PPT Slide
Calculation of Scanner Coverage :
Z-axis coverage per Rotation = Collimation × Pitch + Collimation
Assuming 32 mm tube collimation (Toshiba-Aquilion)
Pitch 0.75 1.0 1.5 2.0 Z-coverage /rot(mm) 56 64 80 96
Irradiated Phantom Length = 96 mm
Sampled phantom length = 60 mm (for 20 mm slice thickness)
Our phantoms > 120 mm long
Notes:
- One of the main differences in the phantom design of single and MS scanners is the length of the phantom.
- The main factors affecting that is the x-ray beam collimation and scanning pitch. This formula gives the relationship between the beam collimation, pitch and Z-axis coverage per rotation
This table shows examples of Z-axis coverage per rotation for different pitches assuming tube collimation of 32mm, which is currently the largest tube collimation available and provided by the Toshiba Aquilion. For the maximum available pitch, pitch of 2.0 the Z-axis coverage per rotation is 96mm.
- This is equal to the irradiated phantom length. However, only part of the data collected is used in the reconstruction of the image. For example for the largest possible slice thickness of 20 mm data from 60 mm of the phantom will be used.
In fact we made all our phantoms more than 12 mm long so they are suitable for the assessment of up to 40mm slice thickness