August 19, 2011
International Commission on Radiological Protection
280 Slater Street
Ottawa, Ontario K1P 5S9
Canada
Re: Comments on the ICRP draft report; Patient and Staff Radiological Protection in Cardiology.
To Whom It May Concern:
The American Society of Nuclear Cardiology (ASNC) is pleased to provide comments on the International Commission on Radiological Protection’s Draft document report: Patient and Staff Radiological Protection in Cardiology. ASNC is a 4,700 member professional medical society, which provides a variety of continuing medical education programs related to nuclear cardiology and cardiovascular computed tomography, develops standards and guidelines for training and practice, promotes accreditation and certification within the nuclear cardiology field, and is a major advocate for furthering research and excellence in nuclear cardiology and cardiovascular computed tomography.
ASNC would first like to commend ICRP for undertaking this important initiative. Specifically, we are thrilled to see that ICRP has embraced the ASNC/ACC Appropriate Use Criteria as part of this draft document. We also appreciate the recognition of what the field has been working toward in targeted stress only imaging and in new technologies to decrease population exposure. We believe this report will be an invaluable publication on an integral aspect of medical imaging with important public health implications.
We offer comments on the following areas of major concern within the report as it relates to nuclear medicine, specifically nuclear cardiology studies:
· On page 23, line 969 we suggest rewording this statement. We believe it may read more appropriately if it were rewritten as: The choice of cardiac imaging modality should be based on the appropriate use criteria where an appropriate indication is by definition one where the clinical benefit far exceeds the projected risk. Moreover, consideration of alternative modalities should occur where there is clinical uncertainty, and especially for indications which are rated as inappropriate. In the case of an inappropriate indication, the projected risk of radiation exposure exceeds the no-minimal clinical benefit of the study. As part of this, reductions in inappropriate testing provide an important means to decrease population exposure
· On page 82, sections 7.1 and 7.2, we would call the ICRP’s attention to the fact that the National Council of Radiation Protection (NCRP) Report 160 assumed SPECT MPI studies using the radiopharmaceutical thallium comprised 33 percent of the nuclear cardiology market. It is our belief, based on current data, that thallium studies actually represent a much smaller portion of the market, more accurately quoted at approximately 18 percent of studies, and continually declining. [1] This is in large part due to the adoption of ALARA principles by the nuclear medicine community.
· We believe Table 7.2 (p.84) would be enhanced by adding equivalent doses in mCi in parenthesis to the listed doses which are in MBq. While this is an international publication with international units, it will make the document more easily usable to providers who still operate using mCi.
· In Table 7.1 (p.83), we find the “effective dose” column confusing. Specifically the link to delivered activity used to derive the calculation is not clear to the reader. In addition, ICRP’s dose coefficients do not appear consistent with the manufacturer’s dose coefficients. We also believe the ratio presentation is confusing, particularly when placed alongside the well presented graph in Figure 7.1 (top on page 86). Specifically, Figure 7.1 (top) suggests the effective dose of a Technetium (Tc) one day study is about 10 – 11 mSv (with breakdown as given) and a low dose stress study includes only as 2-3 mSv. We believe these are key concepts for ICRP’s consideration and inclusion.
· Further, we would point out that within Table 7.1 the appropriately quoted effective dose range for MUGA studies is 25-35 mCi for a stress study and 20-25mCi for a rest study.
· Finally, we have some concerns with the language on page 88, section 7.7.1 in the second paragraph where it reads “For clinical scenarios in which more than one imaging modality might be used, appropriateness criteria should simultaneously address these multiple modalities. (ACR, 2010). Alternative techniques (such as stress echocardiography) are available, and should be considered whenever possible.” While we understand and agree with the ICRP’s overall sentiment that for low risk patients alternate modalities may be considered, this is based on individual patient characteristics and clinical judgment ( in the end, the very best diagnosis and prognostication must be made). We suggest alternate wording such as: In cases where more than one imaging modality may be considered for a clinical complaint, physicians should weigh the additive benefits or risks of each test and utilize appropriate use criteria to determine which modality would provide the highest quality diagnostic information for the individual patient, while still maintaining the principles of ALARA in selecting and administering the imaging study.
ASNC greatly appreciates the opportunity to provide comment on this draft report. As previously stated, we strongly support this endeavor by ICRP and we look forward to continued collaboration on this document as it continues to evolve. Should you have any questions, please feel free to contact Jenna Wilkes, ASNC Director of Health Policy, at 301-215-7575 x207 or email at jwilkes@asnc.org. Thank you.
Sincerely,
Leslee J. Shaw, Ph.D., FASNC
President
American Society of Nuclear Cardiology
[1] Based on 2010 AMR quarterly data.