Dosimetry and radiobiology of negative pions and heavy ions

Conference · Sat Dec 31 23:00:00 EST 1977

DOI:https://doi.org/10.1016/B978-0-08-024383-2.50031-7· OSTI ID:6222115

Raju, M R

The depth dose distribution of pion beams has not been found superior to protons. Pion radiation quality at the plateau region is comparable to conventional low-LET radiations, and radiobiology results also indicate RBE values close to unity. In the pion stopping region, the radiation quality increases considerably. Radiobiology data for negative pions at the Bragg peak position clearly indicate the increase in RBE and the reduction in OER. Even at the Bragg peak position, compared to fast neutrons, the average LET of negative pions is lower. Pion radiobiology data have indicated lower RBE values and higher OER values compared to fast neutrons. The radiation quality of fast neutrons is in between that of carbon and neon ions at the peak region and that of neon ions at the plateau is lower than for fast neutrons. The mean LET value for helium ions, even at the distal end of the peak, is lower than for fast neutrons. Dose localization of heavy ions has been found to decrease slowly with increasing charge of the heavy ion. The intercellular contact that protects cells after exposure to low-LET radiations is not detected after exposure to heavy ions. Single and fractionated doses of heavy ions produce dose-response curves for heavy ions having reduced shoulders but similar slopes when compared to gamma rays. Fractionated treatments of heavy ions produce an enhanced effect in the peak region compared to the plateau region and could lead to a substantial gain in therapeutic ratio. The OER for protons was similar to that for x rays. The OER values for negative pions, helium ions, and carbon ions were larger, for neon ions similar, and for argon ions smaller when compared to fast neutrons.Negative pions, helium ions, and carbon ions may be very effective clinically because the radiation quality of these beams is similar to that of the mixed scheme of neutrons and x rays. (ERB)

• Research Organization: Los Alamos Scientific Lab., NM (USA)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 6222115
• Report Number(s): LA-UR-78-2705; CONF-780984-2
• Country of Publication: United States
• Language: English

Related Subjects

550603* -- Medicine-- External Radiation in Therapy-- (1980-)
62 RADIOLOGY AND NUCLEAR MEDICINE
ARGON IONS
ATOMIC IONS
BARYONS
BIOLOGY
BOSONS
CARBON IONS
CHARGED PARTICLES
DEPTH DOSE DISTRIBUTIONS
DOSIMETRY
ELEMENTARY PARTICLES
ENERGY TRANSFER
FAST NEUTRONS
FERMIONS
HADRONS
HELIUM IONS
IONS
LET
MEDICINE
MESONS
NEON IONS
NEUTRONS
NUCLEAR MEDICINE
NUCLEONS
OXYGEN ENHANCEMENT RATIO
PIONS
PIONS MINUS
PROTONS
PSEUDOSCALAR MESONS
RADIATION DOSE DISTRIBUTIONS
RADIOBIOLOGY
RADIOLOGY
RADIOTHERAPY
RBE
SPATIAL DOSE DISTRIBUTIONS
THERAPY