How can I know if prostate cancer has spread without an MRI?

I was diagnosed with prostate cancer on 05/04/26. I have a unique situation where I cannot have an MRI. IN 1967 I was hit by a car. My spleen and one kidney was removed. They used metal in those days to...in a sense... hold my other organs in place. Im fearful, because there's no other path to tell if the cancer has spread outside of the prostate than a CT scan to look for growths or misformed organs. I'm almost certain that I'm going to have the prostate removed. However, If the cancer has spread it is most likely a better option to do chemo. All the while knowing there's no definitive way to know if it has already spread. Sorry for ranmbling.