I-125 Basic Physics Data from TG43

Half-life: 59.4 days
Photon energy: 0.028 MeV (avg)
Half-value layer: 0.025 mm lead

---

model 6711:
Recommended dose rate constant in water: 0.88 cGy/U-hr (0.98 NIST 99)
Air kerma strength conversion factor: 1.270 U/mCi

---

model 6702:
Recommended dose rate constant in water: 0.93 cGy/U-hr (1.04 NIST 99)
Air kerma strength conversion factor: 1.270 U/mCi

---

I-125 seeds (model 6711) are available from
Nycomed Amersham
1-(800)-228-0126
1-(800)-633-4123 for customer service

changed to 1999 NIST standard on 7/26/1999

New activity midpoints (±7%) as of 9/99

U mCi price 2.51 1.98 2.73 2.15 2.97 2.34 3.21 2.53 $54.50 3.49 2.75 3.80 2.99 4.11 3.24 4.46 3.51 4.84 3.81 $81.90 5.26 4.14 5.72 4.50 6.20 4.88 6.73 5.30 7.30 5.75 $101.50
other suppliers are North American Scientific and BEBIG.

---

Guide Contents

---