Evaluation of materials for ESR-dosimetry: Salts of formic and lactic acid as an example.
Independent thesis Basic level (professional degree), 20 credits / 30 HE creditsStudent thesis
The technique of ESR-dosimetry and strategies for investigation of new materials as in regard to their applicability as ESR-dosimeters for radiotherapy has been reviewed. As an example six salts of formic and lactic acid has been evaluated. The applicability of the dosimeter has been judged by evaluating the tissue equivalence, radical yield, radical stability, spectral suitability, optimal readout parameters, dose response and sensitivity of the dosimetric system. Dependence of material characteristics and influence parameters has been analysed.
The reviewed methods have been successfully used for evaluation of the new materials. Lithium formate has been shown to be a good candidate relative to the state of the art dosimeter of alanine. Using optimal readout parameters lithium formate has been shown to be nine times as sensitive but even at moderate settings lithium formate is more sensitive. The results for lithium formate are in accordance to those of previous studies. The signal intensity of sodium formate has also proved to be high but unfortunately the signal fades rapidly.
Two new methods have been proposed as synthesis of the reviewed methods. The first allows flexible, effective and objective baseline correction of the ESR-spectrum. The second deals with dose response measurement by linear regression of the entire spectrum and was found to be successful in separating the spectral peaks of the induced radicals from the background signal.
Place, publisher, year, edition, pages
2008. , 66 p.
ESR-dosimetry, Isotopes, SAR, 2-methylalanine
Radiology, Nuclear Medicine and Medical Imaging
IdentifiersURN: urn:nbn:se:su:diva-8318OAI: oai:DiVA.org:su-8318DiVA: diva2:200076
Lund, Eva, Professor
Nilsson, Bo, Docent