Risks and safety aspects related to PET/MR examinations

IntroductionThe introduction of positron emission tomography (PET)/magnetic resonance (MR) systems into medical practice in the foreseeable future may not only lead to a gain in clinical diagnosis compared to PET/computed tomography (CT) imaging due to the superior soft-tissue contrast of the MR technology but can also substantially reduce exposure of patients to ionizing radiation. On the other hand, there are also risks and health effects associated with the use of diagnostic MR devices that have to be considered carefully.ObjectivesThis review article summarizes biophysical and biological aspects, which are of relevance for the assessment of health effects related to the exposure of patients to both ionizing radiation in PET and magnetic and electromagnetic fields in MR. On this basis, some considerations concerning the justification and optimization of PET/MR examinations are presented—as far as this is possible at this very early stage.DiscussionCurrent safety standards do not take into account synergistic effects of ionizing radiation and magnetic and electromagnetic fields. In the light of the developing PET/MR technology, there is an urgent need to investigate this aspect in more detail for exposure levels that will occur at PET/MR systems.

[1]  Peter Hunold,et al.  Increased time rate of change of gradient fields: effect on peripheral nerve stimulation at clinical MR imaging. , 2004, Radiology.

[2]  Frank G. Shellock,et al.  Reference Manual for Magnetic Resonance Safety, Implants, and Devices , 2009 .

[3]  Gunnar Brix,et al.  A survey of PET activity in Germany during 1999 , 2002, European Journal of Nuclear Medicine and Molecular Imaging.

[4]  G Brix,et al.  PET/CT , 2005, Nuklearmedizin.

[5]  Robert J. Griffin,et al.  Improvement of Tumor Oxygenation by Mild Hyperthermia , 2001, Radiation research.

[6]  David W Townsend,et al.  Dual-Modality Imaging: Combining Anatomy and Function* , 2008, Journal of Nuclear Medicine.

[7]  J. Overgaard,et al.  Hyperthermia: a potent enhancer of radiotherapy. , 2007, Clinical oncology (Royal College of Radiologists (Great Britain)).

[8]  J. Walleczek,et al.  Increase in radiation-induced HPRT gene mutation frequency after nonthermal exposure to nonionizing 60 Hz electromagnetic fields. , 1999, Radiation research.

[10]  John F Schenck,et al.  Physical interactions of static magnetic fields with living tissues. , 2005, Progress in biophysics and molecular biology.

[11]  P. Colletti.  Magnetic Resonance Procedures and Pregnancy , 2000 .

[12]  J D Bourland,et al.  Physiologic effects of intense MR imaging gradient fields. , 1999, Neuroimaging clinics of North America.

[13]  M. L. Wood,et al.  Magnetic Resonance Procedures: Health Effects and Safety , 2001 .

[14]  I. Bradbury,et al.  Overview of the clinical effectiveness of positron emission tomography imaging in selected cancers. , 2007, Health technology assessment.

[15]  Thomas Beyer,et al.  Radiation exposure of patients undergoing whole-body dual-modality 18F-FDG PET/CT examinations. , 2005, Journal of nuclear medicine : official publication, Society of Nuclear Medicine.

[16]  伊沢 正実,et al.  Recommendations of the International Commission on Radiological Protection , 1961 .

[17]  M Hiraoka,et al.  Exposure to strong magnetic fields at power frequency potentiates X-ray-induced DNA strand breaks. , 2000, Journal of radiation research.

[18]  Risks of Screening and Preventive Diagnosis , 2008 .

[19]  J. Patrick Reilly,et al.  Applied Bioelectricity: From Electrical Stimulation to Electropathology , 1998 .

[20]  Charles Polk,et al.  CRC Handbook of Biological Effects of Electromagnetic Fields , 1986 .

[21]  R. Sievert,et al.  Book Reviews : Recommendations of the International Commission on Radiological Protection (as amended 1959 and revised 1962). I.C.R.P. Publication 6. 70 pp. PERGAMON PRESS. Oxford, London and New York, 1964. £1 5s. 0d. [TB/54] , 1964 .

[22]  Francis A. Duck,et al.  Electrical Properties of Tissue , 1990 .

[23]  Division on Earth.  Health Risks from Exposure to Low Levels of Ionizing Radiation: BEIR VII Phase 2 , 2006 .

[24]  Gesine Hellwig,et al.  Estimation of heat transfer and temperature rise in partial-body regions during MR procedures: an analytical approach with respect to safety considerations. , 2002, Magnetic resonance imaging.

[25]  Frank G Shellock,et al.  Magnetic resonance imaging and permanent cosmetics (tattoos): Survey of complications and adverse events , 2002, Journal of magnetic resonance imaging : JMRI.

[26]  Christoph Palm,et al.  MR-based attenuation correction for torso-PET/MR imaging: pitfalls in mapping MR to CT data , 2008, European Journal of Nuclear Medicine and Molecular Imaging.

[27]  C. Collins,et al.  PET/CT in oncology: for which tumours is it the reference standard? , 2007, Cancer imaging : the official publication of the International Cancer Imaging Society.

[28]  K. Foster,et al.  Dielectric properties of tissues and biological materials: a critical review. , 1989, Critical reviews in biomedical engineering.

[29]  Yasuhito Isozumi,et al.  Combined exposure of ELF magnetic fields and x-rays increased mutant yields compared with x-rays alone in pTN89 plasmids. , 2005, Journal of radiation research.

[30]  H. Kay.  Environmental Health Criteria , 1980 .

[31]  Frank G. Shellock.  Magnetic Resonance Procedures: Health Effects and Safety , 2000 .

[32]  Wolfhard Semmler,et al.  MAGNETIC RESONANCE TOMOGRAPHY , 2008 .

[33]  Junji Miyakoshi,et al.  Effects of static magnetic fields at the cellular level. , 2005, Progress in biophysics and molecular biology.

[34]  Icrp.  1990 Recommendations of the International Commission on Radiological Protection , 1991 .

[35]  D E Hintenlang,et al.  Synergistic effects of ionizing radiation and 60 Hz magnetic fields. , 1993, Bioelectromagnetics.

[36]  Jack Valentin,et al.  Radiation dose to patients from radiopharmaceuticals , 1991 .