Exam 23: Computed Tomography Simulation

Prior to the use of computed tomography (CT)in the simulation process,contouring was performed by use of solder wire or plaster.

A CT scanner specifically designed for use in the radiation therapy department should have which characteristics? I.high performance scanner II.laser and patient marking system III.virtual simulation capabilities

Of the four methods by which contrast media may be introduced into the body,which are the most common in CT simulation? I.oral II.intrathecal III.intravascular IV.intra-articular

Monthly quality assurance check for a CT simulator should include: I.spatial resolution II.Hounsfield number/electron density verification III.reconstruction slice location IV.image transfer protocols V.left/right registration and distance between known points check

Which of the following are benefits of CT simulation? I.the ability to outline critical structures and view these structures in three dimensions II.machine setup parameters and treatment accessories unable to be verified on the CT scanner III.virtual simulation allows for construction of DRRs without patient present

The reconstructed field of view that is displayed on the computer monitor should be large enough to display: I.the entire contour II.the immobilization device III.pertinent anatomy only

The level of noise on a CT image is affected by which of the following factors? I.mAs and kVp II.filtration III.pixel size IV.slice thickness

Of the following list of contrast agents,which is not water soluble and therefore should not be used in the gastrointestinal tract if there is an increased risk of perforation?

The aperture or bore size of a CT scanner should be large to allow for patients to be scanned in treatment planning position.

What does spatial resolution measure?