Summary: Short-lived elementary particles found in cosmic radiation or produced from nuclear disintegration. Their mass is between that of protons and electrons and they can be negative, positive, or neutral. pi-Mesons (pions) are heavier than mu-mesons (muons) and are proposed for cancer radiotherapy because their capture and disintegration by matter produces powerful, but short-lived, secondary radiation.

Top Publications

  1. van der Kogel A, Jarrett K, Paciotti M, Raju M. Radiation tolerance of the rat rectum to fractionated X-rays and pi-mesons. Radiother Oncol. 1988;12:225-32 pubmed
    ..The RBE of pions for rectal injury at 250 days was 1.2 for single doses, increasing to about 1.4-1.5 at a dose per fraction of 4 Gy. These values are similar to those obtained in other acute and late responding tissues. ..
  2. O brien K, Friedberg W, Sauer H, Smart D. Atmospheric cosmic rays and solar energetic particles at aircraft altitudes. Environ Int. 1996;22 Suppl 1:S9-44 pubmed
    ..The spectra incident on the atmosphere were determined assuming diffusive shock theory. Unfortunately, there are essentially no experimental data with which to compare these calculations. ..
  3. Wambersie A, Auberger T, Gahbauer R, Jones D, Potter R. A challenge for high-precision radiation therapy: the case for hadrons. Strahlenther Onkol. 1999;175 Suppl 2:122-8 pubmed
    ..Appropriate selection between low- and high-LET radiation for a particular tumor is indeed a radiobiological problem, independent of technical development. ..
  4. Jayasooriya U, Grinter R, Hubbard P, Aston G, Stride J, Hopkins G, et al. Muon implantation of metallocenes: ferrocene. Chemistry. 2007;13:2266-76 pubmed
    ..Correlation time for the ring rotation dynamics of the Fe-Mu radical at this temperature is 3.2 ps. Estimated electron g values and the changes in zero-field splittings for this temperature range are also reported. ..
  5. Thum P, Greiner R, Blattmann H, Coray A, Zimmermann A. [Pion radiotherapy of unresectable soft tissue sarcomas at the Swiss Institute for Nuclear Research]. Strahlenther Onkol. 1988;164:714-23 pubmed
    ..These preliminary results stimulate the intensification of this clinical program. 1986 the same number of patients with non-resectable soft tissue sarcomas was treated as in the whole period 1982 to 1985 before. ..
  6. Raju M. Particle radiotherapy: historical developments and current status. Radiat Res. 1996;145:391-407 pubmed
    ..International cooperation in the development of the field of particle therapy, its impact on radiobiology and conventional radiotherapy, and some personal reflections and conclusions are also presented briefly. ..
  7. Lauzon J, Arseneau D, Brodovitch J, Clyburne J, Cormier P, McCollum B, et al. Generation and detection of the cyclohexadienyl radical in phosphonium ionic liquids. Phys Chem Chem Phys. 2008;10:5957-62 pubmed publisher
    ..Comparison of the hyperfine interactions in the ionic liquid and in molecular solvents and with theoretical calculations, suggests significant and unforeseen solvent interaction with the cyclohexadienyl radical. ..
  8. McKenzie I, Roduner E. Using polarized muons as ultrasensitive spin labels in free radical chemistry. Naturwissenschaften. 2009;96:873-87 pubmed publisher
    ..It is reviewed here how the muon can be used to obtain information about muonium and radical reaction rates, radical structure, dynamics, and local environments. It can even tell us what a fragrance molecule does in a shampoo. ..
  9. Marples B, Skov K. Small doses of high-linear energy transfer radiation increase the radioresistance of Chinese hamster V79 cells to subsequent X irradiation. Radiat Res. 1996;146:382-7 pubmed
    ..78 +/- 0.03 to 0.84 +/- 0.03 with a priming dose of Bragg-peak negative pi mesons. The results indicate that a protective effect, as measured by an increase in radioresistance, is induced by high-..

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  1. Goodman G, Skarsgard L, Thompson G, Harrison R, Lam G, Lugate C. Pion therapy at TRIUMF. Treatment results for astrocytoma grades 3 and 4: a pilot study. Radiother Oncol. 1990;17:21-8 pubmed
    ..04). It appears that optimal pion dose for brain tumours is 33 Gy minimum with a possible maximum of 36 Gy and doses delivered in 15 fractions in 3 weeks. Requirements for future trials are discussed. ..
  2. Pickles T, Goodman G, Rheaume D, Duncan G, Fryer C, Bhimji S, et al. Pion radiation for high grade astrocytoma: results of a randomized study. Int J Radiat Oncol Biol Phys. 1997;37:491-7 pubmed
    ..However, this study has demonstrated no therapeutic gain for pion therapy of glioblastoma. ..
  3. Kummermehr J, Schraube H, Ries G, Koster L, Höver K, Blattmann H, et al. Biological effectiveness of neutrons and pi-mesons in gut, bone, and transplantable tumours. Strahlenther Onkol. 1989;165:276-82 pubmed
    ..e. a high RBE at the surface and a fast decline of the biologically effective depth dose suggest possible advantages of the RENT beam when applied in the treatment of selected superficial tumours. ..
  4. Marples B, Lam G, Zhou H, Skov K. The response of Chinese hamster V79-379A cells exposed to negative pi-mesons: evidence that increased radioresistance is dependent on linear energy transfer. Radiat Res. 1994;138:S81-4 pubmed
    ..Fitting the data with an induced repair model indicates that the phenomenon of increased radioresistance is almost certainly dependent on LET. ..
  5. Bevelacqua J. Environmental radiation effects from muon and tau colliders and their impact on facility licensing. J Environ Radioact. 2012;113:123-30 pubmed publisher
    ..The analysis presented herein suggests that a linear collider concept with the lepton beams collided in air offers a means to limit the environmental radiation effects from these accelerators. ..
  6. Schneider J, Norbury J, Cucinotta F. Parameterization of spectral distributions for pion and kaon production in proton-proton collisions. Astrophys J Suppl Ser. 1995;97:571-4 pubmed
    ..The parameterizations depend on the outgoing meson momentum and also the proton energy, and are able to be reduced to very simple analytical formulas suitable for cosmic-ray transport. ..
  7. van der Kogel A, Martin J, Smith A, Raju M. Late effects of fractionated pi-mesons compared to X rays on mouse lung. Int J Radiat Oncol Biol Phys. 1988;14:1175-84 pubmed
    ..4 compared to fractionated high dose-rate X rays. These RBE's are similar to values reported for acute effects in skin. ..
  8. Nishioka A, Ohizumi Y, Lam G, Pickles T, Chaplin D, Ogawa Y, et al. The effects of nicotinamide plus carbogen or pions for microscopic SCCVII tumors. Oncol Rep. 1999;6:583-6 pubmed
    ..However, N&C can be considered to provide an advantage for treatment of even clinical microscopic tumors. ..
  9. Ohizumi Y, Lam G, Pickles T, Chaplin D. Biological effectiveness of fractionated dose of pions in microscopic SCCVII tumors: comparison between tumor control dose and tumor growth time assays. Jpn J Cancer Res. 1995;86:600-6 pubmed
    ..3 Gy (CL; 36.3-44.2 Gy) for photons. In conclusion, the RBE for TCD50 was not predictable from the RBE for TGT assay. The cRBE value of 1.4 for microscopic tumor control was in close agreement with the reported values for skin reaction. ..
  10. Goldhagen P, Reginatto M, Kniss T, Wilson J, Singleterry R, Jones I, et al. Measurement of the energy spectrum of cosmic-ray induced neutrons aboard an ER-2 high-altitude airplane. Nucl Instrum Methods Phys Res A. 2002;476:42-51 pubmed
    ..In all cases, ambient dose equivalent was greater than effective dose for cosmic-ray neutrons. ..
  11. Wissmann F, Dangendorf V, Schrewe U. Radiation exposure at ground level by secondary cosmic radiation. Radiat Meas. 2005;39:95-104 pubmed
    ..The measured seasonal variations exhibit a negative correlation with the temperature changes in the upper layers of the atmosphere where the ground level muons are produced. ..
  12. Matthiä D, Sihver L, Meier M. Monte-Carlo calculations of particle fluences and neutron effective dose rates in the atmosphere. Radiat Prot Dosimetry. 2008;131:222-8 pubmed publisher
    ..Furthermore, secondary muon fluences have been computed and are compared with CAPRICE measurements. ..
  13. Shirato H. Biological equivalent dose prediction in pion irradiation using pion star density and the mixed beam lesion additivity model. Phys Med Biol. 1989;34:769-76 pubmed
    ..The predicted RBE were consistent with previously published results through the flat dose peak, except at the decreasing portion of the dose profile. The practical usefulness of this model in clinical treatment is stressed. ..
  14. Shirato H, Harrison R, Kornelsen R, Lam G, Gaffney C, Goodman G, et al. Detection of pion-induced radioactivity by autoradiography and positron emission tomography. Med Phys. 1989;16:338-45 pubmed
    ..This new technique is capable of defining the stopping region in phantoms with a better resolution than PET scanning and is useful as a complementary technique to other methods of pion dosimetry. ..
  15. Zhang Y, Skupin S, Maucher F, Pour A, Lu K, Krolikowski W. Azimuthons in weakly nonlinear waveguides of different symmetries. Opt Express. 2010;18:27846-57 pubmed publisher
    ..We explain these dynamics using the concept of energy difference between different orientations of the azimuthon. ..
  16. Jüling Pohlit L, Latz D, Pohlit W, Thonke A. The RBE of euoxic and hypoxic Ehrlich ascites tumour cells irradiated with negative pions in vitro and in vivo. Radiother Oncol. 1990;19:57-72 pubmed
    ..Side effects in the mouse gut showed a RBE of 2.0, corresponding to irreparable lethal lesions in euoxic in vitro cells. ..
  17. Raju M, van der Kogel A. Radiobiology of pions in comparison with other heavy particles. Radiother Oncol. 1990;17:1-5 pubmed
    ..Such knowledge combined with pion and heavy ion dynamic treatment could lead to a further step in heavy particle radiotherapy. ..
  18. Wilson W, Beedoe S, Bossingham R, Bougteb M, Carroll J, Gong W, et al. Inclusive dielectron cross sections in p + p and p + d interactions at beam energies from 1.04 to 4.88 GeV. Phys Rev C Nucl Phys. 1998;57:1865-78 pubmed
    ..The beam energy dependence of the integrated cross sections is also presented. ..
  19. Deutchman P, Norbury J, Townsend L. Total and differential cross sections for pion production via coherent isobar and giant resonance formation in heavy-ion collisions. Can J Phys. 1985;63:1242-8 pubmed
    ..It is shown that the pion angular distributions, in coincidence with the target giant resonance excitations, might provide a well-defined signature for these coherent processes. ..
  20. Rhodes C, Dintinger T, Moynihan H, Reid I. "Spin-labelling" with the second hydrogen radioisotope: radicals formed from squalene by muonium addition. Free Radic Res. 2000;33:75-9 pubmed
  21. Pickles T, Bowen J, Dixon P, Gaffney C, Pomeroy M, Rheaume D, et al. Pions--the potential for therapeutic gain in locally advanced prostate cancer: dose escalation and toxicity studies. Int J Radiat Oncol Biol Phys. 1991;21:1005-11 pubmed
    ..Local response rates of 94% are reported. A Phase III study is now under way. ..
  22. Chatrchyan S, Khachatryan V, Sirunyan A, Tumasyan A, Adam W, Bergauer T, et al. Measurement of inclusive W and Z boson production cross sections in pp collisions at sqrt[s] = 8 TeV. Phys Rev Lett. 2014;112:191802 pubmed
    ..Ratios of cross sections are reported with a precision of 2%. This is the first measurement of inclusive W and Z boson production in proton-proton collisions at sqrt[s] = 8 TeV. ..
  23. Ogawa Y, Goodman G, Chaplin D, Grulkey W, Lam G. The response of mouse tumours to fractionated doses of pions: determination of therapeutic gain factor. Oncology. 1991;48:81-7 pubmed
    ..As for therapeutic gain factor, a maximum value of 1.45 was obtained with 10 fractions using the SCCVII tumour. Pions seem to be most effective (in multiple fractions) against tumours of relatively slow growth. ..
  24. Deutchman P, Buvel R, Maung K, Norbury J, Townsend L. Quantum mechanical signature in exclusive coherent pion production. Phys Rev C Nucl Phys. 1986;33:396-8 pubmed
    ..The theoretical quantum mechanical results obtained for the pion spectra represent an important improvement over our previous microscopic, many-body calculations. ..
  25. Norbury J, Townsend L. Theoretical estimates of photoproduction cross sections for neutral subthreshold pions in carbon-carbon collisions. Phys Rev C Nucl Phys. 1986;33:377-8 pubmed
    ..Comparisons with recent experimental data indicate that the photoproduction mechanism makes an insignificant contribution to these measured cross sections. ..
  26. Rhodes C, Hinds C, Morris H, Reid I. Muon spectroscopy applied to biological systems: a study of thiyl radicals, RS. Free Radic Res. 1997;27:347-52 pubmed
    ..radicals may be dependent on the polarity (philicity) of the environment in which they are formed. ..
  27. Greiner R, Blattmann H, Thum P, Bosiger P, Coray A, Kann R, et al. Anaplastic astrocytoma and glioblastoma: pion irradiation with the dynamic conformation technique at the Swiss Institute for Nuclear Research (SIN). Radiother Oncol. 1990;17:37-46 pubmed
    ..From these findings, further dose escalation programs, together with a shaping of the target volume close to the tumour, are not contraindicated. ..
  28. Chaplin D, Douglas B, Saito T, Skarsgard L, Lam G, Denekamp J. Preclinical evaluation of pions in vivo: experience at TRIUMF. Radiother Oncol. 1990;17:7-15 pubmed
    ..The results show that for a constant field size, RBE decreases with increasing peak width. However, if peak width is held constant and field size increased, there is evidence for an increased RBE.(ABSTRACT TRUNCATED AT 250 WORDS) ..
  29. Tripathi R, Townsend L. Bose condensation of nuclei in heavy ion collisions. Phys Rev C Nucl Phys. 1994;50:R7-9 pubmed
    ..Nonetheless, some suggestions for the possible experimental verification of the existence of this phenomenon are made. ..
  30. Feng X, Chen J. Regarding the charmed-strange member of the 2³S? meson state. ScientificWorldJournal. 2013;2013:658105 pubmed publisher
    ..The results may be useful for the discovery of the unobserved meson and the determination of the quantum number of the newly discovered states. ..
  31. Chatrchyan S, Khachatryan V, Sirunyan A, Tumasyan A, Adam W, Aguilo E, et al. Measurement of the ?1S, ?2S, and ?3S polarizations in pp collisions at sqrt[s] = 7 TeV. Phys Rev Lett. 2013;110:081802 pubmed
    The polarizations of the ?(1S), ?(2S), and ?(3S) mesons are measured in proton-proton collisions at sqrt[s] = 7 TeV, using a data sample of ?(nS) ? ? +?- decays collected by the CMS experiment, corresponding to an integrated luminosity of ..
  32. Nakajima T. A scheme to polarize nuclear-spin of atoms by a sequence of short laser pulses: application to the muonium. Opt Express. 2010;18:27468-80 pubmed publisher
  33. Greiner R, Munkel G, Kann R, Blattmann H, Coray A, Thum P, et al. Pion irradiation at Paul Scherrer Institute. Results of dynamic treatment of unresectable soft tissue sarcoma. Strahlenther Onkol. 1990;166:30-3 pubmed
    ..Dynamic spot scan pion irradiation proves to be a successful treatment technique for unresectable sarcomas with a high rate of tumor control and a very low rate of severe late reactions. ..
  34. Scheuermann R, Tucker I, Dilger H, Staples E, Ford G, Fraser S, et al. Partitioning of small amphiphiles at surfactant bilayer/water interfaces: an avoided level crossing muon spin resonance study. Langmuir. 2004;20:2652-9 pubmed
  35. Duncan G, Philips N, Pickles T. Report on the quality of life analysis from the phase III trial of pion versus photon radiotherapy in locally advanced prostate cancer. Eur J Cancer. 2000;36:759-65 pubmed
    ..There was a significant impact from hormonal therapy at relapse. Hormonal treatment produced a stepwise significant worsening in global QOL, particularly for physical and psychological domains. ..
  36. Cucinotta F, Townsend L, Wilson J. Production of 3H at large momentum in alpha-12C collisions at 2A GeV. Phys Lett B. 1992;282:1-6 pubmed
    ..Comparisons to momentum distributions obtained through (p, 2p) and (e, ep) reactions on 4He are made. ..
  37. Akoev I, Yurov S. Peculiarities of biological action of hadrons of space radiation. Life Sci Space Res. 1975;13:187-93 pubmed
    ..of secondary particles (among them, probably, highly effective multicharged and heavy nuclei, antiprotons, pi(-)-mesons), and the spatial distribution of secondary particles as a narrow cone with extremely high density of particles in ..
  38. Skarsgard L. Radiobiology with heavy charged particles: a historical review. Phys Med. 1998;14 Suppl 1:1-19 pubmed
    ..We have arbitrarily limited our discussion to mammalian systems, except for a few very early experiments of historical interest. ..
  39. Pickles T, Goodman G, Fryer C, Bowen J, Coldman A, Duncan G, et al. Pion conformal radiation of prostate cancer: results of a randomized study. Int J Radiat Oncol Biol Phys. 1999;43:47-55 pubmed
    ..This contrasts with the late toxicity observed with higher LET particle therapy such as neutron therapy. No improvement in local control with pion therapy was observed. ..
  40. Cormier P, Alcorn C, Legate G, Ghandi K. Muon radiolysis affected by density inhomogeneity in near-critical fluids. Radiat Res. 2014;181:396-406 pubmed publisher
    ..In carbon dioxide, an increase in electron mobility contributes to the lost fraction. The hydrated electron in water is responsible for the lost fraction and decreases the muonium fraction. ..
  41. Aad G, Abbott B, Abdallah J, Abdelalim A, Abdesselam A, Abdinov O, et al. Search for a light Higgs boson decaying to long-lived weakly interacting particles in proton-proton collisions at sqrt[s] = 7 TeV with the ATLAS detector. Phys Rev Lett. 2012;108:251801 pubmed
    ..No excess of events is observed above the expected background and limits on the Higgs boson production times branching ratio to weakly interacting, long-lived particles are derived as a function of the particle proper decay length. ..
  42. Cox S, Lord J, McKenzie I, Adjizian J, Heggie M, Jayasooriya U, et al. Muonium chemistry and spin dynamics in sulphur, modelling interstitial hydrogen. J Phys Condens Matter. 2011;23:315801 pubmed publisher
  43. Creamer N, Mikheenko I, Johnson C, Cottrell S, Macaskie L. Local magnetism in palladium bionanomaterials probed by muon spectroscopy. Biotechnol Lett. 2011;33:969-76 pubmed publisher
    ..We show the first use of ?SR as a tool to probe the internal magnetic environment of a biologically-derived nanocatalyst material. ..
  44. Jüling Pohlit L, Pohlit W, Blattmann H. Repair inhibition in tumours irradiated with fast protons and negative pions. Strahlenther Onkol. 1990;166:6-9 pubmed
    ..Application of 2-DG raised the radiation effect due to the sparsely ionizing component again by a factor of 1.4. This indicates that clinical results in radiotherapy might be improved by application of 2-DG during the treatment. ..
  45. Ohizumi Y, Lam G, Pickles T, Fryer C, Chaplin D. Radiosensitizing effect of nicotinamide and carbogen combined in fractionated pions or x-rays in SCCVII tumors. Radiat Med. 1995;13:291-5 pubmed
    ..In conclusion, N + C afforded no additional benefit with fractionated pions, but it was thought to be of value for fractionated X-rays, even in a dose rate of 0.2 Gy/min. ..
  46. Armstrong T, Colborn B. Predictions of secondary neutrons and their importance to radiation effects inside the International Space Station. Radiat Meas. 2001;33:229-34 pubmed
    ..Also, the important neutron energy ranges for producing these effects have been estimated, which provides guidance for onboard neutron measurement requirements. ..
  47. Greiner R, Blattmann H, Thum P, Coray A, Crawford J, Kann R, et al. Dynamic pion irradiation of unresectable soft tissue sarcomas. Int J Radiat Oncol Biol Phys. 1989;17:1077-83 pubmed
    ..Dynamic spot scan pion irradiation proves to be a successful treatment technique for unresectable sarcomas with a high rate of tumor control and a very low rate of severe late reactions. ..
  48. Espinosa Garcia J. Theoretical rate constants and kinetic isotope effects in the reaction of methane with H, D, T, and Mu atoms. Phys Chem Chem Phys. 2008;10:1277-84 pubmed publisher
    ..These were the zero-point energy, tunneling effect, and the role of the reactivity from methane excited vibrational states. ..
  49. Karasawa K. [Pion therapy at SIN--7 years' experience]. Gan No Rinsho. 1988;34:1845-51 pubmed
    At SIN (Swiss Institute for Nuclear Research) cancer treatment with negatively charged pi-mesons was initiated in 1980, and 331 patients have been treated by the end of 1987...
  50. Rao K, Blattmann H, Fritz Niggli H. Variations of pion RBE in a volume with an asymmetric beam configuration. Strahlenther Onkol. 1987;163:739-41 pubmed
    ..The variation of the RBE is smaller than for the same field irradiated by a single pion beam. ..
  51. Joković D, Dragic A, Udovicić V, Banjanac R, Puzovic J, Anicin I. Monte Carlo simulations of the response of a plastic scintillator and an HPGe spectrometer in coincidence. Appl Radiat Isot. 2009;67:719-22 pubmed publisher
    ..Obtained coincident spectra of both detectors are presented and discussed. ..
  52. Marples B, Adomat H, Koch C, Skov K. Response of V79 cells to low doses of X-rays and negative pi-mesons: clonogenic survival and DNA strand breaks. Int J Radiat Biol. 1996;70:429-36 pubmed
    ..the increased radioresistance and linear energy transfer of 250 kVp X-rays and plateau and Bragg peak negative pi-mesons. The results support our hypothesis since the size of the increased radioresistant response appears to correspond ..
  53. Yamaguchi C, Mares V, Blattmann H. Pionic carbon/oxygen capture ratios in blood and muscle tissue of pig. Phys Med Biol. 1987;32:1327-34 pubmed
    ..It was expected that some of them originated from haemoglobin and could be observed in the spectrum for a blood sample. TE plastic (Shonka A-150) and Lucite were also investigated for comparison with other work. ..