Liver cancer radiotherapy:

Hepatocellular carcinoma accounts for
most liver cancers.
In most cases, the cause of liver
cancer is usually scarring of the liver
(cirrhosis). Cirrhosis may be caused by:

Alcohol abuse (the most common
cause in the U.S.)
Certain autoimmune diseases of the
Diseases that cause long-term
inflammation of the liver
Hepatitis B or C virus infection
Too much iron in the body
Patients with hepatitis B or C are at
risk for liver cancer, even if they do not
have cirrhosis.

This novel form of radiotherapy, called
radiomicrosphere therapy, offers new
hope for patients with inoperable
hepatic metastases or unresectable
primary liver tumors (hepatocellular
carcinoma or cholangiocarcinoma).
The tiny beads packed with
yttrium-emitting radioisotope might also
buy some additional time for patients
waiting for liver transplants by
preventing tumor.
These benefits come only if the
cancer-killing microbeads can be kept
around the tumor. Unlike monoclonal
antibody therapy, these beads are not
naturally drawn to nor do they meld
with the cancer. Instead they are
infused in a nearby region and then
carried via the circulatory system to
the tumor.
A form of molecular imaging called
SPECT/CT, which combines single
photon emission computed
tomography and X-ray computed
tomography, may be the best tool for
determining the likely path of these
cancer-killing microbeads. With this
form of radiotherapy, also called
radioembolization, tiny beads are
impregnated with a radioisotope and
injected into the liver with a catheter
inserted through the groin.
Prior to therapy, nuclear medicine
physicians simulate therapy by
injecting patients with the imaging
agent Tc99m-MAA, which emulates the
migration pattern the spheres will take.
Molecular and X-ray imaging with
SPECT/CT technology provide the
essential information interventional
radiologists need to then block blood
vessels surrounding the targeted
organ with small metal coils, effectively
isolating the microbeads during

Varian's Trilogy system: combines the
capabilities of other external beam
radiation technologies -- including
Cyberknife, Tomotherapy, and Novalis;