Gamma camera start-up company aims to improve scintimammography

Gamma Medica displays breast camera at SNM show

Scintimammography has been slow to catch on, despite the promise of using nuclear medicine’s functional imaging ability to view the metabolism of cancerous lesions in the breast. A California start-up company hopes to overcome some of what it believes are the limitations of current gamma camera technology by developing what could be the first dedicated breast gamma camera to hit the market.

Gamma Medica of Northridge, CA, made its corporate debut at this month’s Society of Nuclear Medicine meeting in Los Angeles with LumaGem, a small gamma camera dedicated to imaging of small organs, including the breast. LumaGem has a novel design that improves the camera’s spatial resolution and reduces background scatter, thus creating clearer images.

LumaGem features a detector head with a 5 x 5-inch field of view mounted on an articulated arm that can be moved close to the patient. Rather than using a conventional detector with sodium iodide scintillation crystals and photomultiplier tubes, LumaGem employs a technology that Gamma Medica calls pixellated array of crystals. The detector array consists of 5600 crystal elements made from cesium iodide, paired with very high resolution, position-sensitive PMTs. The discrete pixel elements restrict light to each channel, thus reducing light spread and producing better spatial resolution.

Other advantages of the camera include its ability to be positioned very close to the breast, and the small amount of dead space around the edges of the detector head. LumaGem’s detector has about 7 mm of dead space at the edge, compared with 5 cm or more for conventional gamma cameras, according to Bradley Patt, executive vice president at the company. This enables the camera to be positioned very close to the patient’s chest wall, an important capability for breast imaging. It can also be positioned under the patient’s arm for lymph node imaging.

“It really gives you a lot of flexibility in positioning around the breast to get very close to the cyst,” Patt said.

The small size of the detector is another advantage for breast imaging, the company believes. When conducting scintimammography on a conventional gamma camera, large field-of-view systems often detect radiopharmaceutical uptake in organs near the breast, such as the liver and the heart. This can interfere with the acquisition of a clear breast image. LumaGem’s 5 x 5-inch detector effectively screens out background radiation because it isn’t large enough to cover areas beyond the organ being imaged.

Taken together, elements of LumaGem’s technology result in a camera with an intrinsic spatial resolution of 1.75 mm, compared with around 4 mm for conventional gamma cameras. This higher resolution is crucial when trying to image the small lesions that are the early stages of breast cancer. Part of the problem with scintimammography has been the inability of conventional gamma cameras to visualize tumors smaller than 1 cm, according to Patt.

Gamma Medica is developing LumaGem in collaboration with breast imaging specialists at the University of California, Los Angeles, and the company is in the process of filing a 510(k) application for the product. LumaGem will probably carry a list price of between $100,000 and $150,000, which includes a workstation featuring dedicated software that incorporates standard mammography views into LumaGem’s imaging protocols. Gamma Medica will most likely sell LumaGem through a mix of direct sales, dealers, and, possibly, OEM relationships.

Gamma Medica was formed earlier this year as a division of Photon Imaging, a developer of solid-state detectors and other advanced imaging systems. LumaGem is Gamma Medica’s first product, Patt said. Gamma Medica’s president and CEO is Jan Iwanczyk, formerly a researcher at the University of Southern California and a founder of Advanced Photonix.

Besides LumaGem, other technologies under development at the firm include a solid-state photodetector that could replace PMTs in Anger-style cameras. Called silicon drift photodetectors (SPDs), the technology could result in a gamma camera with intrinsic spatial resolution of about 1 mm. Gamma Medica researchers presented a paper on the technology at the SNM meeting.

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