By photoacoustic spectroscopy, it is possible to observe absorption spectra of opaque samples such as animal tissues, blood and semiconductors. We measured the absorption changes for small drops of the whole blood from a mouse with methemoglobinemia induced by amyl nitrite. Also photoacoustic spectra of surgical specimens from rabbit organs such as lung, kidney and liver were presented and future applications of this method for biological systems were commented.

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Flash x-ray (FX) generators for biomedical radiography and their applications are described. The FX generators may be generally used for condenser charging voltages of 50 to 100kV, and peak currents of more than lOkA. The exposure times of the FX were about ips. The FX intensity and quality were primarily determined by controlling the condenser charging voltage, the anode-cathode (A-C) space, and insertion of metal filters. The effective focal spot varied according to the anode and cathode electrode combinations and the insertion of metal filters. The serial exposure type of FX generators could produce high intensity FX having variable photon energies and time intervals. The FX generators have many future possibilities for performing biomedical radiography utilizing their high speed capabilities.

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A design of radioactive beam line and the analysis of expected beam quality have been made. In the heavy ion cancer therapy, radioactive beam (positron emitter) can be used to verify the range of the charged particles in tissue, because the radioactive nuclei which are produced by the peripheral fragmentation of relativistic heavy ions, have a similar characteristics with the primary particles. For example, about 1 % of 20Ne will be converted into 19Ne (half life 17.4 S) in a 5cm thickness of beryllium target.19Ne are magnetically selected and purified from other fragments, then transported to the experimental area. To increase precision of the range measurement, the momentum spread of the 19Ne beam will be reduced to ±0.2 % by a wedge degrader. Around 50 % of the primary particles pass through the target, then are deflected by a super-conducting coil and wasted at a beam dump. Other unuseful particles are stopped at slits. The shielding of the neutrons produced at the target and slits are also discussed.

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