The essential role of radiobiological figures of merit for the assessment and comparison of beam performances in boron neutron capture therapy

Boron neutron capture therapy using cyclotron-based epithermal neutron source and borofalan (10B) for recurrent or locally advanced head and neck cancer (JHN002): An open-label phase II trial

“…Recently, cyclotron-based epithermal neutron source called C-BENS, which is composed of a 30-MeV cyclotron and a beryllium target, was developed [5]. C-BENS has been optimized to maximize the thermal neutron flux delivered to deeper-seated tumors by giving a peak of neutron spectrum in the energy range of 10-20 keV based on the report of a Monte Carlo investigation by Yanch, et al, which has advantages for clinical use [3,[6][7][8]. In the context of the development of a new widely available BNCT system, clinical trials to investigate the efficacy and safety of BNCT using C-BENS, and 10 B-condensed boronophenylalanine (BPA) as a 10 B agent are urgently needed.…”

Evaluating the Therapeutic Potential and the Suitability of Neutron Beams Designed for Clinical BNCT

“…15 ppm in blood, which results in 30 ppm in mucosa and 52.5 ppm in tumour [32]. Figure 2 shows the simulated set-up, where the phantom is irradiated with a beam-to-phantom distance of 7.5 cm, reproducing the average distance of patients from the beam port in clinical experience [33]. The dose was calculated with the photon iso-effective model [34].…”

“…The dose was calculated with the photon iso-effective model [34]. To assess the therapeutic potential, we calculated the Uncomplicated Tumour Control Probability (UTCP) [33], defined as the probability to control the tumour without complication in the relevant healthy tissue, in this case, mucosa. UTCP is the product of the tumour Control Probability (TCP) and the complementary of Normal Tissue Complication Probability (1-NTCP).…”

“…The closer this FOM is to 1, the highest is the probability to control the tumour without normal tissue complications. This criterion was used for the first time by Provenzano et al [33] for the comparison of different clinical facilities, and it is proposed here as a criterion to select adequate beams among different candidates. UTCP was computed using TCP model for inhomogeneous dose distribution [33] and NTCP model that can predict mucositis of grade 3 or higher (≥G3) after head and neck cancer radiotherapy with photons and BNCT [34].…”

“…Based on the obtained irradiation time, photon iso-effective doses and the Dose Volume Histogram (DVH) were calculated in the contoured tumour volume. UTCP curve was computed as described by Provenzano et al [33]. Table 4 shows the results of the calculation of physical FOMs for each beam ( Table 2 and Figure 1), compared to the recommended values.…”