Tungsten Eyeshield Backscatter Data

The doses are normalized to dmax without the eye shield (Diagram 1) using a 10 x 10 cone. When 100% is delivered to dmax using 6 MeV with the shield, you get 108% to the undersurface of the eyelid (Point 1) and 3.4% to the lens (Point 2) (See table).

Tungsten Eye Shields   Tungsten Eye Shields

 

Transmission Using
XV– 2 Film* 		Backscatter Using TLD**  
6 MeV 9 MeV 6 MeV 9 MeV
3.4% 5.6% 108% 111% 2 mm Tungsten
3.0% 4.8% 103% 106% 2 mm Tungsten +
0.5 mm Aluminum
3.0% 4.4% 95% 102% 2 mm Tungsten +
1 mm Aluminum
2.5% 3.3% 112% 113% 3 mm Tungsten
2.4% 2.9% 102% 105% 3 mm Tungsten +
0.5 mm Aluminum
2.5% 2.8% 97% 106% 3 mm Tungsten +
1 mm Aluminum

Unreferenced data on this product is preliminary findings of Radiation Products Design, Inc. and is not to be used as a technical reference. *XV-2 Film placed under/below tungsten eye shield at 3 mm depth (anterior surface of lens) **TLD Microcubes placed under simulated eye lid using tungsten eye shields.

Reference: Evaluation of Eye Shields made of Tungsten and Aluminum in High-Energy Electron Beam - Randi D. Weaver B.S. Fairview - University Med. Ctr. PO Box 494, 420 Delaware St. SE, Mpls., MN 55455 Int. J. Radiation Oncology Biol. Phys, Vol. 41 Nal, pp 233-237-1998