NOTE The report of the Committee without its annexes appears as Official Records of the General Assembly, Sixty-third Session, Supplement No. 46. The designations employed and the presentation of material in this publication do not imply the expression of any opinion whatsoever on the part of the Secretariat of the United Nations concerning the legal status of any country, territory, city or area, or of its authorities, or concerning the delimitation of its frontiers or boundaries. The country names used in this document are, in most cases, those that were in use at the time the data were collected or the text prepared. In other cases, however, the names have been updated, where this was possible and appropriate, to reflect political changes. Scientific Annexes Annex A. Medical radiation exposures Annex B. Exposures of the public and workers from various sources of radiation INTROdUCTION 1. In the course of the research and development for and the application of atomic energy and nuclear technologies, a number of radiation accidents have occurred. Some of these accidents have resulted in significant health effects and occasionally in fatal outcomes. The application of technologies that make use of radiation is increasingly widespread around the world. Millions of people have occupations related to the use of radiation, and hundreds of millions of individuals benefit from these uses. Facilities using intense radiation sources for energy production and for purposes such as radiotherapy, sterilization of products, preservation of foodstuffs and gamma radiography require special care in the design and operation of equipment to avoid radiation injury to workers or to the public. Experience has shown that such technology is generally used safely, but on occasion controls have been circumvented and serious radiation accidents have ensued. 2. Reviews of radiation exposures from accidents have been presented in previous UNSCEAR reports. The last report containing an exclusive chapter on exposures from accidents was the UNSCEAR 1993 Report [U6]. 3. This annex is aimed at providing a sound basis for conclusions regarding the number of significant radiation accidents that have occurred, the corresponding levels of radiation exposures and numbers of deaths and injuries, and the general trends for various practices. Its conclusions are to be seen in the context of the Committee's overall evaluations of the levels and effects of exposure to ionizing radiation. 4. The Committee's evaluations of public, occupational and medical diagnostic exposures are mostly concerned with chronic exposures of …

sources and effects of ionizing radiation

An electrosurgical generator has an output power control system that causes the impedance of tissue to rise and fall in a cyclic pattern until the tissue is desiccated. The advantage of the power control system is that thermal spread and charring are reduced. In addition, the power control system offers improved performance for electrosurgical vessel sealing and tissue welding. The output power is applied cyclically by a control system with tissue impedance feedback. The impedance of the tissue follows the cyclic pattern of the output power several times, depending on the state of the tissue, until the tissue becomes fully desiccated. High power is applied to cause the tissue to reach a high impedance, and then the power is reduced to allow the impedance to fall. Thermal energy is allowed to dissipate during the low power cycle. The control system is adaptive to tissue in the sense that output power is modulated in response to the impedance of the tissue.

Electrosurgical generator with adaptive power control

A closed-loop control system is disclosed for use with an electrosurgical generator that generates electrosurgical energy. The closed loop control system includes a user interface for allowing a user to select at least one pre-surgical parameter, such as the type of surgical instrument operatively connected to the generator, the type of tissue and the desired surgical effect. A sensor module is also included for continually sensing at least one of electrical and physical properties proximate a surgical site and generating at least one signal relating thereto. The system also includes a control module for continually receiving the at least one selected pre-surgical parameter from the user interface and each of the signals from the sensor module, and processing each of the signals in accordance with the at least one pre-surgical parameter using at least one of a microprocessor, computer algorithm and a mapping. The control module generates at least one corresponding control signal relating to each signal from the sensor module, and relays the control signal to the electrosurgical generator for controlling the same. A method is also disclosed for performing an electrosurgical procedure at a surgical site on a patient. The method includes the steps of: applying at least one electrical pulse to the surgical site; continually sensing electrical and physical properties proximate the surgical site; and varying pulse parameters of individual pulses of the at least one pulse in accordance with the continually-sensed properties.

Method and system for controlling output of RF medical generator

An electrosurgical system is disclosed. The electrosurgical system includes an electrosurgical generator adapted to supply electrosurgical energy to tissue. The electrosurgical generator includes impedance sensing circuitry which measures impedance of tissue, a microprocessor configured to determine whether a tissue reaction has occurred as a function of a minimum impedance value and a predetermined rise in impedance, wherein tissue reaction corresponds to a boiling point of tissue fluid, and an electrosurgical instrument including at least one active electrode adapted to apply electrosurgical energy to tissue.

Vessel sealing system

An electrosurgical system is disclosed. The electrosurgical system includes an electrosurgical generator adapted to supply electrosurgical energy to tissue. The electrosurgical generator includes impedance sensing circuitry which measures impedance of tissue, a processor configured to determine whether a tissue reaction has occurred as a function of a minimum impedance value and a predetermined rise in impedance, wherein tissue reaction corresponds to a boiling point of tissue fluid, and an electrosurgical instrument including at least one active electrode adapted to apply electrosurgical energy to tissue. A tissue cooling period is provided to enhance operative outcomes.

System and method for tissue sealing

This invention is directed to an x-ray source comprising a housing (12), a power supply (12A), an elongated tubular probe (14), a target assembly (26), and a beam steering assembly (29). The housing encloses an electron beam source (22), and has elements for generating an electron beam along a beam path. The power supply (12A) is programmable to control the voltage, current and timing of an electron beam. The elongated tubular probe (14) extends along a central axis from the housing (12) about the beam path. The target assembly (26) extends along the central axis and is adapted for coupling to end of the probe (14) distal from the housing (12). The target assembly (26) includes target element (26A) positioned along the beam path, wherein the target element (26A) is adapted to emit x-rays in a predetermined spectral range in response to incident electrons. The beam steering assembly (29) includes a deflection element (30), a feedback network (31) and a deflection controller (144). The deflection element (30) deflects the beam from a nominal axis to a selected surface region on the target element (26) in response to a deflection control signal. The feedback network (31) includes deflection sensing elements for sensing the deflection of the beam and elements for generating a feedback signal representative thereof.

X-ray source with shaped radiation pattern

The present invention is directed to an x-ray source (10) for irradiating a surface defining a body cavity. The source comprises a housing (12), an elongated tubular probe (14), a target assembly (26), and an inflatable balloon (410). The housing (12) encloses an electron beam source (22) and includes elements (23) for generating an electron beam along a beam path. The tubular probe (14) extends along a central axis from the housing (12) about the beam path. The target assembly (26) extends along the central axis and is coupled to the probe distal end. The target assembly (26) includes a target element (26A, 26B) adapted to emit x-rays in response to electrons incident thereon. The probe tip assembly and associated control electronics include elements for positioning the target element in the beam path, and is substantially x-ray transparent. The balloon (410) affixed to the distal end is inflatable so as to be inflated to stretch the cavity to a shape, thus allowing a uniform delivery of dose of radiation to the surface defining a body cavity.

X-ray apparatus for applying a predetermined flux to an interior surface of a body cavity

A synchrocyclotron comprises a resonant circuit that includes electrodes having a gap therebetween across the magnetic field. An oscillating voltage input, having a variable amplitude and frequency determined by a programmable digital waveform generator generates an oscillating electric field across the gap. The synchrocyclotron can include a variable capacitor in circuit with the electrodes to vary the resonant frequency. The synchrocyclotron can further include an injection electrode and an extraction electrode having voltages controlled by the programmable digital waveform generator. The synchrocyclotron can further include a beam monitor. The synchrocyclotron can detect resonant conditions in the resonant circuit by measuring the voltage and or current in the resonant circuit, driven by the input voltage, and adjust the capacitance of the variable capacitor or the frequency of the input voltage to maintain the resonant conditions. The programmable waveform generator can adjust at least one of the oscillating voltage input, the voltage on the injection electrode and the voltage on the extraction electrode according to beam intensity and in response to changes in resonant conditions.

Programmable radio frequency waveform generator for a synchrocyclotron

A radiation applicator system is structured to be mounted to a radiation source for providing a predefined dose of radiation for treating a localized volume of tissue, such as the tissue surrounding the site of an excised tumor. The applicator system includes an applicator and, in some embodiments, an adapter. The adapter is formed for fixedly securing the applicator to a radiation source, such as a radiosurgery system which produces a predefined radiation dose profile with respect to a predefined location along its radiation producing probe. The applicator includes a shank and an end cap, wherein the end cap includes a substantially flat or convex treatment surface and is located at a distal end of the applicator shank. A proximate end of the applicator shank couples to the adapter. A distal end of the shank includes the end cap, which is adapted for engaging and preferably supporting the area to be treated with a predefined does of radiation. The applicator can include a low energy radiation filter inside of the applicator end cap to reduce undesirable low energy radiation emissions. A plurality of applicators having end caps of different sizes and shapes can be provided to accommodate treatment sites of various sizes and shapes. And, an adaptable applicator having a plurality of radiation positions can be provided to deliver a substantially cylindrical dose of radiation.

Apparatus for local radiation therapy

Interposing a programmable path length of one or more materials into a particle beam modulates scattering angle and beam range in a predetermined manner to create a predetermined spread out Bragg peak at a predetermined range. Materials can be “low Z” and “high Z” materials that include fluids. A charged particle beam scatterer/range modulator can comprise a fluid reservoir having opposing walls in a particle beam path and a drive to adjust the distance between the walls of the fluid reservoir under control by a programmable controller. A “high Z” and, independently, a “low Z” reservoir, arranged in series, can be used. When used for radiation treatment, the beam can be monitored by measuring beam intensity, and the programmable controller can adjust the distance between the opposing walls of the “high Z” reservoir and, independently, the distance between the opposing walls of the “low Z” reservoir according to a predetermined relationship to integral beam intensity. Beam scattering and modulation can be done continuously and dynamically during a treatment in order to deposit dose in a target volume in a predetermined three dimensional distribution.

A programmable particle scatterer for radiation therapy beam formation

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