intravascular brachy

Question 1

what is IVBT being replaced by?

Answer 1

drug-eluting stents

Question 2

Where is IVBT used?

Answer 2

used with balloon angioplasty or stents to lower the rate of neointimal growth of tissues

• this growth happens when you have wound healing followed by angiplasty
• IVBT inhibits growth of neointimal tissues by killing cells, which reduces risk of restenosis (re-narrowing)

Question 3

what is angioplasty?

Answer 3

alternative to bypass surgery

widens narrow or obstructed arteries

Question 4

where does AAPM recommend depth of dose prescription for intracoronary irradiation

Answer 4

2 mm from source centre

Question 5

where does AAPM recommend depth of dose prescription for peripheral arteries?

Answer 5

2 mm beyond the average lumen radius

Question 6

how much length is irradiated?

Answer 6

2-5 cm

Question 7

what sources are recommended for IVBT?

Answer 7

• Beta sources are recommended since they typically give higher dose rates (have higher specific activity), longer half-life, have less radiation shielding concerns, and have extremely rapid radial dose falloff. Example: strontium-90: emission: beta minus, half-life = 28 years, mean energy = 970 keV

Question 8

other word for IVBT

Answer 8

endovascular

Question 9

permanent or temp. implants?

Answer 9

sealed sources, liquid filled balloons, or permanent radioactive stents