CHAPTER 1. INTRODUCTION ......................................... 1
1.1. From screen-film radiography to digital techniques ...... 1
1.2. Patient exposures in radiology .......................... 3
1.3. Quality assurance and dose management ................... 4
1.4. Need for dosimetry ...................................... 5
CHAPTER 2. FRAMEWORK ............................................ 7
2.1. Introduction ............................................ 7
2.2. Clinical needs .......................................... 7
2.2.1. Dosimetry requirements ........................... 8
2.2.2. Goals of the Code of Practice .................... 9
2.3. The international measurement system (IMS) ............. 10
2.3.1. SSDLs ........................................... 11
2.3.2. Diagnostic radiology standards .................. 12
2.3.3. Mutual recognition arrangement (MRA) ............ 14
CHAPTER 3. DOSIMETRIC QUANTITIES AND UNITS ..................... 19
3.1. Basic dosimetric quantities ............................ 19
3.1.1. Fluence ......................................... 19
3.1.2. Energy fluence .................................. 19
3.1.3. Kerma and kerma rate ............................ 20
3.1.4. Energy imparted ................................. 20
3.1.5. Absorbed dose ................................... 21
3.2. Application specific dosimetric quantities ............. 21
3.2.1. Rationale for choice of quantities .............. 21
3.2.2. Incident air kerma .............................. 23
3.2.3. Entrance surface air kerma ...................... 24
3.2.4. X ray tube output ............................... 24
3.2.5. Air kerma-area product .......................... 25
3.2.6. Air kerma-length product ........................ 25
3.2.7. Quantities for CT dosimetry ..................... 26
3.3. Quantities related to stochastic and deterministic
effects ................................................ 28
3.3.1. Organ and tissue dose ........................... 28
3.3.2. Equivalent dose ................................. 29
3.3.3. Effective dose .................................. 29
3.4. Conversion coefficients for the assessment of
organ and tissue doses ................................. 29
CHAPTER 4. DOSIMETRY FORMALISM ................................. 33
4.1. Nk based formalism ..................................... 33
4.1.1. Reference conditions ............................ 33
4.1.2. Influence quantities ............................ 34
4.2. Cross-calibration of dosimeters ........................ 37
CHAPTER 5. SELECTION OF INSTRUMENTATION ........................ 41
5.1. Introduction ........................................... 41
5.2. Dosimeters ............................................. 42
5.2.1. Ionization chambers ............................. 42
5.2.2. Solid state dosimeters .......................... 45
5.2.3. Dosimeter energy dependence ..................... 48
5.2.4. Other considerations ............................ 50
5.3. Requirements on user dosimetric equipment .............. 51
5.4. Requirements on the dosimetric equipment of SSDLs ...... 51
CHAPTER 6. ESTABLISHMENT OF A DIAGNOSTIC SSDL CALIBRATION
FACILITY ............................................ 55
6.1. Introduction ........................................... 55
6.2. General considerations ................................. 55
6.3. Environmental conditions ............................... 56
6.4. Apparatus .............................................. 57
6.4.1. Dosimetry equipment ............................. 57
6.4.2. X ray equipment ................................. 62
6.4.3. Shutter and apertures ........................... 63
6.4.4. Monitor chamber ................................. 65
6.4.5. Filters and attenuators ......................... 65
6.4.6. X ray tube voltage measuring devices ............ 66
6.4.7. Equipment for the calibration of CT chambers .... 67
6.4.8. Equipment for the calibration of КАР chambers ... 67
6.5. Establishing radiation qualities ....................... 69
6.5.1. General ......................................... 69
6.5.2. Standard radiation qualities RQR ................ 70
6.5.3. Standard radiation qualities RQA and RQT ........ 73
6.5.4. Standard radiation qualities RQR-M and RQA-M .... 75
6.5.5. Other radiation qualities for mammography ....... 76
6.6. Calibration of non-invasive X ray tube voltage
measuring instruments .................................. 77
6.6.1. Establishing the value for the practical peak
voltage ......................................... 77
6.7. Calibration uncertainties at the SSDL .................. 80
6.8. Quality management system .............................. 82
CHAPTER 7. CODE OF PRACTICE FOR DIAGNOSTIC CALIBRATIONS
AT SSDLs ............................................ 87
7.1. Introduction ........................................... 87
7.2. General considerations ................................. 87
7.3. Use of detectors ....................................... 89
7.3.1. Secondary standard .............................. 89
7.3.2. Instrument to be calibrated ..................... 90
7.4. Calibration procedures ................................. 91
7.4.1. Generalized protocol for calibration ............ 91
7.4.2. Procedures preceding calibration ................ 92
7.4.3. Procedures during calibration ................... 92
7.4.4. Calibration by the substitution method using
a monitor chamber ............................... 94
7.4.5. Determination of the correction factor kQ
using a monitor chamber ......................... 95
7.4.6. CT .............................................. 95
7.4.7. КАР meters ...................................... 97
7.5. Calibration of non-invasive X ray tube voltage
measuring instruments .................................. 98
7.5.1. Use of a voltage divider to calibrate a
non-invasive device ............................. 99
7.5.2. Use of non-invasive devices to calibrate
non-invasive devices ............................ 99
7.6. Procedures following calibration ...................... 100
7.6.1. Uncertainty budget ............................. 100
7.6.2. Calibration certificate ........................ 100
CHAPTER 8. CODE OF PRACTICE FOR CLINICAL MEASUREMENTS ......... 105
8.1. Introduction .......................................... 105
8.2. Selection of patients ................................. 107
8.3. Dosimetry formalism ................................... 108
8.3.1. Determination of application specific
quantities ..................................... 108
8.3.2. Uncertainties in quantities directly measured
by diagnostic dosimeters ....................... 109
8.3.3. Uncertainties in quantities derived from
directly measured quantities ................... 111
8.3.4. Uncertainties in thermoluminescence
measurements ................................... 112
8.4. General radiography ................................... 113
8.4.1. Choice of dosimetric quantities ................ 113
8.4.2. Measurements using phantoms .................... 113
8.4.3. Patient dosimetry .............................. 125
8.5. Fluoroscopy ........................................... 139
8.5.1. Choice of dosimetric quantities ................ 139
8.5.2. Measurements using phantoms .................... 139
8.5.3. Patient dosimetry .............................. 150
8.6. Mammography ........................................... 155
8.6.1. Choice of dosimetric quantities ................ 155
8.6.2. Measurements using phantoms .................... 155
8.6.3. Measurements on patients ....................... 173
8.7. CT .................................................... 188
8.7.1. Choice of dosimetric quantities ................ 188
8.7.2. Measurements using phantoms and free in air .... 188
8.7.3. Measurements on patients ....................... 202
8.8. Dental radiography .................................... 209
8.8.1. Choice of dosimetric quantities ................ 209
8.8.2. Measurements using phantoms .................... 209
8.8.3. Patient dosimetry .............................. 209
APPENDIX I: UNCERTAINTY OF MEASUREMENT ..................... 231
APPENDIX II: EXAMPLE OF UNCERTAINTY ANALYSIS FOR THE
CALIBRATION OF A USER DOSIMETER IN TERMS
OF AIR KERMA FOR RADIATION QUALITY, Q0 ......... 240
APPENDIX III: EXAMPLE OF DATA SHEET FOR CALIBRATIONS AT
AN SSDL ........................................ 253
APPENDIX IV: DETERMINATION OF THE PRACTICAL PEAK VOLTAGE .... 256
APPENDIX V: DETERMINATION OF THE HVL ....................... 261
APPENDIX VI: APPLICATION OF PATIENT DOSE MEASUREMENTS ....... 265
APPENDIX VII: BACKGROUND TO THE CODE OF PRACTICE FOR
CLINICAL MEASUREMENTS .......................... 291
APPENDIX VIII: BACKSCATTER FACTORS FOR GENERAL RADIOGRAPHY
AND FLUOROSCOPY ................................ 330
APPENDIX IX: FIELD CALIBRATIONS ............................. 335
GLOSSARY ...................................................... 347
CONTRIBUTORS TO DRAFTING AND REVIEW ........................... 357
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