11.16.2 DOSIMETRIC INDICATIONS IN TERMS OF CTDI (FOR CBCT EXAMS)
The following tables provide dosimetric indications related to the execution of CBCT exams using X-MIND trium.
The radiation dose is reported in terms of Computed Tomography Dose Index (CTDI), which represents the integral of dose
prole along a line perpendicular to the tomographic plane divided by the product of the nominal tomographic section
thickness and the number of tomograms produced in a single scan.
CTDI values were measured setting the following loading factors and without the application of any lter:
Patient gender Patient size Tube Voltage [kV] Anodic Current [mA]
Man
Small 90 6
Medium 90 8
Large 90 10
Woman
Small 85 6
Medium 85 8
Large 85 10
Child
Small 80 6
Medium 80 8
Large 80 10
The dosimetry phantom used to perform the test is the QUART DVT_AP. All dose measurements were performed with the CT
dosimetry phantom placed on a support device, without additional attenuating materials present.
The following table reports the CTDI values measured at the indicated locations in the dosimetry phantom, with the typical
settings suggested for a CBCT exam using X-MIND trium (e.g. Man Medium, FOV 40x40):
Location CTDI [mGy]
Along the axis of rotation 2,86
Along a line parallel to the axis of rotation and 1.0 cm interior to the
surface of the phantom
1.25
Along a line parallel to the axis of rotation and 1.0 centimeter
interior to the surface of the phantom at position 90 degrees from
the position b)
1.12
Along a line parallel to the axis of rotation and 1.0 centimeter
interior to the surface of the phantom at position 180 degrees from
the position b)
1.17
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