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Re: IoGold seed calibration
>Date: Tue, 28 Jul 1998 18:08:10 -0400
>Reply-To: Medical Physics Mailing List <MEDPHYS@LISTS.WAYNE.EDU>
>Sender: Medical Physics Listserver <medphys@cwis-20.wayne.edu>
>From: "Geoffrey S. Ibbott, Ph.D." <ibbott@POP.UKY.EDU>
>Subject: Re: IoGold seed calibration
>To: MEDPHYS@LISTS.WAYNE.EDU
>
>At 3:04 PM -0400 7/28/98, deguzman@BGSM.EDU wrote:
>>Good day everyone,
>>
>>We are preparing to order some I-125 seeds from Mentor (the IoGold seeds
>>from NASI).
>>Has everyone out there who uses these seeds sent their chamber in to be
>>calibrated with the IoGold standard?????
>>Has anyone done an "in house" intercomparison to get a "conversion factor"
>>from one seed to another (Amersham 6711 to IoGold)????
>>Does anyone have any advise or suggestions ??
>
>Both manufacturers of I-125 seeds presently on the market are calibrating
>seeds in reference to the NIST air-kerma standard that has been in use for
>a number of years. They are converting the air-kerma strength to apparent
>activity, again as has been done for a long time.
>
>Users of the IoGold seeds should refer to published parameters for the
>TG-43 algorithm. You should not have to apply a correction factor to the
>manufacturer's staement of activity, although this may depend on the
>instrument you're using.
>
>You may have heard about an correction to the calibrations based on use of
>a new wide-angle free-air chamber (WAFAC) at NIST. This change has NOT YET
>been implemented. The ADCLs are preparing to calibrate chambers to this
>"new" standard in the near future, but will not do so for several months
>yet. Similarly, the manufacturers will be able to calibrate seeds in
>reference to the "new" standard, but will not until a date yet to be agreed
>upon.
>
>What you might perceive as delays in implementing a new standard are
>necessary to make sure everyone understands clearly when the change is to
>take place.
>
>Both manufacturers should soon include a package insert with the shipments
>of seeds helping to explain this process. However, please feel free to
>contact one of the ADCLs or myself if you have additional questions. (I
>hope I haven't just raised a lot more questions!)
>
>Geoff Ibbott
>Chair, AAPM Subcommittee on Accreditation of Calibration Laboratories
>_______________________________________
>Geoffrey S. Ibbott, Ph.D, DABR, FAAPM.
>Associate Professor and Director of Physics
>University of Kentucky Medical Center
>Department of Radiation Medicine
>Lexington, KY 40536-0084
>tel: 606-323-1144 fax: 606-323-1350
>mailto:ibbott@pop.uky.edu http://radweb.hosp.uky.edu/
>
> *****
>Frequently Asked Questions (FAQ) for Medphys at:
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>
Chris Alston
alstonc@odrge.odr.georgetown.edu
I am not here a representative of my employer.
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