FDA clears Siemens artifact correction

Siemens Medical Systems has become the second gamma camera vendor to win Food and DrugAdministration 510(k) clearance for a nonuniform attenuation correctionproduct. Siemens' Hoffman Estates, IL, nuclear medicine grouplast month got the FDA's imprimatur to market the technique asan option for the open-configuration versions of its MultiSPECT2 and MultiSPECT 3 dual-head and triple-head gamma cameras. Siemenscompetitor Picker International was the first vendor to marketattenuation correction last year (SCAN 6/1/94).

The Siemens approach relies on offset fan-beam collimators,which have advantages over the centered fan-beam techniques usedin competing systems, according to Reinout Vogt, manager of newproduct development. A radioactive source is mounted to the sideof a detector rather than in the center, with the gamma rays detectedby the offset fan-beam collimator opposing the source. This increasesthe detector's effective field-of-view and avoids truncation artifacts,Vogt said.

The radioactive source used by the technique is americium,which has a half-life of 433 years and thus does not need to bereplaced for the life of the gamma camera. The vendor of the americiumsources has agreed to take them back when the camera is retired,Vogt said.

Siemens plans to begin shipping open-configuration MultiSPECT2 and MultiSPECT 3 cameras later this year. They can be linkedwith any DICOM 3.0-compatible workstation (SCAN 11/23/94).