Dose Perturbation Caused by Stents: Experiments with a Model {sup 90}Sr/{sup 90}Y Source
- Medical University of Silesia, Silesian Center for Heart Diseases, 3rd Chair and Clinical Hospital for Heart Diseases (Poland)
- Henryk Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, Department of Nuclear Physical Chemistry (Poland)
- Henryk Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, Physical Chemistry and Surface Engineering Laboratory (Poland)
- Henryk Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, Department of Health Physics (Poland)
- Andrzej Soltan Institute for Nuclear Studies, Department of Medical Physics (Poland)
Purpose. Biological effects of intravascular brachytherapy are very sensitive to discrepancies between the prescription and the applied dose. If brachytherapy is aimed at in-stent restenosis, shielding and shadowing effects of metallic stents may change the dose distribution relative to that produced by the bare source. The development of new generations of stents inspired us to a new experimental study in this field. The effect was studied for 14 stents which we have recently encountered in clinical practice. Methods. The model source was a continuous 20-mm column of {sup 90}Sr/{sup 90}Y solution sealed in a 1-mm-I.D. Plexiglas capillary. The dose distribution in the Plexiglas phantom was mapped using GafChromic MD-55-2 film. The stent masses varied from 2.5 to 25 mg; the strut thicknesses, from 0.075 to 0.15 mm; and the atomic numbers of stent materials, from 24 (Cr) to 79 (Au). Results. Dose perturbations depend on a variety of stent features. Local reduction of the mean dose rates near the reference distance (r{sub 0} = 2 mm) varied from 11% to 47%. No simple correlation was found between these data and stent characteristics, but it seems that the atomic number of the stent material is less important than the strut thickness and mesh density. Conclusion. The results provide a warning that clinical indications for in-stent radiation therapy must always be confronted with another aspect of the patient's history: the kind of implanted stent. Intravascular brachytherapy using pure beta sources may be recommended only for patients 'wearing' light, thin-strut stents. The presence of thick-strut stents is a contraindication for this modality, due to excessive dose perturbation.
- OSTI ID:
- 21090788
- Journal Information:
- Cardiovascular and Interventional Radiology, Vol. 30, Issue 5; Other Information: DOI: 10.1007/s00270-007-9148-9; Copyright (c) 2007 Springer Science+Business Media, LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0174-1551
- Country of Publication:
- United States
- Language:
- English
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