Defnyddir sganiau CT a MRI i gynhyrchu delweddau manwl iawn o'r tu mewn i'r corff. Defnyddir sganiau CT i wneud diagnosis o gyflyrau gan gynnwys niwed i esgyrn, anafiadau i organau mewnol, problemau llif gwaed, strôc a chanser. Maent hefyd yn helpu i ddod o hyd i leoliad, maint a siâp tiwmor cyn cael radiotherapi.
CT and MRI scans are used to produce detailed images of inside the body. CT scans are used to diagnose conditions including damage to bones, injuries to internal organs, problems with blood flow, strokes and cancer. They also help to determine the location, size and shape of a tumour before having radiotherapy.