT can cause CHF

Doxorubicin/adriamycin

283

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

284

2 symptoms of the breast at 2000 cGy

Erythema can develop to dry desquamation
Mild tenderness of breast

285

Shedding of the epidermis

Desquamation

286

3 symptoms of the breast at 4500 cGy

Most desquamation
Mild firmness
Edema

287

______ cGy can cause obvious fibrotic changes; smaller and harder breast and persistent changes after treatment (spider veins)

6000 cGy

288

Bundle/network of nerves from neck to armpit

Brachial plexus

289

Cervical nerves begin at ______________

Base of the skull

290

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

291

3 treatments brachial plexus is contoured for

Head and neck
Breast (axillary nodes)
Lung

292

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

293

Spinal cord injury comes ___-____ months post treatment

8-48 months

294

2 spinal cord injuries from radiation therapy

Characterized motor deficit below treatment (circuit)
Para- or quadriplegia (higher damage = quad)

295

With head and neck treatments, swallowing becomes an issue that affects nutritional intake and leads to increased ________

Morbidity

296

Dose at which mandible can develop osteonecrosis

About 50-60 Gy

297

Xerostomia seen at this dose; little recovery once salivary glands are suppressed (artificial saliva, water)

About 2000 cGy

298

Xerostomia

Drymouth

299

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

300

Squamous cells that for lips, mouth, pharynx, and larynx

Mucosa

301

Erythema of mucosa at ______ cGy

2000 cGy

302

Mouth can get thrush (whitening) at about ______ cGy; antifungal therapies

3000 cGy

303

Soft palate vulnerable and site where radiation _________ appears first

Mucotitis

304

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

305

Negative pressure and fluid in middle ear caused by obstruction of eustachian tube

Serous otitis

306

Dose that causes serous otitis due to obstruction (lack of drainage); decongestants

4000 cGy

307

3 organs that become red and inflamed during treatment of the ears

Ear canals
Drains
Eustachian tubes

308

3 sound conducting bones of the ears that can develop fibrosis later due to higher radiation doses

Incus
Stapes
Malleus

309

Clouding of lens; non-stochastic (increases with dose)

Cataracts

310

Cataracts can develop at _____ cGy over a period of years of low dose

500 cGy

311

Irradiation of this gland can lead to loss of tear creation and chronic dry eyes (artificial tears)

Lacrimal gland

312

Drains conjunctiva

Punctum lacrimal

313

Tear duct can develop fibrosis and cause obstruction leading to this

Watery eyes

314

Develops when anterior chamber of eye is irradiated

Glaucoma

315

Dose at which retina, optic nerve and chiasma can experience vision loss

5000 cGy

316

X-shaped structure formed at the point below the brain where the two optic nerves cross

Chiasma

317

Muscle that opens and closes mouth; more vulnerable to radiation and develops fibrosis before other muscles

Pterygoid muscle

318

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

319

Trismus gradually develops over doses of ________ cGy or greater

6000 cGy

320

3 symptoms that develop around doses of 5000 cGy due to swelling of supraglottic larynx

Hoarseness
Dysphagia
Airway obstruction

321

Difficulty swallowing

Dysphagia

322

Whole larynx being treated at ______ cGy = can start seeing chronic laryngeal inflammation

6500 cGy

323

Death or disintegration of a cell or tissue caused by disease or injury

Cartilage necrosis

324

After cartilage necrosis, removal of the larynx and separation of the airway from the mouth, nose, and esophagus

Laryngectomy

325

Endocrine gland, non-dosing structure

Thyroid gland

326

Underactivity of the thyroid, decreased function/hormones

Hypothyroidism

327

5 symptoms of hypothyroidism

Fatigue
Weakness
Hair loss
Depression
Memory loss

328

Disorder from hypothyroidism that causes the eyes to bulge; treat muscles with radiation to relax them back

Graves disease

329

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

330

3 organs radiation of pituitary gland impairs

Gonads
Thyroid
Adrenal function (hormone replacement, surgery through nose)

331

After we administer so much radiation to a tumor, the tumor can be seen better; can change treatment plan

Tumoritis

332

Dose at which tumor borders are visible

Around 1000 cGy

333

Obstruction of the blood supply to an organ or region of tissue, causing local death of the tissue

Infarction

334

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

335

2 abnormalities that show up on kids CT scans during/after brain treatment that cause medical problems

Dilated ventricles
Calcifications throughout brain

336

Infants/kids are more susceptible to chronic brain injury during treatment because their ______ cells are still proliferating

Mitotic

337

Brain tumors rare in first _____ years of life

2

338

Moderate to severe neurological handicaps will follow in about _____% or _____ of kids dosed/treated in brain

33% or 1/3

339

Why is palliative treatment delivered with high doses per fraction?

It gets rid of symptoms faster

340

____ 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

341

Vision loss can start to occur at _____ cGy or greater to the optic nerves and chiasm

4500 cGy

342

Temporary hair loss occurs at about _____ cGy usually around the first two weeks of treatment (____-____ fractions)

1000 cGy; 10-12 fractions

343

Hair regrowth will usually occur as long as we don't hit doses of ___-___ Gy where it can be permanent

40-45 Gy

344

Skull radionecrosis _____ unless doses are high

Rare

345

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

346

Doses to foot greater than ___-___ Gy should be avoided in elderly because of slowed healing process

35-40 Gy

347

Avoid irradiating epiphysis in kids, ____ Gy can affect growth

20 Gy

348

Radiotherapy of a surgically dissected axilla and supraclavicular region leads to this

Lymphedema

349

Halves of body, less toxic

Hemibody

350

Radiation given in a way to cover whole body

Total body irradiation (TBI)

351

2 forms of TBI

Low dose
High dose

352

2 reasons TBI is done

Suppress patient's immune system
Prevent rejection of donor bone marrow after a bone marrow transplant

353

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

354

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

355

2 types of high dose TBI

Single
Fractionated

356

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

357

6 symptoms patient can experience from fracionated high dose TBI

Radiation induced enteritis
Xerostomia
Diffuse (spread-out) skin erythema
Temporary hair loss
Sterilization
Cataracts

358

TD5/5 (3/3 volume) and side effect of kidney

2300 cGy - clinical nephritis

359

TD5/5 (3/3 volume) and side effect of symptomatic bladder contracture and volume loss

6500 cGy - symptomatic bladder contracture and volume loss

360

TD5/5 (3/3 volume) and side effect of femoral head

5200 cGy - necrosis

361

TD5/5 (3/3 volume) and side effect of TMJ mandible

6000 cGy - marked limitation of joint function

362

TD5/5 (3/3 volume) and side effect of rib cage

5000 cGy - pathologic fracture

363

TD5/5 (3/3 volume) and side effect of brain

4500 cGy - necrosis, infarction

364

TD5/5 (3/3 volume) and side effect of brain stem

5000 cGy - necrosis, infarction

365

TD5/5 (3/3 volume) and side effect of optic nerve I & II

5000 cGy - blindness

366

TD5/5 (3/3 volume) and side effect of chiasma

5000 cGy - blindness

367

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

368

TD5/5 (3/3 volume) and side effect of brachial plexus

6000 cGy - clinically apparent nerve damage

369

TD5/5 (3/3 volume) and side effect of eye lens I & II

1000 cGy - cataract requiring intervention

370

TD5/5 (3/3 volume) and side effect of eye retina I & II

4500 cGy - blindness

371

TD5/5 (3/3 volume) of ear mid/external that causes acute serous otitis

3000 cGy

372

TD5/5 (3/3 volume) of ear mid/external that causes chronic serous otitis

5500 cGy

373

TD5/5 (3/3 volume) and side effect of parotid I & II

3200 cGy - xerostomia

374

TD5/5 (3/3 volume) of larynx that causes cartilage necrosis

7000 cGy

375

TD5/5 (3/3 volume) of larynx that causes laryngeal edema

4500 cGy

376

TD5/5 (3/3 volume) and side effect of lung I

1750 cGy - pneumonitis

377

TD5/5 (3/3 volume) and side effect of heart

4000 cGy - pericarditis

378

TD5/5 (3/3 volume) and side effect of esophagus

5500 cGy - clinical stricture/perforation

379

TD5/5 (3/3 volume) and side effect of stomach

5000 cGy - ulceration perforation

380

TD5/5 (3/3 volume) and side effect of small intestine

4000 cGy - obstruction perforation/fistula

381

TD5/5 (3/3 volume) and side effect of colon

4500 cGy - obstruction perforation/ulceration/fistula

382

TD5/5 (3/3 volume) and side effect of rectum

6000 cGy - severe proctitis/necrosis/fistula, stenosi

383

TD5/5 (3/3 volume) and side effect of liver

3000 cGy - liver failure/damage

384

TD5/5 (3/3 volume) and side effect of spleen

3000-4000 cGy - hypofunction