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Microbeam radiation therapy: Tissue dose penetration and BANG-gel dosimetry of thick-beams’ array interlacing
- Source :
- European Journal of Radiology. 68:S129-S136
- Publication Year :
- 2008
- Publisher :
- Elsevier BV, 2008.
-
Abstract
- The tissue-sparing effect of parallel, thin (narrower than 100 μm) synchrotron-generated X-ray planar beams (microbeams) in healthy tissues including the central nervous system (CNS) is known since early 1990s. This, together with a remarkable preferential tumoricidal effect of such beam arrays observed at high doses, has been the basis for labeling the method microbeam radiation therapy (MRT). Recent studies showed that beams as thick as 0.68 mm (“thick microbeams”) retain part of their sparing effect in the rat's CNS, and that two such orthogonal microbeams arrays can be interlaced to produce an unsegmented field at the target, thus producing focal targeting. We measured the half-value layer (HVL) of our 120-keV median-energy beam in water phantoms, and we irradiated stereotactically bis acrylamide nitrogen gelatin (BANG)-gel-filled phantoms, including one containing a human skull, with interlaced microbeams and imaged them with MRI. A 43-mm water HVL resulted, together with an adequately large peak-to-valley ratio of the microbeams’ three-dimensional dose distribution in the vicinity of the 20 mm × 20 mm × 20 mm target deep into the skull. Furthermore, the 80–20% dose falloff was a fraction of a millimeter as predicted by Monte Carlo simulations. We conclude that clinical MRT will benefit from the use of higher beam energies than those used here, although the current energy could serve certain neurosurgical applications. Furthermore, thick microbeams particularly when interlaced present some advantages over thin microbeams in that they allow the use of higher beam energies and they could conceivably be implemented with high power orthovoltage X-ray tubes.
- Subjects :
- Monte Carlo method
Gel dosimetry
Models, Biological
Radiotherapy, High-Energy
Optics
Planar
Humans
Scattering, Radiation
Dosimetry
Medicine
Computer Simulation
Radiology, Nuclear Medicine and imaging
Irradiation
Radiometry
business.industry
Radiotherapy Planning, Computer-Assisted
Brain
Radiotherapy Dosage
General Medicine
Microbeam
Mockup
business
Nuclear medicine
Gels
Monte Carlo Method
Algorithms
Synchrotrons
Beam (structure)
Subjects
Details
- ISSN :
- 0720048X
- Volume :
- 68
- Database :
- OpenAIRE
- Journal :
- European Journal of Radiology
- Accession number :
- edsair.doi.dedup.....472c79bc6935f6f8a9d7224158637eea