BACKGROUND: Intravascular brachytherapy is an effective method for inhibiting coronary restenosis after percutaneous transluminal coronary angioplasty. A new concept for preventing restenosis is the use of a liquid-filled balloon containing a beta-ray-emitting radioisotope. Generator-produced rhenium-188 (Re-188) is a good candidate for intravascular brachytherapy. However, in the unlikely event of balloon rupture, release of Re-188 perrhenate may cause a high radiation dose to the thyroid and stomach. In this study, we compared the biodistributions of three Re-188 preparations (Re-188 perrhenate, Re-188 pentetic acid [DTPA], and Re-188 MAG3) to assess the radiation dose to organs in a rat model that mimicked balloon rupture. METHODS AND RESULTS: After injection of Re-188 preparations intravenously, rats were killed at 10 minutes, 30 minutes, 60 minutes, 2 hours, and 6 hours (n = 5/group). Tissue concentrations were calculated and expressed as percent injected dose per gram or per milliliter. In addition, urine excretion and thyroid gland uptake were evaluated in rats (n = 5/group) with a gamma camera after administration of 37 MBq (1 mCi) of each agent. Our data showed all 3 agents were excreted primarily via urine. In the Re-188 MAG3 group, 82% was excreted within 1 hour, but in the Re-188 perrhenate group, only 28% was excreted. The biodistribution data for these agents revealed that radioactivity levels in the stomach and the thyroid gland were high in the perrhenate group but low in the Re-188 DTPA and Re-188 MAG3 groups. The concentration levels in other tissues including lung, liver, testis, muscle, and blood were low throughout this study for all 3 agents. The thyroid radiation values were 0.163, 0.0167, and 0.00728 mGy/MBq for Re-188 perrhenate, Re-188 DTPA, and Re-188 MAG3, respectively. The stomach radiation values were 0.127 mGy/MBq for Re-188 perrhenate, 0.013 mGy/MBq for Re-188 DTPA, and 0.0104 mGy/MBq for Re-188 MAG3. CONCLUSIONS: In the event of balloon rupture, the release of Re-188 MAG3 or Re-188 DTPA results in lower radiation doses than release of Re-188 perrhenate, especially to the thyroid gland and the stomach.
BACKGROUND: Intravascular brachytherapy is an effective method for inhibiting coronary restenosis after percutaneous transluminal coronary angioplasty. A new concept for preventing restenosis is the use of a liquid-filled balloon containing a beta-ray-emitting radioisotope. Generator-produced rhenium-188 (Re-188) is a good candidate for intravascular brachytherapy. However, in the unlikely event of balloon rupture, release of Re-188perrhenate may cause a high radiation dose to the thyroid and stomach. In this study, we compared the biodistributions of three Re-188 preparations (Re-188perrhenate, Re-188pentetic acid [DTPA], and Re-188MAG3) to assess the radiation dose to organs in a rat model that mimicked balloon rupture. METHODS AND RESULTS: After injection of Re-188 preparations intravenously, rats were killed at 10 minutes, 30 minutes, 60 minutes, 2 hours, and 6 hours (n = 5/group). Tissue concentrations were calculated and expressed as percent injected dose per gram or per milliliter. In addition, urine excretion and thyroid gland uptake were evaluated in rats (n = 5/group) with a gamma camera after administration of 37 MBq (1 mCi) of each agent. Our data showed all 3 agents were excreted primarily via urine. In the Re-188MAG3 group, 82% was excreted within 1 hour, but in the Re-188perrhenate group, only 28% was excreted. The biodistribution data for these agents revealed that radioactivity levels in the stomach and the thyroid gland were high in the perrhenate group but low in the Re-188DTPA and Re-188MAG3 groups. The concentration levels in other tissues including lung, liver, testis, muscle, and blood were low throughout this study for all 3 agents. The thyroid radiation values were 0.163, 0.0167, and 0.00728 mGy/MBq for Re-188perrhenate, Re-188DTPA, and Re-188MAG3, respectively. The stomach radiation values were 0.127 mGy/MBq for Re-188perrhenate, 0.013 mGy/MBq for Re-188DTPA, and 0.0104 mGy/MBq for Re-188MAG3. CONCLUSIONS: In the event of balloon rupture, the release of Re-188MAG3 or Re-188DTPA results in lower radiation doses than release of Re-188perrhenate, especially to the thyroid gland and the stomach.
Authors: H I Amols; M Zaider; J Weinberger; R Ennis; P B Schiff; L E Reinstein Journal: Int J Radiat Oncol Biol Phys Date: 1996-11-01 Impact factor: 7.038
Authors: P S Teirstein; V Massullo; S Jani; J J Popma; G S Mintz; R J Russo; R A Schatz; E M Guarneri; S Steuterman; N B Morris; M B Leon; P Tripuraneni Journal: N Engl J Med Date: 1997-06-12 Impact factor: 91.245
Authors: T A Fischell; B K Kharma; D R Fischell; P G Loges; C W Coffey; D M Duggan; A J Naftilan Journal: Circulation Date: 1994-12 Impact factor: 29.690
Authors: M J Favus; A B Schneider; M E Stachura; J E Arnold; U Y Ryo; S M Pinsky; M Colman; M J Arnold; L A Frohman Journal: N Engl J Med Date: 1976-05-06 Impact factor: 91.245