P&P Flashcards
1
Q
TRUE OR FALSE
1 Gy=100J/kg
A
FALSE–1 Gy=1J/kg
2
Q
describe scatter and talk about how it effects dose
A
scatter ends up being a majority of dose a patient receives. it occurs when the primary beam is interfered with and causes secondary beams/scatter. it is caused by blocks/wedges/electrons already in patient’s body.
3
Q
________ occurs at the point at which the energy of the electrons coming to rest equals the energy of electrons set into motion by new photon interactions.
A
Dmax
4
Q
the ratio of the absorbed dose at a given depth in phantom to the absorbed dose at the same point in free space
A
TAR (tissue air ratio)
5
Q
the ratio of absorbed dose at a given depth to the absorbed dose at a fixed reference depth
A
backscatter factor
6
Q
the ratio of absorbed dose at any given depth in a phantom to the dose at the same point at a reference depth in phantom
A
TPR (tissue phantom ratio)
7
Q
TAR at the level of Dmax
A
PDD (% depth dose)
8
Q
the ratio of scattered dose at a given point in a medium to the dose in air at the same point
A
SAR (scatter air ratio)
9
Q
describe what it means if you have a wedge transmission factor of 94%
A
94% of the beam is transmitted & 6% of the beam is attenuated
10
Q
TRUE OR FALSE
having a tray in the path of the radiation beam means that you will have to increase the number of MUs in your calculation
A
TRUE
11
Q
what does it mean when you have a wedge angle of 30 degrees
A
the angle between the isodose line and a line perpendicular to it is 30 degrees
12
Q
calculate the equivalent square of 12.7 x 8.3 field size
A
4A/P = 4 (105.41) / 42 = 421.64 / 42 = 10.04 x 10.04 field size
13
Q
what four factors are PDD dependent upon? describe how each of them effect PDD
A
energy ^ PDD ^
field size ^ PDD ^
SSD ^ PDD ^
depth ^ PDD v
14
Q
beam energy=200kV
Dmax=?
A
0.0
15
Q
beam energy=1.25MV
Dmax=?
A
0.5
16
Q
beam energy=4MV
Dmax=?
A
1.0
17
Q
beam energy=6MV
Dmax=?
A
1.5
18
Q
beam energy=10MV
Dmax=?
A
2.5
19
Q
beam energy=18MV
Dmax=?
A
3.5
20
Q
beam energy=20MV
Dmax=?
A
4.0
21
Q
what field arrangements is PARALLEL OPPOSED FIELDS used to treat? angles?
A
whole abdomen
AP/PA, LAO/RPO, left lat/right lat
22
Q
what field arrangements is FOUR FIELD BOX used to treat? angles?
A
pelvis
AP/PA, left lat/right lat, RAO/LPO/LAO/RPO
23
Q
what field arrangements is THREE FIELD used to treat? angles?
A
colon, rectum, pancreas
RPO/LPO/AP
24
Q
what two things must occur for clinically useful electrons to be produced in the head of the linear accelerator?
A
the target and flattening filter must be removed from the path of the beam AND the electron gun current must be lowered
25
describe the characteristic shape of electron isodose lines
balloon out laterally
26
TRUE OR FALSE
placing a high Z number material between the tissue and the shield helps to minimize the backscatter dose when treating with electrons
FALSE--a *low* Z number material minimizes back scatter
27
when might it be important to gap an electron field
when you have abutting fields. to avoid an over/underdose/hot spots
28
what is the significance of the build-up region
this area is at risk for being underdosed
29
calculate the following for a 12 MeV electron beam:
| 80% isodose line
12 / 3 = 4 cm
30
calculate the following for a 12 MeV electron beam:
| 90% isodose line
12 / 4 = 3 cm
31
calculate the following for a 12 MeV electron beam:
| range
12 / 2 = 6 cm range
32
the rate at which an electron beam loses energy is approximately
2 MeV/cm
33
in what part of the lung are primary squamous cell carcinomas usually found?
centrally
34
identify the number one cause of lung cancer
tobacco
35
which of the following mediastinal lymph nodes are classified as superior mediastinal nodes?
upper paratracheal and pretracheal
36
symptoms associated with regional disease include
dysphagia and cyanosis/dyspnea and superior vena cava syndrome
37
this form of lung cancer occurs most often in women
adenocarcinoma
38
the most significant variables that affect lung cancer prognosis are:
stage of the disease, clinical performance status, and weight loss
39
which form of lung cancer is staged as limited or extensive?
small cell lung cancer
40
in order for a true pancoast tumor to be diagnosed as person must be clinically present with certain symptoms, identify 2 of these symptoms
pain around the shoulder and down the arm, atrophy in hand muscles, horner's syndrome, bone erosion in the ribs and sometimes the vertebral column
41
list 5 common sites for lung cancer to metastasize to
liver, brain, bone, other lung, spleen
42
TRUE OR FALSE
| only 35% of lung cancer patients are surgical candidates.
FALSE--*20%* of lung cancer patients are surgical candidates
43
the primary lymph nodes that drain the lungs are:
mediastinal nodes, superior mediastinal nodes, inferior mediastinal nodes
44
name the disorder associated with lung cancer characterized by a clubbing of the distal phalanges of the fingers
Hypertrophic pulmonary osteoarthropathy
45
what is the standard of care for patients with local disease or those who are not surgical candidates?
radiation therapy and chemo
46
doses of ______ can provide symptomatic relief for brain mets from lung cancer
3000 to 4000 cGy in 10 to 15 fractions
47
if the tumor is located in the upper lobe, what lymph nodes need to be included in the treatment field?
superclav lymph nodes
48
TRUE OR FALSE
| boost fields are usually delivered to the GTV and involved lymph nodes
FALSE--boost delivered to GTV *excludes* involved lymph nodes
49
what are the three most important organs to consider when treating the lung?
spinal cord, heart, other lung
50
an acute side effect of lung irradiation is
esophagitis
51
what is the most effective single agent chemotherapeutic drug used to treat lung cancer
cisplatin
52
identify 5 epidemiological factors of lung cancer
2nd most common cancer in men & women
occurs in older people
black men 40% more likely than white men
risk of development for men is 1:13, women is 1:16
accounts for 14% of all new cancer diagnosis
53
identify 5 etiological factors of lung cancer
significant tobacco exposure
occupational exposure
fumes from coal, tar, nickel, chromium, and arsenic
radioactive materials that give off alpha emissions
radon exposure
uranium exposure
54
what is a typical total dose when treating superior vena cava syndrome?
4500 to 5000 cGy
55
TRUE OR FALSE
| the bifurcation of the trachea is located at the level of T4-T5
TRUE
56
which of the following symptoms appear in 2/3 of ALL patients
anemia and thrombocytopenia
57
80% to 85% if ALL is characterized by
B cell markers
58
identify the two sanctuary sites for ALL
CNS and testes
59
name the two staging systems used to stage CLL
Rai & Binet
60
briefly describe the cells that leukemia develops from
begins with pluripotent stem cells (myeloid & lymphoid). during differentiation and maturation, hematopoietic or lymphopoietic progenitors is uncontrolled and greatly accelerated, resulting in incomplete or defective cellular maturation.
61
TRUE OR FALSE
| 10% to 20% of people diagnosed with AML exhibit some form of chromosomal abnormalities
FALSE--*30 to 50%* diagnosed with AML have chromosomal abnormalities
62
what genetic disorder increases a persons chance of developing ALL to 10 to 30 fold?
down syndrome
63
what are we trying to achieve when performing a total body irradiation
preparation for bone marrow transplant. kills overproductive cells
64
what procedure must be performed in order to give a definitive diagnosis of leukemia
bone marrow biopsy
65
AML/ALL/CML/CLL:
a person with a 1st degree relative with this type of leukemia has a 2 to 7 fold increased chance of developing the same leukemia
CLL
66
AML/ALL/CML/CLL:
| 95% of cases of this leukemia express the philadelphia chromosome
CML
67
AML/ALL/CML/CLL:
| approximately 80% of adults with acute leukemia have this subtype
AML
68
AML/ALL/CML/CLL:
| TBI is not used as a treatment for this type of leukemia
CLL
69
AML/ALL/CML/CLL:
| an allogenic bone marrow transplant is the only cure for this form of leukemia
CML
70
AML/ALL/CML/CLL:
| this form of leukemia impairs erythropoiesis
CML
71
AML/ALL/CML/CLL:
| this form of leukemia is the most common pediatric malignancy
ALL
72
AML/ALL/CML/CLL:
| symptoms of this form of leukemia include: night sweats, weight loss, enlarged spleen, and lymphadenopathy
CLL
73
AML/ALL/CML/CLL:
| this form of leukemia can be treated with chemotherapeutic agents such as gleevec, interferon and hydroxyurea
CML
74
AML/ALL/CML/CLL:
| this type of leukemia is identified by the circulation of auer rods in the cytoplasm of the leukocyte
AML
75
AML/ALL/CML/CLL:
| this leukemia is a disease of the older population with the average age of 70 at the time of diagnosis
CLL
76
AML/ALL/CML/CLL:
if more than 30% blast cells are present in a bone marrow biopsy sample, a positive diagnosis of this form of leukemia is made.
AML
77
AML/ALL/CML/CLL:
| the t cell variety of this leukemia tends to be more aggressive
CLL
78
the most common testicular tumor pathology is
seminoma
79
70% of prostate carcinomas develop in which zone
peripheral
80
TRUE OR FALSE
| 95% of prostate tumors are squamous cell in origin
FALSE--95% of prostate tumors are *adenocarcinomas*
81
an elevation of what protein would signal a diagnosis of nonseminoma
alpha-fetoprotein (AFP)
82
what isotopes are commonly used for prostate seed implants
palladium 103 and iodine 126
83
where is the most common site of metastatic spread from renal cell carcinoma?
lung
84
TRUE OR FALSE
patients who suffer from long term catheterization and renal calculi are at greater risk for developing adenocarcinoma of the bladder
FALSE--patients who suffer from long term catheterization and renal calculi are at greater risk for developing *squamous* cell carcinoma of the bladder
85
what is considered a normal PSA level
< 4 ng/mL
86
what two organs does nonseminoma tend to metastasize to?
lung, liver
87
a man with a PSA > 20 is a predictor that would indicate the patient should undergo what form of treatment
hormonal therapy
88
what is the most significant cause of bladder cancer
cigarette smoking
89
which lymph nodes are the most common site of spread for penile cancer
inguinal lymph nodes
90
what genetic disease has renal cell carcinoma been linked to
von hippel lindau
91
TRUE OR FALSE
| prognosis for carcinoma of the urethra varies depending based on the location of the primary lesion
TRUE
92
TRUE OR FALSE
| cisplatin based chemotherapy is the mainstay of treatment for nonseminoma
TRUE
93
identify two important prognostic factors of renal pelvic and urethral cancer
stage and grade
94
what are the three subtypes of seminoma
classic, anaplastic, spermatocytic
95
list three ways a person with penile cancer might present clinically
presence of phimosis may obscure the primary lesion, secondary infection and foul smell, inguinal lymph nodes are palpable in 30 to 45% of patients.
96
bladder cancer primarily spreads via _______
direct extention
97
why would including or excluding the seminal vesicles in a treatment field need to be taken into account when planning a prostate treatment?
increases dose to rectum
98
how might a person with T1 or T2 renal cell carcinoma be treated
radical nephrectomy
99
identify 4 epidemiologic factors of renal cell carcinoma
represents 2% of all new cancers and cancer deaths annually
average age at time of diagnosis is 55 to 60 years
men are more likely to develop the disease than women at a rate 2:1
environmental, occupational, hormonal and genetic factors have been linked
100
how are gleason scores determined
2 most prominent types of cells in sample are rated and added together. lower scores have better prognosis.
101
which form of GYN malignancy is the most common
endometrial
102
which form of GYN malignancy has the highest rates of death due to the disease
ovarian
103
what staging system is used for all GYN malignancies
FIGO (international federacy of gynocology and obstetrics)
104
where is the most common location for vulvar carcinoma to develop
labia majora
105
TRUE OR FALSE
| adenocarcinoma accounts for 80% to 90% of all vaginal carcinomas
FALSE--*squamous* cell carcinoma accounts for 80% to 90% of all vaginal carcinomas
106
identify three presenting signs and symptoms of cervical cancer
abnormal bleeding, discomfort during intercourse, nonspecific GI symptoms
107
which of the following are risk factors for endometrial carcinoma
late menopause and obesity
108
average age of OVARIAN
between 50 and 70
109
average age of ENDOMETRIAL
median age is 61
110
average age of CERVICAL
younger than 50
111
average age of CLEAR CELL VAGINAL
19
112
average age of VULVAR
7th and 8th decade
113
75% of women with endometrial carcinoma clinically present with which of the following symptoms?
post-menopausal bleeding
114
80% of women with this form of carcinoma will have abdominal cavity involvement at the time of diagnosis
ovarian
115
where does vaginal carcinoma most commonly arise
posterior upper third
116
lymphatic spread from cervical carcinoma is known to be orderly. place lymph node involvement in the correct order.
parametrial, pelvic, common iliac, periaortic.
117
serum CA125 levels may be elevated in what form of carcinoma
ovarian
118
TRUE OR FALSE
| 90% of ovarian carcinomas are clear cell
FALSE--90% of ovarian carcinomas are *epithelial* cell
119
when treating vaginal cancer with a vaginal cylinder, what isotope is typically used
cesium 137
120
the most common site for a woman to develop skin cancer is
legs
121
afterloading techniques were developed primarily to reduce the
exposure to personnel
122
this form of treatment has been the mainstay in the treatment of cervical brachytherapy: cancer for over 50 years
intracavitary
123
brachytherapy: places radioactive material within blood vessels
intravascular
124
brachytherapy: rigid needles or flexible tubes are placed directly into the tumor
interstitial
125
brachytherapy: can be used to treat the esophagus, trachea, rectum, bronchi
intraluminal
126
TRUE OR FALSE
| activity is directly proportional to the decay constant, as decay increases, activity increases
FALSE--decay increases, activity *decreases*
127
describe the differences between LDR and HDR. identify 2 advantages of one over the other
LDR has a long history of use and success. HDR can be as effective, higher dose in shorter amount of time, less expensive.
128
average energy for RADIUM 226
.830 MeV
129
average energy for CESIUM 137
.662 MeV
130
average energy for COBALT 60
1.253 MeV
131
average energy for IODINE 125
.028 MeV
132
average energy for GOLD 198
.412 MeV
133
average energy for IRIDIUM 192
.380 MeV
134
point B, an anatomical point used for cervical and uterine treatment, is located
1 cm lateral to the medial aspect of the pelvic side wall
135
define brachytherapy
radiation therapy that involves placing a radioactive material directly into or immediately adjacent to the tumor
136
identify 3 significant factors to the prognosis of skin cancer
thickness, ulceration, age, location, depth, gender
137
identify 5 characteristics of basal cell carcinoma
slow growing, arise as smooth red or milky lumps and have pearly border and multiple telangiectases, can be shiny or pale, arise from stem cells of stratum basale, most prevalent form of skin cancer, 80% on head and neck.
138
TRUE OR FALSE
| 50% of malignant melanoma develops from a preexisiting nevus
FALSE--*70%* malignant melanoma develops from a preexisting nevus
139
identify 5 characteristics of squamous cell carcinoma
faster frowing than basal cell type, scaly crusty slightly elevated lesion, 80% of UV induced SCC occur on head neck and arms, higher rate of mets, arise from mature keratinocytes of upper layers of epidermis, most common on sun exposed areas such as face head neck arms and hands.
140
this isotope is monoenergetic and can be used to treat the prostate
gold 198
141
the technique in which the tumor is removed and analyzed one layer at a time is
moh's surgery
142
when using a tandem and ovoid in a gyn implant, the typical resultant dose distribution shape is
pear
143
SCC has been associated with
prolonged arsenic exposure, HPV infection, sun exposure
144
isotope's half life: RADIUM 226
1622 years
145
isotope's half life: RADON 222
3.82 years
146
isotope's half life: CESIUM 137
30 years
147
isotope's half life: COBOLT 60
5.27 years
148
isotope's half life: IODINE 125
59.4 days
149
isotope's half life: GOLD 198
2.7 days
150
isotope's half life: IRIDIUM 192
73.83 days
151
the physical length of a radioactive source is 3 cm. if you were to open the source, you would see that there is .21 cm of space at each end between where the actual source lies and the end of the casing. what is the active length of the source
2.58 cm
152
describe the four main categories of people who are more prone to developing skin cancer
geographic location-closer to equator at greater risk
skin type-fair skin more likely
prior skin cancer-increases odds
gender-men more likely for melanoma. women 3x more likely for nonmelanoma.
153
a typical border for a radiation therapy field when treating skin lesions is
1 to 2 cm
154
the average lifetime for the decay of radioactive atoms is the definition of
mean life
155
the disease that is most commonly treated by total skin irradiation is
mycosis fungoides
156
point A, an anatomical point used for cervical and uterine treatment is located
2 cm superior and 2 cm lateral to the center of the cervical canal
157
TRUE OR FALSE
| a person that lives farther from the equator has an increased risk of developing skin cancer
FALSE--*closer* to the equator, increased risk
158
the most common subtype of malignant melanoma is known as
superficial spreading melanoma
159
identify 5 characteristics of malignant melanoma
most lethal form of skin cancer.
originates in melanocytes of stratum basale.
most common sites for men are trunk and the face, for women its legs.
can also arise in places such as the choroid or ciliary body of the eye, eyelids, mucosa of oral cavity, genitalia, and anus.
160
what is the role of radiation therapy in SCC, BCC, and malignant melanoma?
Nonmelanoma: treats lesions on lips ears scalp nose eyelids and face because good cosmetic results.
malignant melanoma: treats metastases and large facial lentigo maligna melanomas.
161
clark method for classifying melanoma is based on
level of invasion from the epidermis into the dermis
162
TRUE OR FALSE
| squamous cell carcinoma accounts for more than half of all radiation induced skin cancers
TRUE
163
calculate the mean life of cesium 137
30.0 years
164
list two advantages of brachytherapy over external beam
allows a very high dose or radiation to be delivered locally to the tumor in a relatively short time while very low doses are administered to surrounding tissues.
