Mini-accelerator springs from Star Wars research

A California start-up firm is hoping that a new type of linearaccelerator it is developing will make the acquisition of positronemission tomography scanners more palatable for hospitals. Theaccelerator would use superconducting technology and would bemore compact than cyclotrons now used to manufacture PET radioisotopes.

AccSys of Pleasanton, CA, is working with Argonne NationalLaboratory to develop a "tabletop" linear acceleratorthat will be small enough to overcome many of the problems hospitalsencounter when siting the cyclotrons that accompany PET scanners.

The short half-lives of PET radiotracers require that theybe produced as close to scanners as possible, usually in the samefacility. Nearly all PET sites use cyclotrons to produce tracers.Cyclotrons weigh many tons and often require extensive buildingmodifications before they can be sited.

If AccSys is successful in bringing its drawing-board plansto fruition, the company's superconducting linear acceleratorwould reduce the need for such modifications significantly, accordingto James M. Potter, senior research scientist at AccSys.

The accelerator would be about 5 ft long and about 2 ft highby 2 ft wide, Potter said. It would weigh about 1500 lbs. Standardlinear accelerators are about three times as long and weigh fouror five times as much.

Reducing the size of the tracer-producing machinery is amongthe developments that must take place before PET can move beyondresearch institutions and into community hospitals, accordingto Potter.

"This promises to be even more compact and suited fora hospital environment," Potter said. "There won't beany special requirements on the building for linear accelerators."

Because of the superconducting technology, the AccSys linearaccelerator would consume less power and create a very high acceleratingfield in a smaller space than room-temperature accelerators. Thedrawback is that the AccSys would require a special refrigerationunit to keep it cold. The refrigerator could be remotely located,however, making it possible to place the accelerator near thePET scanner for convenient access to isotopes.

The accelerator is based on technology called radio-frequencyquadrupole, developed at Los Alamos National Laboratory in theStrategic Defense Initiative (Star Wars) program and spun offto AccSys.

Another PET linear accelerator system developed with fundingfrom the National Institutes of Health and the SDI program isbeing tested by Science Research Laboratories of Somerville, MA(SCAN 7/31/91).

AccSys has received a federal small business innovation researchgrant to pursue development of the superconducting accelerator.The company is planning to build a proof-of-principle acceleratorand test it with a charged particle beam. That could take severalyears, and full commercialization could be several years beyondthat. But if the tabletop accelerator does become a reality, itcould have a significant impact on the PET market.

"This may be the thing that makes the PET scanner a morepowerful clinical tool," Potter said.