   
 Dosimetric External Beam Measurement
With
the increasing complexity of radiation therapy techniques, it is
important that physicists have the tools necessary to perform composite
dose verification tests accurately and efficiently. Designed by
experts, including Jake Van Dyk, at the London Regional Cancer Centre,
the QUASAR™ Verification Phantom enables accurate measurements on a
wide variety of radiotherapy techniques, including IMRT, SRS and
rotational therapies, such as VMAT, RapidArc™ and TomoTherapy®.
The Verification Phantom is comprised of a cylindrical phantom, a film
cassette and several inserts for holding and positioning an ion hamber.
The cylinder is 25 cm long, long enough for many head and neck
treatment plans. Film cassettes are available for Gafchromic or
light-sensitive film. Inserts are available for ion chambers from
several major vendors.
The cylindrical design of the Phantom allows the user to reposition the
film and ion chamber without having to re-image the phantom or
re-calculate the dose distribution.
Simultaneous Film and Chamber Measurements
360° rotation of cylinder allows film
to be orthogonal to any beam angle
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The
cylinder is supported at both ends and can be rotated to any angle
about the horizontal axis (as shown to the left). The rectangular
opening is large enough to hold both a film cassette and an ion chamber
holder at the same time for simultaneous measurements.
The ion chamber can be placed on the central axis of the cylinder or repositioned radially in 2.5 mm increments. |
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