J. Lee et al., Dosimetry of rhenium-188 diethylene triamine penta-acetic acid for endovascular intra-balloon brachytherapy after coronary angioplasty, EUR J NUCL, 27(1), 2000, pp. 76-82
Citations number
27
Categorie Soggetti
Radiology ,Nuclear Medicine & Imaging","Medical Research Diagnosis & Treatment
To examine the possibility of using rhenium-188 diethylene triamine penta-a
cetic acid (DTPA) for endovascular intra-balloon brachytherapy after angiop
lasty, dose distribution around the balloon was calculated and validated by
film dosimetry. Medical internal radiation dosimetry (MIRD) was calculated
assuming that the balloon had ruptured and that the contents had been rele
ased into the systemic circulation. Re-188-perrhenate eluate from the W-188
/Re-188 generator was concentrated using an ion column and used to label DT
PA. The dose distibution around the angioplasty balloon (20 mm length, 3 mm
diameter cylinder) was estimated by Monte Carlo simulation using the EGS4
code. The time required for 17.6 Gy to be absorbed at 1 mm from the balloon
's surface following application of 3700 MBq/ml Of Re-188 was found to be 2
78 s. Fifty percent of the energy was deposited in the first millimetre of
the vessel wall from the balloon's surface. The calculated radiation absorb
ed dose agreed with that measured by film dosimetry, which was performed us
ing a water phantom, with errors ranging from 9.4% to 17%. Upon balloon rup
ture the total amount of Re-188-DTPA was presumed to enter the systemic cir
culation. The resulting radiation absorbed dose was calculated using the MI
RDOSE3 program and residence times obtained from dogs and amounted to 0.005
6 mGy/MBq to the whole body and 4.56 mGy/MBq to the urinary bladder. The ab
sorbed dose of 188Re-DTPA to the whole body was one-tenth of that of Re-188
-perrhenate. A window-based program was developed to calculate the exposure
time and the radiation dose absorbed as a function of the Re-188 concentra
tion and the arbitrary distance from the balloon to the surrounding tissues
. We conclude that Re-188-DTPA is easy to prepare, safe to use and suitable
for intra-balloon brachytherapy after coronary angioplasty.