SEAL #6 Flashcards

Question 1

Q

Which of the following measurements are needed to aid you in checking the accuracy of the contour? Please select all that apply.

Patient AP and lateral measurements
Field size
source to axis distance (SAD)
percentage depth dose (PDD)

Answer

A

Patient AP and lateral measurements
source to axis distance (SAD)

In order to check the accuracy of a contour, the patients AP and lateral measurements as well as the SAD are needed

Question 2

Q

Patients taking metformin should stop taking the medication ______ hours before having contrast administration for a CT simulation.
12
24
36
48

Answer

A

48

The American College of Radiology recommends discontinuation of metformin 48 hours prior to contrast administration to avoid risk of lactic acidosis

Question 3

Q

When checking the lasers used in radiation therapy, they must be accurate within:
1 mm
2 mm
3 mm
2%

Answer

A

2 mm

Daily localizing lasers must be within 2 mm of accuracy

Question 4

Q

What photon interaction dominates at 50 MeV?
Photoelectric effect
Coherent scattering
Compton effect
Pair production

Answer

A

pair production

Compton effect dominates at energies between 25 KeV and 10 MeV, which encompasses any therapeutic radiation energies. Photoelectric effect dominates at energies less than 25 KeV, most often used in diagnostic equipment.

Question 5

Q

A head and neck patient is treated to midline (separation 14 cm, and .688 fractional depth dose (FDD)) with lateral fields to a total of 5,750 cGy with a 2:1 RT to LT weighting. The left lateral field will contribute _________ cGy to the tumor.
1,319
1,917
2,875
3,833

Answer

A

1,917

5,750 cGy / 3 = 1,916.66 cGy

Question 6

Q

__________ summarizes the 3D doses given to the patient during their radiation treatment. It gives the physician the dose constraints needed for organs that are incorporated in the patient treatment plan.
Clarkson Method
Emami Tables
Quantec
WAN network

Answer

A

Quantec

Emami data/doses were used in the 2D treatment planning arena. Quantitative Analysis of Normal Tissue Effects in the Clinic, also known as Quantec, was published with improved toxicity data for the radiation patients. It looks at normal tissue toxicities, volumes and doses with how they are distributed in a treatment plan.

Question 7

Q

The monthly equivalent dose limit for pregnant radiation workers should not exceed ________ per month.
0.1 mSv
0.5 mSv
1 mSv
5 msv

Answer

A

0.5 mSv

The occupational dose limit for pregnant radiation workers is 0.5 mSv per month and not to exceed 5.0 mSv for the entire pregnancy.

Question 8

Q

A measure of machine output from a linear accelerator is defined as a:
monitor unit
minute of time
dose
energized unit

Answer

A

monitor unit

A monitor unit (MU) is defined as a measure of machine output from a clinical accelerator for radiation therapy. It is the output measurement of radiation exposure. Monitor units delivered to a patient are determined during the planning portion of their treatment. Monitor units may depend on dose, treatment site, patient size, energy of the treatment unit, distance and field size

Question 9

Q

Afterloading techniques _________ exposure to operating room personnel and radiation therapists.
increase
decrease
intensify
double

Answer

A

decrease

The use of afterloading techniques involve no exposure to operating room personnel or therapists.

Question 10

Q

Which of these tumors arises from epithelium?

Ewing sarcoma
Osteosarcoma
Hodgkin lymphoma
Adenocarcinoma

Answer

A

adenocarcinoma

Carcinomas arise from epithelial tissue, whereas sarcomas form from connective tissue. Lymphomas arise in the lymphatic system

Question 11

Q

The pharynx is divided into 3 sections. Which of the following sections is called the epipharynx?
Hypopharynx
Laryngeopharynx
Nasopharynx
Oropharynx

Answer

A

nasopharynx

The nasopharynx/epiphraynx is the uppermost portion of the pharynx. It runs from the nasal cavity to the soft palate. It serves as a pathway for air during breathing

Question 12

Q

Tuberculosis is an example of an infection by which route?
Contact
Droplet
Airborne
Blood borne

Answer

A

airborne

Tuberculosis can be spread very easily, and in the past has spread in hospitals because of air recirculation and low airflow rates.

Question 13

Q

Cell differentiation is referred to as:
Stage.
Histologic type.
Grade.
Sensitivity

Answer

A

Grade

Tumor grade refers to the aggressiveness and differentiation. Tumors may be classified as well differentiated, moderately well differentiated, poorly differentiated, or undifferentiated.

Question 14

Q

______ is a technique used to set an open area around the planning target volume (PTV), from the beam’s eye view (BEV), to shape the field following contour of the PTV.
Normalization
Histogram
Autofielding
Autoblocking

Answer

A

Autofielding

The autofield should include a margin around the PTV that allows for beam penumbra and block edge effects and allow isodose line of 90% or greater to cover the PTV.

Question 15

Q

Which of these values is a normal adult creatinine level?
0.2 mg/dl
0.8 mg/dl
1.7 mg/dl
2.0 mg/d

Answer

A

0.8 mg/dL

A creatinine level greater than 1.4 could indicate the kidneys would have difficulty excreting the contrast material. This would be a contraindication to contrast administration.

Question 16

Q

Calculate the hinge angle between two fields if a patient is being treated with 30-degree wedges.
90
120
150
180

Answer

A

120

Use this formula to calculate hinge angle. HA = 180-2(wedge angle). It is defined as a measure of the angle between central rays of 2 intersecting treatment beams. The amount of tilt that an isodose curve has is dependent on the size of the wedge used. Wedges with a larger incline or degree have more of an isodose tilt.

Question 17

Q

A ______ dosimeter response is almost independent of energy in the megavoltage range of photon and electron beams.
optical stimulated luminescence (OSL)
thermoluminescent (TLD)
pocket ionization
personnel digital ionization

Answer

A

thermoluminescent (TLD)

Use this formula to calculate hinge angle. HA = 180-2(wedge angle). It is defined as a measure of the angle between central rays of 2 intersecting treatment beams. The amount of tilt that an isodose curve has is dependent on the size of the wedge used. Wedges with a larger incline or degree have more of an isodose tilt.

Question 18

Q

Conditions acquired in the hospital setting are known as:
Bacterial infections.
Isolation infections.
Medical infections.
Nosocomial infections.

Answer

A

nosocomial infections

Nosocomial infections refer to infections that have been caught by a patient in a hospital. According to the CDC, the most common pathogens that cause nosocomial infections are Staphylococcus aureus, Pseudomonas aeruginosa, and E. coli. Some of the common nosocomial infections are urinary tract infections, respiratory pneumonia, surgical site wound infections, bacteria, gastrointestinal and skin infections.

Question 19

Q

Permanent alopecia is seen in radiation doses that reach ___ Gy
25
30
40
45

Answer

A

45

Alopecia may develop during the course of radiation treatment depending on the area of the body being treated and often is reversible after treatment concludes. Modern radiation therapy treatment techniques aim to spare skin, thus sparing the hair follicles and reducing the likelihood of permanent alopecia

Question 20

Q

The biologic effectiveness of low-dose rate treatments can be reproduced using remote afterloading with ____________ brachytherapy.
high dose rate (HDR)
medium dose rate
surface
pulsed-dose rate

Answer

A

pulsed-dose rate

A remote afterloader similar to an HDR unit is used to deliver short pulses of radiation.

Question 21

Q

Of the following tumors, which is more likely to be well differentiated?
Squamous cell carcinoma of the cervix
Andenocarcinoma of the lung
Meningioma
Osteosarcoma

Answer

A

Meningioma

Meningiomas are usually benign; the other diseases listed are malignant and can be more aggressive

Question 22

Q

MOST importantly, a patient being treated for Hodgkin’s disease must be monitored for:
Myelosuppression.
Nausea and vomiting.
Weight loss.
Neural signs.

Answer

A

myelosuppression

It is important to monitor a Hodgkin’s disease patient for myelosuppression as a large quantity of bone marrow is irradiated in the treatment field of these patients which can lower immunity.

Question 23

Q

Areas around the treatment are designated as controlled or uncontrolled. Areas designated as controlled include the:
Examination room.
Waiting room or lobby.
Control console.
Offices.

Answer

A

control console

Controlled areas are defined as a limited access area in which the occupational exposure of personnel to radiation producing equipment is supervised. Of these, the only one that is supervised is the control console.

Question 24

Q

Radiation treatments are given in daily fractions, sometimes expanding over a period of 5 - 8 weeks. What is this called?
Hyperfractionation
Forward planning
Fractionation
Protraction

Answer

A

fractionation

Fractionation can occur once or twice daily. If a patient receives 3,000 cGy at 300 cGy once daily, the fractionation will be 10.

Question 25

Q

Brachytherapy __________ categories are based on the relationship between the rate of tumor cell proliferation and treatment duration.
half-life
substitute
dose rate
isotope

Answer

A

dose rate

The categories are low (0.3 - 2 Gy/h), medium (2 - 12 Gy/h) or high dose rate (greater than 12 Gy/h).

Question 26

Q

_________ that give visible and audible warnings are required when the treatment is in progress and when the treatment is terminated.
beam-on indicators
limitation devices
backup timer
personnel digital ionization

Answer

A

beam-on indicators

Warning lights provide visual cues indicating when the beam is on. Audible devices indicate the end of the treatment.

Question 27

Q

The MOST common metastatic site for prostate cancer is the:
Brain.
Bone.
Lung.
Liver.

Answer

A

bone

Prostate cancer metastasizes to bone 90% of the time, followed by lungs and liver.

Question 28

Q

The _____ portion of the wedge allows for less transmission of photons.
Heel
Lateral
Middle
Toe

Answer

A

heel

Wedges are used on sloping surfaces. The thick end is called the heel and the thin end is called the toe. The thinner end will allow for more transmission of the radiation beam.

Question 29

Q

What is the term used for devices placed internally that are used to define a coordinate system in the treatment planning and delivery process which can be the basis to target the tumor by using an external 3D frame of reference?
Wedge
Stereotactic frame
Brachytherapy implant
Fiducial

Answer

A

fiducial

A fiducial can be implanted in a patient, typically at the tumor bed, and can give a visual coordinate system for which to base planning.

Question 30

Q

In 3D planning, evaluation of the doses that involve the organ at risk (OAR) and their localization within the structures are BEST demonstrated by _____________.

isodose lines
dose clouds
autofielding
autoblocking

Answer

A

dose clouds

Dose distributions are best displayed as isodose lines for 2D planes and as dose clouds for 3D planning. 3D dose clouds allows the planner to see if any portion of the planning target volume (PTV) extends outside of the isodose cloud and is not properly covered.

Question 31

Q

The chain of infection follows which cycle?
Reservoir-host-mode of transmission-infectious microorganism
Host-infectious microorganism-reservoir-mode of transmission
Host-reservoir-infectious microorganism-mode of transmission
Infectious microorganism-host-reservoir-mode of transmission

Answer

A

Host-infectious microorganism-reservoir-mode of transmission

This cycle is a continuous loop wherein an infectious agent or microorganism is able to survive within a reservoir (a person, animal, or environmental component), be transmitted through a mode of transmission and finally reside within a new host. Each link has a role in the cycle and each can be interrupted or broken in various ways.

Question 32

Q

Of the following staging scenarios, which is the most advanced?
T1N0M0
T0N1M0
T1N1M0
T0N2M0

Answer

A

T0N2M0

T0N2M0 is the most advanced, as the level of lymph node involvement is greater than the others. Regardless of tumor size, once lymph nodes are involved, the staging advances.

Question 33

Q

A lifetime effective dose or cumulative effective dose limits a radiation worker’s exposure limit to his/her age multiplied by _________.
1 mSv
5 mSv
10 mSv
50 mSv

Answer

A

10 mSv

The cumulative effective dose pertains to the whole body and includes external and internal exposure.

Question 34

Q

A tumor assigned a grade of G4 indicates the tumor is:
Well differentiated
Moderately differentiated
Poorly differentiated
Undifferentiated

Answer

A

undifferentiated

A tumor assigned a G4 is undifferentiated, or more aggressive. The degree of differentiation is greater in a high-grade tumor than a low-grade tumor.

Question 35

Q

Half value layer can be calculated with which of the following equations?
I1/I2 = (d2/d1)2
0.693/μ
A0e-λt
ln2/λ

Answer

A

0.693/μ

Half value layer, or HVL, is the amount of material necessary to attenuate a beam to half of its original intensity.

Question 36

Q

A patient is being treated for a primary glioma of the brain. The prescription reads a total dose of 6,000 cGy to be delivered, but the gross tumor volume (GTV) is on the left side of the brain. The written directive says to use weighted lateral fields. Right : Left 2 : 3. What total dose will each field receive?
2,000 cGy : 4,000 cGy
3,000 cGy : 3,000 cGy
1,200 cGy : 4,800 cGy
2,400 cGy : 3,600 cGy

Answer

A

2,400 cGy : 3,600 cGy

The left side would get more radiation due to the field being weighted more than the right. Take the total dose (6000cGy) and divide it by the total parts (5 parts: 2 from the right and 3 from the left) 6,000 cGy/ 5 = 1,200 cGy per part. For the right side: 1,200 cGy x 2 parts= 2,400 cGy and the left side: 1,200 cGy x 3 parts= 3,600 cGy

Question 37

Q

Seizures are separated into which two groups?
Generalized seizures and focal seizures
Acute and chronic
Short and long
Tonic and clonic

Answer

A

Generalized seizures and focal seizures

Seizures are separated into two groupings based on how and where they begin in the brain.

Question 38

Q

Which of the following tumors originates from smooth muscle?
Rhabdomyosarcoma
Neuroblastoma
Angiosarcoma
Leiomyosarcoma

Answer

A

leiomyosarcoma

The term “leio” refers to smooth muscle. Therefore, leiomyosarcoma originates from smooth muscle. Angiosarcoma arises from blood vessels, and neuroblastoma arises from nerve cells.

Question 39

Q

CT number for accuracy with water is checked on a _____ basis in a CT simulator.
Daily
Weekly
Monthly
Annually

Answer

A

daily

At monthly QA, CT number accuracy is checked for four to five different materials with varying materials.

Question 40

Q

The range of electrons in water for a 12 MeV beam is:
3 cm
4 cm
6 cm
Infinite

Answer

A

6 cm

The approximate depth of the 80 and 90% isodose line can be determined by R80= E/3, and R90 = E/4.

Question 41

Q

Which of the following malignancies is MOST likely to invade lymph nodes?
Chondrosarcoma
Squamous cell carcinoma
Liposarcoma
Ewing sarcoma

Answer

A

squamous cell carcinoma

Carcinomas arise from epithelial cells, which are located in superficial surfaces all over the body. Epithelial cells form glands, which makes lymph nodes more likely to be affected by carcinomas

Question 42

Q

Anaphylactic shock may occur during which of the following procedures?
immobilization device creation
tattoo skin marking
contrast administration
brachytherapy

Answer

A

contrast administration

Anaphylactic shock, an extreme, possibly life-threatening allergic reaction, can occur during contrast administration. Although tattoo skin marking, immobilization device creation, and brachytherapy are all situations in which caution must be taken, they do not use agents that would lead to an anaphylactic shock response.

Question 43

Q

When simulating a patient with a glioblastoma (GBM), the patient is:
Supine with arms at side. A thermoplastic mask and IV contrast are used.
Prone with hands by head. A thermoplastic mask and IV contrast are used.
Supine with hands over head. Barium sulfate contrast is used.
Supine with arms akimbo. IV contrast is used.

Answer

A

Supine with arms at side. A thermoplastic mask and IV contrast are used.

Supine with arms at side and a thermoplastic mask and IV contrast is the best answer as immobilization is the key for reproducing the patient setup. Without the mask, the precious target coverage will be lost, therefore missing the appropriate treatment volume.

Question 44

Q

Examples of hyperfractionation include which of the following treatments? Please select all that apply.
once a day treatments
twice a day treatments (BID)
three times a day treatments (TID)
once every other day treatments

Answer

A

twice a day treatments (BID)
three times a day treatments (TID)

When BID (twice a day) radiation treatment is utilized, treatments must be delivered at least 6 hours apart. Delivering treatment 6 or more hours apart ensures that normal tissues are allowed time to completely repair from the previous fraction.

Question 45

Q

A patient is being treated with isocentric parallel opposed lateral whole brain fields. The right lateral target to skin distance (TSD) is 92 cm and the left lateral TSD is 90 cm. If you need to treat to the field midline, what would the TSD read on the patients skin?
no change
90 cm on both sides
91 cm on both sides
100 cm on both sides

Answer

A

91 cm on both sides

This question requires figuring out the depth to each side. The right side is 8 cm and the left is 10 cm. Add each depth together to get the patients total separation, 18 cm. To treat to midline, divide the separation in half, 18 cm/ 2= 9 cm from each side. The isocenter is at 100 cm therefore you need to subtract the depth from the isocenter distance. 100 cm - 9 cm = 91cm (from each side).

Question 46

Q

When using thermoplastic masks for immobilization, the patient skin dose must be considered. The skin dose will depend on:
The amount of water used to heat up the mask when constructing.
The beam energy and the thickness of the mask.
The beam energy only.
The thickness of the face mask only.

Answer

A

The beam energy and the thickness of the mask.

Studies have been done to prove there is a reduction of skin sparing when using thermoplastic masks for radiation treatments. There is an increased dose to the skin the first few millimeters. Also non-perforated sheets have shown to have more of a skin dose than perforated. The true skin dose can be difficult to determine due to the variability in thickness and perforations within and between different masks.

Question 47

Q

Two fields that are separated by 180 degrees are termed?
Parallel opposed beams
Tangents
Orthogonal beams
Laterals

Answer

A

Parallel opposed beams

Two beams separated by 180 degrees are termed parallel opposed beams. Orthogonal images are 90 degrees apart, and laterals are describing the location of the beam in regards to the patient. Tangents are fields used in breast treatment. They may be 180 degrees apart, but not necessarily.

Question 48

Q

When the x-ray photon strikes an atom within the tissue being imaged and loses all its energy to an inner shell electron of that atom, the photon is said to have been ________ and undergone the ________.
transmitted; Compton effect
absorbed; photoelectric interaction
attenuated; Compton effect
scattered; coherent interaction

Answer

A

absorbed; photoelectric interaction

The photoelectric interaction involves the absorption of the energy of an x-ray photon by an inner shell electron.

Question 49

Q

What is the single most important means of preventing the spread of infection?
Using personal protective equipment
Wearing gloves
Coughing into shoulder
Hand washing

Answer

A

hand washing

Hand washing is the single most important means of preventing the spread of infection. Hand washing can prevent the spread of germs, including those that are resistant to antibiotics. The most common means of hand washing include using an alcohol-based hand sanitizer and washing thoroughly with soap and water.

Question 50

Q

Which of the following has the longest wavelength?
UV rays
Visible rays
Microwaves
Gamma rays

Answer

A

microwaves

Of these, microwaves are the furthest to the left in the electromagnetic spectrum, thus having the longest wavelength, followed by visible rays, UV rays and finally gamma rays. Wavelength and frequency are inversely related.

Question 51

Q

Which of the following does not take attenuation of a radiation beam into account?
Bolus
Cerrobend block
Compensator
Target

Answer

A

target

Anything placed in the beam is attenuated and an attenuation factor must be applied to the calculation in order for the correct amount of radiation to be delivered.

Question 52

Q

Verification of the correct treatment field placement to the treatment plan isocenter relative to patient anatomy is BEST performed by using _________ images.
CT
MR
PET-CT
beam’s eye view

Answer

A

beams eye view

Not all treatment fields can be imaged. The use of BEV images should be considered to verify correct placement of the treatment plan isocenter relative to the patient anatomy. This should be done with the patient on the treatment table in the correct treatment position.

Question 53

Q

When the x-ray photon strikes an atom within the tissue being imaged and loses only part of its energy to an outer shell electron of that atom, the photon is said to have been ________ and undergone a(n) ________ interaction.
transmitted; coherent effect
absorbed; photoelectric
attenuated; pair production
scattered; Compton

Answer

A

scattered; Compton

The interaction that occurs between the outer shell electron and the x-ray photon is known as the Compton interaction and the remnant photon is scatter radiation.

Question 54

Q

Cerrobend blocks are made using a combination of which of the following metals?
Iron, steel, tin, copper
Aluminum, lead, copper, tin
Bismuth, lead, tin, cadmium
Bronze, tin, lead, nickel

Answer

A

Bismuth, lead, tin, cadmium

Cerrobend blocks, such as those used in lead block shielding or for electron radiotherapy, are made using the combination of bismuth, lead, tin, and cadmium. Cerrobend has a low melting point and has been a reusable resource in many radiation therapy departments. Recently, some departments have transitioned to a form of Cerrobend that is cadmium-free as cadmium has been shown to have toxic properties.

Question 55

Q

Seminoma of the testes arises from:
Sweat glands.
Nerve cells.
Germ cells.
Fibrous tissue.

Answer

A

germ cells

At least 95% of seminomas arise from germ cells. There are 3 subtypes: classic, anaplastic, and spermatocytic. The immature nature of germ cells causes increased sensitivity; therefore a lower radiation dose is necessary.

Question 56

Q

Which of the following describe areas of the treatment room that directly interact with the useful beam, and are required for proper shielding?
Cerrobend blocks
Primary barriers
Secondary barriers
Constant monitoring

Answer

A

primary barriers

Shielding by primary barriers is required for any wall intercepting the useful or primary beam. This includes the floor, ceiling, and side walls.

Question 57

Q

Which of these contrast reactions is considered minor?
Dyspnea
Nausea
Syncope
Cardiac arrhythmia

Answer

A

nausea

Compared to the other reactions, nausea is considered minor because treatment would not be required

Question 58

Q

________ scattering takes place at the level of an outer shell electron.
Unmodified
Compton
Coherent
Classical

Answer

A

Compton

The interaction between the incident photon and the outer shell electron produces Compton (modified) scatter.

Question 59

Q

Surface brachytherapy is MOST commonly used to treat ___________ skin cancer.
melanoma
nonmelanoma
basal
squamous

Answer

A

nonmelanoma

Nonmelanoma skin cancer can be treated using a custom mold of the body part prepared by placing sources in an arranged pattern to deliver the prescribed dose.

Question 60

Q

Which of the following statements about percentage depth dose (PDD) are correct? Please select all that apply.
PDD increases with an increase in beam energy
PDD decreases with an increase in field size
PDD increases with an increase in source to surface distance (SSD)
PDD decreases as the depth in tissue increases.

Answer

A

PDD increases with an increase in beam energy

PDD increases with an increase in source to surface distance (SSD)

PDD decreases as the depth in tissue increases.

PDD increases with an increase in beam energy, field size, and SSD. PDD decreases as the depth in tissue increases.

Question 61

Q

The anatomical location of the hilum of the kidneys is located at:
T5 - T6
T12 - L2
L1 - L5
S1 - S3

Answer

A

T12-L2

The kidneys are retroperitoneal with the right kidney lower, due to the liver pushing it downward. The hilum of the right kidney sits at L2 and the hilum of the left kidney sits at L1

Question 62

Q

Collision interlocks of the on board imagers should be checked.
Daily
Weekly
Monthly
Annually

Answer

A

daily

Collision interlocks should be checked daily. The test is a pass/fail test. The interlocks are designed to protect the safety of the patient, staff and equipment.

Question 63

Q

When treating pancreatic cancer, what target volume does not have to be routinely identified?
Kidneys
Liver
Rectum
Small Bowel

Answer

A

rectum

As recommended by The International Commission on Radiation Units and Measurements (ICRU) report 62, other routine anatomy that needs to be identified is the spinal cord. This is due to the location and dose received as critical structures in that treatment area. Total GTV dose is between 50.4 to 54Gy. All the organs at risk tolerance doses are higher than the prescribed doses.

Question 64

Q

A patient suffering from hypoglycemia should be offered:
Orange juice sweetened with sugar.
A salad.
Coffee.
Water.

Answer

A

Orange juice sweetened with sugar.

Hypoglycemia refers to a condition caused by a very low blood sugar level. Hypoglycemia is often related to diabetes but there are other illnesses and conditions that can cause low blood sugar. Symptoms of low blood sugar include fatigue, pale skin, an irregular heart rhythm, shakiness, anxiety, sweating, hunger, irritability, tingling sensation around the mouth and crying out during sleep. Severe hypoglycemia symptoms include confusion, blurred vision, seizures, and loss of consciousness. A patient suffering from hypoglycemia should be given juice sweetened with sugar to raise their sugar level.

Answer 65

A

L4

The common iliac nodes side at the bifurcation of the common iliac arteries. The bifurcation of the common iliacs comes off the abdominal aorta at the level of L4

Answer 66

A

measurement of electron beams
output constancy checks
instananeous response

Silicon diodes are useful due to their high sensitivity, instantaneous response, and small size. They are also used for patient dose monitoring.

Answer 67

A

To block the exit beam and protect the nasal septum

Lead may be inserted into a cavity beneath a primary field in order to block the exit beam and reduce dose to structures below the surface.

Answer 68

A

well differentiated

Well differentiated tumor cells are most similar to the original cells. This means they are less aggressive and typically carry a more favorable prognosis.

Answer 69

A

timing the radiation beam is on

An example of gating would be when the beam is on within the breathing cycle when treating lung cancer. This occurs during the resting phase of the breath, on expiration.

Answer 70

A

Interlocks

Interlocks will prevent machine operation when something is incorrect. Interlocks are designed to protect patients, staff and the equipment. Additional examples of interlocks include door interlocks, time delays, pressure and temperature interlocks, and many more.

Answer 71

A

Determine the degree of cell differentiation

The purpose of cancer staging is to define the tumor size, determine optimal treatment, and determine the degree of lymph node invasion. Grading is the process to determine the degree of cell differentiation.

Answer 72

A

± 2 mm

ACR practice guidelines state that the delivery treatment should be within ± 2 mm for mechanical tolerances.

Answer 73

A

photoelectric

The photoelectric interaction results in the ejection of an inner shell electron. The loss of the inner shell electron creates an unstable atom that causes transition of an electron from another shell into the vacant shell. The movement of the electron from one shell to another produces a secondary x-ray photon.

Answer 74

A

isocenter

Isocenter is the intersection of the three axes of machine rotation, gantry, collimator and base of couch

Answer 75

A

T5

The bifurcation of the trachea into the right and left main stem bronchus is called the carina. The carina generally sits at T4 - T5.

Answer 76

A

dry desquamation

A stage II skin reaction follows erythema. It results in dry, flaky skin and is referred to as dry desquamation. It is usually itchy and can be treated with a mild topical steroid. Further radiation can cause the skin to break down changing dry desquamation into moist desquamation and, rarely, to ulceration. Skin reactions tend to worsen as treatment continues and often reaches its worst point a week following the completion of treatment.

Answer 77

A

controlled

A controlled area is supervised by a person trained in radiation protection and includes the treatment room, console control, and any adjacent treatment rooms

Answer 78

A

low fiber diet

A change in bowel habits is a common side effect of radiation therapy to the pelvic area. To assist patients during this time a low-fiber, or low-residue, diet is recommended for patients receiving pelvic irradiation. Eating a diet low in residue such as fiber, fat, and some milk or vegetable products, helps to reduce the frequency of bowel movements, which may help reduce or prevent diarrhea.

Answer 79

A

44 cm x 44 cm

Use the similar triangle philosophy or the following equation:
a/b=a^’/b^’〖field〗_1/〖field〗_2 =
〖TSD〗_1/〖TSD〗_2 → 40/x=100/110 → 40*110=100x → 4400 =100x → 4400/100=100x/100 → 44 = x

Answer 80

A

upper outer

The upper outer quadrant is the most common location, followed by central, upper inner, lower outer, and lower inner quadrants.

Answer 81

A

20

If a medical event has occurred, the licensee in an NRC state must notify by telephone the NRC operations center no later than the next calendar day after the discovery of the medical event. In addition, a written report must be submitted to the NRC regional office within 15 days after the discovery of the medical event. The report must include the licensee’s and prescribing physician’s name, a description of the event, what effect occurred, why the event occurred and actions taken, and certification that the individual or relative was notified.

Answer 82

A

bacteria

Strep throat is an example of infection by bacteria. It is contagious and can be treated with antibiotics.

Answer 83

A

Angstrom

A unit of length equal to one hundred-millionth of a centimeter(10-10meter), the angstrom is used mainly to express wavelengths of electromagnetic radiation.

Answer 84

A

photoelectric absorption

The interaction between the incident x-ray photon and an inner shell electron is the photoelectric absorption.

Answer 85

A

C3

The angle of the mandible is approximately 6 cm below the external occipital protuberance and associated with cervical spine C2 - C3. Also, the hyoid bone is approximately 1 cm below the angle of the mandible when the head is in a neutral position.

Answer 86

A

itching and urticaria

A mild allergic reaction presents with itching and urticaria (hives). Mild allergic reaction symptoms can progress to severe symptoms if not treated. Sudden severe allergic reaction symptoms, such as in the case of anaphylaxis, can include laryngeal tightening, shock, and cardiac arrest.

Answer 87

A

450 mSv

The cumulative effective dose to the whole body for occupational workers is calculated by multiplying the person’s age by 10 mSV. (45 years)10 mSv = 450 mSv

Answer 88

A

Leaf transmission

Leaf transmission is an example of an attenuation test. Other categories of MLC tests include positional precision tests (such as leaf speed), position accuracy, and field shaping.

Answer 89

A

percussion

Inspection involves looking at the patient and is useful when identifying edema, skin lesions, asymmetry, etc. Palpation uses a light finger touch and is used to identify lymphadenopathy, inflammation, presence of inflamed nodes, etc. Auscultation involves listening to sounds in the body, such as the heart, lungs and bowels.

Answer 90

A

beam shape and position
projection of the beam’s central axis

Portal images verify the beam’s eye view, including the beam shape, position, and projection of the beams central axis.

Answer 91

A

50 mSv

NCRP established an annual effective dose limit of 50 mSv for occupationally exposed personnel.

Answer 92

A

kidneys

Blood work is required to check renal function prior to contrast administration, as nephrotoxicity can result if the renal funtion is poor.

Answer 93

A

fomite

This type of transmission involves inanimate objects that can become contaminated with infectious agents and serve as a mechanism for transfer between hosts.

Answer 94

A

localization

Verification images document that the treatment portals and patient positioning compare to the reference treatment area for accurate treatment. This is typically done prior to initial treatment and throughout the course of treatment as prescribed by the radiation oncologist.

Answer 95

A

type of source
amount of radioactive material

The thickness of protective shielding required for brachytherapy sources depends on the type and amount of the radioactive material.

Answer 96

A

T4-T5

The carina is the bifurcation of the trachea at the level of T4-T5. This is where the right and left main bronchi branch, which is a common location for reference mark placement during lung CT simulation.

Answer 97

A

11.2 x 11.2

To solve, the area of open area must be found, then the area of blocked area. Subtract the difference and square root the answer.

Answer 98

A

platelets

Platelets are the most radioresistant in circulating blood as they can withstand greater than 50 cGy.

Answer 99

A

Compton and photoelectric

Compton and photoelectric interactions both result in ionization of atoms. When atoms are ionized, energy is imparted. Coherent (classical) interactions do not ionize atoms; therefore, no energy is given up. Therefore, Compton and photoelectric interactions result in the highest exposure to the patient.

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