about a year or so ago my physician in a regular exam noted that I had a small nodule on one side of my prostate. I had just had a psa test and it showed a reading of 2.3. My doctor noted that my prostate seemed quite normal. That is ,no enlargment or inflamation, and few symtoms except slow urinary flow. Three months later, he saw the same nodule still with no other prostate problems and ordered another psa test, which came back about 4.2. Based on that he sent me to a urologist.
The rest "they say" is history...and so is my prostate.
If your doctor thinks that a biopsy is a good idea...then it is a good idea. It is a simple mostly painless test. I will admit that the indignities of all the poking and prodding that followed were not fun, but they are past now.
All of the other tests you mention are expensive and sometimes invasive too. Urologists agree that a biopsy is the way to find if you have a cancer beginning to grow.
Please let us know what you decide and how things are going with you.