IAEA-TECDOC-796. Radiation doses in diagnostic radiology

Transcription

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2 IAEA-TECDOC-796 Radiation doses in diagnostic radiology

3 The IAEA does

4 The originating Section

5 FOREWORD It is well recognized that diagnostic radiology is the largest contributor to the collective dose from all man-made sources of radiation. Large differences in radiation doses from the same procedures among different X ray rooms have led to the conclusion that there is a potential for dose reduction. An exercise in dose reduction, while maintaining the quality of the diagnostic information in the image, is a genuine process of optimization associated with an improved use of the X ray equipment.

6 In preparing this publication EDITORIAL NOTE

7 CONTENTS 1. INTRODUCTION...

8 Radiation doses from diagnostic radiology 1. INTRODUCTION

9 reference levels

10 TABLE l. GENERAL INFORMATION DESCRIBING THE CRP PILOT PROGRAMME Country Argentina Brazil Czech Republic Ethiopia Ghana Iran, Islam. Rep. Romania Number of hospitals Number of X ray rooms To ensure a close interaction and co-operation with the radiology staff, a small number of hospitals was selected (see Table I and Appendix). Comparisons are only possible if some examinations are common to all participants, and preferably belonging

11 3.1. INDICATOR FOR DOSE ASSESSMENT In order to be able to assess patient doses, to compare them with the reference dose values and

12 TABLE

13 Initially, after annealing procedures, TLDs of each participating country were sent to the X ray Dosimetry Laboratory

14 TABLE V. TECHNICAL CHARACTERISTICS OF TLD SYSTEMS Country Argentina Brazil Czech Republic Ethiopia Iran, Islam.Rep. Ghana Romania TL reader Harshaw 2000 Harshaw Victoreen Vinten Solaro Harshaw Harshaw 2000 Harshaw 2000 TL material LiF-TLD 100 LiF-TLD 100 LiF-TLD 100 LiF-TLD 100 LiF-TLD 100 LiF-TLD 100 LiF-TLD 100 SD of batch (*) < 4 7 < 6 < 4.5 < 5 Annealing procedure 400 C/lh 100 C/3h 400 C/lh 100 C/2h 400 C/lh 80 C/16h 300 C/l,6h 80 C/17h 400 /lh 100 C/2h 400 C/lh 100 C/2h 400 C/lh 80 C/25h Annealing after each reading (Y/N) Y Y Y Y Y Y Y Reading process: ~TMAX -time -N 2 (Y/N) 300 C 15s Y Y 256 C 23s Y 300 C 12s Y 280 C 25s Y 300 C 20s Y 240 C 30s N Reading period after exposures (days) ~1 Calibration after each annealing procedure (Y/N) Source used for calibration Y ^Co Y «'Co Y 137 Cs Y»Sr Y «Co^'Cs Y Xray (48) kev Y 137 Cs Cleaning procedure (Y/N) Y Y Y Y Y Y N After each reading, the annealing procedures were performed according to manufacturer's recommendations and routine calibration using ß, y or X radiation was carried out by all the countries PLAN OF WORK

15 8. To organize the checking of the radiographie images using to the CEC quality criteria document. 9. To collect the occupational exposures data from the personnel dosimetry, and classify them in different ranges SCOPE

16 Filtering Additional filtration 4 is needed to avoid unnecessary skin exposure due to low energy components of the X ray spectrum. The latter do not actually contribute to image formation but are absorbed

17 Film processing

18 TABLE VI. CHARACTERISTICS OF TLD SYSTEMS EVALUATED DURING THE CALIBRATION OF THE PILOT PROGRAMME Energy response relative

19 TABLE VIL INTERCOMPARISON OF THE PILOT PROGRAMME OF TLD SYSTEMS Country Czech Rep. Ethiopia Ghana Iran, Islam. Rep. Romania TL group Air kerma (mgy) Effective energy (kev) Evaluated air kerma (mgy) (VC) (%) Bl (2.2) (3.7) 20.6 B (3.1) (8.9) B (6.6) (14.6)

20 Range of dose values The overall statistics of the dosimetry measurements are given in Table VIII for each examination type. One observes the large variations in dose, particularly for chest and abdomen examinations, as found

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22 TABLE

23 TABLE X. (cont.) Brazil 3/2 Country Hospital/Room Iran, Islam. Rep. 1/1 Iran, Islam. Rep. 1/2 Iran, Islam. Rep. 1/3 Iran, Islam. Rep. 2/4 Romania 1/4 Argentina 3/5 Argentina 3/6 Iran, Islam. Rep. 2/4 Abdomen Abdomen Abdomen Abdomen Abdomen Abdomen Breast Breast Breast Examination and Projection Method Increased filtration Increased kv Increased

24 TABLE XI. COMPLIANCE WITH THE CEC REFERENCE DOSE VALUES Examination type Lumbar spine (PA) Pelvis Chest (PA) Abdomen Breast (4.5

25 In

26 TABLE Xm. REJECT RATES AND FILM USAGE BY X RAY ROOM AND BY COUNTRY Country Hospital/Room Argentina 1/1-1/2 Brazil 1/D Brazil 2/D Czech

27 J y 2 - CHEST ABDOMEN L. SPINE PELVIS MAMMOG. FIG.

28 20 15-' HSxl 10-' xt~tx1 o Too Dark Too Light Posit. Cent. Procès. Pat. Mot. Others FIG. 6. Rejected films (relative percentages) averaged over 22 rooms in six countries.

29 TABLE XIV. REJECT RATES BY CAUSE AND BY COUNTRY Country Hospital/Room Argentina (chest) Argentina (abdomen) Argentina (breast) Brazil Czech 1/1 (chest) Czech

30 Among the most important causes of reject, one observes inadequate setting of physical parameters which lead

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32 REFERENCES

33 [20] SULEIMAN, O.H.,

34 Appendix SUMMARY OF REPORTS BY PARTICIPANTS This appendix deals with individual patient dose data and quality control measurement results obtained by each country participating in the CRP. It provides

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36 Chief investigator ARGENTINA

37 TABLE I. SUMMARY OF THE MEASUREMENTS OF PATIENT ENTRANCE SURFACE DOSE (ARGENTINA) HOSPITAL

38 TABLE

39 U) oo TABLE III. COMPLIANCE WITH THE CEC IMAGE CRITERIA. CHEST (PA) (ARGENTINA) IMAGE CRITERIA Performed

40 Chief investigator BRAZIL

41 -po TABLE

42 TABLE IL QC PARAMETERS CONTROLLED (BRAZIL) PARAMETERS Film processing conditions kv Accuracy (10%)* kv Reproducibility (4%)* kv Consistency (10%)* HVL, mm of Al (measured at 80 kv) Timer accuracy (10%)* Timer reproducibility (5%)* ma- s linearity, consistency Output (mgy/ma- s) (5%)* Consistency Light/radiation beam alignment (deviation

43 to TABLE HI. COMPLIANCE WITH THE CEC IMAGE CRITERIA. CHEST (PA) (BRAZIL) IMAGE CRITERIA Performed

44 TABLE

45 TABLE VI. COMPLIANCE WITH THE CEC IMAGE CRITERIA. ABDOMEN (AP) (BRAZIL) IMAGE CRITERIA Symmetrical reproduction

46 CZECH REPUBLIC Chief investigator and research team: Chief investigator: Research team: O. Kodl I. Zachariasova V. Klener

47 TABLE

48 TABLE II. SUMMARY OF THE MEASUREMENTS OF PATIENT ENTRANCE SURFACE DOSE (CZECH REPUBLIC) HOSPITAL X RAY ROOM 1

49 TABLE III. QC PARAMETERS CONTROLLED (CZECH REPUBLIC) PARAMETERS Film Processing Conditions

50 TABLE

51 TABLE

52 TABLE VI. COMPLIANCE WITH THE CEC IMAGE CRITERIA. PELVIS (AP) (CZECH REPUBLIC) IMAGE CRITERIA Symmetrical reproduction of the pelvis Visualization of the sacrum and its intervertébral foramina Visualization

53 ETHIOPIA Chief investigator and research team: Chief investigator: Research team: Wondwosen Mengesha Hailu Wolde Tsegaye Tolossa Dereje Anbessei Institution(s): Radiation Protection Unit Institute

54 TABLE

55 TABLE II. QC PARAMETERS CONTROLLED (ETHIOPIA) PARAMETERS Film Processing Conditions kv Accuracy (10%)* kv Reproducibility (4%)* kv Consistency (10%)* HVL, mm of AI (measured

56 TABLE III. COMPLIANCE WITH THE CEC IMAGE CRITERIA. CHEST (PA) (ETHIOPIA) IMAGE CRITERIA Performed

57 ON TABLE

58 Chief investigator and research team: GHANA

59 TABLE I. SUMMARY OF THE MEASUREMENTS OF PATIENTS ENTRANCE SURFACE DOSE (GHANA) HOSPITAL

60 TABLE

61 TABLE III. COMPLIANCE WITH

62 TABLE IV. COMPLIANCE WITH THE CEC IMAGE CRITERIA. PELVIS (AP) (GHANA) IMAGE CRITERIA Symmetrical reproduction

63 O\ (O TABLE V. COMPLIANCE WITH THE CEC IMAGE CRITERIA. LUMBAR SPINE (AP) (GHANA) IMAGE CRITERIA Linear reproduction of the upper

64 Chief investigator and research team: Chief investigator: ISLAMIC REPUBLIC OF BRAN

65 TABLE I. SUMMARY OF THE MEASUREMENTS OF PATIENT ENTRANCE SURFACE DOSE (IRAN, ISLAM. REP.) HOSPITAL X RAY ROOM

66 TABLE II. QC PARAMETERS CONTROLLED (IRAN, ISLAM. REP.) PARAMETERS Film Processing Conditions kv Accuracy (10%)* kv Reproducibility (4%)* kv Consistency (10%)* HVL, mmofal (measured at 80 kv) Timer Accuracy (10%)* Timer Reproducibility (5%)* ma s Linearity, Consistency Output (mgy/ma s) (5%)* Consistency Light/Radiation Beam Alignment (deviation

67 o\ OS TABLE III. COMPLIANCE WITH THE CEC IMAGE CRITERIA. MAMMOGRAPHY (IRAN, ISLAM. REP.) IMAGE CRITERIA Visually sharp reproduction of

68 TABLE

69 GO TABLE V. COMPLIANCE WITH THE CEC IMAGE CRITERIA. ABDOMEN (AP) (IRAN, ISLAM. REP.) IMAGE CRITERIA* Symmetrical reproduction

70 ROMANIA Chief investigator and research team: Chief investigator: Research team: C. Milu

71 TABLE

72 TABLE II.

73 (O TABLE III. COMPLIANCE WITH THE CEC IMAGE CRITERIA. CHEST (PA) (ROMANIA) IMAGE CRITERIA Performed at deep inspiration and with suspended respiration Symmetrical reproduction

74 Annex

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76 ABDOMEN AP/PA, FTRST ROUND OF MEASUREMENTS. RESULTS BY COUNTRY, HOSPITAL AND X RAY ROOM Countries Hospital Argentina Brazil Brazil Brazil Iran, Islam. Rep. Iran, Islam. Rep. Iran, Islam. Rep. Romania

77 CHEST AP/PA, FIRST ROUND

78 IVU, FIRST ROUND

79 oo MAMMOGRAPHY, FIRST ROUND OF MEASUREMENTS Countries Hospital Argentina Argentina Iran, Islam Rep

80 PELVIS

81 ABDOMEN AP/PA, SECOND ROUND OF MEASUREMENTS Countries Hospital Argentina Brazil Brazil Brazil Iran, Islam. Rep. Iran, Islam. Rep. Iran, Islam. Rep. Romania

82 CHEST PA, SECOND ROUND OF MEASUREMENTS Countries Hospital X ray Room Argentina Argentina Brazil Brazil Czech Republic C 2 D 2 2 Ethiopia Ethiopia Ghana Ghana Iran, Islam. Rep. Iran, Islam. Rep. Iran, Islam. Rep. Romania Romania

83 00 to IVUR, SECOND ROUND

84 MAMMOGRAPHY, SECOND ROUND OF MEASUREMENTS Countries Hospital Argentina Iran, Islam. Rep.

85 CRP RESULTS BY COUNTRY, BY HOSPITAL AND BY X RAY ROOM. (SKULL) - SECOND ROUND OF MEASUREMENTS Countries Hospital Brazil Brazil Brazil Brazil

86 Annex n EXAMPLES OF IMAGE QUALITY CRITERIA AND OF GOOD RADIOGRAPHIC TECHNIQUE, TAKEN FROM

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88 LUNGS CHEST

89 AP/PA PROJECTIONS LUMBAR SPINE 1. DIAGNOSTIC REQUIREMENTS Image criteria 1.1 Linear reproduction of the upper and tower-plate surfaces in the centred beam area and visualisation of tite intervertébral spaces 1.2 Visually sharp reproduction of the pedicles 1.3 Visualisation of the intervertébral joints 1.4 Reproduction of the spinous and transverse processes 1.5 Visually sharp reproduction

90 Alm Carlsson, G. Benini,