The influence of guiding equipment and stents on the beta dose distribution in the brachytherapy of in-stent restenosis.
BACKGROUND
Intracoronary devices such as stents or guide wires may disturb the dose distribution of beta sources in cardiovascular brachytherapy. As clinical observations indicate that underdosage increases the risk of restenosis, accurate measurements are mandatory to investigate these effects.


RESULTS
Dose perturbation effects of different interventional equipment were systematically determined. Dose distributions of 90Sr-beta line sources were measured by means of a special set-up employing plastic scintillator dosimeters in a water phantom. Shielding effects were found to be 2-5% for single stents and 5-10% for graft stents, stent-in-stent geometries, and guiding catheters. Guide wires close to the source reduced the dose by 25-30%.


CONCLUSIONS
Beta dose perturbation effects of typical stent types are almost negligible and can be corrected by an increased source dwell time if necessary. Guide wires produce effects which are clinically much more important and should therefore be retracted from the irradiation area.
Flühs
D
D
Department of Radiotherapy, Clinical Radiation Physics, University of Essen, Hufelandstr. 55, 45122 Essen, Germany. dirk.fluehs@uni-essen.de
Wilke
C
C
Naber
C
C
Hienz
M
M
Bambynek
M
M
Kaiser
C
C
Langner
I
I
Baumgart
D
D
Sauerwein
W
W
Wegener
D
D
Quast
U
U
D001918:Brachytherapy / Q000295:instrumentation; D023903:Coronary Restenosis / Q000532:radiotherapy*; D006801:Humans; D019047:Phantoms, Imaging; D011879:Radiotherapy Dosage; D015607:Stents; D013326:Strontium Radioisotopes
D013326:Strontium Radioisotopes