Naviration
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NaviRation™ – mobile optical system
for all geometrical tests of linear accelerators
The principle
The principle of NaviRation™ is synchronous registration of two stereo images of the target attached to a moving part of the accelerator (gantry, collimator, treatment table).
Camera mounting
Cameras are mounted at a distance of ~100 cm from each other on a horizontal beam, which is attached to the vertical boom (Figure 2).
The position of the boom and the beam may be defined by the user.
Workstation
The camera mounting structure is attached to the mobile platform on which the workstation is located. The workstation consists of a PC with peripheries, a UPS system and an electronic system responsible for power supply and synchronisation of cameras.
Cameras
In the current version of the measuring device, cameras with a 5 Mpix matrix are used (with a single pixel size 5 ηm x 5 ηm, ensuring image acquisitions with a frequency of up to 22 Hz (mono image, 8 bit per pixel).
Software and measuring
An integral part of the system is the software written by our team.
The developed app allows for detection and rotating the target (Figure 3). The software receives a synchronised signal from stereo cameras and analyses the images of the marker. During one turn of the shoulder of the accelerator’s arm 1200 images that determine the marker’s position (more than 3 images per 1 degree) are being collected. A similar number of data is collected for the collimator and the therapeutic table. Then, the registered set of images is analysed.
The isocentre of the medical accelerator (treatment table and collimator) for every angle of rotation is obtained with an accuracy of below 0.1 mm. The whole measuring time is about 20 minutes.
Functionalities of the current version of the system NaviRation™ allow for:
- Determining the sphere of the isocentre, and the location of the rotation for every angle of rotation for the gantry, the treatment table and the collimator.
- Determining the mutual position of the rotation axes of the gantry, the table and the collimator.
- Determining the precision of the translational movements of the therapeutic table.
- Determining the position of lasers relative to the average location of the isocenter.
- Checking the accuracy of the telemeter indicator.
One of many reasons to choose NaviRation™
NaviRation™ enables to make all tests recommended by the TG142 protocol of the American Association of Medical Physicists.
It assures measurement of the geometric movements of the accelerator with an accuracy level unsurpassed by any other device. The maximum measurement error does not exceed 0.1 mm.
The measurement outcomes are idependent of the measured device (accelerator) and from the person performing the measurement.
The reliability of the measurement is confirmed by a certificate of calibration received from the Polish Central Office of Measures.
NaviRarion provide remote user support.
NaviRation™ enables to make all tests recommended by the TG142 protocol of the American Association of Medical Physicists.
NaviRation™ assists ccelerators’ service teams in tasks related to mechanical calibration of the line accelerator.
