Gadolinium neutron capture brachytherapy (GdNCB), a new treatment method for intravascular brachytherapy
- Division of Biomedical Radiation Sciences, Department of Oncology, Radiology and Clinical Immunology, Rudbeck Laboratory, Uppsala University, SE-751 85 Uppsala (Sweden)
Restenosis is a major problem after balloon angioplasty and stent implantation. The aim of this study is to introduce gadolinium neutron capture brachytherapy (GdNCB) as a suitable modality for treatment of stenosis. The utility of GdNCB in intravascular brachytherapy (IVBT) of stent stenosis is investigated by using the GEANT4 and MCNP4B Monte Carlo radiation transport codes. To study capture rate, Kerma, absorbed dose and absorbed dose rate around a Gd-containing stent activated with neutrons, a 30 mm long, 5 mm diameter gadolinium foil is chosen. The input data is a neutron spectrum used for clinical neutron capture therapy in Studsvik, Sweden. Thermal neutron capture in gadolinium yields a spectrum of high-energy gamma photons, which due to the build-up effect gives an almost flat dose delivery pattern to the first 4 mm around the stent. The absorbed dose rate is 1.33 Gy/min, 0.25 mm from the stent surface while the dose to normal tissue is in order of 0.22 Gy/min, i.e., a factor of 6 lower. To spare normal tissue further fractionation of the dose is also possible. The capture rate is relatively high at both ends of the foil. The dose distribution from gamma and charge particle radiation at the edges and inside the stent contributes to a nonuniform dose distribution. This will lead to higher doses to the surrounding tissue and may prevent stent edge and in-stent restenosis. The position of the stent can be verified and corrected by the treatment plan prior to activation. Activation of the stent by an external neutron field can be performed days after catherization when the target cells start to proliferate and can be expected to be more radiation sensitive. Another advantage of the nonradioactive gadolinium stent is the possibility to avoid radiation hazard to personnel.
- OSTI ID:
- 20774984
- Journal Information:
- Medical Physics, Vol. 33, Issue 1; Other Information: DOI: 10.1118/1.2146050; (c) 2006 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-2405
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BIOPHYSICS
BLOOD VESSELS
BRACHYTHERAPY
DOSIMETRY
FOILS
FRACTIONATION
GADOLINIUM
KERMA
MONTE CARLO METHOD
NEUTRON CAPTURE THERAPY
NEUTRON REACTIONS
NEUTRON SPECTRA
PHOTONS
RADIATION DOSE DISTRIBUTIONS
RADIATION DOSES
RADIATION HAZARDS
RADIATION SOURCES
RADIATION TRANSPORT
SWEDEN
THERMAL NEUTRONS