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As a result of an arms reduction treaty between the United States and the Russian Federation, both countries will each be storing over 40,000 containers of plutonium. To help detect any deterioration of the containers and prevent leakage, we are designing a digital radiography and computed tomography system capable of handling this volume reliably, efficiently, and at a lower cost.

Xenon-filled multi-wire proportional chambers have a high detection efficiency for x rays commonly used in diagnostic radiology, and through electronic amplification every detected event can be made visible on a final picture. Since the image is obtainable from electrical signals, these devices also afford the opportunity to obtain digital data.We present here the results obtained with a 20x20 cm.2 wire-chamber filled with a mixture of 94.5 per cent xenon, 5 per cent CO2, and 0.5 per cent freon 13B-1. The spatial resolution of the chamber was of the order of 1 mm. and the detection efficiency varied between 97 and 2.5 per cent in the x-ray energy range from 5 kev. to 100 kev.

We describe a camera for the laminographic imaging of the thyroid without administration of radiopharmaceuticals to the patient. An external source of gamma-rays is used to excite the characteristic x-rays of natural iodine in the patient's thyroid, source geometry limiting excitation to well-defined planes. The camera consists of a parallel hole collimator and a xenon-filled proportional wire chamber with digitized readout of coordinates. Pulse height selection is provided to limit events in the image display to a selected energy range. We estimate that the system will obtain high resolution laminography for local exposures on the order of 1 to 5 rad, with exposure times of a few minutes for each laminogram.

Magnetostrictive spark chambers are operated with difficulty in magnetic fields. By inducing secondary sparks to a pickup wire, signals can be generated which are similar to those from a magnetostrictive chamber but which are unaffected by magnetic fields. Piezoelectric pickup transducers complete a field insensitive digital spark chamber system.

The pressurized xenon-filled multi-wire proportional chamber (MWPC) is an imaging detector with high intrinsic spatial resolution and good uniformity of response. We describe the design and operation of a 20 x 20 cm2 MWPC with a mass of 0.14 g/cm2 of xenon, maintained at 60 psi absolute. Electromagnetic delay-lines are used to obtain position information. Imaging studies have been performed using a Nuclear Chicago low-energy high-resolution collimator. The intrinsic resolution of the system was determined for 60 keV and 140 keV photons using bar phantoms, and was found to be 1 mm and 2 mm respectively. The Modulation Transfer Function for 140 keV is down to 70 percent response at 1.4 cycles per cm. Stopping-power is about 65 percent for 1-125 and 10 percent for Tc-99m. The distribution of thyroid hormones in the rat was clearly demonstrated. Picker thyroid phantoms filled with 1-125 and TC-99m were imaged with good detail. Preliminary 1-125 thyroid studies in humans have shown a promising potential. Other studies in rats have included liver/spleen imaging with Tc-99m-sulfur colloid and skeletal imaging with Tc-99m-polyphosphate. The excellent spatial resolution of the detector, together with the addition of higher efficiency collimators and operation at higher pressures realize a system with characteristics that are adequate for clinical use. These components are now being incorporated in a 30 x 30 cm2 MWPC.

What is the role of lay deliberation – if any – in health-care rationing, and administration more generally? Two potential answers are suggested by recent debates on the subject. The one, which I will call the technocratic answer, suggests that there is no distinctive role for lay participation once ordinary democratic politics have set the goals and priorities which reform should implement. Determining how best to achieve those ends, and then actually achieving them, this view suggests, is a matter for experts, armed with the best evidence available to them, both of the subject area involved, and of management and administrative excellence. By contrast, the second, deliberative, view holds that lay deliberation has an important role in the administration and execution of government policy, both because these latter inevitably have a political element which needs to reflect democratic norms and values, and because lay people are, themselves, a source of information, even of wisdom, that experts will want to use in fulfilling their professional responsibilities. Recent debates on the value of lay participation in healthcare provision can illuminate the strengths and weaknesses of both approaches, as can the experience of NICE. So, I will start by examining two articles by Albert Weale, which attempt to clarify the role that lay deliberation should have in healthcare, before turning to the dilemmas for both the technocratic and deliberative views which emerge from the experience of NICE. [First lines]

What is the role of lay deliberation – if any – in health-care rationing, and administration more generally? Two potential answers are suggested by recent debates on the subject. The one, which I will call the technocratic answer, suggests that there is no distinctive role for lay participation once ordinary democratic politics have set the goals and priorities which reform should implement. Determining how best to achieve those ends, and then actually achieving them, this view suggests, is a matter for experts, armed with the best evidence available to them, both of the subject area involved, and of management and administrative excellence. By contrast, the second, deliberative, view holds that lay deliberation has an important role in the administration and execution of government policy, both because these latter inevitably have a political element which needs to reflect democratic norms and values, and because lay people are, themselves, a source of information, even of wisdom, that experts will want to use in fulfilling their professional responsibilities. Recent debates on the value of lay participation in healthcare provision can illuminate the strengths and weaknesses of both approaches, as can the experience of NICE. So, I will start by examining two articles by Albert Weale, which attempt to clarify the role that lay deliberation should have in healthcare, before turning to the dilemmas for both the technocratic and deliberative views which emerge from the experience of NICE. [First lines]