  The theory of Thomson scattering from high-temperature high-density plasmas
is revisited from the view point of plasma fluctuation theory. Three subtle
effects are addressed with a unified theory. The first is the correction of the
first order of $v/c$, where $v$ is the particle velocity and $c$ is the light
speed, the second is the plasma dielectric effect, and the third is the finite
scattering volume effect. When the plasma density is high, the first effect is
very significant in inferring plasma parameters from the scattering spectra off
electron plasma waves. The second is also be notable but less significant. When
the size of the scattering volume is much larger than the probe wavelength, the
third is negligible.
