Presentation Transcript
Nuclear Medicine Math :Nuclear Medicine Math Carlos Fernandez
NMT 1713
Group 4
Objectives :Objectives Describe the following formulas:
Precalibration
Postcalibration
Inverse Square Law
Scientific notation
Half Value Layer
Conversions
Precalibration :Precalibration The formula is as follows:
A = A0e (Te/t ½)(0.693)
Where:
A = activity
A0= activity at start
Te= time elapsed
T ½ = half life
Postcalibration :Postcalibration The formula is as follows:
A = A0e (Te/t ½)(-0.693)
Where:
A = activity
A0= activity at start
Te= time elapsed
T ½ = half life
Inverse Square Law :Inverse Square Law This formula states that intensity will be reduced as distance is increased:
(I1)(D1)2=(I2)(D2)2
Where:
I1 = Intensity at start
D1 = Distance at start
I2 = Intensity at second distance
D2 = Second Distance
Scientific Notation :Scientific Notation Scientific notation is a way to shorten numbers by removing zeros
Examples:
22000 = 5x104 or 2.2E4
0.005 = 5x10-3 or 5E-3
Half Value Layer :Half Value Layer The formula for Half Value Layer as follows:
I = I0e (Te/t ½)(-0.693)
Where:
I = Intensity
I0= Intensity at start
Te= time elapsed
T ½ = half life
Conversions :Conversions Curies and Becquerels
How to convert curies to becquerels
1 Ci = 3.70 x 1010
1 Ci = 37 GBq
1 mCi = 37 MBq
1 µCi = 37 kBq
How to convert becquerels to curies:
1 Bq = 2.7 x 10-11 Ci
1 GBq = 0.027 Ci
1 MBq = 0.027 mCi
1 kBq = 0.027 uCi
Conversions :Conversions Other conversions:
1 sievert = 100 rem
1 gray = 100 rad
1 lb = 0.45 kg