Aerial view of the Los Alamos Neutron Science Center

New Isotopes Take Aim at Cancer

October / November 2004 By: Jeff Stewart Volume 2 Number 5

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Until recently, cancer radiotherapy had much in common with the trade of blacksmithing.

To repair a tiny crack, the blacksmith of the early 19th century had to plunge the metal into the hot forge. As the smith pumped the bellows, the metal glowed cherry-red. The blacksmith then had to hammer the metal on the anvil until the crack was beaten completely out. Metal held too hot, too long became weak and brittle.

To treat cancer, radiologists in the early 20th century had to load their patients into large X-ray machines. When the radiologist flipped the switch, the patient was exposed to a near-lethal dose of X-rays. The cancer may have been beaten down, but the patient emerged from the treatment weak at best.

Welding and radiotherapy have both undergone recent revolutions. Modern TIG (Tungsten Inert Gas) welders replace the forge with very small, very hot electric arcs. Likewise, modern radiotherapy replaces the X-ray machine with very small, very energetic radioactive isotopes. Modern welders no longer heat up the whole piece of metal; instead, the heat is applied just where it is needed, and an argon/helium sheath prevents the heat from damaging the rest of the metal. Likewise, modern radiotherapy no longer exposes the whole body to X-rays but uses antibodies to target radioactive isotopes to the surface of cancer cells, and the short-lived radioisotopes decay quickly before damaging the rest of the body. The modern welder does not hammer the metal or keep it hot for long periods, so the metal emerges whole and strong. Likewise the modern radiologist can expect the patient to suffer from many fewer side effects and to emerge from treatment with greatly improved heath.

With the new generation of targeted cancer radiotherapy comes the need for a new generation of very hot, short-lived radioactive isotopes. The Isotope Production Facility (IPF) at Los Alamos National Laboratory is stepping up to that challenge.

The $23 million IPF opened its doors in January 2004. In attendance at the IPF's dedication were New Mexico Governor Bill Richardson, U.S. Senator Jeff Bingaman, Los Alamos Director Pete Nanos and the chief of the Department of Energy Office of Nuclear Energy, William D. Magwood IV.

The IPF is the first dedicated isotope production facility constructed in 20 years. The IPF does not compete with commercial isotope manufacturers.
Instead, the IPF generates research and medical isotopes not available in the commercial market.

The IPF works by diverting a portion of the Los Alamos Neutron Science Center (LANSCE) main proton beam to the IPF's underground target chamber. In the chamber, the proton beam collides with target elements, and the target elements undergo nuclear reactions. With the high-energy beam properly targeted, the IPF creates new short half-life isotopes with very high purity. (See illustration at left.)

The Isotopes

The IPF produces about 30 different isotopes in any one year (see table). The specific isotopes produced each year are based on customer requests received by the DOE. This flexibility is especially important when drug manufacturers attempt to incorporate new, short half-life isotopes in the next generation of cancer drugs and medical diagnostics. The IPF supports the small production runs necessary for clinical trials and is not constrained by profit motives.

Historically, almost all commercially important medical isotopes were created in universities and national laboratories and only later produced by industry. For example, Los Alamos first generated 82Sr and 68Ge, which are today widely used in PET (positron emission tomography) scans.

"The short lived isotopes produced by this facility and other accelerators in the DOE complex provide vital isotopes required to diagnose, treat and research serious illnesses such as heart disease and cancer," said Secretary of Energy Spencer Abraham. "The radioisotopes produced by the new beam spur at the Los Alamos accelerator center will help assure the uninterrupted supply of these isotopes."

The new, short half-life isotopes created by the IPF not only deliver high-dose radiation to cancer but also cease being radioactive in a very short time period. Thus, these isotopes are less likely to cause damage to non-target organs such as the liver or kidneys.

To learn more about the IPF, visit the IPF website at http://cstis2.lanl.gov/external/inc/isotopes/default.htm. To order specific isotopes, contact the IPF Team at isotopes@lanl.gov.

Jeff Stewart is a business development executive with the LANL tech transfer office.