Phenol compounds as new materials for Electron Paramagnetic Resonance dosimetry in clinical photon and electron beams,

In the last decades several research laboratories have shown an increasing interest aimed at extending the applicability of Electron Paramagnetic Resonance (EPR) dosimetry to radiotherapy with different types of radiation beams. EPR is a spectroscopic method for investigating the structure and dynamics of such paramagnetic species. Free radicals are known to be produced when a compound is irradiated with ionizing radiations. The concentration of radiation-induced free radicals is proportional to the energy released inside in the medium and this allows for dosimetric measurements through EPR technique. The use of alanine as a dosimetric material gave the possibility to apply EPR spectroscopy…

Characterization of phenolic pellets for ESR dosimetry in photon beam radiotherapy.

We report a study of the dosimetric features of phenolic compounds for applications in radiation therapy dosimetry of clinical photon beams by using ESR spectroscopy. After the optimization of the ESR readout parameters, basic dosimetric properties (such as intra-batch reproducibility, dose-response, sensitivity, linearity, dose rate dependence, tissue-equivalence and signal stability) of laboratory-made phenolic dosimeters in form of pellets were investigated. Furthermore, these dosimeters were tested for measuring the depth dose profile of a 6 MV clinical photon beam. The results reported show that these dosimeters are promising materials for ESR dosimetric applications in radiation thera…

PVA-GTA Fricke gel: studio della risposta NMR in funzione della concentrazione degli additivi e studi preliminari con scanner MRI 7 T

Sono stati analizzati tramite rilassometria NMR ed acquisizioni MRI dosimetri gel di tipo Fricke realizzati utilizzando un'innovativa matrice gel sintetica e tessuto equivalente: Polyvinyl alcohol (PVA) attivando chimicamente il processo di gelificazione tramite l'aggiunta di Glutaraldehyde (GTA). Questi gel sono stati irradiati con fasci di fotoni (LINAC) nel range 0--20 Gy. Per valutare la sensibilità a fotoni è stata studiata la dipendenza dei tempi di rilassamento nucleari dalla dose e dalla concentrazione di ferro nei gel. Inoltre è stata monitorata la stabilità del segnale dopo l'irraggiamento. Acquisizioni preliminari MRI con uno scanner MRI da 7 T sono state affiancate alle misure N…

Dosimetric analysis of phenolic solid state pellets exposed to radio-therapeutic photon and electron beams through electron spin resonance technique

Rare-earth doped silica optical fibres for ionizing radiation detection

Scintillating silica optical fibre sensors have shown interesting results for ionizing radiation monitoring and therefore can be useful for dosimetry applications in medical field. In fact, they enable a remote, punctual and real-time dose assessment (Mones et al., 2008). In addition, the high radiation hardness that characterizes silica optical fibers, makes these systems promising for radiation detection in high energy physics experiments (Chiodini et al., 2014). This work aims to review the recent progresses in the development and characterization of rare-earth doped silica fibres. The radioluminescent and dosimetric properties of Ce, Eu, Yb and Pr-doped silica matrices are described and…

Phenol compounds for EPR dosimetry in radiation therapy

PVA-GTA Fricke gel dosimeters exposed to clinical photons beams: Nuclear Magnetic Resonance Relaxometry and Imaging

Fricke Gel (FXGs) dosimetric system is based on the radiation induced oxidation of ferrous to ferric ions. The application of Fricke gels for ionizing radiation dosimetry is continuously increasing worldwide due to their many favorable properties. However, one of their shortcomings is that ferrous and ferric ions diffuse in the gel matrix. To maintain the spatial integrity of the dose distribution, Fricke gels must be undergoing measurement within a few hours of their irradiation, so that ferric ions remain close to their point of production. Thus, the spatial integrity of the dose distribution in the Fricke gel is maintained (Schreiner, 2015). The gel matrix also contributes to the oxidati…

New materials for ESR dosimetry in clinical photon and electron beams: Phenol Compounds.

In the last decades several research laboratories have shown an increasing interest aimed at extending the applicability of ESR-dosimetry to radiotherapy with different types of radiation beams. ESR is a spectroscopic method for investigating the structure and dynamics of such paramagnetic species. The concentration of radiation-induced free radicals is proportional to the energy released inside in the medium. Our research group has started an investigation of the ESR response of some phenols compounds for possible ESR dosimetric applications suitable features, such as high efficiency of radiation-matter energy transfer and radical stability at room temperature. In particular, the phenoloct…