Gantry Sensor + (GS+)
The GS+ is a wireless gantry angle measurement device intended to be used during verification of patient treatment plans (patient QA) and the verification of the treatment unit performance (machine QA) by qualified and trained clinical personnel (e.g., Medical physicist or dosimetrist). The GS+ is not a standalone device, but an accessory to dose measurement devices.
Powered by two exchangeable AA batteries, the device is connected to the detector via Bluetooth. The unit consists of a base and a sensor.
Sensor
The sensor is a single unit that is mounted on the base. There is no adjustment for tilt introduced during mounting.
Base
The base is attached directly to the gantry and normally stays on the gantry while the sensor can be easily
mounted or unmounted from the base. If more than one location is needed, it is convenient to have a base installed at each location.
Left: GS+ front view, 1: RGB-LED indicating the GS+ initiation; Right: GS+ side view, 2: Sensor, 3: Base
GS+ Holder for Halcyon/Ethos machines
To enable use of the GS+ with a Halcyon/Ethos machine, a HALO Gantry Sensor + holder has been designed to securely place the device inside the machine. The HALO GS+ Holder is intended to hold the base plate and angle sensor on the back side of the Halcyon/Ethos LINAC.
Example of the holder inside a machine with the GS+ attached
The HALO GS+ Holder consists of:
- A homogenous holder with base plate extension
- Fixation screws (1)
HALO GS+ Holder
The holder can be easily mounted on and removed from the machine without any tools (see Section 4.3.1).
Left: Base plate / bayonet lock for GS+; Right: GS+ side that locks onto the base/base plate
miniPhantom R
miniPhantom R is a solid phantom used with the MatriXX Resolution to simulate measurements at a certain material depth. The phantom is provided as a basic unit with chamber and film insert sets.
Left: MatriXX Resolution in a miniPhantom R; Right: miniPhantom R with a chamber detector: 1: Basic unit, 2: Uniform insert
miniPhantom R has a round / cylindrical shape, ideal for rotational cases. The central pixels of the device
can be positioned at isocenter using the corresponding markers. It also has special markers for large field
measurement by using the Combine Fields wizard (see Section 4.1 in myQA Patients Instructions for Use).
Phantom Inserts
The inserts are designed so the geometric center of the chamber sensitive volume and film layer position
coincide with the sensor layer of the MatriXX Resolution. For material and mass density information see Section 6.2.
Two inserts are available for the miniPhantom R:
- Uniform Chamber insert (1); comes with chamber adapters (2) for:
- CC13
- CC04
- FC65-G
- Film insert (3)
CAUTION: ENSURE PROPER POSITIONING OF FILM INSERT IN THE PHANTOM
Always pay particular attention to the proper positioning of the film insert in the phantom. Make sure that the insert is not flipped, and that the film is not flipped in the insert.
Plates
Build-up Plates
The corresponding equivalent depth in water of the sensor area can be adjusted via the build-up plates, which are provided in different thicknesses (10 mm, 5 mm, 2 mm, and 1 mm). See Section 6.2 for technical specifications.
Energy Verification Plates
For energy verification measurement, a proper build-up plate is required. Special designed build-up plates for photon beams and electron beams are available. See Section 6.2 for technical specifications.
Gantry Mount
The Gantry Mount consists of two parts:
- Advanced Holder
- XY Table
- Supporting frame
- Gantry fixture
The Gantry fixture is customized to the type of LINAC used, whereas the holder is the same for all types.
Gantry mount example (Elekta with SDD 100cm). 1: Gantry fixture; 2: XY Table; 3: Supporting frame
Holder
The detector holder consists of an adjustable XY table and a supporting frame.
- The XY table is used to finely adjust the detector position to the crosshairs in the light field or positioning lasers of the accelerator.
- The supporting frame holds the detector and build-up plates on the top of the detector area.
Gantry fixture
Gantry fixtures are designed to fit to three types of LINACs from Elekta, Siemens, and Varian. Each type has two versions to achieve 100 and 76.2 cm SDDs.
Table 3.3. Gantry fixtures for Elekta, Siemens, and Varian; 1: current version, 2: previous version
| Type | SDD = 100 cm | SDD = 76.2 cm |
| Elekta | ||
| Siemens | ||
| Varian |
CAUTION: ENSURE PROPER AND SAFE POSITIONING
Always ensure proper and safe positioning of the detector in the gantry holder or the 360° holder.
Ensure that the gantry fixture and its locking mechanism are suitable for the weight of the device with gantry fixture and build-up plates.
The detector must be properly mounted, to prevent it from falling down.