Microdistribution of alpha particles in pathological sections of tissues from thorotrast patients detected by imaging plate autoradiography.
Thorotrast is a colloidal suspension of radioactive (232)ThO(2) that naturally emits alpha particles (90%), beta particles and gamma rays (10%). Thorotrast was used as a radiographic contrast agent in the 1930s-1950s; it caused liver cancer several decades after injection because of its life-long deposition and exposure. Determination of the amount and the distribution of radioactive thorium are essential for assessment of radiation risks. We visualized alpha particles on ordinary archival tissue sections using an imaging plate and a BAS5000 image analyzer. Furthermore, we confirmed that the imaging system is sensitive enough to detect alpha particles and accurate in measuring the total amount of thorium deposited in the organ from a single tissue section. This method revealed that the amount of thorium deposited in tumor tissue is correlated to that in non-tumor tissue. Thorotrast deposition was not associated with DNA damage determined by histochemistry. In combination with histological findings, it is suggested that radioactive thorium always migrates within the deposited organs by macrophages, and that the organs are evenly exposed to alpha particles.
Goto
Akira
A
Department of Pathology, Institute of Development, Aging and Cancer, Tohoku University, Aoba-ku, Sendai 980-8575, Japan.
Takebayashi
Yuji
Y
Liu
Duo
D
Li
Li
L
Saiga
Tatsuyoshi
T
Mori
Takesaburo
T
Yamadera
Akira
A
Fukumoto
Manabu
M
D000368:Aged; D000369:Aged, 80 and over; D000512:Alpha Particles; D001345:Autoradiography / Q000379:methods; D004249:DNA Damage; D005260:Female; D006801:Humans; D008099:Liver / Q000473:pathology* / Q000528:radiation effects*; D008297:Male; D008875:Middle Aged; D013910:Thorium / Q000032:analysis; D013911:Thorium Dioxide / Q000627:therapeutic use*
D013910:Thorium; D013911:Thorium Dioxide