• 7/2/2006
  • Clarksville, TN
  • Greg Kline
  • Clarksville Leaf Chronicle

Head and neck cancers kill about a person a day. Even when treated successfully, they tend to leave patients hurting both physically and psychologically.

“The side effects of our treatment are really devastating in some respects,” said Kenneth Watkin, a University of Illinois speech and hearing science professor.

Watkin, whose research focuses on the diagnosis and treatment of oral cancers, might have found a new way to do both better, using particles 80,000 times smaller than the width of a human hair.

The particles of a material called gadolinium oxide, developed by the UI professor and former graduate student Michael McDonald, make tumors show up more clearly in magnetic resonance and molecular imaging and in ultrasound and CT scans. That could allow the cancer to be located and attacked with greater precision and less collateral damage to surrounding tissue.

Moreover, the particles are better at gathering neutrons and emitting alpha and gamma radiation than the boron commonly used in neutron capture radiation therapy now, which could permit the use of lower doses of radiation in eradicating a tumor and reduce the negative side effects as a result.

“The treatment (benefit) is a bonus, a great bonus,” said Watkin, who refers to the particles as “multimodal” because of their dual purposes.

Watkin and McDonald, now a postdoctoral researcher at Stanford University, also have developed a method of coating the particles in dextran, a natural carbohydrate. The coating helps prevent unwanted chemical reactions and particle clumping, which makes for a clearer MRI picture.

Watkin likened the carbohydrate coating to the outer shell of a tiny M&M. It has no effect on the properties of the gadolinium oxide particles.

The coating also provides a surface to which the researchers can attach biologically reactive molecules, for instance antibodies that tend to gravitate to cancer cells.

That technique might be used to make the capsules, in effect, a cancer-seeking smart bomb sized to travel through the bloodstream and find and hit its target.

Watkin said the capsules might be made with payloads other than gadolinium oxide, like drugs for chemotherapy treatment or genetic materials for gene therapy.

“We just encapsulate that inside the shell,” Watkin said.

He said the payload can be released once it reaches the target by using ultrasound to break open the shell.

“It is working really well,” Watkin said.

The researchers already have employed the method to deliver interference RNA, a basic component of our genetic system, to cancer cells cultured in the lab. The intervention halted the cells’ propagation.

They began working with gadolinium oxide because the material is particularly sensitive to the magnetics employed in MRI.

They then decided to test the particles, which they make by breaking up already minuscule nanoparticles of gadolinium oxide, with other medical imaging techniques and were pleasantly surprised by the results.

That, in turn, led them to explore the material’s potential therapeutic properties, said Watkin, who is part of bioimaging research efforts at the UI’s Beckman Institute and a fellow with the National Center for Supercomputing Applications at the UI.

The researchers outlined the project in the journal Academic Radiology recently. Watkin, who also studies cancer imaging in conjunction with Carle Foundation Hospital in Urbana, said a lot of work remains before the UI technique is used for diagnostic and treatment purposes, which could take years.

Still to be explored: what the nanoparticles do in the body beyond their relation to cancer diagnosis and treatment; and how long any effects last.