The parameter RT is a table that image signal digital values (virtually proportional to density) to determine the degree of enhancement.
The data in table can be used to control the degree of enhancement variously for all densities.
Under normal conditions, tables are selectively used so that the degree of enhancement is low
for the low-density portion and high for high-density portion.
RT = F provides uniform enhancement RT = V on the other hand, does not enhance the low-density portion.If the exposure X-ray dose is extremely low and noise likely to be intrusive,the parameter RT should be set to X or W to generate blurred images.