Table 1.

The parameters of the collimators simulated. The hole length was 25.1 mm for all collimators.

System resolution at centre-of-rotation (mm)	Collimator sensitivity (×100)	Hole size (mm)	Septal thickness (mm)
8 mm	0.076	0.920	0.127
9.5 mm (chosen to match the Siemens LEHR collimator)	0.113	1.117	0.154
12 mm	0.190	1.451	0.200
14 mm	0.264	1.710	0.235
16 mm	0.349	1.966	0.271
18 mm	0.445	2.222	0.306
20 mm	0.553	2.476	0.341
22 mm	0.672	2.730	0.376
24 mm	0.803	2.984	0.411
26 mm	0.944	3.237	0.466