Re: Tc-99m Dose

[mwilliam@mailbox.uq.oz.au (Michael Williamson)]

>I hate to do this, but "can anybody out there" provide a quick ROT type
>estimate for dose from injected Tc-99m used in bone scans.
>I believe the chemical form is Technetium phosphate.

Keith, the effective dose equivalent (ICRP 53 terminology) resulting from
injected Tc99 phosphates and phosphonates varies quite a bit with the age
of the patient and the state of their kidneys (and their bone metabolism).


For an adult with normal kidney function and bone uptake, the dose
coefficient is about 8 microgray per MBq of injected activity;

For an adult with abnormally high bone uptake &/or impaired kidney
function, the effective d.e. is much the same but those for other organs
can be a lot higher or lower depending.

The coefficients for children are generally higher, much higher in some
cases.

Check out ICRP 53 p215 for details of both individual organ and effective
d.e. coefficients.


Michael Williamson
Radiation Protection Adviser
Occupational Health and Safety Unit
University of Queensland
Brisbane 4072
Australia

ph +61 7 3365 4504
fax +61 7 3365 1577

 yes, that is an 8 digit phone  number.  We've just switched in this state.