Protocol CTDIw (SD) Effective Dose   CTDIw  Scatter to the brain (SD) Scatter to the torso (SD) Efffective Dose due to scatter Effective Dose incl scatter   mGy mSv mSv mSv mSv mSv 1* 1.5 (0.01) 0.015 0.0045(0.00004) 0.0012 (0.00001) 0.0003 0.015 2# 1.7(0.01) 0.017 0.0094(0.00012) 0.0031(0.00002) 0.0008 0.018 3# 1.6(0.01) 0.016 0.0080(0.00017) 0.0022(0.00002) 0.0006 0.017 average 1.6 0.016 0.0073 0.0022 0.0006 0.017 4# 3.9(0.04) 0.039 0.010(0.00006) 0.0044(0.00005) 0.0012 0.040 5# 2.2(0.01) 0.022 0.0076(0.00009) 0.0028(0.00004) 0.0007 0.023 Average 3.1 0.031 0.0090 0.0036 0.0010 0.032 *CTDIw was measured 6 times. The scatter to the brain and torso was measured 3 times for protocol 1, 4 and 5, (half of total in setting A and half in setting B) #CTDIw was measured 10 times. The scatter to the brain and torso was measured 5 times for protocol 2 and 3 (half of total in setting A and half in setting B)

Table 2: Overview of mean (standard deviation (SD)) for measured CTDIw, scatter to the torso, scatter to the brain and calculated ED for five different CT protocols used for diagnosing occult scaphoid fractures without (1,2 and 3) and with (4 and 5) a plaster cast.