February 5th, 2021

лошадь, диаграмма, Фейнман

Моделирование УЗИ в MATLABe

Пакет с открытым кодом:

SIMUS: an open-source simulator for ultrasound imaging. Part I: theory & examples: https://arxiv.org/abs/2102.02738
Damien Garcia
Computational ultrasound imaging has become a well-established methodology in the ultrasound community. Simulations of ultrasound sequences and images allow the study of innovative techniques in terms of emission strategy, beamforming and probe design. There is a wide spectrum of software dedicated to ultrasound imaging, each having its specificities in its applications and in the numerical method. I describe in this two-part paper a new ultrasound simulator (SIMUS) for Matlab, which belongs to the Matlab UltraSound Toolbox (MUST). The SIMUS software is based on far-field and paraxial approximations. It simulates acoustic pressure fields and radiofrequency RF signals for uniform linear or convex probes. SIMUS is an open-source software whose features are 1) rapidity, 2) ease of use, 3) frequency domain, 4) pedagogy. The main goal was to offer a comprehensive turnkey tool, along with a detailed theory for pedagogical and research purposes. This first part of the paper describes in detail the underlying linear theory of SIMUS and provides examples of simulated acoustic fields and ultrasound images. The second part is devoted to the comparison of SIMUS with popular software: Field II, k-Wave, and the Verasonics simulator. The Matlab open codes for the simulator SIMUS are distributed under the terms of the GNU Lesser General Public License, and can be downloaded from this https URL.
лошадь, диаграмма, Фейнман

Кто-то еще пытается развивать бор-нейтрон-захватную терапию

Уже не новая, остроумная и потенциально эффективная идея: вводим пациенту препарат бора, такой, чтобы он в силу физиологических механизмов накапливался в опухоли, потом облучаем нейтронами, ядра бора захватывают нейтроны и превращаются в радиоактивные, бомбардируя затем опухоль изнутри. Вся проблема в том, что для этого нужны нейтроны несколько нетипичных энергий, так называемые надтепловые, о них и речь.

On the Eptihermal Neutron Energy Limit for Accelerator-Based Boron Neutron Capture Therapy (AB-BNCT): Study and Impact of New Energy Limits: https://arxiv.org/abs/2102.02698
Marine Hervé, Nadine Sauzet, Daniel Santos
Background and purpose: Accelerator-Based Boron Neutron Capture Therapy is a radiotherapy based on compact accelerator neutron sources requiring an epithermal neutron field for tumour irradiations. Neutrons of 10 keV are considered as the maximum optimised energy to treat deep-seated tumours. We investigated, by means of Monte Carlo simulations, the epithermal range from 10 eV to 10 keV in order to optimise the maximum epithermal neutron energy as a function of the tumour depth.
Methods: A Snyder head phantom was simulated and mono-energetic neutrons with 4 different incident energies were used: 10 eV, 100 eV, 1 keV and 10 keV. 10B capture rates and absorbed dose composition on every tissue were calculated to describe and compare the effects of lowering the maximum epithermal energy. The Therapeutic Gain (TG) was estimated considering the whole brain volume.
Results: For tumours seated at 4 cm depth, 10 eV, 100 eV and 1 keV neutrons provided respectively 54 %, 36 % and 18 % increase on the TG compared to 10 keV neutrons. Neutrons with energies between 10 eV and 1 keV provided higher TG than 10 keV neutrons for tumours seated up to 6.4 cm depth inside the head. The size of the tumour does not change these results.
Conclusions: Using lower epithermal energy neutrons for AB-BNCT tumour irradiation could improve treatment efficacy, delivering more therapeutic dose while reducing the dose in healthy tissues. This could lead to new Beam Shape Assembly designs in order to optimise the BNCT irradiation.