Bias-emission voltage and dose-dependent current gain is a key parameter in detecting the physical properties of the bipolar transistor. The first objective of this work is to measure the influences of gamma radiation on current gain in lateral PNP bipolar transistors. Substantial differences of the current gain as a function of voltage between bias and emission are observed. Then, based on the calculated results from the non-linear curve fitting method, the voltage between bias and emission-dependent current gain is theoretically explained successfully via the asymmetric peak function. The simulations agree very well with the observed curves (current gain versus voltage). The minimum correlation coefficient between the experimental and calculated data is 0.998. The average relative errors between the measured and modeled values do not exceed 9.14% in all considered cases. Finally, the mathematical relationships between the parameters, which serve to link the current gain and voltage together with dose, are obtained. Consequently, the current gain can be predicted by both voltage between bias and emission and dose using only one function. To the best knowledge of the author, the effects of gamma irradiation on the lateral PNP transistors are quantitatively discussed for the first time in current gain. [ABSTRACT FROM AUTHOR]