Læknablaðið - 01.10.1968, Page 62

220
LÆKNABLAÐIÐ
INCIDENCE OF LEUKEMIA
i i i i---------------------1—
80 400 800 5000
ESTIMATED DOSE IN RADS
1------SURVIVAL DUE TO SHIELDING---1
Fig. 5.
Incidence of leukemia in Hiroshima and Nagasaki survivors related
to distance and total body dose received.
best approximations possible tliey may have had enough over
years of practice in some instances to aggregate several tbousand
R.15 Otlier forms of radiation exposure of bone marrow may be
leukemogenic. Tlie question is still moot as to whetber radiation
therapy of polycythemia vera by 32phosphorus administered
internally, may increase the prevalence of leukemia in those so
treated. The possibility, if not probability, of such an effect is
strong.
Abnormalities of chromosomal structure in circulating
lvmphocytes, which some believe might predispose to developmenl
of leukemia, are readily induced by radiation and may persisl
for years. Such changes have been found after both therapeutic
and accidental radiation. However, only a few instances of
occurrence of the Philadelphia chromosome have heen found
among tlie radiation-induced chromosomal changes. Tliis
ahnormality is associated with some cases of myelocytic
leukemia but not specific to tbe disease. Most abnormalities of