In vitro evaluation of head and neck radiation shields used to reduce exit dose.
OBJECTIVE
To determine the optimal thickness of protective oral radiation shields composed of an acrylic resin stent and a lead shield, which are used in head and neck radiotherapy to minimize undesired normal tissue radiomorbidity.


METHODS
Intraoral acrylic resin stents and lead shields of different thicknesses were inserted into a specially designed human mandible phantom with thermoluminescent lithium fluoride dosimeter chips (TLD-100) placed on the buccal and lingual sites and exposed to irradiation of different energies. Fifty-cGy irradiation was performed and TLD-100 dose measurements were obtained for each irradiation type, acrylic resin stent thickness, and lead shield thickness.


RESULTS
Acrylic resin stents with a 2-mm lead shield reduced 20% and 15% of the normal tissue dose for Co-60 and 6 MV X photon radiations, respectively, whereas the stents with a 4-mm lead shield achieved a higher reduction of the normal tissue dose (30% and 23% for Co-60 and 6 MV X photons, respectively).


CONCLUSIONS
In protective oral radiation shields, acrylic resin stent thickness has little effect on the reduction of normal tissue dose, but lead shield thickness significantly effects the reduction of normal tissue dose.
Dirican
Bahar
B
Department of Radiation Oncology, Gulhane.
Ozen
Julide
J
Beyzadeoglu
Murat
M
Oysul
Kaan
K
Surenkok
Serdar
S
Sipahi
Cumhur
C
D000180:Acrylic Resins; D016371:Cranial Irradiation; D006801:Humans; D007854:Lead; D008334:Mandible; D009064:Mouth Protectors; D011832:Radiation Injuries / Q000517:prevention & control*; D011835:Radiation Protection / Q000295:instrumentation*; D011879:Radiotherapy Dosage; D015607:Stents; D013819:Thermoluminescent Dosimetry
D000180:Acrylic Resins; D007854:Lead