Midmark Preva - Electrical Verification

Preva Dental X-ray System User Manual, 00-02-1576, Revision ZA1
44
Kerma
8
, K , is the quotient of d E
tr
divided by d m where
d
E
tr
is the sum of the initial kinetic energies of all the charged particles liberated by uncharged
particles in a mass of material
d
m is the mass of the material
K is the kerma in J/kg, expressed in the SI unit gray (Gy)
When the material is air, the quantity is referred to as air kerma.
Kerma area product, abbreviated KAP, has replaced the older terminology, dose area product (DAP).
The air kerma-area product, expressed in the SI units mGy∙cm
2
, is a commonly used quantity
associated with the amount of X-ray used in dental panoramic and CBCT radiography. It is calculated
with this formula:
KAP = (air kerma) × (area of the cone opening)
8
As defined by the International Commission on Radiation Units and Measurements
Kerma Area Product
Modular BLD Cone Dimensions
Part
Number
Length
(cm)
Width
Opening
Area (cm
2
)
(mm)
(cm)
30-A2196
20
60 6 18.84
30-A2228
20
30-A2198
20
30 × 40
3 × 4
12.00
30-A2199
20
20 × 30
2 × 3
6.00
30-A2221
20
35 × 45 3.5 × 4.5 15.75
30-A2222
20
30-A2223
30
30-A2224
30