[ RadSafe ] Nuclear Cleanup Could Derail an Experimental Cancer Treatment, Study Says

[gelsg at aol.com]

I agree that this material is a national (perhaps a global) resource and should not be disposed of.  The use of antibodies to carry alpha emitters directly to cancer cells is an extremely exciting prospect for treating cancers.  I will definitely lend my voice to others who will protest the disposal of this material.

Gerald Gels, CHP
Cincinnati, OH


-----Original Message-----
From: ROY HERREN <royherren2005 at yahoo.com>
To: radsafe at radlab.nl
Sent: Thu, 5 Jun 2008 4:48 pm
Subject: [ RadSafe ] Nuclear Cleanup Could Derail an Experimental Cancer Treatment, Study Says




_______________________________
June 4, 2008
uclear Cleanup Could Derail an Experimental Cancer Treatment, Study Says 
y MATTHEW L. WALD
ASHINGTON — A cleanup of nuclear waste from the cold war era threatens to 
liminate the supply of an obscure isotope that shows great promise in cancer 
reatments, according to a report by the Energy Department’s inspector general.
ut the department has concluded that the material, uranium 233, which does not 
xist in nature, is too expensive and risky to keep. The dispute is a rare 
nstance where environmental cleanup and human health are in direct opposition. 
The department is poised to dispose of a national resource,” said the report, 
hich was released on Monday.
ost of the material was produced by reactors at the Oak Ridge National 
aboratory in Tennessee by irradiating a naturally occurring material, thorium, 
ut those reactors no longer operate. A smaller amount is stored at the Idaho 
ational Laboratory, in Idaho Falls. The Idaho laboratory has a test reactor 
hat could produce uranium 233, but replacing the 700 pounds already stored 
here would take about 1,000 years, the report said.
omplicating the situation is that uranium 233 can be used as fuel in nuclear 
eapons, meaning it cannot be commercially distributed, and can be handled only 
n small quantities, to avoid the risk of an unwanted chain reaction.
roduced by adding an extra neutron to thorium, the uranium slowly breaks down 
nto another form of thorium, and then into other isotopes, including actinium 
25 and bismuth 213. What distinguishes both of these for cancer treatments is 
hat as they decay into new materials, they emit alpha particles. These 
articles can be superior to the standard form of radiation used to treat 
ancer, gamma rays, because the rays travel long distances through tissue and 
amage many cells, while the alpha particles have very short trajectories, and 
arry relatively huge amounts of energy.
A single atom delivered to a cancer cell can kill that cell,” said Dr. David A. 
cheinberg, chairman of the experimental therapeutics center at Memorial 
loan-Kettering Cancer Center in New York. “Nothing else approaches that.” 
esearch trials at Sloan-Kettering on patients with acute myeloid leukemia are 
howing promising results, Dr. Scheinberg said, using antibodies to deliver the 
adioactive atoms directly to the tumors. Researchers there are testing the 
echnique in animals for prostate, colon, lymphoma and brain tumors. 
he isotopes have a convoluted history. Uranium 233 very slowly breaks down into 
horium 229, half of it making the conversion over 159,000 years. There is a 
ignificant amount of thorium 229 only because the Energy Department has had 
ons of uranium sitting around for decades. 
he thorium is not medically useful, but its half-life, the time for half to 
onvert, is 7,340 years, and it decays into a radium isotope, and then into 
ctinium, which has a 10-day half-life. (Short half-lives are desirable in this 
ind of cancer treatment, because such materials deliver their dose promptly.) 
ne of the “daughters” of actinium is bismuth, which has a half-life of only 
5.6 minutes. Researchers are testing both the actinium and the bismuth as 
herapeutic drugs.
he bismuth, in turn, decays to a stable isotope, with “acceptable toxicity,” 
ccording to the research.
arious alternative processes have been proposed for making actinium and 
ismuth, but none have been proved. 
he Food and Drug Administration has approved two radioactive materials for 
elivery by antibody, both beta emitters, Dr. Scheinberg said; it has not yet 
pproved an alpha emitter. Beta particles have less energy and travel farther, 
aking them less helpful in treatment. 
he Energy Department spends $5 million a year on security at the building at 
he Oak Ridge National Laboratory where most of the uranium 233 is stored, and 
he building needs a one-time investment of about $25 million if it is not 
etired soon, the agency told the inspector general. 
n 2005, Congress, concerned about security and safety, told the Energy 
epartment to dispose of the material; the plan is to dilute it with depleted 
ranium, cast the mixture in cement and bury it at an underground repository 
ear Carlsbad, N.M. But shipments would not begin for another few years. 
It is the highest-security building we have down at the Oak Ridge facility 
ight now,” said Frank Marcinowski, a deputy assistant secretary of energy. 
That’s one of the reasons why we’re behind Congress’s direction for us to 
isposition it.”
llen G. Croff, a retired Oak Ridge executive who served on a National Academy 
f Sciences panel on the cleanup of radioactive materials, said in an e-mail 
essage, “In essence, this is yet another decision concerning federal budget 
riorities.” The current conclusion, Mr. Croff said, is that maintaining the 
tockpile “is not worthwhile,” but he said it might be time for an independent 
eview.

     
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