title: Optical imaging of dose distributions in Fricke gels.
abstract: Ferrous-sulphate infused gels, or 'Fricke gels', encounter great interest in the field of radiation dosimetry, due to their potential for 3D radiation dose mapping. Typically, magnetic resonance (MR) relaxation rates are determined in these systems in order to derive the absorbed dose. However, when large concentration gradients are present, diffusion effects before and during the MR imaging may not be negligible. In these cases, optical techniques may represent a viable alternative. This paper describes research aimed at measuring 3D dose distributions in a Fricke-xylenol orange gel by measuring optical density with a CCD camera. This method is inexpensive and fast. A series of early experiments is described, in which optical density profiles were measured with a commercial microdensitometer for film dosimetry. The light box of the device was modified to work at 567 nm, close to the maximum absorbance of the ferric ion-xylenol orange complex. Under these conditions, the gel shows linearity with dose and high sensitivity.
authors.affiliation: Yale University School of Medicine, New Haven, CT 06510, USA. viti@iss.it
authors.forename: V
authors.initials: V
authors.lastname: Viti
authors.forename: F
authors.initials: F
authors.lastname: d'Errico
authors.forename: M
authors.initials: M
authors.lastname: Pacilio
authors.forename: A M
authors.initials: AM
authors.lastname: Luciani
authors.forename: A
authors.initials: A
authors.lastname: Palma
authors.forename: S
authors.initials: S
authors.lastname: Grande
authors.forename: C
authors.initials: C
authors.lastname: Ranghiasci
authors.forename: N
authors.initials: N
authors.lastname: Adorante
authors.forename: L
authors.initials: L
authors.lastname: Guidoni
authors.forename: A
authors.initials: A
authors.lastname: Rosi
authors.forename: M
authors.initials: M
authors.lastname: Ranade
authors.forename: F
authors.initials: F
authors.lastname: de Pasquale
authors.forename: P
authors.initials: P
authors.lastname: Barone
authors.forename: G
authors.initials: G
authors.lastname: Sebastiani
mesh_terms: D004307:Dose-Response Relationship, Radiation; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005296:Ferrous Compounds / Q000737:chemistry* / Q000528:radiation effects*; D005782:Gels / Q000737:chemistry* / Q000528:radiation effects*; D008027:Light; D008422:Materials Testing; D011829:Radiation Dosage; D015203:Reproducibility of Results; D012542:Scattering, Radiation; D012680:Sensitivity and Specificity; D012996:Solutions / Q000737:chemistry* / Q000528:radiation effects*; D013819:Thermoluminescent Dosimetry / Q000295:instrumentation* / Q000379:methods
chemical_list: D005296:Ferrous Compounds; C075364:Fricke solution; D005782:Gels; D012996:Solutions