MRI tracking of tumour ablation by carbon nanotubes
26 July 2010
A new way of monitoring carbon nanotubes as they destroy
tumour cells by laser induced heating has been developed by researchers
from Wake Forest University Baptist Medical Center in the US.
The work builds on an experimental technique for treating cancer
called laser-induced thermal therapy (LITT), which uses energy from
lasers to heat and destroy tumours.
Multi-walled carbon nanotubes (MWCNTs) can absorb the energy of a
laser and convert it into heat. If the nanoparticles are within a
tumour the heat will kill the cancerous cells.
The problem with LITT, however, is that while a tumour may be
clearly visible in a medical scan, the particles are not. They
cannot be tracked once injected, which could put a patient in danger
if the nanoparticles were zapped away from the tumour because the
aberrant heating could destroy healthy tissue.
Now the team from Wake Forest Baptist has shown for the first
time that it is possible to make the particles visible in the MRI
scanner to allow imaging and heating at the same time. By loading
the MWCNT particles with iron, they become visible in an MRI
scanner. Using tissue containing mouse tumours, they showed that
these iron-containing MWCNT particles could destroy the tumours when
hit with a laser.
The research was presented at the 52nd Annual Meeting of the
American Association of Physicists in Medicine (AAPM) in
Philadelphia this month.
"To find the exact location of the nanoparticle in the human body
is very important to the treatment," says researcher Xuanfeng Ding
MS. "It is really exciting to watch the tumour labelled with the
nanotubes begin to shrink after the treatment."
The results are part of Ding's ongoing Ph.D. thesis work -- a
multi-disciplinary project led by Suzy Torti, Ph.D., professor of
biochemistry at Wake Forest Baptist, and David Carroll, Ph.D.,
director of the Wake Forest University Center for Nanotechnology and
Molecular Materials, that also includes the WFB Departments of
Physics, Radiation Oncology, Cancer Biology, and Biochemistry.
A previous study by the same group showed that laser-induced
thermal therapy using a closely-related nanoparticle increased the
long-term survival of mice with tumours. The next step in this
project is to see if the iron-loaded nanoparticles can do the same
If the work proves successful, it may one day help people with
cancer, though the technology would have to prove safe and effective
in clinical trials.