The Possibility of Therapeutic Applications of Beams of Negative π-Mesons

Instrumentation for treatment of cancer using proton and light-ion beams

“…As discussed in section ll.A. 5.a below, the variable water column is also used for dosimetric purposes. A Bragg curve can be generated by varying the water column in steps and measuring the beam before and after the water column at each step.…”

“…14 Clinical advantages of negative pions (m1t === 267 me) are also being studied as the penetrating pions deposit a large amount of energy at the end of their flight path due to the Bragg peak and nuclear "star" formation. [5][6][7] The negative pions are the lightest member of the heavy charged-particle family. Even though the dose distributions of fast neutron beams do' not have the dose localizing advantage, 8 clinical trials are also underway using beams of fast neutrons of tens of MeV to exploit their radiobiological advantages over photons due to the fastneutron's high LET (linear energy transfer) characteristics.…”

Calculation of the dose induced in tissue by negatively charged pion beams.

“…Therefore, range straggling was t~ken into account here by using an approximate method whereby the incident pion energy was chosen from a distribution defined to give the same spatial distribution of stopped primary pions as would be obtained if range straggling were included. The spatial distribution of stopped primary pions caused by range straggling was taken to be Gaussian in shape with a standard deviation given by the formula of Fowler and Perkins (1961) for the range straggling of pions in water. - .... A summary of the primary-and secondary-particle contributions to the absorbed dose in the plateau and peak regions of the depth-dose distributions is given in table 1.…”

“…The use of negatively charged pions in cancer radiotherapy offers significant advantages over those radiations conventionally employed because negatively charged pions have properties which, in principle, allow a better localization of the dose and improved biological effectiveness (e.g., Fowler and Perkins 1961, Raju and Richman 1970, Rosen 1968. To obtain some basic quantitative information on the physical effects produced by negative-pion beams and to provide data to aid in the design of the biomedical pion channel for the meson facility under construction a:t the Los Alamos Scientific Laboratory, detailed calculations have been carried out to determine the spatial distribution of the absorbed dose produced in tissue by monoenergetic negative-pion beams.…”

The Absorbed Dose and Dose Equivalent from Negatively and Positively Charged Pions in the Energy Range 10 to 2000 MeV

“…2 Since the results presented here are for the case of incident beams of infinite width, they do not apply directly to cancer therapy; that is, in cancer therapy the lateral spread of narrow beams of negatively charged pions is of importance. The results do, however, include reliable estimates of the absorbed dose and dose equivalent produced by the reaction products that arise from the nuclear capture of negative pions which come to rest in tissue.…”