| Radio frequency noise from clinical linear accelerators. | |
| | |
MedLine Citation:
|
PMID: 19336849 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
|
There is a great deal of interest in image-guided radiotherapy (IGRT), and to advance the state of IGRT, an integrated linear accelerator-magnetic resonance (linac-MR) system has been proposed. Knowledge of the radiofrequency (RF) emissions near a linac is important for the design of appropriate RF shielding to facilitate the successful integration of these two devices. The frequency spectra of both electric and magnetic fields of RF emission are measured using commercially available measurement probes near the treatment couch in three clinical linac vaults with distinct physical layouts. The magnitude spectrum of the RF power emitted from these three linacs is then estimated. The electric field spectrum was also measured at several distances from the linac modulator in order to assess the effects of variations in spatial location in the treatment vault. A large fraction of RF power is emitted at frequencies below 5 MHz. However, the measured RF power at the Larmor frequency (8.5 MHz) of the proposed 0.2 T MR in the linac-MR (0.4-14.6 microW m(-2)) is still large enough to cause artifacts in MR images. Magnetron-based linacs generally emit much larger RF power than klystron-based linacs. In the frequency range of 1-50 MHz, only slight variation in the measured electric field is observed as a function of measurement position. This study suggests that the RF emissions are strong enough to cause image artifacts in MRI systems. |
| | |
Authors:
|
B Burke; M Lamey; S Rathee; B Murray; B G Fallone |
Related Documents
:
|
7869179 - Magnetophoresis: i. detection of magnetically labeled cells. 19505179 - Quadrupole magnetic sorting of porcine islets of langerhans. 11846579 - Probe--sample coupling in the magnetic resonance force microscope. 17601659 - Intraorbital apocrine hidrocystoma. 1501539 - Bio-effects of high magnetic fields: a study using a simple animal model. 20608659 - Exchange-coupled cobalt(ii) dimer with unusual magnetic circular dichroism saturation b... 7577219 - False-positive sonographic hip examinations in newborns with congenital varus deformity... 16311039 - Multi-day radon signals with a radioactive decay limb -- occurrence and geophysical sig... 8667979 - Acoustic reflexes, auditory brainstem response, and mri in the evaluation of acoustic n... |
Publication Detail:
|
Type: Journal Article; Research Support, Non-U.S. Gov't Date: 2009-04-01 |
Journal Detail:
|
Title: Physics in medicine and biology Volume: 54 ISSN: 0031-9155 ISO Abbreviation: Phys Med Biol Publication Date: 2009 Apr |
Date Detail:
|
Created Date: 2009-04-07 Completed Date: 2009-06-24 Revised Date: - |
Medline Journal Info:
|
Nlm Unique ID: 0401220 Medline TA: Phys Med Biol Country: England |
Other Details:
|
Languages: eng Pagination: 2483-92 Citation Subset: IM |
Affiliation:
|
Department of Physics, University of Alberta, 11322-89th Avenue, Edmonton, Alberta, T6G 2G7, Canada. bburke@phys.ualberta.ca |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
Artifacts* Electricity Humans Magnetic Resonance Imaging / methods* |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: Three-dimensional dosimetry of small megavoltage radiation fields using radiochromic gels and optica...
Next Document: Evaluation of the effect of locally administered amitriptyline gel as adjunct to local anesthetics i...