QUASAR™ MLC Beam Geometry Phantom

IMRT and other conformal therapies have led to increased demands on the physicists who must commission and maintain these systems. AAPM Task Group reports including TG 66(4), TG 53(3), and TG 51(5) make clear recommendations regarding the importance of dosimetric and non-dosimetric tests within an overall integrated QA process.

  • Tests beam integrity from CT simulation and planning to the linear acceleration and portal imaging system
  • Reveals errors in beam imaging, DICOM transfer, registration, alignment, and orientation
  • Compatible with standard collimators, MLCs, mini MLCs, and micro MLCs from multiple vendors
  • For IMRT, 3D conformal RT, and conventional RT.
  • Supports non-dosimetric tests for equipment commissioning, system characterisation, and routine QA protocols



  • 10 and 15cm square collimated beam phantom plus 3mm, 4mm and 10mm steps 17cm long
  • Phantom rotates about isocentre on vertical (couch) and horizontal (gantry) axes
  • Rotational scale readouts correspond to ICRU 42
  • 1mm diameter stainless steel ball located at the iscocentre
  • "Z" wire fiducial marker (stainless steel) in base
  • Three point leveling system with built in level indicator
  • Laser alignment marks
  • Overall height 28cm, width 36.6cm, length 42.5cm
  • Weight 13kg
  • Materials: acrylic, delrin, nylon, s.steel markers
  • Users guide with quality assurance worksheets
  • Optional shipping case - recommended

MLC Beam Geometry Phantom tests:

  • Multiplanar CT image reconstruction, geometric accuracy, orientation, and 3D measurement tools on CT simulators, radiation therapy planning systems and other imaging workstations
  • Beam display graphics at oblique gantry and couch angles
  • Digitally reconstructed radiographs
  • Portal images on linear accelerators
  • Image transfer, storage, retrieval, DICOM tools on all workstations
  • 2D image geometric accuracy and measurement tools
  • 5mm (MLC), 4mm (mini MLC) and 3mm (micro MLC) steps allow Medical Physicists to test the integrity of treatment planning systems and CT-simulators in the display of MLC-shaped fields on transverse or reconstructed images

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