1. VIII.3. Optimization of Protection for Medical Exposures in Nuclear Medicine. 4. Guidance levels Postgraduate Educational Course in Radiation Protection and the Safety of Radiation Sources

2. VIII.3.4. Guidance levels2 BSS II.17. Registrants and licensees shall ensure that: (a) the medical practitioners who prescribe or conduct diagnostic applications of radionuclides: (i) ensure that the exposure of patients be the minimum required to achieve the intended diagnostic objective; (ii)take into account relevant information from previous examinations in order to avoid unnecessary additional examinations; and (iii) take into account the relevant guidance levels for medical exposure; Optimization of medical exposure in Nuclear Medicine

3. VIII.3.4. Guidance levels3 OPTIMIZATION OF PATIENT EXAMINATION Diagnostic objective Medical exposure

4. VIII.3.4. Guidance levels4 OPTIMIZATION OF MEDICAL EXPOSURE Administered activity Radiation risk Quality of equipment etc Effective dose Image quality Radionuclide Biokinetics Patient

5. VIII.3.4. Guidance levels5 Optimization of image quality Image quality depends on: l Administered activity l Technical factors - equipment used - acquisition protocol - image processing & evaluation - noise - spatial resolution - scatter - scatter l Patient factors - size - age - age - disease - movement - disease - movement

6. VIII.3.4. Guidance levels6 OPTIMIZATION OF ADMINISTERED ACTIVITY In general, doses should be maintained as low as reasonable achievable but high enough to obtain the desired diagnostic information. This means that exposures above clinically acceptable maximum doses must be avoided as well as doses below clinically acceptable minimum doses

7. VIII.3.4. Guidance levels7 Optimization of Administered activity Value of diagnostic information Administered activity There is a threshold below which no useful information can be expected Above this threshold the diagnostic quality increases steeply with the administered activity Once an acceptable level has been reached further increase of activity will not improve the result (ICRP 52)

8. VIII.3.4. Guidance levels8 Administered activity to children Optimization is necessary! Administered activity to children referred to DMSA scan in Swedish hospitals

9. VIII.3.4. Guidance levels9 2.27. Guidance levels for medical exposure shall be established for use by medical practitioners. The guidance levels are intended: (a) to be a reasonable indication of doses for average sized patients; (b) to be established by relevant professional bodies in consultation with the Regulatory Authority following the detailed requirements of Appendix II and the guidance levels given in Schedule III; (c) to provide guidance on what is achievable with current good practice rather than on what should be considered optimum performance; (d) to be applied with flexibility to allow higher exposures if these are indicated by sound clinical judgment; and (e) to be revised as technology and techniques improve. GUIDANCE LEVELS (BSS)

10. VIII.3.4. Guidance levels10 GUIDANCE LEVELS II.24. Registrants and licensees should ensure that guidance levels for medical exposure be determined as specified in the Standards, revised as technology improves and used as guidance by medical practitioners, in order that: (a) corrective actions be taken as necessary if doses or activities fall substantially below the guidance levels and the exposures do not provide useful diagnostic information and do not yield the expected medical benefit to patients; (b) reviews be considered if doses or activities exceed the guidance levels as an input to ensuring optimized protection of patients and maintaining appropriate levels of good practice; and (c) for diagnostic radiology, including computed tomography examinations, and for nuclear medicine examinations, the guidance levels be derived from the data from wide scale quality surveys which include entrance surface doses and cross-sectional dimensions of the beams delivered by individual facilities and activities of radiopharmaceuticals administered to patients for the most frequent examinations in diagnostic radiology and nuclear medicine respectively.

11. VIII.3.4. Guidance levels11 GUIDANCE LEVELS II.25. In the absence of wide scale surveys, performance of diagnostic radiography and fluoroscopy equipment and of nuclear medicine equipment should be assessed on the basis of comparison with the guidance levels specified in Schedule III, Tables III-I to III-V. These levels should not be regarded as a guide for ensuring optimum performance in all cases, as they are appropriate only for typical adult patients and, therefore, in applying the values in practice, account should be taken of body size and age.

12. VIII.3.4. Guidance levels12 Guidance levels of activity

13. VIII.3.4. Guidance levels13 How to establish 1. Elimination of outliers 2. State-of-the practice (good practice) 3. State-of-the art (optimal practice) Guidance levels

14. VIII.3.4. Guidance levels14 Distribution of administered activities Number of patients Activity Activity Log-normal distributions Guidance level Optimized?

15. VIII.3.4. Guidance levels15 Max IAEA guidance level Mean and range of mean (Sweden, 1995 ) Bone scintigraphy Optimized? Activity, MBq

16. VIII.3.4. Guidance levels16 Dose constraints (BSS II.27.) Registrants and licensees shall constrain any dose to individuals incurred knowingly while voluntarily helping (other than in their occupation) in the care, support or comfort of patients undergoing medical diagnosis or treatment and to visitors to patients who have received therapeutic amounts of radionuclides or are being treated with brachytherapy sources

17. VIII.3.4. Guidance levels17 Dose limitation for comforters and visitors of patients (BSS Schedule II.9)..The dose shall be constrained so that it is unlikely that his or her dose will exceed 5 mSv during the period of a patient’s diagnostic examination or treatment. The dose to children visiting patients who have ingested radioactive materials should be similarly constrained to less than 1 mSv

18. VIII.3.4. Guidance levels18 Shall the patient be hospitalized? Can the patient leave? Any restrictions?

19. VIII.3.4. Guidance levels19 Guidance level for maximum activity for patients in therapy on discharge from hospital

20. VIII.3.4. Guidance levels20 HOSPITALIZATION OR NOT I-131 1100 MBq stay in hospital stay in hospital or discharged with individual restrictions 600 MBq discharged with individual restrictions 150 MBq discharged, general restrictions

21. VIII.3.4. Guidance levels21 The patient should be kept at least 2h, and if possible one day in the hospital. In the case of cancer treatment, the patient should generally be hospitalized for several days. In all cases, the dose rate at 1 m from the patient should be down to an acceptable level established by the RPC. Therapy Patient I-131

22. VIII.3.4. Guidance levels22 Release of Patients after Therapy with Unsealed Radionuclides (ICRP) l The decision to hospitalize or release a patient should be individually determined and should not be linked only to residual activity in the patient but should take into account factors including the patient’s wishes, occupational and public exposures, family considerations, cost and environmental factors

23. VIII.3.4. Guidance levels23 Patient information needed for the decision: Nausea-intravenous administration to be considered? Living conditions-number of people in house? -children? -separate room? Type of work-working close to other people? -working with children? -pregnant coworkers? Public transport-time?

24. VIII.3.4. Guidance levels24 l separate room with toilet and shower l patient instructions (verbal and written) l local rules for nursing the patient l local rules for visitors l local rules for decontamination l local rules for emergency situations Hospitalized patient Protection of the staff Protection of visitors Protection of general public

25. VIII.3.4. Guidance levels25 II.8. The exposure of humans for medical research is deemed to be not justified unless it is: (a) in accordance with the provisions of the Helsinki Declaration [16] and follows the guidelines for its application prepared by Council for International Organizations of Medical Sciences (CIOMS) [17] and WHO [18]; and (b) subject to the advice of an Ethical Review Committee (or any other institutional body assigned similar functions by national authorities) and to applicable national and local regulations. MEDICAL RESEARCH (BSS)

26. VIII.3.4. Guidance levels26 Medical Research (BSS II.26.) The Ethical Review Committee or other institutional body assigned similar functions on the subject by national authorities shall specify dose constraints to be applied on a case by case basis in the optimization of protection for persons exposed for medical research purposes if such medical exposure does not produce direct benefit to the exposed individual.

27. VIII.3.4. Guidance levels27 MEDICAL RESEARCH Level of Risk:TrivialMinor to Intermediate Moderate Risk Category:II.A.I.III Total detriment~ 10 -6 or less ~ 10 -5 ~ 10 -4 ~ 10 -3 or more Range of effective doses (adults), mSv < 0.10.1 - 11 - 10> 10 a Anticipated level of benefit to Society MinorIntermediate to moderate Substantial a To be kept below deterministic thresholds except for therapeutic experiments. ICRP and WHO categorization of risk

28. VIII.3.4. Guidance levels28 Nuclear medicine therapy l Volunteers: not possible in the conventional way, however considered must be n participants in clinical trials n patients who undergo therapy and are at the same time included in radiobiological evaluations n patients who undergo therapy and have their treatment modified to answer research questions.