Dosimetry and treatment planning of complex electron arc therapy.
Electron arc therapy has been primarily utilized for treatment of the post-mastectomy chest wall. Its clinical usefulness and benefits have been proven. Casting procedures and blocking techniques have been discussed. We have successfully applied electron arc therapy to the treatment of the nasal cavity and associated nodal regions. When compared to the chest wall, the smaller radii and pronounced irregularity of the surface anatomy of the facial region presents multiple new dosimetric and treatment planning challenges. We will discuss these challenges, along with those encountered in the casting procedures and reproduction of patient characteristics required for the execution of this treatment. Many aspects of dosimetry were utilized in unique ways to produce the treatment plans, cast and bolus needed. Due to the insertion of bolus into the nostrils, a unique hollow bite block was constructed to allow patient respiration during treatment. Film dosimetry was used to verify computer predictions and to compare this electron arc treatment technique with alternative fixed electron beam techniques. The potential benefits and difficulties of this technique will be discussed.
Tobler
M
M
Department of Radiation Oncology, University of Utah Medical Center, Salt Lake City 84132, USA.
Leavitt
D D
DD
Hayes
J K
JK
D002294:Carcinoma, Squamous Cell / Q000532:radiotherapy*; D004867:Equipment Design; D005373:Film Dosimetry; D005544:Forecasting; D006801:Humans; D008198:Lymph Nodes / Q000528:radiation effects; D008297:Male; D008875:Middle Aged; D008953:Models, Anatomic; D009296:Nasal Cavity / Q000528:radiation effects*; D009300:Nasal Septum / Q000528:radiation effects*; D009669:Nose Neoplasms / Q000532:radiotherapy*; D011835:Radiation Protection / Q000295:instrumentation; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000295:instrumentation / Q000379:methods; D011882:Radiotherapy, High-Energy / Q000295:instrumentation / Q000379:methods; D012119:Respiration