1. Barcelona, 20-22 January 2011 Workshop on optimization of Radiation Protection of Medical Staff O RAMED SPECIFIC TRAINING MODULE FOR NUCLEAR MEDICINE This training material has been developed in the framework of the Research project ORAMED, Optimization of Radiation Protection of Medical staff, funded by the European Atomic Energy Community's Seventh Framework Programme (FP7/2007-2011) under grant agreement n° 211361. Prepared by: Marta Sans-Mercè University Hospital Center and University of Lausanne, Switzerland Mercè Ginjaume Universitat Politècnica de Catalunya, Spain

2. USE AND DISCLAIMER This is a PowerPoint file. It may be downloaded free of charge. It is intended for teaching and not for commercial purposes. It is based on the results and guidelines derived from the “ORAMED, Optimization of Radiation Protection of Medical staff” project, funded by the European Atomic Energy Community's Seventh Framework Programm.

3. After the training participants should be able to 1.- know the physical characteristics of the different sources of exposure in nuclear medicine and the limits of exposure. 2.- identify the organs at risk for the different diagnostic/ therapy procedures. 3.- recognize and apply radiation protection means to ensure an adequate protection of staff. 4.- select the best dosimetric system and to implement the best monitoring procedure (type of dosemeter, position of use, interpretation of dosemeter reading). 5.- identify good and bad practices, in order to adapt, if needed, changes in the procedures, to improve the daily practic e. Objectives Framework: it is based on lessons learned from the ORAMED project, it mainly concentrates on extremity dosimetry in nuclear medicine

4. 1.- Introduction/revision: (what should be known: Aims of the medical speciality, different types of procedures, types of radiation sources, characteristics + workers dose-limit) 2.- Radiological risks (based on ORAMED results, the critical procedures, organs at risk and associated doses are highlighted). 3.- Staff monitoring: available dosemeters (Different types of available dosemeters together with the recommendations on their use depending on the type of procedure are presented). 4.- Radiation protection means (Based on ORAMED measurements and simulations results, a description of available RP means, shielding, type of syringe, distance, time are shown; first recommendations are presented). 5.- Guidelines, recommendations to optimize radiation protection (summary of previous observations) General structure To confirm knowledge, several questions are introduced in the presentation. When available they can be used with interactive systems.

5. CHAPTER 1: INTRODUCTION / REVISION

6. Nuclear medicine is a branch of medicine dealing with the use of (un-sealed) radioactive materials in the diagnosis and treatment of disease. Ref: Merriam-Webster's Medical Dictionary, © 2007 Merriam-Webster, Inc. Nuclear medicine definition

7. For diagnostic Gamma emitters 99m Tc, 111 In, 123 I, 131 I, 201 Tl, 133 X, …  + emitters (and annihilation photons) 18 F, 11 C, 13 N, 15 O, ( 64 Cu, 82 Rb, 86 Y, 124 I, …) For therapy  - emitters 90 Y, 131 I, 32 P, 89 Sr, 153 Sm, 169 Er, 177 Lu, 186 Re, … Most common radionuclides in nuclear medicine

8. Tc-99m Pure  -emitter E  = 140.5 keV (87%) Y-90 Pure   -emitter E  max = 2280 keV (100%) F-18 Mixed  - and   -emitter E  = 511 keV (194%) E  max = 634 keV (97%) I-131 Mixed  and  emitter E  = 365 keV (82%) E  max = 606.3 keV(89%) Diagnosis with Tc-99m and F-18 Therapy with Y-90 (RIT with Zevalin ®; PRRT with Dotatoc ® ), I-131 Characteristics of the most frequently used radionuclides

9. D.The largest dose-rate is for Y-90, then for Tc-99m and finally for F-18. Q1. Typical activities per patient per diagnostic procedures are of the order of 500 MBq for Tc-99m, 400 MBq for F-18. For Y-90 therapy the activity is 1 GBq. Which is the dose rate in contact of a 5 ml unshielded syringe? A.The lowest dose-rate is for Y-90. B.For Y-90 is 34 times larger than for Tc-99m and 5 times larger than for F-18. C.The largest dose-rate is for F-18. Radionuclides characteristics

10. Hp(0.07) rate (in mSv.min -1 )Time (in min) to reach 500 mSv Contact of an unshielded (5 ml) syringe Dose rates are VERY different For Y-90 the annual limit can be reached in less than 1 minute  Shielding is essential However, the frequencies of use are VERY different Dose rate at contact

11. Q2. As regards the range/penetration of the most typical radiopharmaceuticals. Which is the correct statement? A.The half-value layer in tissue of F-18 is of the order of 7.5 cm.. B.The half-value layer in tissue for Tc-99m is of the order of 2 cm. C.The range of Y-90 in tissue is of the order of 5 cm. D.The range of Y-90 in air is of the order of 10 cm. Radionuclides characteristics

12. x1.6 Properties of the most common radionuclides

13. Q3. As regards the dose limits for extremity dosimetry in nuclear medicine Which is the correct statement? A.No need for routine extremity monitoring, dose limit is never reached. C.The annual dose limit for the skin is 500mSv averaged over 1cm 2 B.The annual dose limit for the skin is 20mSv averaged over 1cm 2 D.The annual dose limit for the skin is 500mSv averaged over the hand Dose limits

14. ICRP 60 recommendations : Annual equivalent dose in the skin 500mSv for 12 months averaged over 1cm 2 area regardless of the exposed surface European directive 96/29: All workers likely to receive an extremity dose larger than 3/10 of the annual limit dose must wear an extremity dosemeter Dose limits for the extremities

15. C HAPTER 2: R ADIOLOGICAL RISKS Staff

16. Radiological risks: Sources of exposure of nuclear medicine workers D 0 / 20 2  Risk of internal contamination Valid for all radionuclides and specially for iodine (volatile) and... Nuclear medicine implies the manipulation of unsealed radioactive sources

17.  Risk of external irradiation Whole body (WB) and extremities irradiation when manipulating radioactive sources  The hands are particularly exposed in nuclear medicine Whole body irradiation from the patient Labelling vialElution vialGenerator Labelling with Tc-99m Injection in diagnostics Radiological risks: Sources of exposure of nuclear medicine workers

18. Q4. As regards nuclear medicine technologists’ annual dose, the main source of exposure, compared with annual limits is related to : A.The WB exposure during preparation and administration of radiopharmaceuticals. B.The WB exposure when assisting and accompanying the patient. C.The extremity exposure during preparation and administration of radiopharmaceuticals. D.The extremity exposure when assisting and accompanying the patient. Radiological risks

19. Source: IAEA teaching slides - Radiation Protection in PET/CT Typical annual whole body staff doses at conventional Nuclear Medicine facilities are 0.1 mSv, but are closer to 6 mSv at PET/CT facilities. While a substantially higher dose, this is still below the ICRP limit of 20 mSv per year WB doses expected (external radiation) Technologist Dose per procedure (  Sv) WB Tc-99m bone scan0.3 ± 0.2 Tc-99m MIBI SPECT1.7 ± 0.2 WB FDG5.9 ± 1.2

20. Procedure Range (µSv/GBq) Mean (µSv/GBq) Patients per year Activity per patient (MBq / mCi) Annual dose (mSv / % limit) Tc-99m administration12 – 951233 1000 (5 patients per day, 10 months) 100 – 850 / 3 – 30 Mean: 500 / 14 117 / 23% Tc-99m preparation33 - 2062432216 / 43% F-18 administration139 - 4113933400 / 11373 / 75% F-18 preparation97 - 44331205500 / 14603 / 121% Is it easy to exceed the skin dose limit? Tc-99m administration Tc-99m preparation F-18 administration F-18 preparation  Depending on the workload, the skin dose may surpass the dose limit or 3/10 of the limit, especially for F-18. D < 150 mSv  72% 150 mSv < D < 500 mSv  28% D > 500 mSv  0% D < 150 mSv  53% 150 mSv < D < 500 mSv  39% D > 500 mSv  8% D < 150 mSv  34% 150 mSv < D < 500 mSv  43% D > 500 mSv  23% D < 150 mSv  13% 150 mSv < D < 500 mSv  47% D > 500 mSv  40% Source: ORAMED - Carnicer et al. Radiat. Measurements, 2012.

21. Q5. What are the procedures at risk for nuclear medicine technologists in diagnostic nuclear medicine, regarding the doses to the extremities? For the same activity, the maximum skin dose... Radiological risks A.Is usually higher for the preparation of Tc-99m than for the administration of F-18. B.Is usually higher for the preparation of F-18 than for the administration of F-18. C.Can be higher for the preparation of Tc-99m than for the preparation of F-18. D.All are correct.

22. Very large range of maximum finger doses. The preparation of the radiopharmaceutical involves higher finger doses per activity than the administration. F-18 involves higher finger doses per activity than Tc-99m. The preparation of F-18 is the most critical among the studied diagnostic procedures. Comparison of diagnostic NM procedures Source: ORAMED - Carnicer et al. Radiat. Measurements, 2012.

23. Attention with contamination, in particular for therapy Dose rate > 200mSv/h approx. 5cm over the contamination spot Y-90 Zevalin® - Therapy Contamination Source: Ilona Barth and Arndt Rimpler

24. C HAPTER 3: S TAFF MONITORING 24

25. Measuring internal contamination  - (or  ) (therapy) In vitro measurement In vivo measurement  (and   ) (imaging) Liquid scintillation counting Whole body counter (WBC) 25

26. Routine external monitoring Routine whole body monitoring with TLDs Quantity to be measured Hp(10) Extremity routine monitoring with TLDs Quantity to be measured H p (0,07) In practice ring or wrist dosemeter are used Should be worn at the most exposed position in the hands 26

27.  Whenever one can be sure that the workplace does not include low- energy beta particles, the use of TLD-100 would be advisable because of its better performance and ease of use (1).  If the contribution of positrons to Hp(0.07) for PET workers cannot be neglected. Thin TL detectors, such as MCP-Ns, are more appropriate for this type of dosimetric application. If thin TL detectors are not used, an underestimation of the order of 30% could be envisaged for 18 F handling. This difference should be added to the underestimation of Hp(0.07) because of the position of the dosemeter (2). (1) Ginjaume et al. Comparison of two extremety dosemeters based on LiF:Mg,Cu,P thin detectors for mixed beta-gamma fields. Radiat. Prot. Dosim. 120, No. 1-4, 316–320 (2006). Type of TLD (2) Ginjaume et al. Comparison of TLD-100 and MCP-Ns for use as an extremity dosemeter for PET nuclear medicine staff. Radiat. Prot. Dosim. 43, 607–610 (2008). 27

28. A.- The ring dosemeter always provides a higher dose reading. Use a ring dosemeter. Q6. Which statement would you consider if you were to recommend some type of extremity dosemeter for nuclear medicine workers? B. – You can use either a ring or a wrist dosemeter. But it is important to use 2 dosemeters. C.- There are no significant differences between wrist and ring. Use a wrist dosemeter in the dominant hand (right) because it is more confortable. D.-There are no significant differences between wrist and ring. Use a wrist dosemeter in the non dominant hand (left). Staff monitoring 28

29. Doses at different positions Doses at wrist position are systematically lower than at any other position 29

30. A. Base of the ring finger of dominant hand (external side) The ring dosemeter is recommended to the wrist dosemeter in nuclear medicine. Q7. In which position should it be worn? B. Base of the ring finger of dominant hand (palm side) C. Base of the index finger of non-dominant hand (external side) D. Base of the index finger of non-dominant hand (palm side) Staff monitoring 30

31. A. You don’t underestimate. The ring dosemeter should be worn as close as possible to the most exposed part of the hand. However this is not easy to do in practice. Q8. How much do you underestimate the maximum skin dose when monitoring it with a ring dosemeter worn in the base of the index (palm side) non-dominant hand? B. Up to a factor of 2 C. Around a factor of 6 D. Around a factor of 10 E. Up to a factor of 100 when you manipulate beta sources. Staff monitoring 31

32.  General ratios considering all data independently of the procedure. 22 18 6.0 9.4 3.1 2.5 5.5 10 Ratios for diagnostics procedures The recommended monitoring position is the base of the index finger of the ND hand (low ratio, high correlation with the maximum) which underestimates the maximum dose by a factor of 5.5. (outliers excluded) Source: ORAMED - Carnicer et al. Radiat. Measurements, 2012.

33. 201717 2230 14 2 7 15 The recommended position is the base of the index finger of the ND hand (low ratio, high correlation with the maximum) which underestimates the maximum dose by a factor of 7. Ratios for therapy procedures Source: ORAMED - Rimpler et al. Radiat. Measurements, 2012.

34. C HAPTER 4: R ADIATION PROTECTION MEANS 34

35. Q9. What are the 3 most important parameters (in order of importance) influencing the maximum skin dose in nuclear medicine? How to reduce the skin dose? A.Distance – Shielding – Dose monitoring B.Distance – Time – Shielding C.Shielding – Distance - Training D.All of the above Radiation protection means 35

36. 3 basic principles in Radiation protection Shielding Distance Time (training) 36

37. Personal Protective equipment Syringe shield Vial Shield Lead gloves Shielding Room Protective Equipment Lead box Activimeter in the lead box 37

38. RSO with Y-90, dose rate reduction when using adapted tools. Y-90 Zevalin® dose rate during the injection trough a flexible tube 38 Source: Ilona Barth and Arndt Rimpler

39. Q10. Concerning shielding when injecting a radiopharmaceutical.... A.All shieldings have the same reduction factor independently of the radionuclide B.No need of shielding since the injection procedure is fast C.2mm Tungsten and 3 mm lead are equivalent for 99m Tc D.5mm of tungsten is the minimum required shielding 99m Tc Radiation Protection means 39

40. Injection scenarios  Tc-99m: 2 mm W provide about more than 2 orders of magnitude of attenuation  There is little differences between Pb and W, even if W if better performing (because of specific density 11.35 versus 19.3 g/cm 3 ) 40 Tc-99m Source: ORAMED project.

41. Injection scenarios F-18  F-18: (best is 8 mm W) 5 mm W provide a factor of 10 41 Source: ORAMED project.

42. Injection scenarios Y-90 42 For Y-90 5 mm W is better than 1 cm PMMA providing more than 3 order of magnitudes of attenuation. W shields also Bremmsstrahlung radiation. Source: ORAMED project

43. Tc-99m Preparation scenarios 43 3 mm Pb provides more than 3 orders of magnitude in dose reduction. Source: ORAMED project

44. Preparation scenarios F-18 44 3 cm Pb provides 2 orders of magnitude in dose reduction Source: ORAMED project

45. Preparation scenarios Y-90 45 5, 10 and 15 mm of PMMA provide almost the same attenuation. To further reduce the doses at least some mm of Pb are needed. 5 mm W can be directly used instead of using PMMA + Pb. Source: ORAMED project

46. Summary shielding recommendations 46 For the preparation (vial shielding):  For F-18, 3 cm of Pb provides 2 order of magnitudes on dose reduction. The same attenuation for Tc-99m is obtained with 2 mm Pb.  For Y-90 an acceptable shielding is obtained with 10 mm PMMA with an external layer of few mm of lead or alternatively 5 mm of W. For the injection (syringe shielding):  2 mm W (or Pb) for Tc-99m give a dose reduction of at least 2 order of magnitudes;  5 mm W provides up to a factor 10 in dose reduction for F-18 (8 mm W up to a factor 40).  For Y-90 10 mm PMMA completely shield beta radiation, nevertheless 5mm shielding of tungsten provides a better shielding cutting down bremsstrahlung radiation too.

47. Distance Automatic dispensers Twisers/Forceps Distance 47

48. F-18 vial source shielded with 8 mm W. the effectiveness of using forceps is also demonstrated when working with shielded sources. 48 Tools - forceps

49. AB C When handling an Y-90 syringe for RTPE the position of the fingers is very important. The dose rate along the syringe varies dramatically.. Q11. How many times can the doses at the fingers be reduced if the contact with the shielded syringe is in position A (no pharmaceutical, below)? C. Up to a factor of 1000 times from C to A Radiation Protection means B. Up to a factor of 100 times from B to A A. More than 1500 from B to A D. More than 10000 times from C to A E. (A) and (D) are correct 49

50. Dose rates (in  Sv/h) at the different positions in a syringe filled with Y-90 50

51. It is very difficult to correctly estimate the influence of time to a complete procedure, especially for the preparation of radiopharma- ceuticals. (Different steps, very different dose rates in each step, usually for trained workers, the use of shield or the distance are parameters more determinant). Time 51

52. Q12. How many years of experience a worker needs to keep his annual maximum hand dose below the annual limit of 500mSv? C. Minimum 5 years Radiation Protection means B. After 6 months the worker has acquired enough experience A. More than 1 year D. The experience is not always related to low doses 52

53. Not statistically significant differences  The influence of the experience on the dose is not clear (few data, influence overlapped with other parameters). Experience: higher doses for beginners ? Few data Not statistically significant differences Few data Unshielded vial excludedUnshielded syringe excluded 53

54. 54 The accumulated dose is directly proportional to the time. A reduction of 2 in time implies a reduction of 2 in doses. Training is very important to ensure a quick and correct handling of radiopharmaceuticals. However, experience is not always related with good training and good practice. There are cases of bad habits.

55. CHAPTER 5: SUMMARY RECOMMENDATIONS 55

56.  Wide ranges of individual exposures (min/max) for similar procedures, different equipment, radiation protection means and tools.  Skin dose limit (500 mSv/y) can be exceeded by numerous workers in hospitals where RP standard is low  There is adequate potential to further improve radiation protection and decrease exposures  Adequate skin dose monitoring is urgently needed in nuclear medicine General observations 56

57.  The choice of TLD and TLD position is important for an adequate dose assessment  Shielding of vials and syringes are essential and a precondition but not a guarantee for low exposures.  Other RP tools and measures (e.g. pincers, forceps, time etc.) significantly influence the exposure.  Also subjective factors e.g. risk awareness and training affect exposures. Especially in therapy, participants have reduced extremity dose during the project due to the feedback of the measurement results on the RP standard.  Working fast is often not sufficient What we have learned 57

58. Examples of good practices Preparation of Tc-99mPreparation of F-18 Administration of F-18Administration of Tc-99m 58

59. Examples of good practices for Y-90 59

60. Preparation of Tc-99m Examples of bad practices Preparation of F-18 Administration of F-18Administration of Tc-99m Unshielded vial and syringe Unshielded syringe, thumb direclty exposed Unshielded syringe Left hand holding the part of the needle 60

61. Example of bad RP practice The maximum skin dose for this worker is 52 times the mean of the 30 participants Examples of bad practices for Y-90 61

62. T7HF 2 The maximum skin dose for this worker is 16 times the mean of the 30 participants Examples of bad practices for Y-90 62

63. The final outcome of the ORAMED project is to propose, on the basis of the results of measurement and simulation campaign performed, the guidelines in order to minimise radiation risk to medical staff in nuclear medicine. Directed to: physicians nurses technicians radiation protection officers authorities in the field The following recommendations concern only radiation protection aspects. Outcome

64. Recommendation 1 - extremity monitoring For diagnostics procedures: The annual dose estimation is above 150 mSv (3/10 of the annual limit) for 51% of the workers. 20% of the workers exceed the annual dose limit of 500mSv. The annual dose of 60% of the workers monitored for the ORAMED project has been estimated only considering the procedures from which real measured values were available and only for those whom their workload was known. Extremity monitoring is a necessity in nuclear medicine.

65. Recommendation 2 - routine monitoring Recommended monitoring position: base index finger of non dominant hand with TLD directed to the inner side low ratio high correlation with the maximum comfortable for manipulating Best monitoring position: index tip of the non dominant hand BUT not feasible for routine monitoring with ring dosemeters The base of the index finger of the non dominant hand with the detector (TLD) placed towards the inside of the hand is the recommended position for routine extremity monitoring in nuclear medicine.

66. Recommendation 3- estimation of maximum dose 2218 6.0 9.4 3.1 2.5 5.5 10 Diagnostics 201717 2230 14 2 7 15 Therapy A rough estimate of the maximum dose to the hand can be obtained by multiplying the reading of the dosemeter worn in the base of the index of the non dominant hand by 6.

67. Recommendation 4 - shielding Shielding of vials and syringes are essential and a precondition but not a guarantee for low exposures.

68. Recommendation 5 – minimum syringe shield The minimum acceptable shielding required for a syringe is 2 mm of tungsten for 99m Tc and 5 mm of tungsten for 18 F. For 90 Y 10 mm PMMA completely shield beta radiation, nevertheless 5mm shielding of tungsten provides a better shielding cutting down bremsstrahlung radiation too.

69. Recommendation 6 – minimum vial shield The minimum acceptable shielding required for a vial is 3mm and 3cm lead for 99m Tc and 18 F respectively. For 90 Y an acceptable shielding is obtained with 10 mm PMMA with an external layer of few mm of lead.

70. Procedure planning: preparation of tools, estimation of doses to be received (dose estimation tool), first trial with inactive sources.dose estimation tool Recommendation 7 – training and education Training and education on good practice (e.g. procedure planning, repeating procedures using non radioactive sources) are more relevant parameters than the experience of the worker.

71. Recommendation 7 – training and education Dose estimation tool

72. the effectiveness of using forceps is also demonstrated when working with shielded sources. Recommendation 8 – radiation protection tools All tools increasing the distance (e.g. forceps) between the hand/finger and the source are very effective for dose reduction.

73. It is very difficult to correctly estimate the influence of time on the dose during a complete procedure, especially for the preparation of radiopharmaceuticals. Different steps, very different dose rates in each step, usually for trained workers the use of shields or increasing the distance are more effective than pushing on the working speed. Recommendation 9 – time Working fast is not sufficient, the use of shields or increasing the distance are more effective than pushing on the working speed.

74. 2. The base of the index finger of the non dominant hand with the detector (TLD) placed towards the inside of the hand is the recommended position for routine extremity monitoring in nuclear medicine. 3. A rough estimate of the maximum dose to the hand can be obtained by multiplying the reading of the dosemeter worn in the base of the index of the non dominant hand by 6. 4. Shielding of vials and syringes are essential and a precondition but not a guarantee for low exposures. 5. The minimum acceptable shielding required for a syringe is 2 mm of tungsten for 99m Tc and 5 mm of tungsten for 18 F. For 90 Y 10 mm PMMA completely shield beta radiation, nevertheless 5mm shielding of tungsten provides a better shielding cutting down bremsstrahlung radiation too. 1.Extremity monitoring is a necessity in nuclear medicine. Recommendations (summary 1/2)

75. 7. Training and education on good practice (e.g. procedure planning, repeating procedures using non radioactive sources) are more relevant parameters than the experience of the worker. 8. All tools increasing the distance (e.g. forceps) between the hand/finger and the source are very effective for dose reduction. 9. Working fast is not sufficient, the use of shields or increasing the distance are more effective than pushing on the working speed. 6.The minimum acceptable shielding required for a vial is 3mm and 3cm lead for 99m Tc and 18 F respectively. For 90 Y an acceptable shielding is obtained with 10 mm PMMA with an external layer of few mm of lead. Recommendations (summary 2/2)

76. ACKNOWLEDG MENTS Special thanks to all the workers and hospitals that have collaborated Acknowledgment to the European Atomic Energy Community's Seventh Framework Programme for funding the ORAMED project under grant agreement n° 211361.