User manual

74
STAR SHOT ANALYSIS (Video: http://www.youtube.com/watch?v=CPtz-0dHbR8)
I. SCOPE
The protocol applies to GafChromic
™
EBT2, EBT3 and EBT3+ films exposed on
a linear accelerator and analyzed using FilmQA
™
Pro software. It provides an
efficient method for evaluating the isocenter position of linear accelerators using
the star shot test. The exposed films are scanned on an Epson
®
10000XL or
11000XL scanner in either transmission of reflection mode. Dose calibration of
the film is not required as the analyses are performed directly from the scanned
images without transferal to dose space. The method encompasses gantry,
collimator and couch star shots.
II. EQUIPMENT AND MATERIALS
 One (1) 8”x10” piece of Gafchromic
™
EBT2 or EBT3 film or 8”x11” piece of
EBT3+ film per star shot test.
 Adhesive tape
 Two (2) plastics slabs larger than the film. Slabs sized 5x30x30 cm
3
should be
available in most clinics, but other sizes could be used at the discretion of the
physicist.
 Linear Accelerator
 Pencil or fine-tipped marker
 Ruler
 48-bit RGB Epson
®
10000XL or 11000XL flatbed scanner, preferably with
transparency adapter
 Epson
®
Scan software
 FilmQA
™
Pro software
III. PROCEDURE
A single sheet of film is to be exposed for each test. For EBT2 and EBT3 films
use a single 8”x10” sheet for each test. For EBT3+ film, tear a single piece along
the perforation and use the 8”x9½” sheet for the test while saving the 8”x1½”