Abstract: A method of obtaining recommendations for lowered radiation dose for a type of radiological image, executed at least in part by a computer system, obtains at least one clinical image of at least one patient, taken under a baseline set of exposure conditions, as a basis image. Processing instructions related to image simulation under one or more reduced exposure conditions are obtained. The basis image is processed according to the processing instructions to generate a set of one or more simulation images, each simulation image representative of corresponding reduced exposure conditions. One or more simulation images are displayed to one or more diagnostic practitioners and an evaluation obtained from the one or more practitioners related to at least the quality of the one or more simulation images. At least one recommended reduced exposure condition is generated and electronically stored according to the practitioner evaluation.

Abstract: A method for determining a radiation treatment plan includes defining a part of a treatment using control points, defining dose calculation points, calculating dose in the dose calculation points, and changing a number of the dose calculation points. A method for determining a radiation treatment plan includes modeling a first part of a treatment plan using a fluence map, and modeling a second part of the treatment plan using a first machine parameter. A method for determining a radiation treatment plan includes determining a plurality of dose calculation points, determining a level of complexity of fluence for one of the plurality of dose calculation points, and converting a fluence map to one or more machine parameters for the one of the plurality of dose calculation points based on the determined level of complexity.

Abstract: Recent advances in treatment planning and in the apparatus able to deliver such plans has called for the dose rate, i.e. the instantaneous power output of the radiation source, to be varied with time. This presents a difficulty in that the checking systems must monitor a varying power level against a varying valid range. We therefore monitor, instead, the energy of the individual pulses that form the beam. Known checking systems average out many pulses to determine the recent average power output by checking an ionization chamber every 100 ms or so. By reducing that time to less than a few milliseconds, a single pulse can be captured. The usual manner of varying the output of a radiation source of this type is to vary the pulse repetition frequency (PRF) and therefore the measured power output will remain constant notwithstanding changes to the time-averaged power output, and can be compared to a standard.

Abstract: A radiotherapy apparatus includes an acceleration unit configured to generate a charged particle beam. A target is configured to generate a radiation when the charged particle beam is irradiated to the target. A sensor is configured to measure an electric current flowing through the target. A dosimeter is configured to measure a dose of the radiation. A control unit is configured to control the acceleration unit based on the measured electric current and the measured dose.

Abstract: A method is disclosed for producing a computed tomography display of tissue structures by applying a contrast medium. A contrast medium is applied to a patient for better visualization of the tissue structure to be examined. An X-ray scan is performed during the presence of the one contrast medium, and computed tomography 2- or 3-dimensional pictures are subsequently reconstructed from the X-ray scan data obtained. In the method, absorption data are measured for at least two different energy spectra, a computed tomography intermediate image is reconstructed per energy spectrum, and the distribution of the one contrast medium in the tissue is determined from the different energy-specific absorption behavior between tissue and contrast medium.

Abstract: An irradiation dose calculator calculates a pre-exposure-mode-required irradiation dose using the thickness of a breast which measured by a thickness measuring unit, as a parameter, and the irradiation time of a pre-exposure mode is controlled to apply a radiation to the breast in the pre-exposure mode. According to the dose of the radiation detected by a dose detecting sensor in the pre-exposure mode, the irradiation dose calculator calculates a main-exposure-mode-required irradiation dose, and the irradiation time of a main exposure mode is controlled to apply the radiation to the breast in the main exposure mode, thereby capturing a radiation image of the breast.

Abstract: The present invention provides an X-ray imaging apparatus and X-ray controlling method which allows appropriate X-ray control irrespective of the type and position of a subject. The X-ray controller device for controlling the X-ray emission condition of the X-ray emitter device based on the image information of a fluoroscopic image sets within one frame of the fluoroscopic image a plurality of narrow regions and one single wide region encompassing these narrow regions, selects as the formal region, from within the plurality of narrow regions and the wide region, the region in which the subject is assumed to be present, or selects as the formal region the wide region if there is no region in which the subject is assumed to be present, then control the X-ray emission condition of the X-ray emitter device based on the image information in the formal region.

Abstract: A mammography apparatus capable of obtaining a breast image having an optimum density with reduced burden on the subject. The apparatus includes a radiation irradiation section and an object table connected to an arm such that they face each other, and the breast compressed onto the object table using a compression paddle is imaged by rotating the arm by an arm rotation means according to the imaging direction. In the apparatus, the size of the breast is detected, and the position of a dose detector is moved along the side of the object table facing the chestwall of the subject according to the detected size of the breast and the angle of rotation of the arm when rotated by the arm rotation means.

Abstract: In three-dimensional X-ray imaging, with C-arm systems, scan setup has to be performed manually under fluoroscopic control. According to an exemplary embodiment of the present invention, a scan planning system for planning a data acquisition process is provided, which is adapted to predict a field of view to be reconstructed and an image quality in the field of view with respect to the actual three-dimensional scan parameter set and previously acquired images or other information. The scan planning system may be accomplished by a stand control unit.

Abstract: Method and systems are disclosed for radiating a moving target inside a heart. The method includes acquiring sequential volumetric representations of an area of the heart and defining a target tissue region and/or a radiation sensitive structure region in 3D for a first of the representations. The target tissue region and/or radiation sensitive structure region are identified for another of the representations by an analysis of the area of the heart from the first representation and the other representation. Radiation beams to the target tissue region are fired in response to the identified target tissue region and/or radiation sensitive structure region from the other representation.

Abstract: A method of determining a patient dose during or prior to therapy from an external radiation beam includes determining a dose distribution from a patient plan as delivered in a QA phantom at each appropriate beam angle and comparing the dose distribution determined from measurements or calculations to a corresponding treatment planning system (TPS) dose modeled distribution in the QA phantom and providing a correction distribution when applied to the TPS dose modeled distribution results in the dose distribution determined. The correction distribution may optionally be interpolated to non-measured points for each beam angle and geometrically projected toward the source of radiation through a volume that equals a dose volume of the TPS for a patient beam for each beam angle. The correction distribution is applied to the TPS patient dose volume for each beam angle for providing a corrected dose distribution in the patient.

Abstract: A general imaging scheme is proposed for applications of CBCT. The approach provides a superior CBCT image quality by effective scatter correction and noise reduction. Specifically, in its implementation of CBCT imaging for radiation therapy, the proposed approach achieves an accurate patient setup using a partially blocked CBCT with a significantly reduced radiation dose. The image quality improvement due to the proposed scatter correction and noise reduction also makes CBCT-based dose calculation a viable solution to adaptive treatment planning.

Abstract: A radiotherapeutic apparatus comprises a source able to emit a beam of therapeutic radiation along a beam axis, a multi-leaf collimator arranged to collimate the beam to a desired shape, wherein the source is rotateable about a rotation axis that is substantially orthogonal and intersects with the beam axis thereby to describe an arc around that axis, and further comprises a control means able to control the dose/time rate of the source, the rotation speed of the source, and the multi-leaf collimator position. The control means is arranged to receive a treatment plan in which the arc is divided into a plurality of notional arc-segments, and specifying the total dose for the arc-segment and a start and end MLC position.

Abstract: A breast imaging system leverages the combined strengths of two-dimensional and three-dimensional imaging to provide a breast cancer screening with improved sensitivity, specificity and patient dosing. A tomosynthesis system supports the acquisition of three-dimensional images at a dosage lower than that used to acquire a two-dimensional image. The low-dose three-dimensional image may be used for mass detection, while the two-dimensional image may be used for calcification detection. Obtaining tomosynthesis data at low dose provides a number of advantages in addition to mass detection including the reduction in scan time and wear and tear on the x-ray tube. Such an arrangement provides a breast cancer screening system with high sensitivity and specificity and reduced patient dosing.

Abstract: An X-ray image apparatus (100) for imaging an object under examination (101), the X-ray image apparatus (100) comprising an X-ray source (103) adapted for generating an X-ray beam (104) to be directed to the object under examination (101), a dose measuring device (106) for measuring an X-ray dose of the X-ray beam (104) in at least one selected (110, 112) of a plurality of measurement fields (108 to 114) after transmission of the X-ray beam (104) through the object under examination (102), and an illumination device (115) for illuminating a surface portion (117) of the object under examination (101) which surface portion (117) is indicative of the at least one selected (110, 112) of the plurality of measurement fields (108 to 114).

Abstract: A radiation image capturing apparatus is capable of setting highly accurately an optimum dose of radiation to be applied to an area of interest of a subject. A solid-state detector acquires radiation image information of a breast from a radiation that has been emitted from a radiation source and passed through the breast. A detected value is compared with a predetermined threshold value used to identify the area of interest, and a detection corrective value is calculated based on detected values from the region including the area of interest and detected values from the area of interest. Based on the detection corrective value, an AEC corrector corrects a radiation dose detected by an identified one of AEC sensors, and an exposure control condition depending on the area of interest to be imaged of the subject is determined based on the corrected radiation dose.

Abstract: A controller for controlling the dose rate (exposure kV tube voltage) of an X-ray system, in which the actual dose rate is measured and compared with an optimal dose rate, and the resultant difference value is fed to a module (20) (e.g. a PID module) which is arranged to adjust the dose rate (by adjusting the exposure kV voltage) so as to minimize the difference value. No preset parameters are required to be entered prior to exposure.

Abstract: A photo timer includes an X-ray dose detector for detecting the dose of X-rays irradiated from an X-ray irradiation apparatus, a stop-signal output means for outputting a stop signal to stop irradiation of the X-rays from the X-ray irradiation apparatus when the detected X-ray dose exceeds a predetermined value, and a communication means for sending the stop signal to the X-ray irradiation apparatus by wireless means. A radiographic apparatus includes the photo timer, a solid state detector for recording image information by irradiation of X-rays which carry the image information and outputting an image signal representing the image information, and a communication means for sending the image signal to a photography control means by wireless means. Further, cables are not required to connect the X-radiographic apparatus (photo timer) and the X-ray irradiation apparatus, or the X-radiographic apparatus and the photography control means.

Abstract: A shielding system which can be applied to a radiation therapy system and/or diagnostic system includes a scatter shield configured to absorb scattered radiation from a patient, a source shield to absorb unwanted radiation from the radiation source, and an anti-reflective beam dump configured to absorb radiation that is transmitted through a patient. The radiation therapy and/or diagnostic system includes a radiation source positioned in the source shield, and a patient support positioned in the scatter shield.

Abstract: An X-ray CT apparatus that transmits X-rays toward a subject on the basis of a set scan condition and reconstructs images from detected X-rays that passes through the subject, including a scan plan setting unit configured to set the scan condition, a reference dose storage unit configured to store reference dose information, including an relation between an attribute information about a plurality of kinds of subjects and reference doses to be referenced for an exposure dose, and an exposure dose calculation unit configured to calculate the exposure dose corresponding to the set scan condition in accordance with the timing of setting of the scan condition.

Abstract: An x-ray receiver for an x-ray apparatus is disclosed. In at least one embodiment, the x-ray receiver includes a detector holding apparatus designed such that it can be connected to a detector for receiving x-rays. The x-ray receiver also includes an x-ray grid, connected to the detector holding apparatus, for reducing scattered x-rays, which is designed and arranged to attenuate scattered x-rays with at least one predetermined directional component parallel to a detector plane. In at least one embodiment, the x-ray receiver includes at least one sensor for detecting x-rays that is designed and arranged to detect x-rays striking the detector and, as a function of the detected x-rays, to generate an irradiation signal that represents an x-ray dose or x-ray intensity of the detected x-rays.

Abstract: The present invention relates to a method and arrangement for controlling exposure in an e-ray apparatus, for depicting an object. The apparatus comprises an x-ray source and a displaceable detector being arranged to move with a controllable speed across an image exposure area. The method comprises the step of: acquiring a signal relating to photons incident on at least a part of the detector, comparing said acquired signal with a target value, and controlling the speed of detector, displacement with respect to the result of the comparison.

Abstract: An apparatus for positioning standing persons to produce X-ray shots comprises a movable frame on which a vertically displaceable standing area is arranged. The standing area has a holding apparatus connected to it which the person can hold onto. To produce optimum positioning in terms of weight too, the standing area has weighing apparatus arranged on it for determining the weight of the person, preferably using two independent weighing sensors for each foot of the person. A description is also given of an apparatus and a method for producing a digital X-ray image, where exposure parameters are calculated on the basis of person-related data and then a plurality of shots are taken sequentially and are subsequently used to compile an overall image.

Abstract: A method for providing a reduced exposure value for radiographic imaging obtains a set of flat-field images at two or more exposure values and measures the noise power spectra using the flat field images. At least one noise table is generated according to interpolated noise power spectra for a set of predetermined exposure values. Values from the at least one noise table are applied to a clinical image to form a reduced exposure simulation image. A noise mask is generated according to at least one noise table and the exposure values of the reduced exposure simulation image and added to the reduced exposure simulation image. The reduced exposure simulation image is assessed to generate a desired dose reduction factor.

Abstract: The present invention relates to a radiation image capturing system. A radiation detector of a radiation detecting cassette detects a radiation that has passed through a patient, and an accumulated exposed radiation dose calculator calculates an accumulated exposed radiation dose by accumulating radiation image information detected by the radiation detector, at every image capturing. The calculated accumulated exposed radiation dose is transmitted, together with cassette ID information, to a console. In the console, a status determining unit compares the accumulated exposed radiation dose with an allowable accumulated exposed radiation dose for the radiation detecting cassette to determine the status of the radiation detecting cassette, and issues a warning based on the determined status.

Abstract: In order to overcome or at least mitigate difficulties in compensating for movement of the target, for example a tumour during radiotherapy, a dosimetry apparatus and method embodying the present invention employ a dosimeter having at least one radiation detector and at least one magnetic position sensor located a predetermined distance apart. Radiation level readings from the radiation detector and position readings from the position sensor are monitored and correlated, conveniently according to time, to obtain the position of the radiation detector when a particular radiation level was detected.

Abstract: The field of the invention is diagnostic and interventional radiology and the invention is a dose indicator for use in a system for performing radiological procedures using ionizing radiation, for indicating a dose of radiation received in an area of skin by a subject during the radiological procedure, in which a zone is displayed which is representative of the extent of the area of skin exposed, and in which is a value of dose is displayed which is associated with the zone. The value of dose is representative of the dose of radiation received in the area of skin exposed during the procedure. The display is easily and quickly understood allowing the user of the system to swiftly understand the skin dose accrued by the patient. The use of zones provides an intuitive display.

Abstract: An X-ray imaging apparatus includes an estimation unit (208) that estimates a cumulative exposure dose of X-rays irradiated onto an object, a remaining exposure tolerance dose calculation unit (213) that calculates a remaining exposure tolerance dose using a difference between a tolerated maximum exposure dose and the cumulative exposure dose, an X-ray irradiation tolerance period calculation unit (206) that calculates an X-ray irradiation tolerance period using a difference between a predetermined scheduled X-ray irradiation period and an actual irradiation period of X-rays irradiated onto the object, an X-ray irradiation reference dose calculation unit (212) that calculates an X-ray irradiation reference dose per unit time that will form a basis of X-ray irradiation based on the remaining exposure tolerance dose and the X-ray irradiation tolerance period, and a control unit (211) that controls X-ray irradiation onto the object by setting an X-ray irradiation dose per unit time within the X-ray irradiation t

Abstract: The invention relates to an X-ray diagnostic device for digital radiography with a high voltage generator (1), an X-ray tube (2) for generating an X-ray bundle (3), an image converter (5 to 9) arranged in the radiation path behind a patient (4), and a control device (15), which is fed one of the signals corresponding to the dose in question, whereby the image converter (5 to 9) and a the image converter (5 to 9) whereby the image converter (5 to 9) comprises an Iontomat chamber (5) connected to the control device (15) and a circuit arrangement (12) for automatic voltage regulation (AVR) without idle time.

Abstract: With a method for generating an x-ray image sequence for supporting an intervention on a patient with a catheter or guide wire for instance, automatic recognition of the catheter is carried out with recorded x-ray images using a computer system. The x-ray image recording parameters are changed on the basis of the determined quality of the imaging of the object, with the x-ray device preferably being automatically activated with the changed x-ray image recording parameters, to record x-ray images. The doctor can therefore concentrate on the actual intervention and does not have to worry about operating the x-ray device.

Abstract: A system and method are disclosed for computing a radiation dose delivered to a patient during a computed tomography (CT) scan of the patient. The CT image dataset generated during the scan of the patient, and one or more parameters relating to a x-ray source are used to calculate the radiation dose delivered to the patient as a function of the CT image data set and the one or more parameters of the x-ray source. The radiation dose is generally found by calculating a primary x-ray dose distribution and scattered x-ray dose distribution from the CT image dataset and taking the sum of the primary x-ray dose distribution and scattered x-ray dose distribution.

Abstract: An imaging device with a radiographic source and with at least one image receiver, with an imaging detector able to be assigned to the image receiver or to each image receiver and with the image receiver or each image receiver including a sensor for registration of the imaging detector, with a signal output of the sensor being connected directly in a circuit to a signal input of the radiographic source.

Abstract: A radiation therapy planning procedure and device provides a model-based segmentation of co-registered anatomical and functional imaging information to provide a more precise radiation therapy plan. The biology-based segmentation models the imaging information to produce a parametric map, which is then clustered into regions of similar radiation sensitivity or other biological parameters relevant for treatment definition. Each clustered region is prescribed its own radiation prescription dose.

Abstract: With a method for controlling the dose or dose rate when recording x-ray images by means of a detector comprising image elements which record a plurality of dose data values, an actual value is determined for the dose or dose rate from the totality of the data values recorded by the image elements of a predetermined image segment, said actual value being compared with a predetermined target value in order to control the dose or dose rate when recording a further x-ray image. In accordance with the invention, the actual value is determined such that on the basis of a frequency distribution of the dose data values of the image elements assigned to the dominant, a p-quantile is determined, and that the dose data value assigned to the p-quantile is used to determine the actual value.

Abstract: A radiation application time upper limit calculator calculates a radiation application time upper limit based on a subject thickness, as measured by a subject thickness measuring unit. While an X-ray tube is controlled according to exposure conditions that have been set in order to apply a radiation X to a breast to capture a radiation image thereof, an X-ray tube controller compares the applied radiation time with the radiation application time upper limit. If the applied radiation time exceeds the radiation application time upper limit, then application of radiation to the subject is interrupted, so as to prevent an inappropriate radiation dosage from being applied to an X-ray detector.

Abstract: In a method and x-ray apparatus for exposure of a patient who can be placed at a variable distance relative to an x-ray source, the dose rate emitted by the x-ray source is reduced given reduction of the distance and/or increased given increase of the distance.

Abstract: The invention relates to an automatic exposure control of an imaging implemented by electromagnetic radiation, in particular to priorizing and selecting several automatic exposure signals in connection with mammography imaging, to be used in such a way that areas having darkened too little would not be left into the image to be formed, at least not in the area of the breast tissue. A selection process of the signals makes up an essential part of the invention, in which signals are selected for the basis of control of imaging parameters according to signal values, and possibly also according to the physical location of the signal sources, on the grounds of the selection criteria according to the invention.

Abstract: Before a radiation image is captured, a rate of change of an output signal from an integrator, during a given period of time after the integrator has been reset and until a radiation start signal is supplied, is calculated. An offset voltage signal at a desired time is calculated using the rate of change, and is supplied to a voltage correcting circuit. An output signal from the integrator after a radiation X has started being applied to a subject is corrected based on the calculated offset voltage signal. The corrected output signal from the integrator is supplied to an X-ray tube controller for controlling application of the radiation X to the subject.

Abstract: According to at least one embodiment of the invention, the measurement of an image dose is performed in the flat X-ray detector itself. The flat X-ray detector, in at least one embodiment, has a scintillator that converts the incident X-rays into light. The actual image signals are then generated in a light converting layer. A portion of the light generated by the scintillator is branched off, with the use of fiber optic elements, to at least one photocounter. The fraction of the branched off light is fixed, that is to say a measured value determined by the photocounter is proportional to the image dose. It is thereby possible to determine the image dose provisionally during image recording, and to intervene for control purposes by, if appropriate, changing the image recording period (beam time on X-ray tube) and the operating voltage of an X-ray tube during the image recording.

Abstract: An X-ray therapy system with equipment for reducing risk that the radiation applied to a patient is other than what is intended. A radiation check is made in which a signal indicative of the radiation to be applied is compared with a reference signal, and/or a configuration check is made using sensors to automatically sense the applicator being used to apply the radiation to the patient.

Abstract: A dosimeter is provided on or adjacent to a circuit board deployed in a radiation environment. The dosimeter may be read or output a value or values indicating radiation dosage over a period of time. The radiation dosage associated with the circuit board may be used for determining disposition of the circuit board, such as whether to reuse the circuit board as a spare part or otherwise dispose of the circuit board.

Abstract: A mobile X-ray detector system is disclosed including a mobile X-ray detector and a mobile dosimeter arranged on the X-ray detector, at least during operation. Furthermore, an X-ray facility is disclosed for cooperating with such an X-ray detector system, an X-ray system including such an X-ray facility, and a corresponding X-ray detector system, as well as a mobile dosimeter and a mobile X-ray detector for constructing such an X-ray detector system.

Abstract: A radiation image capturing apparatus is capable of setting highly accurately an optimum dose of radiation to be applied to an area of interest of a subject. A solid-state detector acquires radiation image information of a breast from a radiation that has been emitted from a radiation source and passed through the breast. A detected value is compared with a predetermined threshold value used to identify the area of interest, and a detection corrective value is calculated based on detected values from the region including the area of interest and detected values from the area of interest. Based on the detection corrective value, an AEC corrector corrects a radiation dose detected by an identified one of AEC sensors, and an exposure control condition depending on the area of interest to be imaged of the subject is determined based on the corrected radiation dose.

Abstract: The invention relates to a radiation detector apparatus (10) with an array (12) of detector pixels. Each pixel (20) of the detector comprises a photogate electrode (21) under which electrical charges produced by incident radiation (v, X) are collected. The change of these charges gives rise to displacement currents in photogate lines (32) connected to the photogate electrodes (21) which may be monitored by current sensors (40). Thus the charges collected by all photogate electrodes (21) connected to a photogate line (32) can be measured during an ongoing exposure, allowing for advanced dose control methods of the illumination.

Abstract: The invention relates to a method of radiotherapy of a malignant neoplasm, defining a location of a malignant neoplasm, and a device for implementation the method, consisting in elimination of the influence of the factor owing to usage of common X-ray beams both for identification of the tissue structure and location of the malignant site, and for rendering the ray action on the malignant site.

Abstract: A method and a suitable x-ray device (1) for carrying out the method are specified for effective and operationally simplified user-specific optimization of a parameter configuration (K) of an x-ray device (1), said configuration comprising at least one recording parameter (U,I,t,F). It is accordingly provided that a user (20) is shown a plurality of reference images (V,V1) for different reference parameter sets (PV) from a reference memory (21) in which are stored a large number of reference images (V,V0) each with an associated reference parameter set (PV), that for each reference image (V,V1) shown the user (20) submits an assessment (BM) of the image quality (V,V1), and that on the basis of the submitted assessments (BM) an optimized parameter configuration (K) is created from the reference parameter sets (PV) of the reference images (V,V1) shown.

Abstract: An X-ray examination apparatus arranged with control means to control a dose of an X-ray source in accordance with a grey-level distribution of an acquired image. The X-ray examination apparatus (1) comprises the X-ray unit (2) arranged to communicate data to the control and processing means (10). The X-ray unit (2) is arranged to generate a beam of X-rays (1f) propagating from an X-ray source (1c). The X-ray source (1c) together with the X-ray detector (1b)can be rotated about an acquisition volume V about a rotation axis (1e). The control and processing means (10) comprises an image processing means (3), which is arranged to compress the first image into the second image. Upon a compression of the first image with the grey-level compression function the resulting second image is forwarded to the control means (6), which is arranged to compute an average pixel value of the second image and to compare it with a pre-stored reference value.

Abstract: Methods and systems for controlling exposure for medical imaging devices is provided. The method includes varying the exposure level of X-rays within an X-ray imaging system to generate a plurality of images having different exposure levels and combining the plurality of images in an additive process to form a single X-ray image.

Abstract: A radiation application time upper limit calculator calculates a radiation application time upper limit based on a subject thickness, as measured by a subject thickness measuring unit. While an X-ray tube is controlled according to exposure conditions that have been set in order to apply a radiation X to a breast to capture a radiation image thereof, an X-ray tube controller compares the applied radiation time with the radiation application time upper limit. If the applied radiation time exceeds the radiation application time upper limit, then application of radiation to the subject is interrupted, so as to prevent an inappropriate radiation dosage from being applied to an X-ray detector.

Abstract: The invention relates to a method for generating an x-ray image. In order to minimize the dose rate the invention proposes that the body to be examined is first irradiated with a first dose rate. On the basis of first signals measured during this process, a second dose rate required for generating the x-ray image is calculated and parameters are determined which are used to subsequently operate the x-ray tube automatically in order to deliver the second dose rate.