Years ago i had 25+ radiation tests of various types. cts, thallium, vq, x-rays. i'm worried if i ever have another i'll get radiation sickness?

You won't: Radiation sickness occurs after heavy radiation exposure that does not normally occur with routine diagnostic exposure. Rare cases of skin injury after prolonged fluoroscopic procedures have happened but are rare. Increased levels of diagnostic exposure to the population are felt to be a risk factor for development of cancers but the actual risk to individuals is difficult to determine.

Cancer: Excessive accumulated irradiation can sometimes increase the possibility of acquiring cancer years later especially in growing indivials or children. Radiation sickness is caused by sudden tremendous irradiation like atomic bomb or radiation leak from nuclear reactor. Xray studies should still be performed if there is valid health reason.

You won't: The most you'll get from even an old fashioned CT is maybe 20 millisieverts and this is less nowadays. Today's CT's give about as much as Mother Nature gives you via cosmic rays in just a year; Denver residents have 3x this but no cancer increase. Radiation sickness follows acute exposures starting about 2500x this. Do yourself a favor and stop thinking and talking like this.