11
10
2.2 Studies and Data on Leakage and Scatter
Besides direct beam, potential exposure from X-ray devices has only two other possibilities:
1)
leakage radiation and
2)
scatter radiation from the patient/
subject in the direct beam.
Leakage
Unique internal shielding of KaVo
NOMAD PRO 2 encases the X-ray
tube, practically eliminating leakage
radiation. This makes it safe to use
PRO 2 as a handheld device during
exposures.
FDA regulations specify that leakage radiation from X-ray devices not exceed 0.88mGy/hr,
while IEC regulations stipulate that devices stay below 0.25mGy/hr, an even tighter limit.
In response to these regulations, KaVo will only ship product that tests below 0.88mGy/hr (at 1
meter), 0.25mGy/hr (at 1 meter), 0.02mGy/hr (at 5 cm) for leakage.
In order to verify compliance with this leakage requirement, each individual device is
tested with a calibrated survey meter at 12 points on the device housing, as shown in the
following diagram. The highest measurement out of these 12 points is reported on the
device Certificate of Conformance (which is shipped with every device) and must be lower
than 0.02mGy/hr in order for the device to successfully pass product release testing.
Primary Protective
Shielding
X-ray Source
Focal Spot
Focal Beam lim-
iting Devices
Backscatter
Radiation
Shielding
Test points for product release testing
A, B, C, D axis
G, H, I axis
H
I
G
F
E
B
A
D
C
