A computed tomography dose index (CTDI) QA phantom consisting of nested adult head and body segments.

TO CTDI permits the user to measure the dose index for computed tomography systems. The test object consists of two PMMA cylinders, one cylinder represents the head (160mm diameter) which, when nested inside the the other, represents the body (320mm diameter). The length of each cylinder is 140mm. Each cylinder contains 13.0mm diameter holes and comes with two adaptors tubes to permit the use of either 8mm, 10mm or 13mm diameter radiation detectors, used to take the dose measurements. There is a hole at the centre of the cylinders and one at each 90° interval, centred 10mm from the edge of the cylinder. TO CTDI includes nine PMMA pegs used to to fill the unoccupied holes and a phantom support for each size of cylinder.

TO CTDI has been designed in accordance with standards IEC 61223-3-5, IEC 61223-3-6 and IEC 60601-2-44.

TO CTDI enables the following tests to be made:

– CTDI100 (centre)
– CTDI100 (peripheral)
– CTDIw (weighted CTDI100)
– CTDIvol (weighted CTDIw)
– CTDIfree air

TO CTDI nested head and body phantom is supplied in a trolley case with a telescopic handle.