Distribution of the dose from neutrons in a thin sample of wet tissue as a function of linear energy transfer (LET)

Dousset, M.; Hamard, J; Ricourt, A.

doi:10.1088/0031-9155/16/3/008

Cited by 10 publications

(5 citation statements)

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“…2) The high LET (~ 40 keV/mm as average [22], or even higher [23]) and very high RBE (≌16 at 2.45MeV) values of fast neutrons should result advantageous for treating radioresistant tumours that require superior dose conformity, by reducing the integral dose and sparing surrounding healthy tissues and critical organs, thus minimizing treatment-related complications and presumably reducing the risk of radiation-induced secondary malignancies (RISMs [41]). Indeed, some pre-clinical studies suggest that DNA ends of DNA damage induced by high-LET IR are more prone to end processing compared to DNA ends of DNA damage induced by low-LET IR.…”

Section: Discussionmentioning

confidence: 99%

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Feasibility Study on the N-IORT® Adjuvant Treatment of Brain and Breast Cancers by Fast Neutrons Produced by a Compact DD-Fusion Generator

Martellinia

2024

AJBSR

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Section: Discussionmentioning

confidence: 99%

“…the high LET (~40keV/μm as average [22], or even higher [23]) and the very high relative biological effectiveness (RBE) of fast neutrons (≌16 at 2.45MeV energy [24]), coupled with the rapid attenuation of the physical (and equivalent) dose in tissues depth which should spare the normal tissues around the tumor bed and the neighbouring organs at risk (OARs);…”

mentioning

confidence: 99%

Feasibility Study on the N-IORT® Adjuvant Treatment of Brain and Breast Cancers by Fast Neutrons Produced by a Compact DD-Fusion Generator

Martellinia

2024

AJBSR

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“…2 shows the computed 2D maps of the neutron flux distributions (in arbitrary units) inside the IORT applicator (marked by a thicker purple line) and in the biological tissues of the surrounding brain surgical cavity. By referring the three criteria (a÷c) previously defined to characterise the IR beam features, the following aspects can be remarked: a) The high LET (~ 40 keV/mm as average 31 ) and very high RBE (@16 20 ) values of fast neutrons, that should result in very efficient killing of cancer cells. These IR features may be advantageous for treating radioresistant tumours that require superior dose conformity by reducing the integral dose and sparing surrounding healthy tissues and critical organs, minimizing treatment-related complications, and reducing the risk of radiation-induced secondary malignancies 17 (RISMs).…”

Section: Radiation Beam Features In Niort®mentioning

confidence: 99%

Feasibility Study on the nIORT® Adjuvant Treatment of Glioblastoma Multiforme through the Irradiation Field of Fast Neutrons Produced by a Compact Generator

Martellini,

Sarotto,

Leung

et al. 2023

MRAJ

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The glioblastoma multiforme (GBM) is the most malignant glial brain tumour with average survival time of 6÷18 months. Emerging evidence suggests that GBM cells appears to reprogram their tumour microenvironment, which is a highly heterogeneous and complex system, so that an efficient GBM radiotherapy (RT) should cover both the cells of the GBM and those of its microenvironment. Relying on a 5-year collaborative research study on the intra-operative radiotherapy (IORT) with fast neutrons - the so-called neutron-IORT (nIORT®) technique - the authors think that this objective could be achieved by using an ionizing radiation field of fast neutrons that behave in the biological tissues as a “foam field” hitting both the GBM cancer cells and the neighbouring microenvironment. The nIORT® research activities - conducted by TheranostiCentre Srl, Berkion Technology LLC and ENEA - led to the fabrication of the first prototype of a compact neutron generator (CNG) that, through the deuterium-deuterium fusion reaction, produces neutrons of 2.45 MeV energy having: i) high linear energy transfer; ii) very high relative biological effectiveness (RBE), about 16 times higher than X-rays (and electrons) used in standard RT and IORT treatments; iii) reduced oxygen enhancement ratio, and hence resulting be very effective in cancer cells necrosis and apoptosis. The CNG is self-shielded, limited in size and weight (~120 kg) and manageable remotely by a robotic arm. A new prototype equipped by a cylindrical applicator to be inserted in the surgical cavities is currently under construction, with some technical advancements making possible its installation in an operating room dedicated to nIORT® treatments without posing any safety and environmental concern. In this article the nIORT® potentiality was investigated in the view of the GBM treatment, but the study is however generalisable for the neutron irradiation of other brain cancer pathologies. Accurate Monte Carlo simulations, modelling the CNG equipped with a couple of cylindrical applicators of 4 and 6 cm in diameter inserted in the brain surgical cavity after craniotomy, demonstrated that the nIORT® device operated at 100 kV-10 mA DC supplies a neutron flux ~108 cm-2 s-1 and can deliver equivalent dose rates ~5 Gy (RBE)/min in the centre of the tumour bed. Thus, it could administer the clinical endpoints foreseen by the standard IORT protocols (~10-20 Gy (RBE)) in treatment times of few minutes, by providing a sort of “switching on and off neutron brachytherapy tool” without using needles of radioisotopes (e.g., 252Cf). The near isotropic neutron emission allows to irradiate the tumour bed margins, normally filled by potential quiescent cancer cells, with lower (but still significant) dose levels. This should improve the local control of the tumour through the reduction of local recurrences and metastasis in the tumour microenvironment, and at the same time to avoid adverse effects of the administered neutron radiation field on the surrounding brain central nervous system. Also, the rapid decrease in tissue depth of the dose gradient (within few centimetres) should avoid any adverse effect on normal brain tissues and the neighbouring organs.

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“…The Monte Carlo programme was first checked by comparing the results obtained using the 14 MeV starting spectrum (without the photon component) against the results of similar calculations by Bewley (1968), Dousset, Hamard and Ricourt (1971) and Edwards and Dennis (1975). The starting monoenergetic neutron energies and numbers of LET intervals used by these authors were, respectively: 14.6 MeV, 8 ; 10 MeV, 12; and 14.7 MeV, 120.…”

Section: Let Distributions At the Centre Of The Phantom For 14 Mev Ne...mentioning

confidence: 99%

Dose and LET distributions due to neutrons and photons emitted from stopped negative pions

Brenner

Smith

1977

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Computer calculations are made of the dose and LET distributions due to neutrons and photons produced when negative pions are stopped in a phantom. When negative pions are stopped in a material they undergo nuclear capture, resulting in the disintegration of the nucleus and the emission of short range charged particles and longer range neutrons and photons. The uncharged radiation constitutes a potentially large source of dose outside the treatment volume. A simple phantom consisting of a 0-25 m cube of either tissue or bone-equivalent material is set up with a 0-05 m cube in the centre to represent the treatment volume. Neutrons and photons are started in this central volume and transported across the phantom using Monte Carlo transport codes. Several different initial energy spectra for the neutrons are used, taken from experimental and theoretical data. These different spectra are found to give significant differences in dose, though the distance to the 80% dose level is always about 0-015 m. Order of magnitude differences in some LET regions are also found. The dose deposited by neutrons in bone is about 24% less than in soft tissue, the photon dose being small compared with the neutron dose.

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Distribution of the dose from neutrons in a thin sample of wet tissue as a function of linear energy transfer (LET)

Cited by 10 publications

References 0 publications

Feasibility Study on the N-IORT® Adjuvant Treatment of Brain and Breast Cancers by Fast Neutrons Produced by a Compact DD-Fusion Generator

Feasibility Study on the N-IORT® Adjuvant Treatment of Brain and Breast Cancers by Fast Neutrons Produced by a Compact DD-Fusion Generator

Feasibility Study on the nIORT® Adjuvant Treatment of Glioblastoma Multiforme through the Irradiation Field of Fast Neutrons Produced by a Compact Generator

Dose and LET distributions due to neutrons and photons emitted from stopped negative pions

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