Biological effects of negative pions

Raju, M. R.; Amols, Howard; Bain, E.; Carpenter, S.G.; Dicello, J.F.; Frank, J.P.; Tobey, Robert A.; Walters, R.A.

doi:10.1016/0360-3016(77)90272-3

Cited by 20 publications

(5 citation statements)

References 28 publications

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“…A comparison between beams of equal initial momentum but different momentum spreads is shown in Fig. For a small momentum spread, therefore, a higher biological effectivity and a better homogeneity of the biological effective dose would be expected in agreement with radiobiological investigations reported from Los Alamos (Raju et al, 1977). Total absorbed dose and three dose fractions associated with different intervals of y are given as a function of depth in phantom.…”

Section: Influence Of Momentum Spread On Radiation Qualitysupporting

confidence: 78%

Energy deposition spectra of negative pions and their application to radiation therapy

Schuhmacher

Menzel

Blattmann

1979

Radiat Environ Biophys

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Treatment planning for pion radiation therapy must take into account changes in radiation quality within the patient. At the biomedical channel piE3 of SIN (Swiss Institute for Nuclear Research) microdosimetric measurements have been performed to investigate radiation quality within pion irradiated phantoms. Results are presented in terms of microdosimetric spectra and derived quantities. As expected marked differences are observed between dose peak and plateau for "narrow" pion beams. The influence of simulated site diameter on measured spectra has been found to be more pronounced in the plateau region than in the peak. Investigation of the influence of peak width on radiation quality revealed a dilution of the high-LET dose fraction for broader peaks.

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Section: Influence Of Momentum Spread On Radiation Qualitysupporting

confidence: 78%

Energy deposition spectra of negative pions and their application to radiation therapy

Schuhmacher

Menzel

Blattmann

1979

Radiat Environ Biophys

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“…As reviewed by Raju et al (1977), the RBE values attributed to peak pions vary between less than one and five depending on the broad range of experimental conditions used. This variance in the reported RBE values of peak pions may be explained by the 'two system' theory suggested by Fritz-Niggli and Blattmann (1977).…”

Section: Fig 3 Survival Data Obtained With Eat Cells Exposed To Plamentioning

confidence: 99%

Effect of negative pions, relative to 140 kV - 29 MeV photons and 20 MeV electrons, on proliferation of Ehrlich ascites carcinoma cells

Rao

Blattmann

Cordt

et al. 1979

Radiat Environ Biophys

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The effect of negative pions (peak and plateau), photons (140 kV and 29 MeV), and 20 MeV electrons on the proliferative capacity of Ehrlich ascites carcinoma cells was investigated. Proliferative survival curves plotted for the modalities employed are presented. Under the experimental conditions used, the peak pions were more effective than plateau pions by a factor of about 1.4. For 50% survival, 140 kV X-rays had the same effect as peak pions but the latter was more effective (factor 1.2) at 10% survival level. When 140 kV X-rays were taken as the standard, following are the RBE values calculated as 50% survival level: plateau pions --0.73; peak pions --about 1.0; 29 MeV photons --0.73 and 20 MeV electrons --0.6. The results obtained are compared with those reported on other tumor systems and biological test objects.

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“…As discussed in Chapter 2, the absorption of charged pions in target materials results in the generation of high-LET target fragments, which deliver significant energy in a short distance. The use of Bragg peak π-mesons using beams with starting energies of ∼100 MeV for cancer therapy was a focus in the 1970’s for cancer treatment (Raju and Richman, 1972; Raju et al, 1977) because the negative charge at the end of its range would lead to capture by a positively charge nucleus and lead to increase in nuclear fragmentation. However, our study shows the majority of the pion energy spectra is at a much higher energy (Fig.…”

Section: Discussionmentioning

confidence: 99%

Tissue-Specific Dose Equivalents of Secondary Mesons and Leptons during Galactic Cosmic Ray Exposures for Mars Exploration

Pak,

Cucinotta

2023

Preprint

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During a human mission to Mars, astronauts would be continuously exposed to galactic cosmic rays (GCRs) consisting of high energy protons and heavier ions coming from outside our solar system. Due to their high energy, GCR ions can penetrate spacecraft and space habitat structures, directly reaching human organs. Additionally, they generate secondary particles when interacting with shielding materials and human tissues. Baryon secondaries have been the focus of many previous studies, while meson and lepton secondaries have been considered to a much lesser extent. In this work, we focus on assessing the tissue-specific dose equivalents and the effective dose of secondary mesons and leptons for the interplanetary cruise phase and the surface phase on Mars. We also provide the energy distribution of the secondary pions in each human organ since they are dominant compared to other mesons and leptons. For this calculation, the PHITS3.27 Monte Carlo simulation toolkit is used to compute the energy spectra of particles in organs in a realistic human phantom. Based on the simulation data, the dose equivalent has been estimated with radiation quality factors in ICRP Publication 60 and in the latest NASA Space Cancer Risk model (NSCR-2022). The effective dose is then assessed with the tissue weighting factors in ICRP Publication 103 and in the NSCR model, separately. The results indicate that the contribution of secondary mesons and leptons to the total effective dose is 6.173%, 9.239%, and 11.553% with the NSCR model in interplanetary space behind 5, 20, and 50 g/cm2aluminum shielding, respectively with similar values using the ICRP model. The outcomes of this work lead to an improved understanding of the potential health risks induced by secondary particles for exploration missions to Mars and other destinations.

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Biological effects of negative pions

Cited by 20 publications

References 28 publications

Energy deposition spectra of negative pions and their application to radiation therapy

Energy deposition spectra of negative pions and their application to radiation therapy

Effect of negative pions, relative to 140 kV - 29 MeV photons and 20 MeV electrons, on proliferation of Ehrlich ascites carcinoma cells

Tissue-Specific Dose Equivalents of Secondary Mesons and Leptons during Galactic Cosmic Ray Exposures for Mars Exploration

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