[ RadSafe ] Study evaluates radiation dose, cancer risk for whole-body PET/CT

[garyi at trinityphysics.com]

Just scanning the posted info, this sure sounds like a lame paper.  They seem to have taken 
a lot of well known (and theoretical) data, added a dash of multiplication, and voila! They are 
publishing.

Guess I should actually read the paper before drawing conclusions though.

-Gary Isenhower


On 14 May 2008 at 11:22, Brennan, Mike  (DOH) wrote:

Subject:        	RE: [ RadSafe ] Study evaluates radiation dose,
	cancer risk for whole-body PET/CT
Date sent:      	Wed, 14 May 2008 11:22:51 -0700
From:           	"Brennan, Mike  (DOH)" <Mike.Brennan at DOH.WA.GOV>
To:             	<radsafe at radlab.nl>

> I am not a PET/CT kind of rad guy, but this study seems to miss an
> extremely important point, and that is what is the life expectancy of
> the individual involved, both with and without the procedure?  If the
> person is going to die in the short-term without the information from
> the scan, then there is no long-term health risk.  If the procedure
> has been properly called for by the medical professionals, then it is
> reasonable to assume that the patient's overall risk is decreased by
> orders of magnitude, regardless of the theoretical increased risk of
> cancer. 
> 
> -----Original Message-----
> From: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl] On
> Behalf Of ROY HERREN Sent: Tuesday, May 13, 2008 5:09 PM To:
> radsafe at radlab.nl Subject: [ RadSafe ] Study evaluates radiation
> dose,cancer risk for whole-body PET/CT
> 
> Study evaluates radiation dose, cancer risk for whole-body PET/CT By
> Wayne Forrest AuntMinnie.com staff writer May 9, 2008
> 
> 
>  A new study from Hong Kong suggests that whole-body PET/CT scans and
> excessive radiation doses can increase the risk of cancer, especially
> among young patients and women. The research from the University of
> Hong Kong and Queen Mary Hospital in Hong Kong also offers effective
> CT radiation doses for men and women, as well as effective doses for
> combined PET/CT procedures. PET/CT "has a very important role in
> oncology and infection, and its role has been expanding," said Dr.
> Bingsheng Huang from the University of Hong Kong's Department of
> Diagnostic Radiology and Department of Clinical Oncology. "However, it
> has increased patient radiation exposure and this radiation has a
> well-known, adverse effect on patients" with a greater cancer risk.
> The purpose of the study, presented at the 2008 American Roentgen Ray
> Society (ARRS) meeting in Washington, DC, was to estimate the
> radiation dose of an adult whole-body PET/CT with a diagnostic CT scan
> and clinically evaluate the cancer risk to the Hong Kong population
> caused by the radiation exposure. Researchers analyzed whole-body FDG
> PET/CT scans from vertex to midthigh acquired on a Discovery PET/CT
> system from GE Healthcare of Chalfont St. Giles, U.K. The hybrid
> scanner is equipped with 64-slice CT technology, and the injected dose
> of F-18 FDG was assumed to be 370 MBq. Direct measurements of CT scan
> dose were performed on a standard phantom equipped with 314
> thermoluminescent dosimeters. The lifetime attributable risk (LAR) of
> cancer incidence was used to estimate the excessive risk caused by the
> radiation of a PET/CT scan. The study's source for that data was the
> "Health Risks from Exposure to Low Levels of Ionizing Radiation: BEIR
> VII Phase 2" report, published by the National Academy of Sciences in
> Washington, DC, in 2006. Researchers used the information to create a
> model to calculate the lifetime attributable risk for the Hong Kong
> Chinese population. "In this (BEIR) report, each organ's cancer risk
> is given and each organ cancer risk is calculated for a special
> radiation dose," Huang said in his presentation. "The whole-body
> cancer risk can be acquired by summing up each organ's risk." The
> researchers found that the effective radiation dose for a CT scan is
> 7.22 mSv for women and 7.42 mSv for men. The effective dose for a PET
> scan was calculated to be 6.23 mSv for both women and men. Huang noted
> a high radiation PET dose of 59.20 mSv in the bladder, attributing the
> finding to the accumulation of FDG in the bladder.
> 
> 
> Chart courtesy of Dr. Bingsheng Huang, University of Hong Kong, ARRS
> 2008 presentation. Subsequently, the total combined effective
> radiation dose for PET/CT is 13.45 mSv for women and 13.65 mSv for
> men. Using the LAR model, the researchers also calculated the cancer
> risk for men and women between the ages of 20 and 80 years. "For
> males, the cancer risk is from 0.33% to 0.09% (per 100,000 men). For
> females, it is from 0.40% to 0.11% (per 100,000 women)," Huang said.
> "We can see that the cancer risk increased when the exposed age
> decreased, and the females' cancer risk is always higher than males'."
> 
> 
> Chart courtesy of Dr. Bingsheng Huang, University of Hong Kong, ARRS
> 2008 presentation. The researchers calculated that the cancer
> incidence induced by one whole-body PET/CT scan contributes
> approximately 1% to 2% to total lifetime cancer incidence. Given this
> finding, Huang said that the radiology community should be mindful of
> the situation and clinically justify the use of PET/CT on patients.
> The researchers further recommended that "modification of scanning
> protocols tailored to the specific clinical indication should be
> considered, so as to balance between good image quality and reduced
> radiation dose exposure." By Wayne Forrest AuntMinnie.com staff writer
> May 5, 2008
> 
> 
>