Boron neutron capture therapy (BNCT) in Finland: Technological and physical prospects after 20 years of experiences  Sauli Savolainen, Mika Kortesniemi, Marjut Timonen, Vappu Reijonen, Linda Kuusela, Jouni Uusi-Simola, Eero Salli, Hanna Koivunoro, Tiina Seppälä, Nadja Lönnroth, Petteri Välimäki, Heini Hyvönen, Petri Kotiluoto, Tom Serén, Antti Kuronen, Sami Heikkinen, Antti Kosunen, Iiro Auterinen  Physica Medica: European Journal of Medical Physics  Volume 29, Issue 3, Pages 233-248 (May 2013) DOI: 10.1016/j.ejmp.2012.04.008 Copyright © 2012 Associazione Italiana di Fisica Medica Terms and Conditions

Figure 1 The fundamental dosimetric process of BNCT occurs at the cellular level due to the short path lengths of alpha and lithium recoil nuclei produced in the boron neutron capture reaction. Macroscopic distribution of the boron carrier in tissues is temporally optimized for the irradiation, the tumor having maximal boron uptake compared to the healthy tissue. Physica Medica: European Journal of Medical Physics 2013 29, 233-248DOI: (10.1016/j.ejmp.2012.04.008) Copyright © 2012 Associazione Italiana di Fisica Medica Terms and Conditions

Figure 2 Relation and use of different dosimetric methods. In BNCT the physical dose must have a metrologically traceable link to the international dosimetry standard. Physica Medica: European Journal of Medical Physics 2013 29, 233-248DOI: (10.1016/j.ejmp.2012.04.008) Copyright © 2012 Associazione Italiana di Fisica Medica Terms and Conditions

Figure 3 The 3D 1H MRSI metabolite maps of a patient with glioblastoma multiforme [136]. The metabolite maps are based on the Gaussian line shape fitting of two peaks detected in the aromatic region 1.5 h after BNCT. This kind of imaging could give an objective exclusion criterion for BNCT. If no indicative signal is detected from the volume of interest located in a region feasible for good quality MRS, then boron is not accumulating sufficiently in the tumor to reach an appropriate radiation dose level in BNCT. Physica Medica: European Journal of Medical Physics 2013 29, 233-248DOI: (10.1016/j.ejmp.2012.04.008) Copyright © 2012 Associazione Italiana di Fisica Medica Terms and Conditions

Figure 4 The aromatic region of the 3D 1H MR spectra measured from tumor (A) and contralateral brain tissue (B) 1.5 h after BNCT in patient with glioblastoma multiforme [136]. In the spectra A and B, baseline correction has been applied. The same data without baseline correction is shown in the spectra C and D for comparison. Two signals can be detected in the tumor spectrum (A). The tumour (E) and contralateral brain tissue (F) spectra measured one month after BNCT and a spectrum measured from 3.0 mm BPA aqueous solution (with 10.1 mm creatine) (G) are also shown. Physica Medica: European Journal of Medical Physics 2013 29, 233-248DOI: (10.1016/j.ejmp.2012.04.008) Copyright © 2012 Associazione Italiana di Fisica Medica Terms and Conditions