Mock Exam 3 Flashcards
1
Q
What is the dose-limiting structure of most concern for radiation treatments of colorectal cancers?
A
small bowel
2
Q
What is the dose-limiting structure of most concern for radiation treatments of the esophagus?
A
spinal cord
3
Q
Management of acute side effects from radiotherapy to the abdomen and rectum will include:
A
low residue diet and lomotil
4
Q
How does the belly board help reduce small bowel in the treatment field?
A
Moves flabby skin folds out of the way pushing small bowel superiorly
5
Q
Patients with unresectable esophageal tumors recieve EBRT doses ranging from _____.
A
60-65 Gy
6
Q
The images above best illustrate EBRT treatment fields for _____.
A
colorectal adenocarcinoma
7
Q
What is a major predisposing factor to cervical cancer?
A
infection with HPV
8
Q
What is the standard total dose used when irradiating the entire bladder?
A
4500 to 5000 cGy
The larger pelvic field to include the bladder and pelvic lymph nodes is generally treated to a dose of 45 to 50 Gy at 180 cGy per day, which requires 5 to mc009-1.jpg weeks of treatment.
9
Q
Which of the following positions and strategies are most frequently used when irradiating the prostate?
I. Supine positioning
II. Prone positioning
III. Full bladder
IV. Empty bladder
A
I and III
10
Q
Where is the inferior border commonly located for a prostate radiotherapy port?
A
Bottom of the obturator foramen
11
Q
Where are the superior and inferior borders normally located for an AP/PA cervical portal?
A
L4-L5 interspace and bottom of the obturator foramen
12
Q
The portal designs above best demonstrate EBRT treatment for cancer of which of the following male reproductive system components?
A
testicle
13
Q
In which anatomical location are soft tissue sarcomas most common?
A
lower extremity
Roughly 60% of STSs are found in extremities, with the thigh being most common.
14
Q
Which of the following would be the best radiologic imaging study used to diagnose soft tissue sarcomas?
A
MRI
15
Q
Which of the following may be used in treating metastatic bone disease resulting from primary prostate or breast cancer?
A
Strontium-89
16
Q
What is the transplantation of healthy bone marrow from a donor to a patient to stimulate formed blood cells?
A
allogenic bone marrow transplant
17
Q
Radiation therapy of which of the following cancers does not include regional lymph nodes?
A
early staged larynx
Limited risk of subclinical disease to the cervical lymphatics in the treatment of Tis and T1 lesions indicate a field encompassing the primary lesion only.
18
Q
The node of Rouviere is particularly important to include when treating the:
A
nasopharynx
19
Q
Lymph nodes of the head and neck region have been separated into ___ levels.
A
7
20
Q
The vertebral level used to identify the location of the true vocal cords:
A
C4
21
Q
BID radiation therapy is a form of:
A
hyperfractionation
22
Q
The shoulders should be displaced _______ as much as possible to maximize the utility of lateral photon fields.
A
inferiorly
23
Q
What is the TD 5/5 for the spinal cord:
A
45-50Gy
24
Q
Which of the following is a characteristic of a benign tumor?
A
cells appear relatively normal
25
Measurement of a patient’s thickness along the central axis is called the:
IFD
26
What is the patient separation if depth from the anterior posterior (AP) is 9 cm and depth from posterior anterior (PA) is 11 cm?
20 cm
27
A ___ is a histogram relating radiation dose to tissue volume in radiation therapy planning.
DVH
28
Which of the following is a more widely accepted procedure for assessing axillary node status once the primary breast tumor has been identified?
Sentinel lymph node
## Footnote
The sentinel lymph node procedure focuses on finding lymph nodes that are the first to receive draining fluid from breast tumor and, therefore, the first to collect cancer cells. A blue dye or radioactive substance is injected near the tumor site and is then absorbed locally through the lymph system traveling to the sentinel node(s).
29
The patient is supine, upper arm abducted 90 degrees, and the head is turned away from the treatment field for which of the following?
Breast
30
What is the most effective single-agent chemotherapy drug used in the management of lung tumors?
Cisplatin
## Footnote
The most effective single-agent drug continues to be cisplatin, with additional agents such as paclitaxel, docetaxel, vinorelbine, gemcitabine, and irinotecan.
31
Which of the following is not a common acute side effect a patient may experience during the course of radiation treatments for lung cancer?
Diarrhea
## Footnote
Common acute side effects that occur during radiation therapy are dermatitis, erythema, and esophagitis. Diarrhea is not an expected side effect.
32
Why should a patient’s arms be positioned above his or her head during radiation treatments of a primary lung cancer?
Avoid treating normal tissue
## Footnote
Accurate positioning of the patient is essential; of critical importance is the arm position with off-cord boosts because the probability of the patient rolling to one side or the other increases if the arms are raised above the patient's head.
33
Which treatment field arrangement is used to increase the mid-axillary dose to the prescribed level in some patients?
Posterior axillary boost field (PAB)
## Footnote
The PAB is used when midplane radiation dose from an anterior SCV field alone is not sufficient.
34
When treating breast cancer through tangential fields, the volume of irradiated lung should be kept to:
< 2 cm
35
Which of the following statements is true?
Microwaves are non-ionizing radiation
36
A course of radiation therapy which is intended to relieve the suffering of an individual with no intent to cure is called a:
palliative therapy
37
Which of these is NOT a method of reducing setup uncertainty?
Respiratory gating
38
The shape of the isodose curves is dependent upon including the central asix distribution, flatness, and curavature near the field borders is largely dependent upon:
The production of x-rays by the electrons
39
Beam intensity is inversely proportional to:
The square of the distance from the source
40
What is the optimum wedge angle for two beams with a 120° hinge angle?
30°
41
What is the most potent chemical modifier when treating with x and gamma radiation?
oxygen
42
Which of the following is a parameter that allows for the adjustment of the gray scale?
Window width
43
The phantom for the dosimetry of electron beams can be made of:
Electron solid water
44
One of the most radiosensitive tissues in the body is _____ tissue.
lymphoid
45
Superior vena cava syndrome is most often a result of:
lung cancer
46
After alpha decay, a nucleus has:
Two fewer protons and two fewer neutrons
47
The type of radium needles that have a higher activity at both ends are termed:
Dumbell needles
48
A(n) _____ effect increases in incidence but not severity as the dose increases.
stochastic
## Footnote
A stochastic effect increases in incidence but not severity as the dose increases.
49
The stomach and tail of the pancreas are located in which of the following abdominal quadrants?
Left upper
50
The treatment prescription should include all of the following except:
monitor units delivered
51
What is the mean life of Y-90 (T1/2 = 64 hrs)?
TAVE = 29 hr
52
The term that means new growth (of abnormal tissue or tumor) is
neoplasm
53
The difference between the mass of a nuclide and the masses of the component nucleons is:
the Mass Defect, and is equal to the binding energy of the nucleus
54
The structure that provides the source of electrons injected into the accelerator tube in a linear accelerator is called the:
Electron gun
55
All patients that have completed treatments with temporary implants are surveyed with radiation detectors to:
Ensure that all sources have been removed from the patient
56
An area outside the target volume area which receives higher dose than the specified target dose is termed a:
hot spot
57
The three cardinal principals of radiation protection involve _____.
time, distance, and shielding
58
For which of the following is fever a presenting symptom?
Hodgkin's disease
59
Which of these terms best describes a target volume based on high standardized uptake values(SUV) values from a PET scan?
GTV
60
A source produces an intensity of 100 mR/hr at a distance of 10 cm. What is the distance from this source at which the intensity would be 25 mR/hr?
5.0cm
61
In a linear accelerator the thick-shelled lead lined covering that prevents the leakage of high energy radiation is called the:
Treatment head
62
The pituitary is located along the baseline:
2cm ant. and 2cm sup. to the tragus
63
RBE depends on all of the following, except:
OER
64
Radiation damage in radioresistant organs is usually caused by:
vasculature damage
65
A megavoltage beam is defined as x-ray or electron source that has an energy above
10^ 6 eV
66
When a treatment distance between the skin and the radiation source remains constant at all times it is referred to as a/an:
Source-to-Skin distance technique
67
The x-rays produced by 18 MeV electrons travel:
in the same general direction as the incident beam
68
If you are treating a tumor with a partial arc, where should the isocenter be located?
At a point deeper than the tumor volume
69
A gamma ray having a 7 x 10-10 cm wavelength will have an energy of (keV) of ____ where h=4.15 x 10-18 kev-sec and c= 3 x 1010 cm/sec.
178 keV
70
The use of after-loading devices in the placement of the sealed radioactive sources has the advantage of:
Lower personnel exposures
71
What is the most common location of tumors in the hypopharynx?
pyriform sinus
72
Low % isodose lines bulge out significantly for _______ energy beams.
Orthovoltage
73
X-ray targets are generally made from:
Dense, high-Z materials
74
The acceleration of the charged particles in a linear accelerator (Iinac) primarily results from their exposure to:
High frequency electromagnetic waves
75
Flatness is specified at _____cm depth.
10cm
76
What does Dq represent on the cell survival curve?
sublethal damage
77
Which of the following macro-molecules has the greatest radiosensitivity?
DNA
78
Characteristic x-rays are produced when:
An electron from an outer shell transitions to an inner shell opening
79
Death due to infection occurs with which syndrome(s)?
1. Bone marrow 2. Gastrointestinal 3. CNS
1 and 2
80
Which of the following devices is incorporated into the design of a linear accelerator to amplify the microwaves used to accelerate the electron beam?
A klystron
81
The thoracic cavity contains the
lungs
82
The vocal cords are located in the:
glottic larynx
83
The linear attenuation coefficient for 1 MV x-rays in copper is 0.520 cm-1. What is the HVL of copper for this beam?
1.33cm
84
Another term for blocked field size is:
effective field size
85
The vertebral level that is associated with the inferior angle of the scapula is the:
seventh thoracic vertebra
86
The highly evacuated section of a cyclotron in which the particles are accelerated is called the:
Dee
87
The HVL of a 60Co beam is 14.4 mm of copper. What is the transmission of this beam through 43.2 mm of copper?
0.125
88
The major process by which x-rays are produced in a linear accelerator is termed:
Bremsstrahlung
89
Determine the equivalent square for a rectangular field with a width of 7cm and a length of 17cm.
9.9 cm2
90
What has the largest effect on uncertainty of dose delivery for RT?
Patient setup and immobilization
91
The proper sequence of materials traveled by an electron in the electron therapy mode of a linear accelerator is:
1. Ion chamber
2. Scattering foil
3. Primary collimator
## Footnote
3, 2, 1
92
The most radiosensitive period during pregnancy for radiation induced congenital abnormalities is during the _____.
first trimester
93
The term axillary refers to the area of the:
armpit.
94
The shielding thickness for an electron beam with an energy of 20 MeV can be estimated at:
10 millimeters of lead or 12 millimeters of Lipowitz metal
95
The point from which an electron beam appears to emanate from a linear accelerator is called the:
Dummy load source
96
The most radiosensitive cells in the hematopoietic system of the human body are the _____.
lymphocytes
97
What is a target volume created from a 4DCT using the average of all respiratory phases?
4DCTV
98
A plane that divides the body into left and right portions is
sagittal
99
The histologic type of lung cancer seen in patients that usually occurs in the periphery of the lung is:
Adenocarcinoma
100
The thoracic lymph duct begins in the abdomen at the level of:
L2
## Footnote
The thoracic duct is on the left side of the body, is approximately 35 to 45 cm in length, and begins in front of the second lumbar vertebra (L2).
101
Which histology of HD has the most favorable prognosis?
lymphocyte predominance
102
A “Caution - High Radiation Area” warning sign must be posted in all areas where a person could receive an exposure in excess of mSv/hr:
0.1
## Footnote
CAUTION HIGH RADIATION AREA" or " CAUTION AIRBORNE RADIOACTIVITY AREA
– Signs necessary when dose rate exceeds 100 mrem per hour and for areas in which the concentrations of radioactivity in air exceed certain standards specified in the regulations.
103
Which of the following is most significant to the prognosis of brain tumors?
Grade
104
Which of the following is the dose at which radiation necrosis of brain tissue is most likely to occur?
6000 cGy
105
What is the most common grade of gliomas?
high grade
106
The Dmax for a 10MV photon beam at an 100cm SSD with a 15 x 15 cm field is approximately:
2.5cm
107
Maximum permissible dose to the general public is:
10% of that for a radiation worker
108
The Pap test is recommended for women at least once every 3 years beginning about 3 years after becoming sexually active or no later than _____ years of age.
21
109
Orthovoltage x-ray machines have energies in the range of which of the following?
150 kV to 500 kV
## Footnote
Orthovoltage therapy operates at 150 to 500 kV. Most equipment operates at 200 to 300 kV and is used for treating superficial lesions.
110
The edges of the light field and radiation field must agree within:
2mm
111
According to the current NCRP recommendations, which of the following will have the highest annual dose limit?
The hands of a pregnant therapist
112
Patients are monitored during treatment delivery with megavoltage treatment units by using which of the following?
I. direct visual
II. closed-circuit television
III. two-way audio
II and III
## Footnote
With low-energy treatment, visualization of patient may be done directly through leaded glass windows. With megavoltage units, an indirect monitoring system must be used. For patient safety and accuracy of treatment, audio and visual contact is maintained at all times, by at least two cameras and audio system.
113
A 6 MV linear accelerator is used at 100cm SSD. The location of maximum dose is found at a depth of:
1.5cm
114
Overall, cervical cancer occurs most frequently with those associated with which of the factors below?
I. Women of lower socioeconomic status
II. Early sexual activity and multiple partners
III. Multiple instances of pelvic infection
I, II, and III
115
The ion chamber monitor unit of a linear accelerator is normally located:
within in the treatment head
116
Which of the following is the correct order to the layers of the skin from deep to superficial?
stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, stratum corneum
117
HIPAA is an acronym for
Health Insurance Portability and Accountability Act
118
A(n) _______ is a patient’s claim that he or she has been wronged.
tort
| tort
119
Which of the following describes the accidental leakage of intravenous drugs into the surrounding tissues?
Extravasation
120
Radiation sickness symptoms associated with the reduced number of leukocytes is a major characteristic of:
Hematopoietic syndrome
121
Which of the following are abnormal cells significant in the diagnosis of Hodgkin’s lymphoma?
Reed-Sternberg
122
The treatment of choice for brain metastasis is:
Radiation therapy
123
As the field size increases, the TAR:
increases
124
Which of the following phosphors are commonly used in TLD’s?
lithium fluoride
125
What is the leading cause of non–small cell carcinoma of the lung?
smoking
126
The diastolic norm would be within a range of:
60 to 80 mm Hg
127
The five stages of the grieving process were first identified by?
Elizabeth Kubler-Ross
128
The final check done by a radiation therapist to ensure the planned treatment beam covers the tumor or target volume is termed _______:
verification
129
The quality factor includes which of the following when considering its value?
RBE
130
Apoptosis refers to:
pre-programmed cell self-destruction
131
What is the most common long-term side effect of total lymphoid irradiation?
secondary malignancy
132
Which of the body cavities is the largest?
Ventral
133
Using a treatment machine in which the field alignment is inaccurate could result in:
failure to treat the entire tumor
134
A deficiency in the number of circulating red blood cells is called:
anemia
135
Which chemotherapy agent can be used to reduce the leukemic cell load and impair the host’s ability to reject the donor bone marrow?
cyclophosphamide
## Footnote
Cyclophosphamide can be used to reduce the leukemic cell load and impair the host's ability to reject the donor bone marrow. Dexamethasone, vincristine, and L-asparaginase are used in induction therapy.
136
# v
The average adult respiratory rate is:
12 to 20
137
What is the most common histologic form of endometrial cancer?
adenocarcinoma
138
If the field size indicator is set for 20 x 20 cm at 80 cm SSD, what is the field size at 84cm?
21 x 21 cm
139
An ionization chamber reading for a given exposure will:
increase as the temperature decreases
140
What is the most common form of skin cancer?
basal cell carcinoma
141
One of the main advantages of a multileaf collimator is to:
customize treatment volume
142
According to the current NCRP recommendations, the guidance levels for cumulative exposures for a 30-year-old occupational worker with 3 years of experience is:
300 mSv
143
Touching a patient without their permission is considered:
Battery
144
Two components of cerrobend that are carcinogen(s):
| 1. Pb 2. Ca 3. Tn 4. Bi
1 & 2
145
What is the given dose for a patient receiving 250 cGy a day treated at 5cm depth with SSD technique, if the %DD is 84.5%?
296
146
The standard photon radiation energy used to determine RBE is:
250 keV
147
What landmark is typically used to determine the lower border of the abdominal portion of the inverted-Y field?
L4-5
148
The TD 5/5 for the whole kidney using standard fractionation is approximately:
23 Gy
149
Lateral brain fields and a posterior spinal field are matched by:
Turning the collimator and the couch when treating the lateral fields
150
The chemical compound material used in optically stimulated luminescence (OSL) radiation measurement is __________.
Aluminum oxide
151
The A in “CAUTION” represents
A sore that does not heal
152
If the exposure rate at 1 meter is 52.7 R/min, at what distance is the exposure rate 35 R/min?
1.23m
153
All of the following adult blood pressure recordings would be considered normal except:
160/95
154
The TD 5/5 for the whole brain using standard fractionation is approximately:
45 Gy
155
The process of cell meiosis results in cells with _____ chromosomes each.
23
156
It is recommended that radiation exposure to the fetus should not exceed ______ for the entire gestation period.
500 mSv
157
A company being punished for the actions of one of its employees is an example of which doctrine?
Doctrine of respondeat superior
158
The treated volume (TV) is defined as:
The volume enclosed by the isodose surface that adequately covers the PTV
159
The immediate symptoms that appear after an acute total body radiation exposure are called:
Prodromal symptoms
160
A subjective indication of a disease or a change in condition as perceived by the patient is a ________.
symptom
161
As the SSD increases, the PDD:
increases
162
As the energy increases, the PDD:
increases
163
Which of the following techniques may be used to adequately irradiate the internal mammary lymph nodes while limiting the exposure to other organs?
AP photon/electron combination
164
The most common histopathology of pancreatic carcinoma is:
adenocarcinoma
165
The normal platelet count is approximately:
250,000/cc
166
The term rhabdomyosarcoma is defined as a
malignant tumor of striated muscle
167
The ____ is the sameness from side to side of the beam profile.
symmetry
168
Which type of detector can be used to distinguish between alpha and beta radiation?
Proportional counter
169
No matter which direction the Compton scatter photon goes, it retains approximately:
two thirds of its energy
170
_____ is a measure of the rate that energy is transferred from ionizing radiation to soft tissue.
LET
171
A patient’s treatment requires 150 mu. A tray is added with a factor of 0.972. How many mu must the therapist now give?
154 mu
172
A port film is considered mandatory not only as good clinical practice but also as a(n):
legal record
173
Which of the following stages in the natural history of CML is also known as blast crisis?
acute
174
Which of the following terms describes the complete destruction or elimination of all living microorganisms?
sterilization
175
Who is primarily responsible for checking the engineering capabilities of the linear accelerator?
physicists
176
Brain mets usually occur as:
multiple foci
177
The spinal cord is protected along its course by a bony foramen of the vertebrae. In adults the spinal cord usually ends at the vertebral level of the:
second lumbar vertebra
178
Where should the upper and lower field edges be placed for the treatment of metastatic spine cancer?
intervertebral space
179
Complications of superior vena cava syndrome usually resolve within the first ____ fractions of radiation therapy treatment.
3
180
Edema associated with inflammation results directly from:
increased fluid and protein in the interstitial compartment
181
The term leukocytosis means:
increased white blood cells in the blood
182
Glucocorticoids are used to treat inflammation because they directly:
decrease capillary permeability
183
What is the rationale for vomiting with increased intracranial pressure?
pressure on the emetic center in the medulla
184
As intracranial pressure rises, the pupil of the eye, ipsilateral to the lesion, becomes dilated and unresponsive to light because of pressure on the:
oculomotor nerve
185
If a Co-60 unit is used at 80cm SSD for a 15 x 15cm field size and has a %DD of 58.4 at 10cm depth, what is the %DD for the same field size and depth at 100cm SSD?
60.9
186
Calculate the equivalent square for a 10 x 15 cm rectangular field:
12cm x 12cm
187
A patient is treated with parallel opposed fields, weighted 2:1, R:L. %DD at 7cm is 0.688. Find the given dose on the left side, if the tumor is treated to 5750cGY.
2786cGy
188
Calculate the mu to deliver 200cGy to the 90% isodose line for a 10 x 10cm 12MeV electron beam. The cGy/mu is 0.787.
282mu
189
A dose of 5000cGy is to be delivered at a depth of 8 cm where the percent depth dose is 60.3. What is the dose to an underlying sensitive organ at a depth of 10cm where the percent depth dose is 55.5?
4600cGy
190
The dosimetric or physical field is normally the distance intercepted by the _____ on a plane perpendicular to the beam axis at the stated source distance:
50% isodose curve
191
The quality of DRRs can be improved by ____ the thickness of CT slices
decreasing
192
A radiation therapist needs to deliver a dose of 150 cGy to the 85% isodose line using a 15 MeV electron beam. The machine's output is calibrated to 0.825 cGy/MU. Calculate the number of monitor units (MU) required to deliver the prescribed dose.
214 MU
193
A patient is undergoing a three-field 6MV photon treatment to a tumor at a depth of 10 cm. The prescribed dose to the isocenter is 200 cGy per field. Field 1 requires a 45-degree wedge, and Field 2 utilizes a blocking tray.
The following parameters are provided:
Output factor at isocenter: 1.02
Tissue Maximum Ratio (TMR) at 10 cm depth: 0.65
Inverse Square Factor (ISF) at 100 cm SSD: 1.00
Field size: 10 cm x 10 cm
Wedge factor: 1.15
Tray factor: 0.98
Collimator scatter factor (Sc): 1.01
Phantom scatter factor (Sp): 1.03
Field 1: 339 MU, Field 2: 301 MU, Field 3: 295 MU
## Footnote
Field 1 (Wedge):
MU = (Prescribed Dose) / (Output Factor * TMR * ISF * Sc * Sp * Wedge Factor)
MU = 200 / (1.02 * 0.65 * 1.00 * 1.01 * 1.03 * 1.15)MU ˜ 339 MU
Field 2 (Tray):
MU = (Prescribed Dose) / (Output Factor * TMR * ISF * Sc * Sp * Tray Factor)
MU = 200 / (1.02 * 0.65 * 1.00 * 1.01 * 1.03 * 0.98)MU ˜ 301 MU
Field 3 (No Wedge or Tray):
MU = (Prescribed Dose) / (Output Factor * TMR * ISF * Sc * Sp)
MU = 200 / (1.02 * 0.65 * 1.00 * 1.01 * 1.03)MU ˜ 295 MU
194
A patient is undergoing a two-field 6MV photon treatment using an SSD technique. The treatment is set up at 100 cm SSD. The prescribed dose to the tumor at a depth of 5 cm is 180 cGy per field. Both fields utilize custom blocks.
The following parameters are given:
Output at 100 cm SSD: 1.00 cGy/MU
Percentage Depth Dose (PDD) at 5 cm depth: 80%
Field size at 100cm SSD: 10 cm x 10 cm
Block Transmission Factor: 0.95
Collimator scatter factor (Sc): 1.01
Phantom scatter factor (Sp): 1.02
232 MU
## Footnote
MU= 180 / (1.00*0.80*1.01*1.02*0.95)
MU= 180/ 0.7816180
MU=230.29
195
Assume the initial treatment portals are AP/PA; after about how many fractions does the typical lung cancer patient start receiving oblique boost treatments?
20
## Footnote
Initial field arrangements are generally prescribed between 4000 and 4500 cGy. Boost fields follow in various combinations until tumoricidal doses are achieved. At standard fractionation of 180 to 200 cGy per day, oblique boost treatments would begin after about the twentieth treatment.
196
What is the first treatment of choice for SCLC?
chemotherapy
197
What is the preferred treatment of choice for NSCLC?
surgery
198
At what age should a person of average risk have his or her first screening colonoscopy?
50
199
Familial adenomatous polyposis (FAP) and hereditary nonpolyposis colorectal syndrome (HNPCC) are most closely associated with which type of cancer?
Colorectal
200
The lymphatic group associated with anal cancers is ___:
inguinal
201
____ is the only established lifestyle risk factor for developing pancreatic cancer?
smoking
202
In which gland is luteinizing hormone (LH) produced?
Pituitary
203
Which of the following conditions most generally occurs in children but not in adults?
Gigantism
204
Ewing sarcomas are cancers of which organ?
Bone
205
Which pediatric cancer occurs in the sympathetic nervous system ganglia?
Neuroblastoma
206
A patient is being treated using an 18 MV photon energy using an AP/PA technique. The collimator setting is 6 × 10 with no blocks. The prescribed dose is 4000 cGy in 20 fractions. What is the dose delivered per fraction?
Answer: 200
207
A patient is being treated using an 18 MV photon energy using an AP/PA technique. The collimator setting is 6 × 10 with no blocks. The prescribed dose is 4000 cGy in 20 fractions. What is the dose delivered per field?
100
