Table 1.
Collimation width (mm) | Phantoms | Measurement position in CTDI phantoms | Measured CTDI100 (mGy∕100 mA s) | Simulated CTDI100 (mGy∕100 mA s) | Percent error (%) |
---|---|---|---|---|---|
80 kVp | Head phantom | Center | 5.3 | 5.1 | −4.1 |
12 o’clock | 6.9 | 6.6 | −3.3 | ||
3 o’clock | 6.5 | 6.3 | −3.4 | ||
6 o’clock | 5.7 | 5.7 | −0.3 | ||
Body phantom | Center | 1.0 | 0.9 | −5.7 | |
12 o’clock | 2.7 | 2.5 | −6.2 | ||
3 o’clock | 2.4 | 2.4 | 1.1 | ||
6 o’clock | 2.1 | 2.1 | 0.4 | ||
100 kVp | Head phantom | Center | 9.7 | 9.2 | −5.2 |
12 o’clock | 11.8 | 11.4 | −3.7 | ||
3 o’clock | 11.3 | 10.8 | −4.3 | ||
6 o’clock | 9.9 | 9.9 | −0.3 | ||
Body phantom | Center | 2.1 | 2.0 | −6.5 | |
12 o’clock | 5.0 | 4.6 | −7.2 | ||
3 o’clock | 4.6 | 4.6 | 0.1 | ||
6 o’clock | 4.0 | 4.0 | 0.0 | ||
120 kVp | Head phantom | Center | 13.8 | 13.1 | −5.2 |
12 o’clock | 16.8 | 15.6 | −7.2 | ||
3 o’clock | 15.6 | 14.9 | −4.6 | ||
6 o’clock | 13.6 | 13.6 | 0.1 | ||
Body phantom | Center | 3.4 | 3.2 | −7.9 | |
12 o’clock | 7.4 | 6.7 | −8.6 | ||
3 o’clock | 6.8 | 6.7 | −2.0 | ||
6 o’clock | 6.0 | 5.9 | −1.0 |