Two lasers better when attacking cancer

Mar 25, 2009

Two lasers may be better than one when attacking cancer cells, according to a paper by Rice University scientists.

Yildiz Bayazitoglu, Rice's H.S. Cameron Chair Professor of Mechanical Engineering and an authority on heat transfer and fluid flow, and doctoral student Jerry Vera are using computer simulations to quantify the effect of heating nanoparticles with near-infrared lasers to kill tumors without damaging healthy tissue.

They hope to raise the efficiency of destroying tumors by fine-tuning methods of heating them based on the size and composition of not only the but also the surrounding tissue.

The paper summarizing their results, "Gold Nanoshell Density Variation with Laser Power for Induced Hyperthermia," is published in the January issue of the .

The researchers found that attacking a tumor with two lasers can heat it more thoroughly than a single laser. For tumors as large as one centimeter, simulations showed opposing lasers surgically inserted via in a minimally invasive procedure produced the most profile in every case.

Lasers and nanoparticles are already being used to treat cancer. A Houston company founded by Rice scientists Jennifer West and Naomi Halas, Nanospectra Biosciences, Inc., is conducting human tests of a system that uses nanoshells heated by near-infrared lasers to kill tumors. Bayazitoglu, West and Halas are all part of Rice's Laboratory for Nanophotonics.

The Bayazitoglu group's approach would refine such treatment by taking into account the light-scattering properties of nanoparticles. Their concern is that nanoparticles near the surface of a tumor will block a laser from reaching those at the center.

"Think about it this way: If you're driving on a very foggy night, you can only see just so far no matter how good your headlights are," wrote Vera in an article about the research. "That's because the millions of small in the air absorb and scatter the light, deflecting the beams from your headlights before they can reflect off of whatever's ahead of you on the road.

"Nanoparticles dispersed within a tumor do exactly the same thing. They're very good at absorbing laser light and generating heat, but within particularly thick tumors, that same quality prevents a lot of the light from reaching deeper into the tissue."

Bayazitoglu said this phenomenon, called "extinction," is "highly undesirable." A uniform temperature profile of at least 60 degrees Celsius has to be created to kill the whole tumor. "Raising the temperature on one end but not the other will simply allow the tumor to re-grow, and that doesn't solve the problem - or cure the patient."

The density and placement of nanoparticles in the tumor are important, said Bayazitoglu. "Ideally, you should put nanoparticles at the center of the tumor, then kill it from the center out," she said.

Laser treatment may be effective even if nanoparticles are not used, she said. "If the tumor has good absorption properties, slow heating can do a good job of killing the cancer, because the heat has time to get inside. If you're doing that, sometimes it's better not to use nanoparticles."

With so many tissue types and the great variety of cancers people face, the importance of accurate simulations cannot be overemphasized, the researchers said. They hope the ability to calculate scenarios will allow doctors to find the best laser therapy to produce the perfect heating environment.

Source: Rice University (news : web)

Explore further: Gold nanoparticles help target, quantify breast cancer gene segments in a living cell

add to favorites email to friend print save as pdf

Related Stories

Nanoparticles and Lasers Create Cancer-Killing Microbubbles

Jun 19, 2006

One promising use of gold nanoparticles is to use them to convert laser energy into heat that can kill malignant cells. Now, in a promising twist on this approach to anticancer therapy, an international team of investigators ...

Nanorods show benefits cancer treatment

Mar 14, 2006

Researchers at the Georgia Institute of Technology and the University of California, San Francisco, have found an even more effective and safer way to detect and kill cancer cells. By changing the shapes of ...

Laser surgery probe targets individual cancer cells

Jun 24, 2008

Mechanical engineering Assistant Professor Adela Ben-Yakar at The University of Texas at Austin has developed a laser "microscalpel" that destroys a single cell while leaving nearby cells intact, which could improve the precision ...

Recommended for you

Cloaked DNA nanodevices survive pilot mission

Apr 22, 2014

It's a familiar trope in science fiction: In enemy territory, activate your cloaking device. And real-world viruses use similar tactics to make themselves invisible to the immune system. Now scientists at ...

Innovative strategy to facilitate organ repair

Apr 18, 2014

A significant breakthrough could revolutionize surgical practice and regenerative medicine. A team led by Ludwik Leibler from the Laboratoire Matière Molle et Chimie (CNRS/ESPCI Paris Tech) and Didier Letourneur ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

E_L_Earnhardt
1 / 5 (1) Mar 25, 2009
WELCOME ENGINEER! I think you've got this cancer thing backwards though! A RECEIVER at infa-red F. will tell you the fault within! TRAP and TRACK the infared signal! Exact frequency,180 out of phase, can RESTORE the cell to normal operation!

More news stories

Research proves nanobubbles are superstable

The intense research interest in surface nanobubbles arises from their potential applications in microfluidics and the scientific challenge for controlling their fundamental physical properties. One of the ...

Google+ boss leaving the company

The executive credited with bringing the Google+ social network to life is leaving the Internet colossus after playing a key role there for nearly eight years.