FBX aqueous chemical dosimeter for measurement of virtual wedge profiles

• Published in: Journal of applied clinical medical physics 2008-10, Vol.9 (4), p.206-210
• Main Authors: Semwal, Manoj K., Bansal, Anil K., Thakur, Pradeep K., Vidyasagar, Pandit B.
• Format: Article
• Language: English
• Subjects: Algorithms; Benzoic Acid - analysis; Calibration; Chemicals; Dosimetry; Equipment Design; FBX dosimeter; Ferrous Compounds - analysis; Ions; Particle Accelerators; Phenols; Photons; Polymethyl methacrylate; Polypropylenes - analysis; profile measurement; Radiation therapy; Radiometry - instrumentation; Radiometry - methods; Reproducibility of Results; Sulfoxides; Technical Notes; virtual wedge; X-Ray Film; Xylenes - analysis
• ISSN: 1526-9914; 1526-9914
• DOI: 10.1120/jacmp.v9i4.2809

We investigated the ferrous sulfate–benzoic acid–xylenol orange (FBX) aqueous chemical dosimeter for measurement of virtual (dynamic) wedge profiles on a linear accelerator. The layout for irradiation of the FBX‐filled tubes mimicked a conventional linear detector array geometry. A comparison of the resulting measurements with film‐measured profiles showed that, in the main beam region, the difference between the FBX system and the film system was within ±2% and that, in the penumbra region, the difference varied from ±1mm to ±2.5mm in terms of positional equivalence, depending on the size of the dosimeter tubes. We thus believe that the energy‐independent FBX dosimetry system can measure virtual wedge profiles with reasonable accuracy at reasonable cost. However, efficiency improvement is required before this dosimetry system can be accepted into routine practice. PACS numbers: 87.53.‐j, 87.53.Dq, 87.53.Mr, 87.53.Xd, 87.66.Ff