. 2016 Jan 8;17(1):49–61. doi: 10.1120/jacmp.v17i1.5527

Table 2.

Effect on the laser position on the wall when the gantry CHL was shifted by 4.8 mm.

Laser Position on the Wall ^b (mm)

Alignment Method

CHL Position Shift (mm)

m^{'}

| m^{'} - m |

Conventional method ^a

4.8

33.4

‐3.5

36.9 (~ 8d)

Proposed method

4.8

32.3

27.0

5.3 (~ d)

^{^a}

A high‐accuracy level with the resolution of 0.44 mm/1,000 mm was used.

^{^b}

The value was averaged over three measurements.

Note: m is for the case of no shift and m' is for the case of existing CHL position error.