Biological Effects of Spot Scanning and Passive Scattering Proton Beams at the Distal End of the Spread-Out Bragg Peak (SOBP) in Single Cells and Multicell Spheroids

Abstract

In pathway analysis, there were significant differences in such as MAPK signaling and NRF2 between protons and X rays combined with cisplatin. Conclusion: In the microarray analysis, proton beam irradiation combined with cisplatin resulted in different gene expression alterations as compared with X rays and cisplatin. These differences suggested the possibility of leading to further development of irradiation methods and new therapeutic strategies using proton therapy.

Comparative assessment of passive scattering and active scanning proton therapy techniques using Monte Carlo simulations

“…Furthermore, under the same conditions and in a homogeneous water phantom, the quantities related to both dose and adaptability properties were investigated and the superiority of spot scanning method in both dose transfer and adaptation was investigated. According to the literature, there are some controversies regarding the distal dose of PSPT against PBS systems [3,6,7]; it might stem from the fact that the estimated physical/ biological dose in passive scattering proton therapy systems are dependent on the specific scattering hardware's that are implemented in the beam trajectory, in some literature, the studies were made to evaluate the effect of secondary product on the total dose of protons, presence of the secondary particles are estimated about 4 to 10 times higher in the scattering techniques compared to pencil beam design, however, it has been reported that their contribution in the total absorbed dose is less than 1% [33][34][35][36]. In this regard, the performance of multiple scattering designs should be simulated and further compared to provide a global conclusion about the advantages and disadvantages of active scanning proton therapy technique against passive scattering mode.…”

“…In PBS, multiple magnets in 𝑥 and 𝑦 directions, based on the charge of particles, are used to drift the beam and scanning the target volume spot by spot with a 3D narrow pencil beam [4,5]. There are some studies in biological dose comparison between active and passive scanning proton therapy techniques in the cellular level [3,6,7]. Gridley et al [7] compared cell response to active scanning and passive beam delivery techniques.…”

“…Michaelidesova et al [3] reported that between two techniques, there is neither considerable beam quality difference from MC simulation, nor statistically significant difference in biological endpoints. Nomura et al [6] reported a higher Linear Energy Transfer (LET) at distal region in active scanning mode compared to passive scattering method. To the best of our knowledge, the current study is the first report that systematically compares physical doses between two modes of proton therapy.…”