Ra-226 Epidemiology

[JMUCKERHEIDE@delphi.com]

Jerry,

Spiers, Lucas, Rundo and Anast at CFR, in HPJ Vol 44 Suppl 1 1983, p65-72 (see 
notes below).  

> Fellow RADSAFERS:
> 
> I am posting this for a colleague, Joe Stencel.  Please reply to him
> directly at jstencel@princeton.edu.
> 
> Does anyone have any references to Ra-226 + daughters and
> relation to leukemia, or does all the data indicate its only related to, for
> example, bone carcinomas?
> 
> Thanks,
> Jerry
> 
> Jerry Gilbert
> Manager, Health Physics
> Princeton Plasma Physics Laboratory
> Telephone:  609-243-3455   Fax:  609-243-2525
> e-mail:  jgilbert@pppl.gov
Spiers et al 1983, Leukemia incidence in the US dial workers, Health Phys,
44 Suppl 1, p65-72

In the Argonne Center for Human Radiobiology study population, "Among the
total number, 2940, of located radium dial workers, 10 cases of leukaemia
were observed, ...9.24 would be expected in the general population." 

In a study group for an epidemiologically unbiased analysis of dial workers
with measured body burdens alive in 1957, with data through 1979, "In the
smaller group of 693..., 2 cases were observed against 2.04 expected
naturally. On the basis of the alpha-particle doses to bone marrow and the
risk factor suggested by the ICRP (ICRP77)..., 2.63 cases would be
expected...additional to natural incidence." 

In "...the total number of 1285 located female radium dial workers followed
for 60 yrs, some 13 excess of radiation-induced leukemia would be expected
additional to 5.4 cases expected naturally, that is a total of about 18 as
against 4 cases observed." 

Note however, that ICRP 1977 used a QF of 20 for alpha particles. 

Note that the 2 cases in the small epidemiologic population were 1 in the
250-499 rad dose group, and 1 in the 1000-2499 rad dose group, none in the
44 cases above 2500 rad, nor in the 3 in the high dose range >10,000 rad
(mean about 19,000 rad).

Of the 9 cases in the whole population, 5 were in measured cases: 11 rad, 21,
305, 1055, and 19,805 rad (these would be calculated to somewhat different
doses today from later results on clearance times. 

Note also that US radium dial painter workroom external gamma dose is
variously estimated at 4-8 rad/yr, while in Britain, based on film badge
measurements, a 3-13 rad/yr bone marrow dose is estimated, (decreasing from
1943-1952). Spiers et al used 8 rad/yr to bone marrow as  typical' for US
workers. 

Also, "Using the average duration of employment for the female workers of
145 weeks, the gamma-ray dose amounts to 22 rad."  This makes the risk in 
the 693 workers an expected 0.11 cases for the follow-up period, 0.30 cases
lifetime, compared to 2.63 from internal exposure for an alpha QF=20. The 
external gamma contribution would be roughly half of the expected alpha 
contribution if the alpha QF=2. The beta contribution would add 0.03.