RE: Re : Dose estimates when dosimetry is lost/damaged

[stephane_jeanfrancois@Merck.Com (Stephane Jeanfrancois)]

I would like to add that this situation of evaluating a dose based on
previous experiences makes absolutly no sense, period. If you had "6"
when rolling a  dice 3 times out of 5, would you still bet on "6" again
?  (Of course if the dice is special...) I may understand  a little in
some research centers with small opened sources ; you know exactly the
activities (and even there, you have to make some form of  investigation
to know if the activities are the same...)

I guess a  complete investigation is always in order to collect as many
"facts" possible, espescially in situation where the exposure to a
significant dose exists. I would seriously be concerned if I was the
dosimetry company who "evaluate" doses based on previous experience
(Liability...).  I hope they are writing that the dose is an estimate
and how the dose was obtained. At least, there is something to start
from !  I think Sandy exposed the entire problem.

Merry Christmas everyone, Joyeux Noel , Bonne Annee 1997

Happy New Year 1997.

Stephane Jean Francois Phys. Eng.
RSO
Merck Frosst Canada
stephane_jeanfrancois@merck.com

_______________________
You wrote:
     Date: Wed, 18 Dec 1996 08:02:06 -0800
     From: "Sandy Perle" <sandyfl@ix.netcom.com>
     Subject: Dose estimates when dosimetry is lost/damaged

     The practice of dose estimates when dosimetry was either lost or
     damaged, during my 22 years as a power reactor health physicist,
was
     to conduct a dose investigation based on survey data, secondary
     dosimetry, dosimetry results from others who worked with the
     individual in question and most importantly, an interview with the
     individual. This investigation led to a dose estimate which was
first
     discussed with the individual, a signature obtained from the
     individual signifying that the investigation was conducted, what
the
     resultant dose was and that the individual concurred with the dose
     estimate. What I am finding in the world of commercial dosimetry
and
     what the customers want is well beyond this, and a practice I find
     disturbing at a minimum.

     I have learned that many of the current dosimetry processors, as
well
     as the former Siemens Dosimetry service, routinely provided their
own
     estimate to the customer when a dosimeter was lost or damaged. They
     would base this estimate on the previous two or more dosimeters.
This
     estimate is based on the assumption that the previous work history
     and doses assigned are indicative and correlated well to the
current
     time period. I find this practice to be disturbing, for many
reasons
     I will elaborate on. Let me also state that it is my policy that my
     operation will not provide an estimate for any lost or damaged
     dosimeter. The methodology is simple as to how this is
accomplished,
     who initiates the estimate and how it is documented.

     In my opinion, when a processor provides an automatic  dose
estimate,
     the following problems are evident:

     1. Isn't it the responsibility of the individual who is monitored
to
     be cognizant of their radiation exposure?

     2. Isn't the RSO or whoever is accountable for the dosimetry
program
     accountable as the caretaker of the individual's doses, to ensure
     that they are as accurate as possible, and if there is a question
     regarding an individual's dose, that they become an integral part
of
     the investigation which results in a dose estimate to be assigned?

     3. IF a processor automatically assigns an estimate, automatically
     without any intervention from the customer, isn't this a liability
     issue, and could within all probablility, end up in litigation some
     time later?

     4. How is the individual notified that their dosimetry was damaged
     during processing, and that an estimate has been assigned? How are
     they informed of the methodology used to arrive at the dose
estimate?

     5. How do the regulators look at a dose assigned without any
     intervention from the customer, especially without any documented
     investigation?

     6. The processor takes on a serious liability without a detailed
     audit trail which shows the chain of command of the dose assignment
     process ... if, there is this automatic dose estimation without any
     intervention from the customer, who I believe should be legally
bound
     to defend the dose assigned, with the assistance of the processor.

     The policy I have implemented is as follows. While it is one that
is
     much different than what our customers have been used to, it is one
     they agree with after the policy and reasons for it are discussed
     with them. As in all things, effective communication is required.


     1. If after a dosimeter is processed, and the flag and intervention
     reports are run, and it is determined that the dosimeter either is
     damaged, had an erroneous processing or some other anomaly is
     identified, the customer is notified and a discussion ensues to
     assist the customer in providing  us with a written estimate of
what
     the most likely dose is, and when it is entered in our database, it
     is identified as a "customer provided dose estimate".

     2. If a customer calls and requests that a dosimeter be
reevaluated,
     and that evaluation determines that the resultant dose is accurate,
     the customer must request in writing that a different dose be
     assigned and their reason for the request. The dose is changed in
the
     radiation history file, the original dose is maintained as one that
     was the result of the processing, and the file is noted that the
     estimate was provided by the customer. This is necessary to protect
     both the customer as well as my operation from liability issues.

     3. If a dosimeter is lost or not returned, it is again the
     responsibility of the customer to provide us with a written
estimate
     for the dose to be assigned.

     If one thinks about this logically, it is NOT very difficult for an
     individual, who is aware that a high dose was received, or that a
     procedural violation has occurred, to simply "lose" the dosimeter
or
     "damage" it in some was to cause an estimate to be assigned. In
this
     event, to assume that the current dose is equivalent to previous
     exposures without an investigation in my opinion is reckless and
     brings into question the entire dosimetry processing program. It is
     critical that when a dose is assigned to any worker, that the
utmost
     in care be assured to arrive at a reasonable representation of an
     individual's dose. In a "litigation happy society" it is essential
     that we, the health physics community" ensure that doses are
treated
     with respect, accuracy and a thorough understanding and practice
     based on sound methods.

     Comments from the group will be appreciated.


     Sandy Perle
     Director, Technical Operations
     ICN Dosimetry Division
     Office: (800) 548-5100 Ext. 2306
     Fax: (714) 668-3149