MOSBY Flashcards
A joule is a unit of:
energy
The space in front of the epiglottis is called the
Vallecula
Which of the following cancer types has the highest mortality rates?
Ovarian
The type of nutrition that bypasses the gastrointestinal tract and introduces nutrients into the veins is called:
parenteral
Which of the following radioactive elements has the shortest half-life? A. Au-198 B. Pd-103 C. I-125 D. Tc-99m
D Tc-99m
Au-198 has a half-life of 2.7 days, Pd-103 is 17 days, I-125 is 59.4 days, and Tc-99m is 6 hours.
Which of the following cells has the highest radiosensitivity? A. neurons B. chondrocytes C. osteoblasts D. lymphocytes
C.Osteoblasts
Osteoblasts are the most sensitive because these bone cells are young and immature. Therefore they are still dividing, making them the most sensitive.
Which of the following techniques is used to treat early pre-cancers of the cervix?
loop electrosurgical excision
The LEEP, loop electrosurgical excision procedure, is a suitable technique used to remove precancerous tissue from the cervix.
A form of anticancer therapy that uses the body’s own immune system will often require the production of:
monoclonal antibodies
Monoclonal antibodies are produced to boost the body’s immune system.
Measuring the heart rate by using a stethoscope over the patient’s heart is an assessment of the:
apical pulse
The apical pulse is measured at the apex of the heart and requires listening at the chest with the ear or stethoscope.
Wilm’s tumor originates in the:
Kidney
The definitive treatment modality for the treatment of colon cancer is:
surgical resection
Endocrine glands are characterized by
secretion of hormones
The law of Bergonnie and Tribondeau state that sensitivity depends on?
The radiosensitivity of a tumor could depend upon the
mitotic activity; histological types have higher mitotic activity than other histological types.
Within the first two weeks of standard, fractionated radiation therapy, the patient will experience:
- erythema
- moist desquamation
- epilation
- Erythema
2. Epilation (hair Loss)
Malignant neoplasms that originate in lympho-reticular tissues are called:
Lymphomas
Patients suffering from _______ will show weight loss, feelings of fullness even with little food consumption, and a lack of strength.
Cachexia
Decreased muscle strength
asthenia
Characteristics of cachexia include all of the following except: A. weight gain B. anorexia C. early satiety D. asthenia
A. weight gain
occurs when you are unable to eat a full meal or feeling of fullness from a small meal
early satiety
A breast bridge may be used to
immobilize the breast tissue
The breast bridge may be used to immobilize and reposition a large breast. It may also be used to assist in the determination of tangential angles of the gantry.
The System International unit for activity is the: A. becquerel B. curie C. hertz D. roentgen
A. becquerel
A common subacute postradiation syndrome following total CNS radiation is:
myelitis
Myelitis is inflammation of the spinal cord. It is a common symptom following total central nervous system radiation
Radon is a natural radioactive gas with a half-life of:
4 days
Which of the following types of crystals can be found in a thermoluminescent dosimeter?
Lithium fluoride
Total parenteral nutrition is also known as:
hyperalimentation
Total parenteral nutrition (TPN) is a method of feeding that bypasses the gastrointestinal tract.
Malnutrition caused by a physiological change or malfunction is called: A. anorexia B. bulimia C. cachexia D. emacia
C. Cachexia
Cancer cachexia is weight loss or malnutrition caused by some physiological situation secondary to cancer.
It is recommended that therapists working on high energy accelerators limit the time used handling physical wedges and custom blocks to protect hands from: A. lead and copper contamination B. proton contamination C. neutron contamination D. alpha particle contamination
C. neutron contamination
Treatment would likely be interrupted if the patient’s platelet count was about:
90,000
The normal platelet count ranges from 150,000 to 450,000 in the adult.
If radiation is used preoperatively for the management of colon cancer, the total tumor dose would be____Gy.
50Gy
Which of the following disorders is the likely cause of reported familial clusters of esophageal squamous cell cancers? A. Barrett's esophagus B. GERD C. HIV/AIDS D. tylosis
D. Tylosis
Radiation to which of the following areas may result in myelosuppression?
A. ilia, vertebrae, ribs, skull, sternum, and long bones
Myelosuppression may be caused at doses above 20 Gy to the sternum, iliac crests, ribs, spine, skull, and long bones.
How much energy is in one atomic mass unit (amu)?
931 MeV
1.66 x 10-27 kg is 1 amu. Use E = mc2 to convert this mass to energy.
A persistently high arterial blood pressure is known as:
hypertension
High blood pressure is also known as hypertension.
For greater tumor control of Ewing’s sarcoma, radiation dose must be higher than:
40 Gy
In radiation therapy, which of the following interactions with matter are least important? A. photoelectric effect B. pair production C. Compton effect D. nuclear disintegration
A. photoelectric effect
The photoelectric effect decreases with increasing photon energy. Beyond 150 keV, the fraction of radiation interactions in water and tissue attributed to the photoelectric effect are negligible.
A dosimeter consisting of ferrous sulfate, sodium chloride, and sulfuric acid is called a/an:
Fricke dosimeter
A sign of low oxygen content in the body is:
cyanosis
A sign of low oxygen content is cyanosis or blue coloring of skin or nail beds.
A patient suffering from a bacterial infection may have an elevated body temperature resulting from _____________released by the bacteria.
. pyrotoxins
Pyrotoxins are chemical agents released by some bacteria triggering fever.
Which of the following is a nonmalignant condition treated by stereotactic radiosurgery?
Arteriovenous malformation is a benign condition treated by SRS.
An abnormal connection between arteries and veins, usually in the brain or spine.
Rigid muscles and jerky body movements are seen in patients experiencing:
convulsive seizure
Which of the following photon interactions with matter involves energy being converted to mass?
Pair production
The photon interacts with the atomic nucleus resulting in the production of an electron and a positron. The energy of the photon was converted in the mass of the electron and positron.
Among the following, which of the following sites is common for the development of Ewing's sarcoma? A. ribs B. skull C. pelvis D. mandible
C. Pelvis
Which photon interaction with matter involves direct photon interaction with the nucleus?
pair production
Pair Production involves a photon with an incident energy greater than 1.022 MV interacting directly with the atomic nucleus
Which of the following tumors originates in osseous tissue?
Chondrosarcoma
Which of the following should be checked on a linac daily?
A. light/radiation field coincidence
B. beam flatness and symmetry
C. field size indicators
D. none of the above
D. none of the above
All of the above parameters are to be checked monthly.
A complex cartilaginous structure that prevents regurgitation of stomach contents is the:
upper esophageal sphincter
The upper esophageal sphincter is a cartilaginous and muscular structure that prevents regurgitation of stomach contents.
In craniospinal irradiation, using 100 cm SSD, the spinal cord field length is 30 cm. The brain field length is 15 cm. To eliminate divergence of the brain portal into the spinal portal while treating the lateral brain fields, the couch should be rotated___degrees toward the gantry.
4.3
The rotation of the couch during the brain fields is given by applying the divergence formula: tan-1 (A/2(SSD)). The divergence of the brain field is what must be known.Therefore, tan-1 (15/2(100)) = 4.28 degrees.
The normal range for platelets in the adult is:
150 to 500 thousand/mm3
On inspiration, the diaphragm moves:
caudad (towards the feet)
A dizzy feeling associated with sitting or standing after a prolonged period of bed rest is calle
postural hypotension
The pathogen among the following that commonly causes infection in cancer patients is:
pseudomonas
Pseudomonas is a bacterium that is commonly an agent of severe nosocomial infections.
The wavelengths of X-rays are measured in:
angstroms
In a linear accelerator, the flatness of the clinical electron beam is created by the:
scattering foil
Scan and couch positional accuracy for CT planning must be:
2mm
The process of cellular growth and development is called:
proliferation
Which of the following are adverse results of cachexia?
- increased caloric intake
- impairment of immunities
- changes in metabolism
- electrolyte imbalance
- impairment of immunities
- changes in metabolism
- electrolyte imbalance
Neuroblastoma originates in the:
nervous system
When adjacent fields are used to treat deep tumors, the fields should be:
separated on the skin and overlap at depth
When adjacent fields are used, a skin gap should be calculated so that the beams overlap at depth beyond any critical organs.
The most common lung cancer found in nonsmokers is:
adenocarcinoma
Custom shielding blocks that are divergent reduce:
beam edge cutoff
Hair loss is usually permanent when the scalp is exposed to radiation doses exceeding:
60Gy
Which of the following is not part of the digestive system?
appendix
Ionizing radiation can disrupt chemical_______in biological material.
Bonds
The average diastolic pressure in the adult is about:
60 to 90 mm of Hg
Another term for the pituitary gland is the:
hypophysis
Which of the following is true regarding stochastic effects of radiation?
There is no dose threshold.
The risk of effect increases with dose, meaning there is no dose threshold for a radiation effect.
The main components of an electronic portal imaging device include all of the following except: A. viewing monitor B. fluorescent screen C. camera D. klystron
D. klystron
The electronic portal image devices have a viewing monitor, fluorescent screen, and television camera.
A patient is mistakenly treated at 82 cm SSD instead of 80 cm SSD due to a misalignment of the ODI. The planned dose was 300 cGy. What was the approximate dose delivered?
Using the inverse square law. 300(80/82)2 = 285.
The output energy will be altered if the _______ malfunctions. The __________ is the source of electrons.
Electron gun
Which of the following photon beam energies would have the highest HVL for the same absorber material? A. 250 KV B. 1.25 MV C. 511 KV D. 6 MV
6mv
Higher beam energies are more penetrating and require more absorber material to reduce the beam to half of its original intensity.
Moh’s surgery may be used to establish diagnosis and staging of which type of cancer?
skin
If there are 168 mCi of cobalt-60 today, how much activity was present eight years ago? A. 56 mCi B. 482 mCi C. 107 mCi D. 627mCi
B. 482
The tissue dose of radiation associated with a 5% complication rate in 5 years is known as the:
TD 5/5
A patient undergoing treatments to the oral cavity and oral pharynx will experience:
- altered taste
- sore throat
- sifficulty swallowing
Superior vena cava syndrome occurs when:
A. Excess fluid in the pericardial space causes pressure and compromises the heart’s ability to pump.
B. Excess fluid in the pleural cavity leads to dyspnea.
C. ECG shows tachycardia.
D. Compression from a tumor or enlarged lymph nodes causes obstruction of the superior vena cava.
D. Compression from a tumor or enlarged lymph nodes causes obstruction of the superior vena cava.
The Trendelenberg position is appropriate for a patient experiencing a medical emergency such as:
shock
The Trendelenberg position has the patient’s feet slightly elevated to promote blood flow to the heart. The position would be beneficial for a patient in shock or syncope.
All of the following are possible complications of intravenous injections except A. air emboli B. infection C. phlebitis D. congestive heart failure
congestive heart failure
Phlebitis
vein inflammation
When irradiating extremities, a strip of soft tissue should be spared in order to:
prevent obstruction of lymphatic flow from the distal portion of the limb
In the adult, a platelet count within normal range would be approximately_______mm3:
400,000
Normal adult platelet count ranges from 150 to 450 thousand per mm cubed.
Most thyroid cancers develop from cells of which histological origin?
papillary
During injection of contrast for CT simulation, your patient complains of difficulty breathing and feeling faint. He is likely experiencing:
moderate symptoms of anaphylactic shock
Anaphylactic shock is not an uncommon response to the injection of contrast material. Moderate signs include difficulty breathing, changing levels of consciousness, nausea, and vomiting. Injection of contrast should stop and physician should be alerted.
The drug Decadron is used to decrease:
inflammation
Decadron is an anti-inflammatory steroid used to manage inflammation and sometimes radiation or chemotherapy-induced nausea and vomiting.
A low residue diet would be recommended for the patient receiving radiation to the:
bladder
What percentage of adenomatous polyps ( A small clump of cells that forms on the lining of the colon or rectum. )of the colon contains invasive cancer cells?
3% to 5%
The normal limits for BUN (A blood urea nitrogen (BUN) test measures the amount of urea nitrogen in your blood) in mg/dL for the adult are:
10 to 20
The type of thyroid cancer characterized by rapid growth and local invasion of structures is:
anaplastic
In treating tumors of the lung, the threshold dose for radiation pneumontis is______cGy
2000 to 2500
The energy of an electromagnetic radiation is inversely proportional to its:
wavelength
A common area of spread for medulloblastoma is:
cerebrospinal fluid
The function of lymph nodes is to
filter lymph
produce antibodies
The normal body substance released by tissue in response to an allergic reaction is:
histamine
The adrenal glands are located at about the level of thoracic vertebrae number:
T12
A treatment plan has a prescription dose of 3000 cGy. The dose is prescribed to the 95% isodose line. What dose value does the 50% isodose line represent?
1579 cGy
Find the maximum dose by dividing 3000 cGy by the prescription isodose line, then multiply the maximum dose by the isodose line.
The linear attenuation coefficient (μ) is expressed in:
1/cm
When treating the floor of the mouth, a bite block may be used to :
move the palate away from the treatment fields
When treating the floor of the mouth, the palate may be spared by using a bite block to move the palate up and away from treatment fields.
Through which route are most drugs excreted from the body after metabolism?
kidney
If the upper mantle is treated, the arms may be elevated above the head or positioned akimbo in order to move the:
axillary nodes away from the thorax
The target volume includes the regional nodes. The caudal margin is the inferior border of the obturator foramen. The cephalad margin is L5. The lateral margins are 1 cm beyond the true pelvis. The nodes included are the external and internal iliacs. The target volume just described is for the treatment of:
Bladder
A lumbar spine field with the central axis at lumbar vertebrae number 3 will be located at about the level of the_________on the patient’s skin surface.
iliac crest
The iliac crest or umbilicus is a good surface landmark for lumbar spine 3.
The prodromal stage of acute radiation syndrome consists of:
nausea
The prodromal stage consists of nausea and vomiting.
In craniospinal irradiation, using 100 cm SSD, the spinal cord field length is 30 cm. The skull field length is 15 cm. To align the skull field with the divergent spinal field, the amount of collimator rotation required for the skull field is:
8.53 degrees
The rotation of the collimator for the skull field is given by applying the divergence formula; tan-1 (A/2(SSD)). The divergence of the spine field is what needs to be known so that the collimator angle is parallel. Therefore, tan-1 (30/2(100)) = 8.53 degrees.
Luteinizing hormone (LH) stimulates sexuality and some reproductive function. LH is secreted by the_______gland.
pituitary
The French-American-British (FAB) staging system is used to classify:
Acute Leukemia
The way a drug interacts with the body to produce its intended effect is called its:
mechanism of action
A patient who has experienced a severe anaphylactic reaction to contrast may be administered:
epinephrine
A severe anaphylactic reaction to contrast may cause cardiac and respiratory distress/arrest. Epinephrine may be administered from the crash cart to rescue this patient.
The signs of a petite seizure include
. sudden cessation of focus and response
. sudden gasp or sharp vocal cry
In a linear accelerator, microwave amplification occurs in the:
Klystron
The klystron amplifies the microwaves used to accelerate electrons in the waveguide.
A necessary instrument for examination of the inner ear would be the
otoscope
The unit of exposure in the air is the:
Roentgen
During X-ray production, the process by which electrons are liberated at the cathode is known as:
thermionic emission
Thermionic emission describes when electrons are burned off of the filament.
All of the following are primary bone malignancies except A. osteosarcoma B. Ewing's sarcoma C. giant cell tumor D. cystosarcoma
D. cystosarcoma
Some histological types of primary bone tumors may be osteosarcoma, Ewing’s sarcoma, giant cell, fibrohistiocytoma, multiple myeloma, and chondrosarcoma.
The process of modifying the beam profile to optimize the dose distribution throughout the treatment volume is called:
intensity modulation
The iliac crest is located at about the level of lumbar vertebrae number:
Lumbar 4
Increasing the dose rate on a linear accelerator will _______the percent depth dose.
not change
In case of an emergency, a patient with advanced directives:
has prior instructions about care
Metastatic disease may lead to an abnormal accumulation of fluid in the pericardial sac. This may lead to:
pericardial tamponade
Pericardial tamponade is a result of abnormal pressure on the cardiac muscle; it manifests as irregular heartbeat and may ultimate lead to cardiac arrest.
Which of the following is true of Beta+ decay?
A proton is converted to a neutron.
Primary skin cancers with the worst prognosis are:
Melanomas are the deadliest skin cancers.
About one week after the infusion of certain chemotherapy agents, the skin in a previously irradiated area may show signs of erythema, blistering, and pain. This phenomenon is known as radiation:
recall
Radiation recall occurs about one week after the administration of chemotherapy drugs like doxorubicin, daunorubicin, 5 FU, or bleomycin. The previously treated area may become red, blistery, and painful.
What type of dose response model applies to MR to address biologic effects of the magnetic fields used to image patients?
nonlinear, threshold
The biological effects on patients undergoing MR shows a nonlinear, threshold dose-response relationship.
A T1 glottic larynx will likely be treated using opposing lateral fields using field sizes of about
6 x 6
When a patient is receiving oxygen, it is important for the therapist to do all of the following except:
A. carry the tank by the regulator apparatus
B. maintain the prescribed flow
C. see that the tube is not accidentally clamped shut
D. make sure that the tank does not run out of oxygen
A. carry the tank by the regulator apparatus
Dense metal accessories should be placed at a suitable distance from the patient’s skin surface in order to prevent contamination from secondary (select two):
1. electrons 2. neutrons 3. lead 4. radon
- electrons
2. neutrons
Fine needle aspiration can be used for bone biopsy. What is the main disadvantage of this procedure?
The histological architecture of the bone might not be preserved.
Which is not true of the electromagnetic spectrum? All photons in the spectrum have the same:
energy
A type of isolation used for highly communicable diseases and requiring personnel to wear gown, gloves. and mask would be called___________isolation:
strict
In which region of the pharynx is the pyriform sinus located?
hypopharynx
A type of shock associated with bacterial infection and its byproduct is called:
septic
Which of the following best describes an isodose curve?
Points within the patient receiving the same dose are joined together forming a curve.
B. Points on the patient’s
Lucite is often used as the material for positioning devices. One major concern when this material is in the path of the treatment beam is:
Beam attenuation
To interact by photoelectric effect, the interacting photon must have energy:
equal to or greater than the binding energy of the orbiting electron
When actual dose delivered needs to be verified, in vivo dosimetry can be accomplished by using:
TLDs
TLDs measure absorbed dose and can be placed on the patient’s skin surface and compared to calculated skin dose.
A high-energy photon strikes an orbital electron and scatters exactly 180 degrees. What is the maximum energy of the scattered photon?
255 kV
From the law of conservation of energy and momentum, it can be shown that an incident photon with a very high energy directly striking an electron and being scattered 180 degrees will have a maximum energy of 255 kV. The majority of the incident photon energy will be imparted to the electron.
The maximum allowable transmission through the multileaf collimators is:
5%
Which of the following is the definition of linear attenuation coefficient (μ)?
fraction of photons attenuated per unit thickness
The correct name for the abdominal region in the middle of the abdomen is:
umbilical
The volume percentage of red blood cells in whole blood per 100 ml is the:
hematocrit
The tolerance for variation in collimator rotation around the point of isocenter is:
2mm diameter
Exchange of oxygen and carbon dioxide to tissues occurs across the walls of:
capillaries
Which radioactive isotope is most commonly used in High-Dose Rate (HDR) afterloading Brachytherapy?
Ir-192
Which of the following foods should be avoided by patients receiving radiation therapy to the pelvis?
- corn
- oatmeal
- raw vegetables
- corn
- oatmeal
- raw vegetables
The lobes of the thyroid gland are separated by the:
Isthmus
The photons produced during the orbital transitions of electrons from a higher to lower energy shell are called:
Characteristic radiation
The preferred material for the patient couch as part of the CT simulator or linear accelerator is carbon fiber. This material is preferred due to its (select two):
- transparency
- radiolucency
- radio-opacity
- low attenuation
radiolucency
low attenuation
Which of the following is true of Co-60 decay?
Excess energy is given off as two gamma rays of discrete energies.
Electron contamination of high energy photon beams may result from photon interactions with the:
Collimators
:When calibrating ion chambers, which of the following correction factors are needed?
- barometric pressure
- volume of the chamber
- temperature
- beam energy
- barometric pressure
- volume of the chamber
- temperature
During treatment requiring the use of whole abdomen fields, the structure at the greatest risk for latent effects after 44 Gy is the:
kidney
The tolerance doses of the kidney and liver are low. TD 5/5 for the whole liver is about 30 Gy whereas the TD 5/5 for the kidney is 23 Gy. The pancreas and gallbladder have higher tolerance doses.
You are called in to treat a spinal cord compression. The physician asks you to set a preliminary field to cover thoracic vertebrae 3, 4, and 5 on the treatment table. The approximate field si
8 x 8
The thoracic vertebrae are about 2.5 cm in length. 3(2.5) = 7.5. To include the transverse processes, the width of the field will be about 8 cm.
Which of the following would be considered a typical α/β ratio for early responding tissue?
10Gy
Which type of nutritional support bypasses the gastrointestinal tract and introduces nutrients into the veins?
total parenteral
The quality factor for gamma radiation is:
1
The quality factor for gamma ray, X-ray, and electrons is 1.0.
Most bladder cancers are histologically classified as:
transitional cell
What is the purpose of the maze in the shielding design of a linac vault?
to prevent direct beam incidence on the door
Soft tissue sarcomas usually spread:
along the muscle plane and compartment where it originated
Your patient receiving radiation to the neck complains of dry mouth and thick, ropy saliva. He is experiencing:
xerostomia
A reduction in overall treatment time without a change in total dose is known as:
accelerated fractionation
A 360 degree rotation has an MU/degree setting of 0.72 MU/degree. How many monitor units will be delivered?
Use direct proportion. 0.72 MU:x as 1 degree:360. 0.72 (360) = 259.
The production of X-rays by bremsstrahlung,
increases with increasing atomic number
Which is true of the definition of Tissue Maximum Ratio (TMR)?
Dose at depth is referenced to dose at Dmax.
Syncope is another name for:
fainting
Exceeding the TD 50/5 for the spinal cord may lead to:
myelitis necrosis
A 10 x 10 cm lung field has a blocked area that is 2 x 5 cm. The blocked equivalent square is:
The blocked equivalent square is found by subtracting the closed area from the open area. 10(10) - 2(5) = 90. Then square root of 90 = 9.5 cm.
For a clinical whole brain without the use of a face mask, the inferior border will be at the mastoid process and (select two):
- lateral canthus
- supraorbital ridge
- external auditory meatus
- lower ear attachment
Supraorbital Ridge
External Auditory Meatus
If custom blocks need to be used, the shadow tray will_________the output.
decrease the output
There is 100 mCi of Cs-137 and 300 mCi of Co-60. Calculate the time it will take for both isotopes to decay until their activities are equal.
10.12 years
Between the thyroid notch and cricoid cartilage lies the:
Larynx
Patients undergoing irradiation for breast cancer can be positioned:
- supine
- lithotomy
- prone
- lateral oblique
supine
prone
lateral oblique
In Relative Biologic Effectiveness (RBE), the biologic effect of a particular type of radiation for a given dose is compared to the biologic effects of _________ for the same dose.
250Kv X-rays
Erythema is defined as:
any congestion of capillaries causing abnormal redness
The medication used to decrease the possibility of clot formation is:
heparin
Heparin is used to reduce the possibility of clots.
Most pancreatic tumors occur in which area of the pancreas?
head
Total body irradiation acute side effects include (select two):
1. nausea 2. parotiditis 3. pneumonitis 4. hypothyroidism
- nausea
2. parotiditis
The normal limits for PSA in the patient under 60 years old is less than or equal to:
4 ng/mL
The supraclavicular fossa should be treated when managing breast carcinoma when:
Supraclavicular lymph nodes are positive.
One type of natural background radiation is:
cosmic
Cosmic and terrestrial radiations contribute to natural background radiation.
The tolerance dose (TD 5/5) for the optic chiasm is:
60 Gy
A muscular organ located in the true pelvis of the female, bordered by the bladder and the rectum is the: A. uterus B. spleen C. fallopian tube D. ovaries
A. uterus (muscle)
The uterus is a muscular, hollow organ superior to the bladder and anterior to the rectum at midline in the pelvis of the female.
1 roentgen in air is equal to:
- 58 x 10-4 C/kg
2. 58 s 10-4 C/Kg is equivalent to 1 roentgen in air.
The average rate for respiration in the adult, in breaths/minute is:
10 to 20
How many atoms are in one gram atomic weight of I-125?
4.81 x 1021 atoms
The number of atoms in one gram atomic weight is given by Avogadro’s number (6.0228 x 1023). Dividing this number by the gram atomic weight of any element will give the number of atoms per gram atomic weight.
0.01 joule/kg is equivalent to:
1 rad
1 cGray = 1 joule/kg. Therefore 1 rad = .01 cGray = .01 joule/kg.
A treatment time of 3 minutes and 4 seconds requires that a wedge be added. If the wedge factor is 0.650, what will the new treatment time be?
First convert the treatment time to minutes only. 3 minutes and 4 seconds = 3.06 minutes. If a factor needs to be added in, compute by dividing the treatment time by the new factor. 3.06/0.65 = 4.71 minutes. Converted to minutes and seconds is 4 minutes and 43 seconds.
Although tamoxifen reduces the risk of breast cancer, what type of cancer may be a side effect of tamoxifen therapy?
endometrial
What is the equivalent square for a 15 cm x 20 cm field size?
Equivalent square = 2 x length x width/length + width.
A patient is treated with a set of parallel opposed fields using SAD technique. The isocenter is located at midplane. If the patient’s thickness along the central axis is 24 cm and the SAD is 100 cm, what is the SSD of each treatment port?
If the patient separation is 24 cm and the isocenter is at midplane, the depth of treatment is 12 cm. SAD-treatment depth = SSD. 100-12 = 88 cm.
The distance between the entrance and exit points for parallel opposed ports is called the:
interfield distance
The primary documented risk for the development of thyroid cancer is:
radiation exposure
The largest lymphatic organ is the:
spleen
The tissue of a malignant carcinoma is:
epithelial
The Dukes staging system uses letters such as A, B, C, and D to classify tumors of the:
Colon
The main route of breast carcinoma as it metastasizes is first through the:
axillary lymph
1500 photons from a photon beam are directed toward a metal block that is 10 cm thick. 375 photons emerge from the other side of the block. What is the half-value layer of this metal block?
5 cm
When protons interact with matter:
A. The rate of ionization increases as the proton is slowed down in matter.
B. Energy can be given off as bremstraahlung.
In which region of the pharynx are the pharyngeal tonsils located?
nasopharynx
Which of the following examination instruments is necessary for a Papanicolaou test?
Speculum
Squamous cell carcinoma would be the likely histological classification for a malignant growth in the: A. stomach B. colon C. testis D. larynx
D. Larynx
Of the sites listed, the larynx will most likely be squamous cell.
Which of the following equipment produces extra nuclear indirectly ionizing radiation?
Linear accelerator
Metastasis from primary bone cancer often shows up in the:
Liver
Metastasis from primary bone cancer shows up in the lungs, liver, adrenal glands, and brain.
The histological type of lung cancer most closely associated with asbestos exposure is:
mesothelioma
Which theory of radiation interaction is illustrated by the operating principles of an ionization chamber?
Bragg-Gray cavity theory
Bragg peak is:
maximum ionization near the end of the range of a heavy, charged particle
The production of red blood cells is regulated by:
erythropoiesis
The appropriate medical term for the shoulder blade is the:
scapula
Which of the following is true of electromagnetic radiation (select two)?
- The electric and magnetic fields are parallel to one another.
- The electric and magnetic fields are perpendicular to one another.
- Electromagnetic radiation has a dual nature exhibiting a wave model and a quantum model.
- The wavelength of electromagnetic radiation increases with energy.
- The electric and magnetic fields are perpendicular to one another.
- Electromagnetic radiation has a dual nature exhibiting a wave model and a quantum model.
In a diagnostic X-ray tube, A/C is converted to D/C by means of:
rectification circuit (diode0
Rectification circuits (also known as diodes) restrict the flow of current to one direction. Therefore, current does not flow in the opposite direction when the polarity reverses, resulting in a single direction of current flow so that the electrons constantly move from the cathode to the anode.
A surgical procedure in which an incision is made through the abdominal wall to examine lymph nodes and establish the extent of disease is called a/n:
laparoscopy
The type of resection in which the tumor is scraped away is known as:
curettage
Beam symmetry and flatness are defined over what percentage of the field?
80%
A squamous cell carcinoma localized to the nasopharynx will most likely be treated by:
external beam radiation therapy to 6,000 cGy in 6 weeks
In which region of the pharynx are the palatine tonsils located?
oropharynx
Which of the following is not a likely symptom of chemotherapy? A. nausea and vomiting B. interference in DNA synthesis C. increase in mitotic rate D. decrease in blood counts
C. increase in mitotic rate
In linac vault shielding, the fraction of time in a treatment day in which a beam will be pointed at a particular barrier is represented by the:
usage factor
All naturally occurring radioactive series ultimately decay to a stable form of:
Lead
The standard treatment of choice for most differentiated thyroid cancers is:
surgery
Compared to X-rays, the LET for protons is:
higher
Germ cells proliferate during:
meiosis
Skin cells are called:
epithelial
Anaplasia describes:
loss of differentiation
Which type of chemotherapy is known to cause hearing loss?
cisplatin
What is the tolerance for the daily check of linac output constancy?
3%
Total dose for prophylactic cranial irradiation for small cell lung carcinoma is typically:
3600 cGy
Prophylactic cranial irradiation for small cell is usually 35 to 40 Gy.
Patients who receive total body irradiation at an early age may develop a second cancer such as:
osteochondroma
The opening to the uterus is known as the:
cervical os
Brachial plexopathy is a possible adverse effect following high dose irradiation to the:
supraclavicular fossa
The brachial plexus is a bundle of nerves in the lower neck, near the supraclavicular fossa. Radiation therapy to the supraclavicular area may cause numbness and limited use in the upper extremity when this bundle of nerves is irradiated to high doses of radiation.
The traditional unit for absorbed dose equivalent is the ______while the SI unit is the sievert.
rem
If the threshold energy of 1.022 MeV is not present for Beta+ decay to occur, then a nucleus with an excess number of protons will release energy by:
electron capture
If the lower mantle is treated for the management of Hodgkin’s disease, gonadal protection is:
desirable b/c most pt are very young
The average energy deposited per unit path length to a medium by ionizing radiation as it passes through that medium best describes:
Linear energy transfer (LET)