Abstract
The following experiments were undertaken in order to study the suitability of goldfish for the problems of experimental radiotherapy. Goldfish have already been used successfully in experimental pharmacology.
A total of 408 commercial goldfish (96 of which were used as controls) were divided into series of 12 for each exposure. After irradiation each series or controls were placed in an aquarium containing 7000 cc of water at a temperature of 19° to 22°C for observation.
The radiation factors were: 200 KV, 30 MA, no filter, HVL 6 mm Al, target distance 50 cm, field 15 × 15 cm, intensity 230 r/min. The fishes were irradiated in an open Petri dish, 15 cm in diameter, suspended between 2 layers of gauze, flush with the surface of the water in a water phantom. This was 32 × 32 × 32 cm, thus permitting the maximum back scatter (Quimby and coworkers 1 ). Ionization measurements with a Victoreen chamber showed an increase in back scatter from the Petri dish of 3%.
The entire dose was given in one session and varied from 500 to 10,000 r without back scatter. When a dose of 1500 r up to 10,000 r was administered, all goldfish died 10 to 18, on an average 14 days after treatment, while nearly 100% of the controls remained alive at this period. After a dose of 1000 r only about 50% of the fishes were dead after a like period. The first intimation of a lethal effect was already noted after 500 r.
For about a week after irradiation the appearance of the fish did not change (latent period). On the sixth to ninth day, however, a brownish black pigmentation appeared on each side of the trunk.
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