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RAD 370 - Techniques and Applications > Quiz 3 > Flashcards

Quiz 3 Flashcards

1
Q

3 main types of skin cancer

A

Basal cell
Squamous cell/cutaneous squamous cell
Malignant melanoma

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2
Q

Slower form of skin cancer, not very aggressive and doesn’t tend to metastasize
Most prevalent cancer in humans
If untreated, can create damage
Can appear anywhere on body; common on head, neck, and other sun-exposed areas
Younger with sunburns at greater risk
1-2 million cases yearly, RT when cosmesis is ideal (face)
Treatment technique selected depends on factors such as previous methods of treatment if any, location on body, risk of recurrence and metastasis, and the volume of tissue invasion
Surgery performed to remove nonmelanoma skin cancers from areas where cosmesis is not a factor, scarring is acceptable, and patient wants to expedite results

A

Basal cell (BCC)

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3
Q

Faster growing and more dangerous than basal but not as much as melanoma; tends to metastasize
Can appear anywhere on body; common on head, neck, and other sun-exposed areas
Younger with sunburns at greater risk
1-2 million cases yearly, RT when cosmesis is ideal (face)
Treatment technique selected depends on factors such as previous methods of treatment if any, location on body, risk of recurrence and metastasis, and the volume of tissue invasion
Surgery performed to remove nonmelanoma skin cancers from areas where cosmesis is not a factor, scarring is acceptable, and patient wants to expedite results

A

Squamous cell carcinoma (SCC)

Cutaneous squamous cell

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4
Q

Basal to squamous cell ratio in men to women

A

5:1 men, 10:1 women

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5
Q

One of the most lethal forms of skin cancer and very common
Most common sites: women’s legs and men’s trunk and face, can also occur in any melanin sites such as eyes, eyelids, mucosa, oral cavity, and anus
Key to treatment is treating it before it metastasizes; palliation; cure usually limited to surgical resection
Chemo and immunotherapy to prevent metastasis or if it’s already metastasized
RT limited to palliation for metastatic dose; radioresistant but can be used adjuvant to surgery or as treatment if surgery is not an option
Superficial, electron, or total skin electron irradiation (TSEI)

A

Malignant melanoma

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6
Q

Skin cancer that usually appear as firm, non-tender, pink-red lesion; nodular
Distinction has climbed and now has its own staging system
Rare, high rate of recurrence and morbidity greater than melanoma
In sun-exposed sites
Chemo and RT combination treatment if too expensive for surgery

A

Merkel cell

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7
Q

Stanford technique: treatment with 12 fields or 6 dual fields; extend SSD to 300-400 cm to include entire body
Using electrons, patient exposed
Mycosis fungoides

A

Total skin electron irradiation (TSEI)

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8
Q

Metastatic melanoma TSEI dose

A

36 Gy in 9 weeks, 1 Gy per fraction, 4 days a week

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9
Q

5 types of surgical treatments for basal and squamous cell cancers

A 
Often the original excisional biopsy contains all of the tumor with acceptable margins
Mohs surgery
Electrodesiccation
Cryosurgery
Photodynamic therapy
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10
Q

Often used to treat BCC and early SCC; with local anesthesia, the cancer is scooped out with a curette and the destruction of any remaining tumor cells and process of bleeding is carried out with a probe emitting a high frequency electric current to destroy tissue and cauterize blood vessels

A

Electrodesiccation

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11
Q

Surgery with best success rate for BCC and SCC

A

Mohs sugery

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12
Q

Instrument in the form of a loop, ring, or scoop with sharpened edges

A

Curette

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13
Q

Treatment of early nonmelanoma skin lesions with liquid nitrogen or carbon dioxide applied to a lesion, lowering its temperature and thereby freezing and killing abnormal cells

A

Cryosurgery

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14
Q

Photosensitizing agent is injected into the body and absorbed by all cells; light from a laser is directed on the tumor area and causes a reaction within the cells that contain the photosensitizing agent that destroys the cells

A

Photodynamic therapy

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15
Q

4 factors that affect the choice between the use of electrons and kV x-rays for the treatment of skin cancer

A

Comes down to what is in clinic, may not have superficial/orthovoltage machine; electrons come from linac
Size of treatment volume, depth of lesion
Underlying anatomical structures, use electrons if critical structure under lesion
Physician preference

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16
Q

_________ have poor small dose field and don’t get good dose coverage
kV x-ray photons allow the target volume to be covered with a smaller field size than with that of a field producing similar effects near the skin surface through the use of electrons because of electron field physical properties
________ get good average to high dose, sharper beam edge

A

Electrons, photons

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17
Q

Surface dose less than ___-___% is generally unacceptable; ___-___% isodose lines encompassing what is being treated (always try to get 100% isodose line to lesion)

A

90-95%

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18
Q

With photons regardless of energy, Dmax always at ________; high energy electrons = ____ surface dose, low energy electrons = ____ surface dose

A

Surface; high, low

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19
Q

Deep tissue dose ______ for photons than electrons
Electrons have rapid falloff, kV x-rays penetrate much deeper and affect a greater volume of underlying tissue
Use electrons when critical structures beneath lesion

A

Higher

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20
Q

No significant difference exists between bone and soft tissue doses for electrons
Absorbed dose is _______ in bone and cartilage than in soft tissue with the use of kV x-rays; photoelectric effect dependant on Z^3/E^3

A

Higher

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21
Q

1 cm of bone = ____ cm of tissue; 1 cm of lung = ____ cm of tissue because of density

A
  1. 65 cm

0. 25 cm

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22
Q

Excellent or good cosmesis in ___% of patients treated with kV x-rays, compared with ___% of patients treated with electrons

A

95%

80%

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23
Q

Cosmetic results were superior for patients in whom less than ___% of the dose was delivered with bolus; with electrons bolus _______ surface dose and _______ cosmesis

A

50%
Increases
Decreases

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24
Q

Depth at which the tangent plotted through the steepest section of the electron depth dose curve intersects with the extrapolation line of the brems tail
Range of electrons (10%), where they stop/dissipate; electrons/2

A

Practical range (RP)

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25
Q

6X loses ___% per cm; 18X loses ___% per cm

A

3%; 2%

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26
Q

Typical SSDs for photons and electrons

A

13-50 cm for photons
110-115 cm for electrons (typical = 105 cm), may need to increase distance for thicker/larger body part (ex: shoulder in the way)

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27
Q

Typical margin surrounding skin cancer, can do electrons clinically on treatment machine
For small basal cell, ___ cm margin adequate because it’s not aggressive if superficial

A

2 cm

1 cm

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28
Q

Inner ear less than ______ cGy

A

1000 cGy

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29
Q

A single dose of ______ cGy may cause cataracts

A

200 cGy

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30
Q

Inflammation of cartilage

A

Chondritis

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31
Q

3 doses to small areas of skin cancer

A

Small dose of 2000 cGy in 1-2 days, 1000 cGy per 1-2 fractions
3000 cGy in 5 fractions; 5-7 days, 600 cGy per day
4000 cGy in 10-16 fractions, 300 cGy per day over 16-28 days; best cosmetic result because dose spread out

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32
Q

Lip cancer dose

A

6000 cGy in 6 weeks, 250 kV

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33
Q

3 doses to large areas of skin cancer

A

4500 cGy over 15-18 fractions, 230-300 cGy per day over 21-30 days
5000 cGy over 20-25 fractions over 28-35 days
6000 cGy (60 Gy) over 20-30 fractions, 200-300 cGy per fraction; 28-40 days

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34
Q

Primary treatment dose for malignant melanoma

A

5000 cGy, 200 cGy per fraction; 25 treatments and boost with 1000-1500 cGy = 6000-6500 cGy

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35
Q

Connective tissue of extraskeletal system outside bone
Can arise anywhere in body, most common site: extremities, retroperitoneum, trunk, visceral areas, head and neck
Important to treat en face with these tumors because if gantry is angled tumor could be missed at depth

A

Soft tissue sarcoma (STS)

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36
Q

3 STS treatment techniques

A

Multimodality treatments: variety of surgery, RT, with or without chemo
Surgery: pathology and remove disease, aggressive or with combination RT and chemo
Radiation therapy

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37
Q

4 advantages of preoperative RT for STS

A

Biological effects better, scar tissue not oxygenated/hypoxia is absent
Tumor shrinkage, less aggressive surgery
Smaller treatment volume because we know no seeding/implantation; surgical contamination reduced and local control leads to smaller field size and decreased morbidity, fibrosis, etc.
Give initial dose, do surgery, and then boost with postoperative margins

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38
Q

2 disadvantages of preoperative RT for STS

A

Affects healing, wait 6 weeks before surgery

Don’t know type or whole location/extent of disease

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39
Q

STS margin, and boost field margin

A

3-6 cm margin

Boost: tumor bed and scar with 2-3 cm margin

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40
Q

Leave ___-___ cm margin of compartment of extremity untreated to avoid lymphedema and fibrosis

A

1-3 cm

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41
Q

Equivalent rectangular field dimensions of the open or treated area within the collimator field dimensions, actual blocked area treated
Only includes what’s being treated, doesn’t include open air

A

Effective field size (EFS)

Blocked field size (BFS)

42
Q

Collimated field

A

Actual field size

43
Q

Appears as multi-colored blotches/lumps on skin in HIV and AIDS patients

A

Kaposi’s sarcoma

44
Q

Margins, energy, and dose for Kaposi’s sarcoma

A

1.5-2 cm margin
Low energy 4-6 MV photons
1000 cGy with boost of 2500 cGy; single dose of 700 cGy but get lasting results with 2000 cGy

45
Q

Postoperative energy, EBRT dose, and dose with no preoperative regimen for STS

A

Low energy, max 6X; thicker area (buttock, abdomen) = 10-15 MV
EBRT: 4500 cGy, cumulative dose (CD) = 63-6500 cGy
No preop: 60-66 Gy

46
Q

STS preoperative dose

A

4500-5580 cGy 6-8 weeks before

47
Q

3 methods for postoperative boost with 50 Gy before surgery for STS

A

Brachytherapy (place catheters during surgery, can be removed after) with 12-20 Gy = 62-70 Gy total, about 3 days after surgery
IORT: 10-16 Gy immediately after removal of tumor = 60-66 Gy
EBRT: 16-18 Gy for microscopic disease = 66-68 Gy; 20-26 Gy for gross residual disease = 70-76 Gy

48
Q

Brachytherapy source, primary treatment dose, boost dose with dose rate, and dwell time for STS

A

Source: interstitial iridium-192, 4-7 days after surgery
Primary: 4500 cGy
Boost: 20-25 Gy with dose rate of 40 cGy per hour
Dwell time: 2000/40 = 50-62.5 hours

49
Q

Head and neck STS initial dose and electron dose

A

Initial: 4500 cGy (spinal cord)
Electrons: 60 Gy

50
Q

Chemo drug for STS

A

Doxorubicin

51
Q

Malignancies involving bone, connective tissue, blood vessels, etc.
Most common factor is pain accompanied by swelling, engorged veins, etc.
Important to treat en face with these tumors because if gantry is angled tumor could be missed at depth

A

Bone tumors

52
Q

2 types of bone cancer

A

Primary: vast array of biological behaviors
Metastatic: more frequent

53
Q

7 types of bone tumors

A 
Osteosarcoma
Chondrosarcoma
Fibrosarcoma
Ewing's sarcoma
Multiple myeloma
Giant cell tumor
Metastatic bone disease
54
Q

Most common osteo-malignant primary bone cancer; 2 to 1 ratio of men versus women
Radioresistant; doses necessary for a clinical response often result in tissue damage and subsequent amputation
Can use radiation if surgery not an option, cure unlikely; palliative RT for pain control to prevent spread

A

Osteosarcoma/osteogenic

55
Q

Primary bone cancer but can occur as secondary
Most common in adults, 40% of adult bone tumors
Men to women ratio of 2 to 1
Treatment of choice is surgery, radiation doesn’t play role because it’s radioresistant but used in high doses for patients with inoperable disease

A

Chondrosarcoma

56
Q

Rare primary bone malignancy, slight male predominance
Fibrous/connective tissue, locally aggressive
Rare disease
Wide radical excision aggressive surgery, still high rate of recurrance

A

Fibrosarcoma

57
Q

Bone cancer most common in 1st decade of life, more predominant in males
Usually highly malignant, arises is bone diaphysis/shaft and can occur in soft tissue
Multimodality approach because of age of patients, want greatest chance of cure: surgery, chemo, and RT
Aggressive therapy including multiagent chemo and adjuvant RT has resulting in positive outcomes in adolescents; more radiosensitive than other bone tumors
Avoid epiphyseal plate or growth could be affected

A

Ewing’s sarcoma

58
Q

Primary bone cancer, affects bone marrow plasma cells
Non-osseous (blood, etc.) arises from marrow
1.5 men to 1 woman
Usually presents as disseminated, lytic lesions
Treatment for palliation: chemo and RT; incurable but can see long-term remission
Before RT primary treatment: in localized presentation, palliate pain, prevent fracture, and spinal cord compression

A

Multiple myeloma

59
Q

Commonly arise in metaphysis and epiphysis in long bones of young adults; extremely aggressive, benign
Usually of bone
Surgery treatment of choice; RT for inoperable disease and palliation, may need to use bolus

A

Giant cell tumor

60
Q

Metastasizes from primary cancer (lung, breast, etc.) to bone
Commonly treated in RT clinic, increase mobility
Gives rise to pain, pathological fractures, frequent neurological problems (can lead to paralysis), and spinal compression (oncologic emergency, needs to be treated quickly to prevent loss of sensory sensation and paralysis that could become permanent)

A

Metastatic bone disease

61
Q

4 important diagnostic tools for detection of bone sarcomas

A

Radiograph (most), can be mistaken as trauma and are difficult to detect
CT helps detect growth and invasiveness
MRI for soft tissue and vascular structures
Bone scans with technetium-99

62
Q

Multiple myeloma TBI and hemibody (HBI) total dose, margins of spine, EBRT dose, and palliative dose with boost

A

TBI: 750-850 cGy; HBI: higher dose per fraction and less toxicity to marrow
Spine margins: 2 vertebral bodies above and below; ex: disease in T3-T8 = treat T1-T10
EBRT: 1500-2000 cGy
Palliative: 30 Gy and boost of 1000 cGy to smaller area

63
Q

Osteosarcoma dose, and post-operative dose

A

Dose: 60-65 Gy in 30-35 fractions, 8 weeks

Post-op: 64-68 Gy to high risk sites, unresectable tumor up to 70 Gy

64
Q

Radionecrosis at ______ cGy in 20 days or less

A

8000 cGy

65
Q

6 adjuvant chemo drugs for unresectable osteosarcoma

A 
Cisplatin
Epidoxorubicin
Ifosfamide
Cyclophosphamide
Etoposide
Bleomycin
66
Q

Chondro-

A

Cartilage

67
Q

Chondrosarcoma dose, preoperative dose, and unresectable tumor/no surgery dose

A

Dose: 6000 cGy in 4-6 weeks
Pre-op: 40-55 Gy
Unresectable: 70 Gy

68
Q

Radiation dose and field technique to stop recurrence of fibrosarcoma

A

66-70 Gy with shrinking field technique

69
Q

Reduces the treated field area one or more times during the course of treatment in response to a tumor that reduces in size and/or the need to limit doses to normal structures; initial and boost field

A

Shrinking field technique

70
Q

Giant cell tumor dose and local control rate

A

Dose: 3500 cGy and 15 treatments, 45-55 Gy in 5-6 weeks

Local control rate: 80%

71
Q

Ewing’s dose and boost margins

A

55-60 Gy; initially 4500 cGy with two 500 cGy boosts, 1st with 5 cm margin and 2nd with 1 cm margin (margins with less than 5 cm show greatest recurrence, use larger fields)

72
Q

Don’t want to go over ___% hot spot

A

110%

73
Q

Isodose goes direction towards ______ of wedge

A

Toe

74
Q

3 metastatic bone disease doses (1 with boost and 2 with lower total dose but higher dose per fraction because the patient has short time left, come in less often)

A

30 Gy in 10-15 treatments with 1000 cGy boost
24 Gy in about 6 fractions
20 Gy in 5 fractions = 400 cGy per fraction

75
Q

2 predominant cancers of lymphoreticular system

A

Hodgkin’s disease

Non-Hodgkin’s lymphoma (NHL)

76
Q

Spreads predictably, systemic
Reed-Sternberg cells must be present
Treatment technique: RT (less common), surgery (biopsy and possible debulking), and chemo (used in combination with RT)
Major lymph node (LN) groups can be treated with large mantle fields: AP and PA; take two separate fields
Mantle and paraaortic field treated sequentially (a few weeks) because large fields greatly tax patient (prophylactic)
Simulation: patient straight on table and in immobilization device because large fields, laser alignments coincide with axis of rotation of machine; smaller field if chemo and RT

A

Hodgkin’s disease

77
Q

Standard treatment for stage 1 & 2 Hodgkin’s

A

ABVD alone or in combination with 25-30 Gy involved field irradiation

78
Q

Calculates dose in an irregularly shaped field; ex: mantle field = irregular field

A

Clarkson algorithm

79
Q

Position with patient supine, chin extended, and arms bent by side with hands on hips which puts axillary LNs away from lungs, shield lungs
Large field requires aggressive immobilization
Alpha cradles and vac-locks, minimal clothing, etc.

A

Akimbo

80
Q

Irradiation that includes only the affected LN region

A

Involved field irradiation

81
Q

Typical Hodgkin’s dose and energy

A

25-30 Gy with chemo before (ABVD, Stanford V, BEACOPP, etc.)

6-10 MV photons provides skin sparing effect, abdomen up to 15 MV

82
Q

5 Hodgkin’s ports

A 
Mantle
Periaortic/para-aortic
Pelvic
Hockey stick
Chimney
83
Q

2 ports that make up the inverted Y

A

Periaortic/para-aortic

Pelvic

84
Q

Superior/upper border follows line of mandible and cuts through tragus of ear
Inferior border at T9-T10 (diaphragm)
Lateral border: flash/extends off side to include axilla
Caudal extent tattooed because gap calculation between this and para-aortic field

A

Mantle port

85
Q

Superior/upper border: inferior border of mantle plus calculated gap
Posterior/inferior: L4-L5 interspace/aortic bifurcation
Lateral: 5 cm off midline to include transverse processes
Can also include spleen but if resected can include splenic pedicle at T11/T12

A

Periaortic/para-aortic port

86
Q

Bottom of ischial tuberosity (BIT) or 2 cm below bottom of obturator foramen (BOF)

A

Pelvic port

87
Q

Treat one side/ipsilateral side of inverted Y, seminoma (testicular disease)

A

Hockey stick port

88
Q

Port for entire pelvis

A

Chimney

89
Q

Makes sure there’s no overlap of two fields over specific structure, ex: spinal cord

A

Gap calculation

90
Q

Gap calculation formula

A

1/2(L1)(d/SSD) + 1/2(L2)(d/SSD)

91
Q

5 blocks for involved-field irradiation treatment of Hodgkin’s

A

Initially block lungs and femoral heads for AP/PA
AP = larynx block, PA = cervical
At 1500 cGy add an apical heart block
At 3000 cGy add subcarinal heart block
At 36-3800 cGy add T-spine block on PA only

92
Q

Involved-field irradiation of Hodgkin’s total dose

A

36-3800 cGy, 150-200 cGy per fraction usually even weighted AP/PA

93
Q

Paraaortic Hodgkin’s treatment dose

A

36-4400 cGy

94
Q

2 paraaortic Hodgkin’s treatment shielding considerations

A

If liver in treatment field, 50% blocking (1 HVL)

Testicular clam shield for scatter (10% of dose can get to testicles), up to 0.75-3% reduced

95
Q

2 chemo agents for Hodgkin’s

A

MOPP: not as common
ABVD: better results and less toxic

96
Q

MOPP

A

Nitrogen mustard
Vincristine
Procarbazine
Prednisone

97
Q

ABVD

A

Doxorubicin
Bleomycin
Vinblastine
Dacarbazine

98
Q

Disease of lymph tissue can arise anywhere lymph is travelling
Chemo with or without RT because of sporadic spread, systemic treatment works best; radiation to site of involvement

A

Non-Hodgkin’s Lymphoma (NHL)

99
Q

Field for no mediastinal involvement; mediastinum not usually involved with NHL but if it is, can treat with mantle field

A

Mini-mantle field

100
Q

Typical, palliative, and dose with least possibility of recurrence of NHL

A

Typical: 40-50 Gy
Palliative: 20-30 Gy
Least possibility of recurrence: 3500 cGy or more

101
Q

Chemo drugs for NHL

A

Alkylating agents: CHOP or CVP

RAD 370 - Techniques and Applications (6 decks)

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