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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
Содержание 187-130
Страница 8: ...1 INTRODUCTION SETUP INSTRUCTIONS 2 2 Figure 2 1 The MCA Uptake Stand ...
Страница 10: ...1 INTRODUCTION SETUP INSTRUCTIONS 2 4 Figure 2 2 The MCA Uptake Stand side view ...
Страница 20: ...1 INTRODUCTION SETUP INSTRUCTIONS 2 14 Figure 2 6 The System Setup Screen ...
Страница 22: ...1 INTRODUCTION SETUP INSTRUCTIONS 2 16 Figure 2 7 The Edit Physicians and Technologists Information Screen ...
Страница 25: ...1 INTRODUCTION 2 19 SETUP INSTRUCTIONS Figure 2 8 The Database Manager Screen ...
Страница 28: ...CONTENTS 3 3 ADMINISTRATION Figure 3 1 The Calibration Screen ...
Страница 29: ...1 INTRODUCTION Figure 3 2 A Calibration Report ADMINISTRATION 3 4 ...
Страница 31: ...1 INTRODUCTION Figure 3 3 The High Voltage Adjustment Screen ADMINISTRATION 3 6 ...
Страница 32: ...1 INTRODUCTION Figure 3 4 The High Voltage Report 3 7 ADMINISTRATION ...
Страница 34: ...1 INTRODUCTION Figure 3 5 The Chi Square Screen 3 9 ADMINISTRATION ...
Страница 35: ...1 INTRODUCTION Figure 3 6 The Chi Square Report ADMINISTRATION 3 10 ...
Страница 37: ...1 INTRODUCTION Figure 3 7 An Administration Report ADMINISTRATION 3 12 ...
Страница 39: ...ADMINISTRATION 3 14 1 INTRODUCTION Figure 3 8 The Isotope Editing Screen ...
Страница 40: ...1 INTRODUCTION 3 15 ADMINISTRATION Figure 3 9 The Select Isotope Window ...
Страница 42: ...1 INTRODUCTION 3 17 ADMINISTRATION Figure 3 10 The Detector Efficiency Screen ...
Страница 44: ...1 INTRODUCTION Figure 3 11 The Geometric Efficiency Window 3 19 ADMINISTRATION ...
Страница 48: ...1 INTRODUCTION 3 23 ADMINISTRATION Figure 3 13 A Spectrum Analysis Report ...
Страница 50: ...1 INTRODUCTION Figure 4 1 The Procedure Definition Screen THYROID UPTAKE 4 2 ...
Страница 51: ...1 INTRODUCTION 4 3 THYROID UPTAKE Figure 4 2 The Patient Definition Screen ...
Страница 56: ...THYROID UPTAKE 4 8 1 INTRODUCTION Figure 4 3 The Thyroid Uptake Screen ...
Страница 58: ...THYROID UPTAKE 4 10 1 INTRODUCTION Figure 4 4 A Thyroid Uptake Report ...
Страница 59: ...1 INTRODUCTION Figure 4 5 A Time Activity Report 4 11 THYROID UPTAKE ...
Страница 63: ...MANUAL MODE 5 2 1 INTRODUCTION Figure 5 1 The Manual Mode Screen ...
Страница 64: ...1 INTRODUCTION 5 3 MANUAL MODE Figure 5 2 A Manual Mode Report ...
Страница 66: ...1 INTRODUCTION WIPE TEST 6 2 Figure 6 1 The Wipe Counting Screen ...
Страница 67: ...6 3 WIPE TEST CONTENTS Figure 6 2 The Wipe Area Setup Screen ...
Страница 68: ...CONTENTS WIPE TEST 6 4 Figure 6 3 The Wipe Preferences Window ...
Страница 70: ...1 INTRODUCTION Figure 6 4 The Background LLD Screen WIPE TEST 6 6 ...
Страница 72: ...1 INTRODUCTION WIPE TEST 6 8 Figure 6 5 The Wipe Results Report ...
Страница 76: ...1 INTRODUCTION 7 3 BIOASSAY Figure 7 2 The Bioassay Preferences Screen ...
Страница 78: ...7 5 BIOASSAY CONTENTS Figure 7 3 An Individual Bioassay Report ...
Страница 79: ...CONTENTS Figure 7 4 An Employee Bioassay Summary BIOASSAY 7 6 ...
Страница 80: ...1 INTRODUCTION 7 7 BIOASSAY Figure 7 5 An Individual Bioassay History Summary ...
Страница 82: ...1 INTRODUCTION SCHILLING TESTS 8 2 Figure 8 1 Defining a Facility Standard Schilling Test ...
Страница 83: ...CONTENTS 8 3 SCHILLING TESTS Figure 8 2 The Schillings Counting Page ...
Страница 84: ...CONTENTS SCHILLING TESTS 8 4 Figure 8 3 A sample Schillings Mallinckrodt Report ...
Страница 87: ...CONTENTS 8 7 SCHILLING TESTS Figure 8 4 The Diopac Schillings Counting Page ...
Страница 88: ...SCHILLING TESTS 8 8 CONTENTS Figure 8 5 A Sample Diopac Schillings Report ...
Страница 90: ...CONTENTS HEMATOLOGY 9 2 9 1 The IHSA Counting Page ...
Страница 92: ...1 INTRODUCTION HEMATOLOGY 9 4 Figure 9 2 A Sample IHSA I 125 Test Report ...
Страница 93: ...CONTENTS 9 5 HEMATOLOGY Figure 9 3 The CR 51 Counting Page ...
Страница 95: ...CONTENTS 9 7 HEMATOLOGY Figure 9 4 A Sample Cr 51 Volume Test Report ...
Страница 96: ...CONTENTS Figure 9 5 The Cr 51 Red Blood Cell Survival Counting Page HEMATOLOGY 9 8 ...
Страница 98: ...CONTENTS HEMATOLOGY 9 10 Figure 9 6 A sample Cr 51 Survival Test Report ...
Страница 100: ...CONTENTS Figure 9 7 The GFR Counting Page HEMATOLOGY 9 12 ...
Страница 103: ...1 INTRODUCTION 9 15 HEMATOLOGY Figure 9 8 A One Sample Glomerular Filtration Rate Report ...
Страница 104: ...1 INTRODUCTION HEMATOLOGY 9 16 Figure 9 9 A Two Sample Glomerular Filtration Rate Report ...
Страница 106: ...1 INTRODUCTION HEMATOLOGY 9 18 Figure 9 10 The ERPF Counting Page ...
Страница 108: ...1 INTRODUCTION HEMATOLOGY 9 20 Figure 9 10 The ERPF Counting Page ...
Страница 109: ...1 INTRODUCTION 9 21 HEMATOLOGY Figure 9 11 An Effective Renal Plasma Flow Report ...