6mm non-obstructing stone in left kidney, one-time hematuria

[SeafoodLicorice]

Hi - I had a one-time episode of hematuria (saw some red spots in underwear and one small red 'thread' in urine). Since all urinalyses have been clean, and I've seen no blood, but an ultrasound revealed a 6mm stone sitting in my left kidney.

I was referred to a Urologist who is recommending a cystoscopy and CT scan to determine if there's any sign of cancer. My question is since a stone has already been detected and I have a history and family history of kidney stones, are these steps actually necessary? I'm concerned about the radiation of the CT Urography as well as obviously I'd prefer to avoid cystoscopy if at all possible. I'm getting a second opinion, but any ideas here? Can a large stone sitting in your kidney cause hematuria?

thanks

[Anne0987]

Most likely it's the stone causing the hematuria but the CT is necessary to complete the work up.