A-5
APPENDIX A
Example Calculation:
Determine the detector efficiency of Am-241 in a well detector with an opening of 0.625 inches and the
source located in the well at 1 inch below the surface.
Geometric Efficiency for a Well: I.D. = 0.625 inches
X - 1.00 inch
G.E. = 97.7% (see earlier example)
Detector Efficiency for Am-241: A = 0.095 µCi @ T = 8/15/84
T
1/2
= 432.2
t = 5/1/93 (date counted in well)
Am-241 was programmed for gain of 12 and an ROI of 50 to 69 keV.
100 second counts resulted in the following:
S = 99,403
B = 83
Now calculate the individual parts of the equation for (D.E. * G.E.)
Count rate = (S-B)/100 s = 993 cps
Disintegration rate = A µCi * 37000 dps/µCi = 3515 dpm
Decay Correction = 2
(T-t)T
1/2
=
2
(84.71 y - 93.42 y)/432.2 y
= 0.986
D.E. * G.E. = 0.286 * 100% = 28.6%
D.E. = {(D.E. * G.E.)/G.E.} * 100% = (28.6/97.7) * 100 = 29.3%
We should now check our result for common sense. The photon emission from Am-241 are 59.5 keV at
35.9% intensity and 26.3 keV at 2.4% intensity. The interaction probability for a 60 keV photon is very
high in the Nal well detector (Nal thickness on sides and bottom is about 0.625 inches), the bulk of this
interaction will be photoelectric which puts most of the counts recorded in the photo peak. The ROI is set
to integrate the photo peak of 59.5 keV. Therefore, we would expect a detector efficiency to be a little less
than photon intensity at 59.5 keV which it is.
Example of a Well Compared to a Probe for Counting Efficiency
If we assume the following parameters:
Isotope: Cs-137
D.E. Probe: 9.86%
D.E. Well: 13.47%
G.E. Well: 96.816% for a source placed 2.54 cm deep in the well
G.E. Probe: 0.278% for a source placed 21 cm in front of the probe
Probe: D.E. * G.E. = 9.86% * 0.278% = .02741%
Well: D.E. * G.E. = 13.47% * 96.816% = 13.04%
A.)
If the detector counts 54 cpm that is equivalent to the following dpm for the parameters listed above.
Probe: 54 cpm/.02741% = 197,008 dpm
Well: 54 cpm/13.04% = 414 dpm
CONTENTS
Summary of Contents for 187-130
Page 8: ...1 INTRODUCTION SETUP INSTRUCTIONS 2 2 Figure 2 1 The MCA Uptake Stand ...
Page 10: ...1 INTRODUCTION SETUP INSTRUCTIONS 2 4 Figure 2 2 The MCA Uptake Stand side view ...
Page 20: ...1 INTRODUCTION SETUP INSTRUCTIONS 2 14 Figure 2 6 The System Setup Screen ...
Page 25: ...1 INTRODUCTION 2 19 SETUP INSTRUCTIONS Figure 2 8 The Database Manager Screen ...
Page 28: ...CONTENTS 3 3 ADMINISTRATION Figure 3 1 The Calibration Screen ...
Page 29: ...1 INTRODUCTION Figure 3 2 A Calibration Report ADMINISTRATION 3 4 ...
Page 31: ...1 INTRODUCTION Figure 3 3 The High Voltage Adjustment Screen ADMINISTRATION 3 6 ...
Page 32: ...1 INTRODUCTION Figure 3 4 The High Voltage Report 3 7 ADMINISTRATION ...
Page 34: ...1 INTRODUCTION Figure 3 5 The Chi Square Screen 3 9 ADMINISTRATION ...
Page 35: ...1 INTRODUCTION Figure 3 6 The Chi Square Report ADMINISTRATION 3 10 ...
Page 37: ...1 INTRODUCTION Figure 3 7 An Administration Report ADMINISTRATION 3 12 ...
Page 39: ...ADMINISTRATION 3 14 1 INTRODUCTION Figure 3 8 The Isotope Editing Screen ...
Page 40: ...1 INTRODUCTION 3 15 ADMINISTRATION Figure 3 9 The Select Isotope Window ...
Page 42: ...1 INTRODUCTION 3 17 ADMINISTRATION Figure 3 10 The Detector Efficiency Screen ...
Page 44: ...1 INTRODUCTION Figure 3 11 The Geometric Efficiency Window 3 19 ADMINISTRATION ...
Page 48: ...1 INTRODUCTION 3 23 ADMINISTRATION Figure 3 13 A Spectrum Analysis Report ...
Page 50: ...1 INTRODUCTION Figure 4 1 The Procedure Definition Screen THYROID UPTAKE 4 2 ...
Page 51: ...1 INTRODUCTION 4 3 THYROID UPTAKE Figure 4 2 The Patient Definition Screen ...
Page 56: ...THYROID UPTAKE 4 8 1 INTRODUCTION Figure 4 3 The Thyroid Uptake Screen ...
Page 58: ...THYROID UPTAKE 4 10 1 INTRODUCTION Figure 4 4 A Thyroid Uptake Report ...
Page 59: ...1 INTRODUCTION Figure 4 5 A Time Activity Report 4 11 THYROID UPTAKE ...
Page 63: ...MANUAL MODE 5 2 1 INTRODUCTION Figure 5 1 The Manual Mode Screen ...
Page 64: ...1 INTRODUCTION 5 3 MANUAL MODE Figure 5 2 A Manual Mode Report ...
Page 66: ...1 INTRODUCTION WIPE TEST 6 2 Figure 6 1 The Wipe Counting Screen ...
Page 67: ...6 3 WIPE TEST CONTENTS Figure 6 2 The Wipe Area Setup Screen ...
Page 68: ...CONTENTS WIPE TEST 6 4 Figure 6 3 The Wipe Preferences Window ...
Page 70: ...1 INTRODUCTION Figure 6 4 The Background LLD Screen WIPE TEST 6 6 ...
Page 72: ...1 INTRODUCTION WIPE TEST 6 8 Figure 6 5 The Wipe Results Report ...
Page 76: ...1 INTRODUCTION 7 3 BIOASSAY Figure 7 2 The Bioassay Preferences Screen ...
Page 78: ...7 5 BIOASSAY CONTENTS Figure 7 3 An Individual Bioassay Report ...
Page 79: ...CONTENTS Figure 7 4 An Employee Bioassay Summary BIOASSAY 7 6 ...
Page 80: ...1 INTRODUCTION 7 7 BIOASSAY Figure 7 5 An Individual Bioassay History Summary ...
Page 82: ...1 INTRODUCTION SCHILLING TESTS 8 2 Figure 8 1 Defining a Facility Standard Schilling Test ...
Page 83: ...CONTENTS 8 3 SCHILLING TESTS Figure 8 2 The Schillings Counting Page ...
Page 84: ...CONTENTS SCHILLING TESTS 8 4 Figure 8 3 A sample Schillings Mallinckrodt Report ...
Page 87: ...CONTENTS 8 7 SCHILLING TESTS Figure 8 4 The Diopac Schillings Counting Page ...
Page 88: ...SCHILLING TESTS 8 8 CONTENTS Figure 8 5 A Sample Diopac Schillings Report ...
Page 90: ...CONTENTS HEMATOLOGY 9 2 9 1 The IHSA Counting Page ...
Page 92: ...1 INTRODUCTION HEMATOLOGY 9 4 Figure 9 2 A Sample IHSA I 125 Test Report ...
Page 93: ...CONTENTS 9 5 HEMATOLOGY Figure 9 3 The CR 51 Counting Page ...
Page 95: ...CONTENTS 9 7 HEMATOLOGY Figure 9 4 A Sample Cr 51 Volume Test Report ...
Page 96: ...CONTENTS Figure 9 5 The Cr 51 Red Blood Cell Survival Counting Page HEMATOLOGY 9 8 ...
Page 98: ...CONTENTS HEMATOLOGY 9 10 Figure 9 6 A sample Cr 51 Survival Test Report ...
Page 100: ...CONTENTS Figure 9 7 The GFR Counting Page HEMATOLOGY 9 12 ...
Page 103: ...1 INTRODUCTION 9 15 HEMATOLOGY Figure 9 8 A One Sample Glomerular Filtration Rate Report ...
Page 104: ...1 INTRODUCTION HEMATOLOGY 9 16 Figure 9 9 A Two Sample Glomerular Filtration Rate Report ...
Page 106: ...1 INTRODUCTION HEMATOLOGY 9 18 Figure 9 10 The ERPF Counting Page ...
Page 108: ...1 INTRODUCTION HEMATOLOGY 9 20 Figure 9 10 The ERPF Counting Page ...
Page 109: ...1 INTRODUCTION 9 21 HEMATOLOGY Figure 9 11 An Effective Renal Plasma Flow Report ...