6533b825fe1ef96bd12833fc
RESEARCH PRODUCT
Dose calculation in biological samples in a mixed neutron-gamma field at the TRIGA reactor of the University of Mainz
Niels BasslerNorbert WiehlC. SchützHugo PalmansTobias SchmitzG. HampelPeter SharpeMichael H. HolzscheiterJens Volker KratzGerd OttoMatthias Blaicknersubject
inorganic chemicalsPhysics::Instrumentation and DetectorsQuantitative Biology::Tissues and OrgansPhysics::Medical PhysicsBoron Neutron Capture TherapyValidation Studies as TopicModels BiologicalIonizing radiationTRIGAHospitals UniversityNuclear ReactorsCell Line TumorGermanyRelative biological effectivenessMedicineDosimetryHumansRadiology Nuclear Medicine and imagingNeutronNeutronsbusiness.industryRadiotherapy Planning Computer-AssistedRadiochemistryLiver NeoplasmsRadiotherapy DosageHematologyGeneral MedicineHep G2 CellsNeutron temperatureNeutron captureOncologyGamma RaysAbsorbed dosebusinessNuclear medicineColorectal Neoplasmsdescription
To establish Boron Neutron Capture Therapy (BNCT) for non-resectable liver metastases and for in vitro experiments at the TRIGA Mark II reactor at the University of Mainz, Germany, it is necessary to have a reliable dose monitoring system. The in vitro experiments are used to determine the relative biological effectiveness (RBE) of liver and cancer cells in our mixed neutron and gamma fi eld. We work with alanine detectors in combination with Monte Carlo simulations, where we can measure and characterize the dose. To verify our calculations we perform neutron fl ux measurements using gold foil activation and pin-diodes . Material and methods . When L- α -alanine is irradiated with ionizing radiation, it forms a stable radical which can be detected by electron spin resonance (ESR) spectroscopy. The value of the ESR signal correlates to the amount of absorbed dose. The dose for each pellet is calculated using FLUKA, a multipurpose Monte Carlo transport code. The pin-diode is augmented by a lithium fl uoride foil. This foil converts the neutrons into alpha and tritium particles which are products of the 7 Li(n, α ) 3 H-reaction. These particles are detected by the diode and their amount correlates to the neutron fl uence directly. Results and discussion. Gold foil activation and the pin-diode are reliable fl uence measurement systems for the TRIGA reactor, Mainz. Alanine dosimetry of the photon fi eld and charged particle fi eld from secondary reactions can in principle be carried out in combination with MC-calculations for mixed radiation fi elds and the Hansen & Olsen alanine detector response model. With the acquired data about the background dose and charged particle spectrum, and with the acquired information of the neutron fl ux, we are capable of calculating the dose to the tissue. Conclusion . Monte Carlo simulation of the mixed neutron and gamma fi eld of the TRIGA Mainz is possible in order to characterize the neutron behavior in the thermal column. Currently we also speculate on sensitizing alanine to thermal neutrons by adding boron compounds.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2010-10-01 |