Radiation detecting apparatus with reduced magnetic field sensitivity
US4523091A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 22, 1982 |
| Grant date | Jun 11, 1985 |
| Priority date | — |
| Expiry date | Mar 22, 2002 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B6/4258
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
The radiation detecting apparatus contains at least one photomultiplier tube for the detection of light. It has been found that the photomultiplier tube will emit erroneous output signals when exposed to a perturbing magnetic field. This is particularly true for photomultiplier tubes used in scintillation cameras and in emission computed tomography systems where the detector head containing photomultipliers changes position during operation. In order to reduce the magnetic field sensitivity, the radiation detection apparatus contains means for superimposing an artificial magnetic field on the perturbing magnetic field at the location of the photomultiplier tube. This artificial field may either be a compensating field or, preferably, an enhancing field which is larger than the perturbing field. The artificial field may be either generated by coils, such as Helmholtz coils, or by a permanent magnet. The coil(s) may be arranged inside or outside the camera head.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.