MDCB Practice Test (Multiple Choice) questions with answers

MDCB Practice Test (Multiple Choice) |\ |\ |\ |\ |\




questions with answers |\ |\




Which one of the following DVH results for a pancreatic
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treatment plan of conventional fractionation meets
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QUANTEC recommended dose tolerances? - CORRECT |\ |\ |\ |\ |\ |\



ANSWERS ✔✔25% of the stomach will receive 45Gy. |\ |\ |\ |\ |\ |\ |\




Which of the following is TRUE regarding clinical electron
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beams? - CORRECT ANSWERS ✔✔High energy electrons
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lose energy at a rate of approximately 2 MeV per cm of
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water or soft tissue. |\ |\ |\




What factors are instrumental in determining the dose
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uniformity in equally weighted parallel opposed beams? -
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CORRECT ANSWERS ✔✔beam energy, tissue |\ |\ |\ |\ |\



inhomogeneity and patient thickness |\ |\ |\




Which of the following computer algorithms can most
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accurately account for the dose calculation uncertainty in
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the interface region between inhomogeneous materials
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for photon calculations?
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*used most often to create uniform dose with photons -
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CORRECT ANSWERS ✔✔Monte Carlo method |\ |\ |\ |\

,An IMRT technique in which the patient is treated slice by
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slice by intensity-modulated beams in a manner
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analogous to CT imaging is called: - CORRECT ANSWERS |\ |\ |\ |\ |\ |\ |\ |\ |\



✔✔helical LINAC |\




Which of the following is the best thermal neutron
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absorber? - CORRECT ANSWERS ✔✔boronated |\ |\ |\ |\ |\



polyethylene


Relative skin dose from a megavoltage photon beam is
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increased by which of the following? - CORRECT
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ANSWERS ✔✔increasing the thickness bolus material
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used


The risk of symptomatic radiation pneumonitis is:
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*more "symptoms" with chemo - CORRECT ANSWERS
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✔✔increased if certain chemotherapy agents are used. |\ |\ |\ |\ |\ |\




DVHs can confirm which of the following? - CORRECT
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ANSWERS ✔✔The normal tissue tolerances are respected.
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When comparing identical (IMRT) treatment plans, one
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delivered with sliding window and the other delivered
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,with step-and-shoot, the sliding window treatment will
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most likely have which of the following? total MU / total tx
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time - CORRECT ANSWERS ✔✔higher / shorter
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What will result if a photon field abuts an electron field at
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the skin surface? - CORRECT ANSWERS ✔✔photon side
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hot spot, electron side cold spot
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Isocentric, parallel opposed oblique fields with unequal |\ |\ |\ |\ |\ |\ |\



depths may result in: - CORRECT ANSWERS ✔✔a plan with
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isodose lines that are similar to a plan with equal depths
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and unequally weighted beams.
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What can cause increased skin dose in IMRT for prostate
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cancer? - CORRECT ANSWERS ✔✔carbon fiber couch
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Which of the following processes best explains how a
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radiation beam is delivered during stepand-shoot IMRT? -
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CORRECT ANSWERS ✔✔Radiation is only delivered while |\ |\ |\ |\ |\ |\ |\



the MLC is stopped.
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Characteristics of MLC, in current medical LINACs, include |\ |\ |\ |\ |\ |\ |\ |\



which of the following: - CORRECT ANSWERS
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✔✔"scalloped" isodose curves in the penumbra region. |\ |\ |\ |\ |\ |\

, Which of the following can be determined from the V20
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obtained from a DVH for both lungs? - CORRECT |\ |\ |\ |\ |\ |\ |\ |\ |\



ANSWERS ✔✔volume of both lungs receiving 20 gy |\ |\ |\ |\ |\ |\ |\




To eliminate the divergence into the lung of both fields
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when planning an intact breast treatment using isocentric
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medial and lateral opposed fields, it would be necessary
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to: - CORRECT ANSWERS ✔✔match the posterior
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diverging beam edges. |\ |\




Physical penumbra width is defined as the lateral distance
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between which two isodose curves at the level of dmax?
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*physical penumbra = geometric & transmission |\ |\ |\ |\ |\ |\



penumbra, so lateral distance is wide - CORRECT |\ |\ |\ |\ |\ |\ |\ |\



ANSWERS ✔✔20% and 80% |\ |\ |\




Two adjacent electron fields are to be used to treat a post-
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mastectomy chestwall. The radiation oncologist has |\ |\ |\ |\ |\ |\



expressed concern that a cold spot at the surface be |\ |\ |\ |\ |\ |\ |\ |\ |\ |\



avoided. Appropriate techniques include which of the
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following? - CORRECT ANSWERS ✔✔Move the junction |\ |\ |\ |\ |\ |\ |\



several times during the treatment course.
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The minimum nominal distance a tissue compensator
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should be placed from the skin surface without affecting
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