I need a surgical app that requires image and formula processing

I need an iPhone app. I would like it designed and built. I am an Urologist, in Urology theres a surgery called percutaneous nephrolitotomy. It consists in getting a needle introduce through the skin to the renal calyx that are like tunnels into the kidney. The way we get that done is either by ultrasound or by xray machines. Xray machines requires we first introduce first a constrast through the urethra so all the urinary conducts get filled all the way to the kidney and then we can see them on the xray and try to direct the needle to one of the calyx. In order to triangulate that we use an cray machine in a form of a "C" that can be rotated in several ways. When that xray "C" is rotated certain degrees, we can see how the needle moves in relationship with the calyx. Depending in which direction i rotate the xray i can determine according to the changes in position of the calyx and needle in the screen which direction i need to move the needle, thats it either angle it up or down. I need an app in which i can fix the phone in a position with the camera directed at the screen and be able to touch my phone screen to define the positions of both the needle and the calyx before and after the rotation of the "c" xray so that it can calculate with a formula with the distance that appears betweeb those 2 pictures what is the angle i have to correct and in which direction (up or down). I have some drawings that can explain better what i mean, i actually think i can do the maths. But in general, thats what i need the app to do. Also, the app has to have the capacity to correct the real distances, with help of some scale, for example i can get in the image a 1 cm object and then select that cm in my phone and tell it thats a cm, so it scale the images that it gets and give real measures