Reduction of the dose to the lens in prophylactic cranial irradiation: a comparison of three different treatment techniques and two different beam qualities.
Three treatment techniques using two beam qualities have been compared on the basis of dose to the lens in prophylactic cranial irradiation. The dose to the lens and the globe was measured with thermoluminescent crystals in an anthropomorphic phantom and calculated by a computer-assisted planning system. A comparison was made of large field and small field techniques using 60Co and 8 MV photons. Modifications to the basic techniques studied included angulation of the gantry, angulation of the couch, and placement of an additional eye block close to the surface. The dose to the lens could be reduced to four percent of the midplane dose by applying the small-field technique combined with the use of 8 MV energy photons, by placing an additional block close to the surface, and by five degree occipitally angling the gantry, as well as rotating the treatment couch to account for the divergence of the beam. The use of 60Co produced an underdosage of the posterior segment of the globe in angled treatment techniques.
Pakisch
B
B
Dept. of Radiotherapy, University of Graz Medical School, Austria.
Stücklschweiger
G
G
Poier
E
E
Urban
C
C
Kaulfersch
W
W
Langmann
A
A
Hauer
C
C
Hackl
A
A
D002386:Cataract / Q000209:etiology / Q000517:prevention & control*; D003037:Cobalt Radioisotopes / Q000627:therapeutic use; D016371:Cranial Irradiation / Q000009:adverse effects / Q000379:methods*; D006801:Humans; D011827:Radiation; D011829:Radiation Dosage; D011882:Radiotherapy, High-Energy
D003037:Cobalt Radioisotopes