title: Fricke gel dosimeter as a tool in quality assurance of the radiotherapy treatment plans.
abstract: Ferrous xylenol gel was evaluated as a dosimeter in verifications of treatment plans for treatments of female breast tumors in external-beam radiation therapy. The dosimeter was calibrated in a cubic wax phantom irradiated with 6 and 15MV beams of an Elekta clinical linear accelerator and then used for measurements of doses in an anthropomorphic phantom of a female torso, which mimicked female breasts after modified radical mastectomy and breast-conserving surgery. Doses measured with the gel in specific locations in the phantom were compared with values predicted by treatment plans created with the XiO treatment planning system (Elekta / IMPAQ) and with results of measurements with an IBA CC13 ionization chamber in the same locations. Differences between the values measured with the gel and predicted by the treatment planning system or measured with the ionization chamber were within 1.5% in most cases. In an area of as steep dose gradient, the difference reached 2.7%, which was explicable in terms of the finite size of the gel dosimeter. The dose response of the gel is dose rate and energy independent in the ranges used in most clinical linacs. The results have shown that ferrous xylenol gels can be used as dosimeters in quality assurance in radiation therapy.
authors.affiliation: National Center for Radiation Research and Technology, Atomic Energy Authority (AEA), P.O. Box 8029, Nasr City, Cairo, Egypt. Electronic address: yasser_shabaan@hotmail.com.
authors.forename: Yasser S
authors.initials: YS
authors.lastname: Soliman
authors.affiliation: Biophysics Branch, Physics Department, Faculty of Science, Al-Azhar University, Nasr City, Cairo, Egypt.
authors.forename: M I
authors.initials: MI
authors.lastname: El Gohary
authors.affiliation: Biophysics Branch, Physics Department, Faculty of Science, Al-Azhar University, Nasr City, Cairo, Egypt.
authors.forename: M H
authors.initials: MH
authors.lastname: Abdel Gawad
authors.affiliation: Medical physics unit, Ain-Shams hospital, Ain-Shams University, ElAbbasia, Cairo, Egypt.
authors.forename: E A
authors.initials: EA
authors.lastname: Amin
authors.affiliation: National Center for Radiation Research and Technology, Atomic Energy Authority (AEA), P.O. Box 8029, Nasr City, Cairo, Egypt.
authors.forename: O S
authors.initials: OS
authors.lastname: Desouky
mesh_terms: D001943:Breast Neoplasms / Q000532:radiotherapy; D005260:Female; D005296:Ferrous Compounds; D005782:Gels; D006801:Humans; D010315:Particle Accelerators; D019047:Phantoms, Imaging; D011785:Quality Assurance, Health Care; D000072232:Radiation Dosimeters; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000592:standards*; D011882:Radiotherapy, High-Energy; D014992:Xylenes
chemical_list: D005296:Ferrous Compounds; D005782:Gels; D014992:Xylenes; C016834:3,5-xylenol
keywords: Dosimetry; Fricke xylenol gel; Quality assurance; Radiotherapy treatment planning