Bentel Treatment Planning

Card Set Information

Bentel Treatment Planning
2014-03-20 12:49:06
radiation therapy
Textbook Review
Bentel Treatment Planning Chapter Review Questions
Show Answers:

  1. Linear accelerators produce high energy beams by accelerating _________ in a _________.
    Charged particles in a Linear tube

  2. Insertion of aluminum, copper & tin filters into the x-ray beam causes:
    Low energy x-rays to be absorbed

  3. Radiation therapy units operating at approx 50-120 kVp are:
    Superficial units
  4. Orthovoltage units usually operate in the energy range of:
    150 to 500 kVp

  5. The penumbra of a linac is ________ than that of a cobalt 60 machine.

  6. A flattening filter reduces the _________ in the center of the beam.
    Reduces the DOSE RATE in the center of the beam

  7. The _________ beam from a linac is intercepted by ionization chambers and a flattening filter.

  8. The secondary collimator of a linac is largely responsible for the _________ of the beam edges.

  9. BSF is independent of _________ but depends on _________ and _________.
    BSF is independent of SSD

    BSF depends on energy & field size

  10. Dose rates in air express the dose measured without a _________ and with a _________ at a given distance.
    w/o a Phantom

    w/ a Build-up cap

  11. Dose rates ________ with increased field size and
    dose rate INCREASE with increased field size.

  12. Dose rates _________ with increased distance.
    dose rates DECREASE w/ increased distance

  13. PDD is dependent on:
    • Energy
    • Field size
    • Distance

  14. Penumbra will __________ with increased SSD, decreased SCD, and increased source size.

    (increases w/ SSD & source size but decreases w/ SCD)

  15. The PDD at a given depth ________ with higher beam energies.

  16. The amount of backscatter ________ with lower beam energies.

  17. The depth of Dmax for any photon beam is reduced by ________ field sizes and ________ incidence.
    • Larger field sizes
    • Oblique incidence

  18. In an electron beam, the ________ isodose curve bulges out and the ________ isodose curve constricts.
    • 20% bulges
    • 90% constricts

  19. When POP 6mV photon beams are used in a 20 cm thick patient, the maximum dose will occur at the:
    Entrance/Exit of each field

  20. The three planes in a patient are across the body, along the body in a lateral view and along the body in an anterior view. What is each one named?
    • Axial: across the body
    • Sagittal: along the body in a lateral view
    • Coronal: along the body in an anterior view

  21. The most commonly used energies to treat H&N cancer are:
    4 MV and 6 MV photons

  22. When carcinoma of the oropharynx is treated, the field junction between opposed lateral and an inferior field should be set _________ of the thyroid notch.
    Cephalad (superior)

  23. To include the entire maxillary sinus without including the eye when the patient is treated for maxillary sinus tumor, the chin is _________ and the head _________.
    • Maxillary sinus tumor:
    • Chin extended
    • Head tilted back

  24. Wedges are _________ (always/never) needed when treating true vocal cord tumors.

  25. Early vocal cord tumors w/ normal mobility are cured by XRT alone in about ____% of cases.

  26. Retinomblastoma is a tumor of the eye that usually occurs in _________.
    Small children

  27. The most common of all intracranial malignancies is:
    Metastatic disease

  28. When adjacent fields are matched, it is more important to match the ________ precisely during a given treatment than to reproduce the ________.
    • Fields
    • Location

  29. To appreciate the position of the the eyes relative to the beam a radiopaque marker is placed on the ________ of each eye.
    Lateral/Outer/Boney Canthus

  30. Dose heterogeneities within the brain when opposed lateral fields are used are increased when ________(lower/higher) energy photon beams are used.

  31. To minimize the divergence into the eye on the opposite side, when treating a brain through opposed lateral fields, the beam is centered at the _____________ of the eye.
    Lateral Canthus of the eye

  32. A vertex field is difficult to treat because the ________ and the ________ must be turned.
    Couch and Gantry

  33. When the entire spinal axis must be treated, the patient's posterior surface should be as flat as possible to ____________.
    Make the dose as uniform as possible

  34. Lateral brain fields and a posterior spinal field are matched by turning the ________ and the ________ when treating the laterals.
    turning the COLLIMATOR and COUCH for lats

  35. When a 3 field (vertex and opposed lats) is uswe to treat a pituitary lesion wedges are used in the ________ field(s).

  36. The disadvantage of a vertex field is that it often exits in the ________ and the ________.
    Pharynx and Spinal Cord

  37. Of all childhood brain tumors, medulloblastoma represents about ____%.

  38. The gross palpable extent and location of malignant growth:
    Gross Tumor Volume   (GTV)
  39. The tissue volume that contains the GTV and subclinical microscopic malignant disease:
    Clinical Target Volume    (CTV)
  40. Contains the tumor and adjacent tissues:
    • Planning Target Volume    (PTV)
    • (always larger than the GTV)
  41. The dose at a point that has been "forced" to 100%
    Dose Normalization
  42. What is the ratio of the absorbed dose at a given depth to the absorbed dose at a fixed reference point, usually Dmax ?
    Percentage Depth Dose  (PDD) or (%DD)

  43. What is the ratio of the absorbed dose at a given depth in tissue to the dose at the same point when it is at Dmax ?
    Tissue Maximum Ratio  (TMR)

  44. The ratio of dose on the central axis at Dmax to the dose at the same point in air is know as the __________.
    • Backscatter Factor (BSF)
    • *depends on energy & field size
    • *independent of SSD
  45. Treatment fields should always be shaped so that the beam edge crosses ___________ to the spinal cord.
  46. The attenuation of Cerrobend is about _______ less than lead.
  47. What is make-up of Cerrobend?
    (percentage of each material)
    • BLT with Cheese 
    • Bismuth: 50%
    • Lead: 26.7%
    • Tin: 13.3%
    • Cadmium: 10%
  48. The frequency of port films varies, but they should always be taken on the _______ day of treatment.
  49. In a typical CSI setup, to avoid having the caudal margin of the lateral brain fields diverge into the cephalad aspect of the posterior spinal field, the foot of the couch is turned:
    in TOWARD the collimator

    CSI: table kicked In towards the gantry
  50. The most commonly occurring cancer in the US is ________ cancer.
    LUNG cancer
  51. Opposed anterior and posterior fields in the chest invariably causes a higher dose near the _________ margin than at the ___________.
    higher dose near the CEPHALAD (superior) MARGIN than at the CENTRAL AXIS
  52. A lung boost is often delivered via:
    Opposed Oblique Fields
  53. Tumors in the lower two-thirds of the esophagus can be boosted via a _______ and two _________ oblique fields.
    Anterior & Two Posterior oblique fields
  54. In setting up opposed oblique boost fields to treat a lung tumor it is important to know the isocenter _________ in each field.
    Depth (SSD)
  55. The regional lymph nodes in breast cancer are the:
    • Internal Mammary LN
    • Supraclavicular LN
    • Axillary LN
  56. In most breast treatment techniques, field matching is a problem between the ______ & _______ fields and the ________ & ________ fields.
    Internal Mammary & Tangential

    Tangential & Supraclavicular
  57. To avoid beam divergence from the tangential fields into the supraclavicular field, the foot of the couch is turned (kicked) ________ from the collimator/gantry.
    AWAY from the gantry

    kick table Away from the gantry for tAngents
  58. The couch angle necessary to avoid beam divergence from the tangential fields into the supraclavicular field depends on the ________ of the _________ field in the direction of the supraclavicular field and the ________.
    LENGTH of the TANGENTIAL field


  59. To avoid beam divergence into the lung by the tangential fields, the central axes of the tangential fields can be separated by slightly more than ______ until the deep margins become _________.

  60. A boost is sometimes delivered to the tumor bed in breast cancer using a _________ beam or an interstitial implant.
    Electron beam
  61. The __________ lymph nodes are sometimes treated in a separate field using a photon and an electron beam or are included in the tangentials.
    Internal Mammary
  62. ________ toxicity from breast irradiation is sometimes a serious problem.
  63. The most important considerations to avoid radiation-induced pneumonitis are:
    • 1. Total Dose 
    • 2. Fractionation schedule
    • 3. Volume of irradiated lung

    DFV = Dose, Fractionation, Volume
  64. What is the most common type of glioma?

    (side note: 50-60 Gy)
  65. What are the average stats for a generic whole brain treatment?

    (field size, dose, energy, fractions)
    • Fields Size: 21x16
    • Dose: 300 cGy*
    • Energy: 6 mv
    • Fractions: 10

    *right & left lateral beams*
  66. What are the borders of a generic whole brain set-up?
    • 1. Orbital Ridge
    • 2. EAM or Tragus
    • 3. Base of Skull

    1-2 cm of flash on all sides
  67. Which type of CNS malignancy represents approx 20% of all primary brain tumors and are considered to be benign in overall nature, but locally malignant?
  68. The gantry angles for tangent fields are usually separated by _______°.
  69. When treating the supraclavicular LN of a breast cancer patient, the gantry is angled _____° away from the side of the cancer.
    15° away
  70. The Abdomen is defined as the portion of the body that lies between the _______ & the ________ and that contains the __________.
    between the THORAX & the PELVIS

    contains the PERITONEAL CAVITY
  71. Generally speaking, the kidney tolerance dose to irradiation in the adult is:
    2000 cGy delivered at 180 to 200 cGy per fraction
  72. The cephalad margin of a whole abdomen irradiation field should be set at the ________ aspect of the ___________ during quiet breathing.
    • Superior
    • Diaphragm
  73. The radioisotope _________ is sometime administered intraperitoneally in the treatment of gynecologic malignancies.
    Phosphorus 32

    (half life: 14 days)
  74. The most common site of pancreatic tumors is the ______ of the pancreas.
    HEAD of the pancreas
  75. Wilms' tumor is a tumor originating in the _______.
    • Kidney
    • (kiddie kidneys)
  76. Neuroblastoma is a tumor most often originating in the __________.
    Sympathetic Nervous System

    often arising in abdomen, chest or neck
  77. To reduce the volume of __________ within a pelvic field, the patient's position could be prone on a belly board.
    Small Bowel
  78. The primary purpose of a testicular shield is to reduce the amount of _________ dose in the testes.
    INTERNAL SCATTERED dose in the testes
  79. Of gynecological tumors treated with radiation therapy, the most common type is:
    Squamous cell carcinoma of the Cervix 

    (overall most common: endometrial)
  80. The depth of the deep inguinal nodes can vary from _____ to _____cm depending on the patient's size.
    2-18 cm
  81. Dose rates _________ with field size.
    (increase or decrease)
  82. In the case of a patient that is unlikely to complete treatment, how should kidney shielding be accomplished?
    Once the kidney tolerance dose has been reached, insert a 5-HVT block in the anterior & posterior fields
  83. The dose under a 5-HVT kidney block is approximately ______ to ______% of the dose delivered at mid-depth on the central axis.
  84. The amount of dose under a 5-HVT kidney block depends on the beam ________, the size of the _______, and the size of the ________.
    • beam ENERGY
    • size of the FIELD
    • size of the KIDNEY BLOCK
  85. The organs in which normal tissue tolerance is of concerns when treating pancreatic tumors are:
    • Kidneys
    • Liver
    • Spinal cord
  86. When a three field technique (anterior and lateral opposed fields) is used in the treatment of pancreatic tumors, the best dose distribution is achieved with wedge(s) in the ________ field(s) and more weighting on the ________ field(s).
    • wedges in the LATERAL fields
    • more weighting on the ANTERIOR field
  87. When children are treated for Wilms' tumor, the medial field margin should be include the __________.
    Width of the spine
  88. What are three methods to reduce the volume of small bowel in the pelvis?
    • 1. Surgically implanted expander
    • 2. Mesh sling placement
    • 3. Prone position
  89. How much of the kidney should be excluded from the treatment field in order to preserve proper function?
    2/3 of the kidney must be excluded
  90. When patients with advanced cervical carcinoma are treated, the majority is delivered via ________ with ________ as a possible boost.
    • External beam irradiation (majority)
    • Brachytherapy (boost)
    • (early stage is opposite)
  91. A ____________ is sometimes used in the treatment of opposed anterior and posterior fields following intra-cavitary irradiation to protect the bladder, rectum, and tissues irradiated to a high dose via the intra-cavitary implant
    Central pelvic shield
  92. In a four-field box technique used to treat a prostate tumor, the best rectal and bladder protection is achieved through ___________
    Conformal Lateral fields
  93. The skin reaction between the buttocks is reduced when a rectal carcinoma patient is treated in the ___________ position.
  94. Due to the dome-like shape of the diaphragm in the anterior-posterior view, it is impossible to treat the entire abdominal cavity without also including some volume of ________ and _________.
    Lung & Heart
  95. Insertion of a 1-HVT block in both fields during the entire course of treatment would deliver approx ______ of the dose in the shielded organs and the dose distribution under the shields would be similar to that of using ______ shields only during a portion of the treatment.
    • 50%
    • 5-HVT
  96. What are the three methods of kidney blocking?
    • 1. Fully blocking the kidneys once tolerance dose is reached
    • 2. Blocks that allow partial transmission of the beam for the entire treatment course 
    • 3. Fully shielding from one field only
  97. For small bowel contrast during simulation of a four-field pelvic plan, the patient should drink the barium _______ prior to the simulation.
    1 to 1.5 hr prior
  98. The 10-year survival for patients with all stages of Hodgkin's disease is approximately:
  99. The patient position for treatment of a mantle field in Hodgkin's disease is usually supine with the ________ extended and the arms __________.
    • CHIN extended
  100. It is always important to align the patient with the ________ laser every day because if it is not, the field is rotated with respect to the patient's body.
  101. Tattoos made in the patient's skin indicating irradiated areas can shift due to _______ and ________.
    • Growth
    • Weight changes
  102. The advantages of ________ therapy are that it provides superior normal-tissue sparing and improved precision.
    Intraoperative radiation therapy (IORT)
  103. High- and low- dose total body irradiation is used in the preparation for a _________ and in the treatment of ____________.
    • BONE MARROW TRANSPLANT (preparation)
    • total dose: 900-1200 cGy

    • total dose: 100-400 cGy
  104. The most common position for patients receiving total-skin electron irradiation is ___________.
    Standing with legs spread & arms raised
  105. The main goal of radiation therapy in patients with bone metastasis is to prevent ________ and reduce _________.
    • prevent FRACTURES
    • reduce PAIN
  106. In patients treated for a spinal cord compression, the treatment field should include approximately two ____________ in each direction beyond demonstrable disease.
    approx TWO VERTEBRAL BODIES in each direction beyond demonstrable disease
  107. Which 6 cancers commonly metastasize to the inguinal nodes?
    • Vulva
    • Distal third of the vagina
    • Urethra
    • Anal canal
    • Penis
    • Uterine Cervix

    *Vance Danced Under A Purple Umbrella Crazily*
  108. Total skin electron irradiation (TSEI) is often used in the treatment of cutaneous diseases such as ________ and _________, where a high dose is needed in the first centimeter of tissue over the entire body while the underlying tissues are spared.
    • Mycosis Fungoides  (incurable)
    • Kaposi's Sarcoma (AIDS related)
  109. The total dose prescribed for TSEI treatment of mycosis fungoides is ________ and typically ____ to ____ electron beam energies are used in order to limit the amount of _________.
    • 3600 cGy
    • 4 to 6 MeV beams
    • Bremsstrahlung
  110. What are the most common sites for bony metastases?
    • Spine (#1)
    • Ribs
    • Sacrum
    • Long bones in extremeties
  111. ________ lesions, which appear on x-rays as a less dense area in a bone, are most frequently associated with __________ or metastasis from malignant disease in breasts, kidneys, or the thyroid gland.
    Lytic lesions (reduced bone density) 

    Multiple Myeloma
  112. ___________ lesions, areas that appear denser than bone on an x-ray, are often metastatic from the breasts, prostate gland, or Hodgkin's disease.
    Osteoblastic lesions (increased bone density)
  113. When a patient requires half-body treatment but the necessary distance cannot be achieved, one can turn the collimator _____° taking advantage of the diagonal direction of the field or angle the _______ a few degrees.
    • angle the collimator 45°
    • or
    • angle the GANTRY a few degrees
  114. ______ ______ photon fields can be used to spare underlying lung tissue when treating rib metastasis.
    OPPOSED TANGENTIALS photon fields for rib mets
  115. What is the average depth of the spinal cord?
    4 to 6 cm
  116. To assure inclusion of the palpable lymph nodes within the xrt field, the lymph nodes should be indicated with __________ during the simulation procedure.
    Radiopaque marker
  117. The average dose and fractionation schedule for multifocal brain metastasis treatment is _____ cGy in ____ week
    _____ cGy in ____ weeks
    • 2000 cGy in 1 week
    • or
    • *3000 cGy in 2 weeks*
  118. A __________ technique is usually the preferred field arrangement when treating bladder tumors.
    • Four-Field Box

    power point indicates IMRT as tx of choice
  119. When a posterior and opposed lateral fields with wedges are used to treat a rectal tumor, to reduce the hot spot under the thin portion of the wedges, one can _________  (increase/decrease) the weight on the lateral fields and ________________.
    DECREASE the weight on the lateral fields

  120. The gap between the mantle & para-aortic fields, assuming the same field length and SAD, is calculated and set correctly if the patient is in the same position and the _________ border of the posterior para-aortic field coincides with the marker indicating the _________ border of the anterior mantle field.
    • Cephalad border of the posterior para-aortic field coincides with the
    • Caudal border of the anterior mantle field
  121. The most serious late consequence of high-dose TBI is __________ but thrombocytopenia occurs after _____ to _____ cGy.
    Radiation pneumonitis

    100-150 cGy (thrombocytopenia)
  122. When higher energy beams are not available to treat a prostate, heavier weight should be placed on the _________ & _________ fields.
    Anterior & Posterior fields
  123. Lesions in the lower 1/3 of the vagina require that the _______ and _______ lymph nodes be treated.
    • Inguinal
    • &
    • Femoral
  124. Name the types of bone marrow transplant:
    1. Marrow is removed from the patient during remission and re-infused after the treatment regimen is completed.
    2. Marrow is removed from a sibling who is immunologically compatible with the patient.
    3. Marrow is removed from an identical twin
    1. Autologous (auto =self)

    2. Allogeneic (all in the family)

    3. Syngeneic (synergistic twin) 
  125. What does DICOM stand for?
    Digital Imaging and Communications in Medicine
  126. Factors to consider in deciding btw an SSD or SAD technique are: 
    1. the importance of ________ in the particular patient
    2. the amount of _____ delivered through the field
    3. the actual _______ between the collimator and the patient's skin surface.
    • 1. the importance of REPRODUCIBILITY in the particular patient 
    • 2. the amount of DOSE delivered through the field 
    • 3. the actual DISTANCE between the collimator and the patient's skin surface
  127. Where is Point A located?

    (gyn brachy)
    • 2cm superior of the external cervical os 
    • and
    • 2cm lateral to the uterine tandem
  128. Where is Point B located?

    (gyn brachy)
    • 2 cm superior from the external cervical os 
    • 5 cm lateral of the patient's midline
  129. In a CT simulator, the window level influences the __________ of an image.

    level = brightness

    width = contrast
  130. In a CT simulator, the window width influences the __________ of the image.

    • width = contrast
    • level = brightness
  131. CT's operate in the energy range of _____ to _____ kev and are highly collimated.
    20 to 140 kev
  132. Positron emission tomography utilizes beta ______ decay.
    Beta PLUS

    Pet = beta Plus
  133. Nuclear medicine utilizes beta _______ decay.
    Beta MINUS

    nuke Med = beta Minus
  134. Patients are not to eat for ____ hours prior to a PET/CT.
    NPO 6 hours

    no exercise for 24 freaking hours!!!!
  135. An off axis point is any point not on the ____________. The off axis point is used as a __________ point to tell the Dr what the dosage and effect on the tissue at that point will be as well as to find the __________.
    • any point not on the CENTRAL AXIS
    • CALCULATION point
    • Off Axis Ratio (OAR)

    often used w/ hodgkin's mantle fields
  136. What is the typical width of spinal cord fields?
    8 cm

    avg length of Thoracic vertebrae: 2.5 cm

    avg length of Lumbar vertebrae: 3-3.5 cm
  137. The staging system for Hodgkin's disease is the __________ system.
    Ann Arbor system
  138. A _______________ is a computer generated 2D radiograph displaying skeletal anatomy rendered from a three dimensional data set, such as CT or MRI.
    Digitally Reconstructed Radiograph (DRR)
  139. Wilm's tumor, which is primarily a tumor of the kidney (peds), has been know to metastasize to the ______ which requires ___________ treatments.
    • metastasizes to the LUNG
    • "whole lung" treatments
  140. Lymph nodes above the diaphragm treated in a typical Mantle field:
    • Cervical
    • Supraclavicular
    • Infraclavicular
    • Axillary
    • Mediastinal
    • Hilar
  141. Lymph nodes below the diaphragm treated in a typical Hodgkin's:
    • Para-Aortic
    • Inguinal
    • Pelvic
  142. In the Paris system, the reference dose is ____% of the basal dose.
  143. The radioactive source used in a tandem and ovoid apparatus usually is _________ and is frequently in the shape of __________.
    • Cesium 137
    • Tubes or needles
  144. In which of the following situations is the use of a tandem and ovoid least useful?
    A.  Pt has large exophytic lesion in the cervix extending into the vaginal apex
    B.  Pt has undergone a supracervical hysterectomy & now has a recurrence in the cervical stump
    C.  Pt has undergone radical hysterectomy for squamous cell ca of the cervix & now has a recurrence in the vaginal apex
    (this multiple choice question has been scrambled)
  145. Ophthalmic plaques can be constructed for use with:
    A. Cobalt 60
    B. Iodine 125
    C. Ruthenium 106
    D. Iridium 192
    E. All of the above
    E. All of the above
  146. High-activity iodine 125 seed (40mCi/seed) are frequently used in ________ implants.
    Brain implants
  147. To produce approximately the same dose rate on the surface of an ovoid, the source activity must be ________ as the ovoid diameter increases.
    To produce approximately the same dose rate on the surface of an ovoid, the source activity must be INCREASED as the ovoid diameter increases.
  148. The isotope most frequently used in nasopharyngeal implants is:
    A. Strontium 90
    B. Iodine 125
    C. Gold 198
    D. Cesium 137
    D. Cesium 137
    (this multiple choice question has been scrambled)
  149. The use of intraluminal implants has been described for various sites except for the:
    A. Esophagus
    B. Bronchus
    C. Duodenum
    D. Biliary Duct
    C. Duodenum
    (this multiple choice question has been scrambled)
  150. The tissue to air ratio (TAR) at Dmax is also known as the _________.
    Back scatter factor (BSF)

    BSF = TAR@Dmax
  151. Identify & describe each whole brain set-up (including borders)
    • A. Classic or traditional whole brain w/o C1 included (borders: orbital ridge, tragus or EAM, base of skull 1-2cm w/ flash)
    • B. Whole brain w/ C1 included by adjusting collimator
    • C. German Helmet field includes whole head with a block over the eyes; no collimation; C1 not included
  152. The _______ is defined as the ratio of dose at a specified point in tissue (or in a phantom) to the dose at the same distance in the beam at a reference depth, usually 5 cm.
    Tissue Phantom Ratio (TPR)

  153. When using a vertex field to treat a pituitary lesion, the neck must be __________ or the if the head is to remain neutral, the gantry must be angled and the couch turned _____°.
    neck FLEXED (chin to chest)


    gantry angled & couch turned 90°
  154. What is a common treatment technique of pituitary lesions?
    A three field technique (vertex & opposed wedged laterals)
  155. When treating a maxillary antrum tumor, a bite block can be used to:
    Push the tongue and lower half of the mouth out of the field
  156. In a fixed SSD technique, the dose is usually normalized (or weighted) at ________. 
    at Dmax
  157. In an isocentric technique, the dose is usually normalized (or weighted) at _________.
    • at the Isocenter
    • aka the Target center
  158. Dose rates ________ with increased field size & ________ with increased distance.
    INCREASE w/ increased field size DECREASE w/ increased distance
  159. Name that fractionation:
    Irradiating a patient twice daily with a smaller than normal daily dose, making it possible to deliver 15-20% more dose over the same period of time.

    (bid or tid)
  160. Name that fractionation:
    Delivering the same or a higher dose over a shorter period of time or in fewer fractions.

    (aka. Accelerated or Canadian)