fair resolution down to about 2 KeV. They have also been used as counters for energies down to 300 eV. In a somewhat different approach at the Lawrence Radiation Laboratory in Berkeley, nonamplifying silicon detectors and external amplifiers have been optimized for low-energy measurements. These detectors have excellent resolution down to about 4 KeV. Both types of detectors should be suitable for 239Pu and 55Fe studies and for X-ray diffraction analysis of organic crystals. THERAPY Detectors have been used for years in radiation therapy to measure X-ray and gamma ray dose distributions. The main purpose of these measurements has been to position a tumor at the point of maximum radiation dose rate and to minimize the dose to normal tissue. The radiobiologist has observed that while to a large extent biological change is related to the amount of energy absorbed per unit mass, the relative response in the presence and absence of oxygen and the ability to repair damage are closely associated with the details of the energy loss process. Tissue is generally more radiosensitive when oxygen is plentiful and consequently anoxic tumor tissue tends to be radiation-resistant relative to surrounding normal tissue. This effect is minimized with densely ionizing radiation. The ability of a biological system to repair radiation damage is also minimal with such radiations. At the Donner Laboratory of the Lawrence Radiation Laboratory in Berkeley, semiconductor detectors with their remarkable resolution are being used to determine the distribution of rates of energy loss in matter irradiated with densely ionizing protons, deuterons, alpha particles, very heavy ions and negative pions. 11,12 The description of the radiation field obtained by the use of these semiconductor detectors permits the radiobiologist and the therapist to formulate strategies which make maximum use of our understanding of those factors which influence the behavior of irradiated cell populations. CONCLUSION I have discussed perhaps somewhat superficially a variety of detector usages in three areas of Biology and Medicine. Other fields of biology in which there are widespread detector applications and needs--Terrestrial and Aquatic Ecology and Marine Biology, for example--have not even been mentioned. In closing, there is a general observation I would like to make: Basic radiation detector development has been in the hands of the physical scientist and is likely to remain there. Many new devices that have appeared in the past have been turned to biomedical use: the first well counter, for example, was developed in a biology laboratory; the multiparameter analyzer has been considerably improved for biological use; spark chamber photograph scanning systems are being adapted for chromosome analysis. Rarely, however, have new detector concepts arisen solely because of biomedical needs. As the physical principles of detectors and instrumentation in general become more complex, it is going to become increasingly difficult for the professional biologist to perceive potential biological applications of new advances. Consequently, there is a definite need for physical scientists and instrumentation experts to concentrate on the problems of experimental biology and medicine. For example, we invite the semiconductor detector experts to consider very large single crystals and arrays of small devices to improve the resolution, sensitivity and geometry in whole body counting. There is a need--perhaps a unique biomedical need--for micro detectors that can monitor the internal physiological dynamics of living systems without perturbing their normal functioning. If one is looking for challenging instrumentation problems, he should not overlook the life sciences. ACKNOWLEDGMENT A survey paper such as this always represents the efforts of numerous contributors. Discussions with Robert W. Wood and Nathaniel F. Barr in the Division of Biology and Medicine and with Hal 0. Anger, Marvin B. Bacaner, Fred S. Goulding and George T. Reynolds were especially helpful. I particularly acknowledge the assistance of Hodge R. Wasson, Division of Biology and Medicine. Senator HARRIS. We certainly agree with the general points you have made which were also made in the memorandum from me as chairman of this subcommittee to our members in advance of these hearings and in the press release following a conference we sponsored in Oklahoma last October, which listed as the first two points the following: It is likely that significant additional benefits to the health of the Nation would follow from more attention to the application of biomedical knowledge. Mounting such a program at the expense of basic research would be disastrous for future progress in solving our national health problems. We are certainly in agreement on your basic points. I am very interested in what you say about additional attention being given to application. In your questions-and-answers section that we have just inserted in the record, I note particularly the portion of that which says: Additional attention should be given to the support of certain groups in one or more agencies which would be specifically charged with identifying workable basic data and showing how that information could be translated into specific utilitarian objects or ideas. Then you go on to say that these might be idea-think-analyst-engineer groups. That is a very intriguing idea and I wonder if you or your associates might comment on that further. Dr. NABRIT. I would like to ask Mr. Dunham if he would not want to speak to this point. Dr. DUNHAM. This is just a thought which Dr. Nabrit threw out. It is certainly apparent to all of us who have worked in biology that there is the problem of communication between the basic scientist and the one who is on the medical firing line as it were, trying to take care of patients. Although, in our National Lab setups there is a good deal of interplay. Even there, I think it could be greatly improved by assigning one or two people to watch the area of the basic research products, and keep in mind what the other people can be doing in terms of applying these things. I think it is not an elaborate concept, but I think it is one that is simply a matter of people giving thought to this. Senator HARRIS. It is a good idea. I would say it borders on another idea that you made later on here, about private industry. That is another interest of this subcommittee, how the private sector might play a greater role, and what, if any, additional incentives might be required. NASA, you know, maintains a program for disseminating to private industry some of the things that they develop. I think that is the general idea also behind the State Technical Services Act that we passed two sessions ago. Perhaps we might do more of that. What sort of program does AEC itself have in that regard? Dr. NABRIT. Dr. English. Dr. ENGLISH. Mr. Chairman, we are aware of the NASA program and, in fact, we make use of it, in connection with their publications, which you mentioned and which they disseminate to private industry. We have groups in several of our national laboratories who are looking at the research results that have come out, and cooperate with NASA in the AEC-NASA Tech Briefs which records, for several |