SBRT 2016

Tilted MRIs

 The slice distance is s . Some TPS look up the slice distance by comparing the z-position of adjacent slices. In this case z .  If angle α > 0, z is not equal to s . E.g. for a tilt of 20 0 the difference is 6%. Pinnacle thus underestimates the length of the scan in the cranial caudal direction.

s

α

z

α