Acquisition scheme for an electron portal imaging system
US6341172B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 28, 1997 |
| Grant date | Jan 22, 2002 |
| Priority date | — |
| Expiry date | Feb 28, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01T1/2928
- WIPO fieldEnvironmental technology
- WIPO sectorChemistry
Abstract
An improved acquisition scheme for a medical imaging and treatment system 100. According to one aspect of the invention, adaptive radiation detection, for determining when therapeutic or diagnostic radiation is being applied, is provided. The imaging device 124 acquires several test images during a preacquisition delay. The maximum intensity level from these test images is defined as the upper limit of a camera 122's response in the darkness. The standard deviation of the intensity distribution is also computed. The image intensity level of the subsequent test images are compared to a radiation detection threshold which is determined to be the upper limit of the camera's dark signal, plus twice the standard deviation of pixel intensity distribution of the dark test images. If the intensities of a statistically significant number of pixels exceeds the threshold, the radiation is considered to be on. According to another aspect of the invention, a single look-up table is used for both the test images and the actual acquisition images. The single look-up table is downloaded upon detection of power to a linear accelerator 101. According to still another aspect of the present invention …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.