Research Group of Medical Physics in Radiotherapy
Research group information
Research group description
Radiotherapy (or radiation therapy) is a cancer treatment using high-energy ionizing radiation to control and kill malignant cancer cells. Ionizing radiation is delivered either externally, most commonly with linear accelerators, or internally, e.g. in brachytherapy. The patient’s individual physiology and anatomy affect not only to the physical aspects of the dose delivery but also to the treatment response. Thus, individually tailored radiotherapy allows more efficient and safer treatments.
Nikkinen Group’s main research topics are medical physics, biophysics and technical methodology in radiotherapy. The group aims to develop methods supporting individually tailored radiotherapy More specifically, Nikkinen group’s focus areas are monitoring treatment response during radiotherapy, and development of external radiotherapy.
Monitoring treatment response during radiotherapy
Group’s main research focus is monitoring the individuals’ response to external radiotherapy using functional MR and NIRS imaging methods. Using MR encephalography, group’s aim is to monitor treatment related changes in glymphatic mechanisms in brain tumor patients. This novel imaging method allows us to monitor individual’s dose response in tumor area and also in healthy brain tissues during radiotherapy course. This method may also be useful to predict microscopic brain tumor areas allowing to treat the disease more efficiently. In the Academy of Finland project "Tailored radiotherapy using novel optics-based technology”, group’s goal is to provide a new method for monitoring radiotherapy response in brain tumors and healthy tissues during irradiation. The changes in cerebral hemodynamics and concentration of the reactive oxygen radicals correlate with the dose and dose rate of radiotherapy. Thus, measuring cerebral dynamics and free water and oxygen radicals during irradiation using fNIRS technology could improve the effectiveness and safety of the radiation therapy.
Development of external radiotherapy
New linear accelerators offer the possibility to intensity modulated treatments (IMRT), image guided treatments (IGRT), volumetric modulated arc treatments (VMAT), respiratory gated treatments as well as treatments with high dose rate using unflattened fields (FFF). Introduction of these technologies and their applicability on the treatment of different target areas is important research topic in the field of radiation oncology. Research on dosimetry with different methods (ionization chambers, RPL, film, gel), imaging prior and during the irradiation, and utilizing the obtained information in the dose planning are needed. Recently, group’s research focus has been on external and internal prostate radiation therapy, where the effects of the variation of prostate location and shape on the prostate actual dose distribution are refined. We have also studied the need of adaptive dose planning and the possibility to use gel between prostate and rectum as rectum protection. These results have been applied in our extreme hypofractionated prostate treatments. Film dosimetry has been utilized in planning of SBRT treatment protocols together with 4D thorax fantom.