We have examined the effects of a wide range of levels of
Therox, a perfluorochemical
emulsion containing bis-perfluorobutyl
ethylene (
F44E) with
carbogen breathing on the
tumor growth delay of the
Lewis lung carcinoma produced by single dose radiation and fractionated radiation. The enhancement in
tumor growth delay with single dose
radiation therapy increased as the dose of
F44E was increased from 1.2 g/kg (0.03 ml) to 4 g/kg (0.1 ml). As the dose was increased further from 6 g/kg (0.15 ml) to 8 g/kg (0.2 ml) and then to 12 g/kg (0.3 ml), there was a progressive decrease in the
tumor growth delay observed. The dose of 4 g/kg was the optimal
F44E level with single dose
radiation therapy, giving a dose modifying factor of 2.4 +/- 0.2. This was true whether administered as a 48% (v/v)
emulsion in 0.1 ml or as a 16% (v/v)
emulsion in 0.3 ml. When the injection volume was varied from 0.1 ml to 0.4 ml at the 4 g/kg or 6 g/kg dose, thereby varying the
emulsion concentration from 48% (v/v) to 12% (v/v) or 18% (v/v), the results tended to indicate that the volume of injection may be more important than the
emulsion concentration, i.e., an injection volume of 0.2 ml produced the greatest
tumor growth delay for both doses, and the
emulsion concentration of 0.2 ml and 4 g/kg of
F44E is 24% (v/v) whereas the
emulsion concentration of 0.2 ml and 6 g/kg of
F44E is 36% (v/v). Administering any dose of the
emulsion with
carbogen for 1 h prior to and during the radiation fraction on Day 1 only of a daily fractionated radiation protocol (3 Gy/fraction x 5 days) had very little effect on
tumor growth delay compared to radiation and daily
carbogen breathing. When
F44E was administered on treatment Days 1, 3, and 5 with
carbogen breathing, there was an increased effect on
tumor growth delay which reached a maximum at 4 g/kg (0.1 ml) of 10.0 +/- 1.2 days compared with 6.7 +/- 1.0 days for radiation with daily
carbogen breathing. However, when the
F44E emulsion was administered every day with fractionated radiation and
carbogen breathing, there was a marked enhancement in
tumor growth delay observed across the entire dosage range, from 1.2 g/kg to 12 g/kg.(ABSTRACT TRUNCATED AT 400 WORDS)