Radiotherapeutic apparatus
US8681936B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Nov 10, 2006 |
| Grant date | Mar 25, 2014 |
| Priority date | — |
| Expiry date | Aug 27, 2029 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61N2005/1056
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
A radiotherapeutic apparatus comprises a source of therapeutic radiation, a source of visible light arranged to cast a light field corresponding to the beam of radiation, and a multileaf collimator for shaping the beams, wherein a filter is disposed in the path of the visible light beam having a plurality of linear dark sections corresponding to leaves of the collimator. This prevents the incident light from falling on the leaves and removes the ghost images at source. By placing the filter in the head, the line can be very narrow and will be blurred into penumbra at the isocentre. This is therefore a very inexpensive yet effective method of reducing ghosting. A mirror can deflect the path of the visible light to correspond to that of the radiation beam, and the filter can be disposed anywhere in the beam path, such as prior to the mirror, subsequent to the mirror and prior to the collimator, or subsequent to the collimator. The filter thus creates dark sections in the light field corresponding to leaves (preferably all the leaves) of the collimator.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.