Dose estimates when dosimetry is lost/damaged

["Sandy Perle" <sandyfl@ix.netcom.com>]

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

E-Mail: sandyfl@ix.netcom.com    

Homepages:

http://www.netcom.com/~sandyfl/home.html
http://www.geocities.com/CapeCanaveral/1205