Abstract: A particle beam therapy system that prevents dispersion of a charged particle beam, reduction of the energy thereof, and upsizing of the system and can accurately monitor the opening shape of a multileaf collimator so as to perform high-accuracy particle beam therapy. An image-capturing unit that takes an image of an outer end of a respective downstream side face of a leaf plate is provided for each row of leaves in such a way as to be situated at a position that is at an outer side of an irradiation field; and adjusted in such a way that a foot of a perpendicular line from a viewpoint, of the image capturing unit, to the downstream side face of a leaf plate, is situated at a position that is at an inner side of the position of the outer end when the leaf plate is maximally driven in the departing direction.

Abstract: In one embodiment, a system for aligning collimators in an imaging system includes a transmitter coupled to a first detector and configured to transmit a beam, and a receiver coupled to a second detector and configured to receive the beam transmitted from the first detector. The alignment system also includes a cart comprising an alignment device with the cart configured to hold at least two collimators. The system includes a control system configured to align the first and second detectors with the at least two collimators using the alignment device.

Abstract: A multi-leaf collimator for a radiotherapy apparatus comprises a plurality of elongate leaves mounted in a carriage, the carriage being mounted on a substrate, wherein the leaves are independently moveable relative to the carriage in a longitudinal direction, and the carriage is moveable in that direction relative to the substrate, and a control apparatus is arranged to receive a signal representing leaf positions relative to the substrate and to control the leaf positions relative to the carriage and the carriage positions relative to the substrate so as to achieve those leaf positions relative to the substrate. Most MLCs sense the current positions of the leaves relative to the substrate. The control apparatus can therefore compare the current leaf positions to the signaled leaf positions, and move the leaves and the carriage accordingly. A corresponding method is also disclosed.

Abstract: The objective of the present invention is to reduce the effect of the hysteresis of a scanning electromagnet so as to obtain a particle beam therapy system that realizes high-accuracy beam irradiation. There are included an irradiation management apparatus (32) that controls the scanning electromagnet (3), based on target irradiation position coordinates (Pi) of a charged particle beam (1b), and a position monitor (7) that measures measurement position coordinates (Ps) of the charged particle beam (1b).

Abstract: Embodiments of the present invention provide a multi-leaf collimator with a plurality of leaves and at least one motor for each leaf. The motor for each leaf has a lateral width which is equal to or narrower than the corresponding leaf, and in this way the motors can be arranged within the lateral extent of the leaf. A cut-out section in the leaf allows the motor to lie at least partially within the depth of the leaf, and in this way the drive mechanism and the multi-leaf collimator as a whole are made extremely compact. This in turn allows the leaves to be deeper than would otherwise be the case, increasing their efficacy in blocking radiation.

Abstract: Light from a light source is made to be reflected by a light source mirror and to pass through a variable collimator, an irradiation field shape shaped by the variable collimator is projected on a photographing screen by the light passed through the variable collimator, a projection portion of the photographing screen is photographed by a photographic device, and an image photographed by the photographic device is analyzed by an image processor.

Abstract: Multi-leaf collimators have a guide frame (1) with a plurality of metal plates (3) arranged in a displaceable fashion, by which each individual metal plate can be displaced by an electric motor (M), with the electric motor (M) being a rotary electromechanical motor (M), which operates according to the form-fit principle, with electromechanical actuators.

Abstract: Portions of the radiation source are obscured so that the radiation only passes through the specific areas of the patient related to the regions-of-interest to the doctor. Scattered radiation received by detector pixels that are obscured by direct-line of sight radiation are used to estimate the scattered radiation in the un-obscured portion, which can be used to increase the accuracy of the image taken through the un-obscured portion.

Abstract: A method of delivering radiation in a session includes delivering radiation towards a patient using a radiation system, wherein the radiation is delivered based at least in part on a physiological phase or a position of the patient, after the radiation is delivered, changing a configuration of the radiation system, wherein the act of changing the configuration is performed independent of at least one motion of the patient, and delivering additional radiation towards the patient after the configuration of the radiation system is changed, wherein the acts of delivering radiation and the act of changing the configuration are performed in response to a processor executing a treatment plan that prescribes a plurality of packages and a transition, the transition prescribing the act of changing the configuration of the radiation system when no radiation is being delivered by the radiation system.

Abstract: An X-ray diagnosis apparatus and a method for controlling an X-ray irradiation region that can appropriately narrow down an X-ray radiation aperture so as to fit a configuration of a region of interest during acquisition of X-ray projection data for reconstructing tomography images of an object. Based on a plurality of 2D image data acquired through a preliminarily X-ray imaging, a 3D region of interest is set up on an examination target portion having a strong directionality. X-ray imaging of the 3D region of interest is performed by sliding and rotating a plurality of aperture blades in an X-ray collimator based on a projected figure of the 3D region of interest along successively renewed imaging directions around a periphery of an object.

Abstract: An X-ray computer tomography apparatus includes an X-ray tube, a two-dimensional array type X-ray detector, a rotating mechanism, a pair of collimators, a collimator moving mechanism which separately moves the pair of collimators in a direction almost parallel to a rotation axis, a reconstruction processing unit which reconstructs image data in a reconstruction range, and a collimator control unit. The collimator control unit controls the position of each collimator in accordance with the distance between an X-ray central plane corresponding to a cone angle 0° and an end face of the reconstruction range. The collimator moving mechanism moves each of the pair of collimators in the range from the outermost position corresponding to the maximum cone angle to the innermost position offset from a position corresponding to a cone angle of nearly 0° to the opposite side.

Abstract: A radiotherapy apparatus comprises a means for producing a beam of radiation directed along a beam axis and having a width in first and second directions transverse to the beam axis, a multi-leaf collimator for selectively limiting the width of the beam in at least the first direction, a block collimator for selectively limiting the width of the beam in at least the second direction, the block collimator comprising a diaphragm moveable into and out of the beam and having a thickness in the direction of the beam axis that varies. The diaphragm can have a front edge of greater thickness than at least one region behind the front edge. It can also have a spine region extending from a rear part thereof towards the front edge that is greater thickness than at least one region displaced laterally with respect thereto. Together, these can cover the areas that will not be fully shadowed by a dynamically moving MLC.

Abstract: A shutter mechanism for collimating x-rays has two parallel drive shafts and two parallel guide shafts orthogonal to the drive shafts to define a rectangular aperture. Two flexible bands moving around a generally rectangular path about the aperture independently control the positions of each set of shutters. Two cams on the drive shafts control the positions of the flexible bands and shutters. A pair of transverse shutters made of an x-ray opaque material are held in sliding engagement between the drive shafts. One end of each transverse shutter is attached to the first flexible band adjacent to the drive shafts. Similarly, a pair of longitudinal shutters are held in sliding engagement between the drive shafts. One end of each longitudinal shutter is attached to the second flexible band adjacent to the guide shafts.

Abstract: A method is proposed for accurate and efficient modeling of head scatter phase space for treatments with dynamic jaws. Specifically, the method enables the efficient calculation of the head scatter phase space in case of a dynamic treatment where jaws and MLC leaves move during the delivery. In one embodiment, the invention can be used to calculate the head scatter contribution during final dose calculation of dynamic treatments. This novel method also enables an accurate calculation of the head scatter contribution from optimal fluence and from jaw positions without having to calculate the leaf sequence. In this embodiment, the invention can be used in optimization of large field IMRT treatments.

Abstract: A system and method are provided for a high resolution radiation treatment system which provide for projecting a field of radiation energy at targeted patient tissue. The system uses a multi-leaf collimator, which is positioned such that a significant clearance is provided between the multi-leaf collimator and the isocenter plane where the targeted tissue is located. The leaves of the multi-leaf collimator are designed to provide for high step resolution in the projected radiation energy shape. Additionally, an embodiment of the system and method herein can provide for a high step resolution in the projected radiation energy shape, and for a dose calculation matrix which has matrix units which coincide with the high step resolution in the projected radiation shape.

Abstract: Disclosed are methods, systems, and computer-product programs for increasing accuracy in cone-beam computed tomography (CBCT) by obscuring portions of the radiation source so that the radiation only passes through the specific areas of the patient related to the regions-of-interest to the doctor. The obscuring action causes less radiation scattering to occur in the patient's body, thereby reducing a major source of error in the image accuracy caused by scattered radiation. Scattered radiation received by detector pixels that are obscured by direct-line of sight radiation may be used to estimate the scattered radiation in the un-obscured portion, which can be used to further increase the accuracy of the image.

Abstract: A lamella collimator, in particular for a beam therapy appliance, is provided. The lamella collimator has a plurality of lamellae, which can be moved by a motor or motors in a movement direction in order to preset a countour of a beam path on an X-ray beam. Each lamella has a position measurement apparatus with a movable measurement element, which is attached directly to the respective lamella.

Abstract: To reduce X-ray exposure, an area of interest is selected in the image. The image of the selected area is updated frequently, comparable to rate of updates used today for the whole image. The rest of the image is updated at a significantly lower rate. Since the area of interest normally is a small part of the overall area, the total exposure is reduced significantly. A movable X-ray shield placed near the X-ray source blocks the radiation from areas outside the area of interest. The shield automatically retracts when the complete image is updated. The area of interest can be selected by the user or automatically selected based on activity in the image.

Abstract: An irradiation field limiting device includes a plurality of aperture leaves arranged in a thickness direction, a flexible linear member secured to a thick portion of the aperture leaf, a driver section which drives the linear member a specific amount, and the like. One end of the linear member is secured to an aperture leaf through a connection section tangentially to the outer arc of the aperture leaf, and the other end is connected with a slider provided in a driver section. The slider is connected with a driving source through a connection portion and moves along an axial direction of a drive shaft inserted into a base accompanying rotation of the drive shaft. A load accompanying the movement of the slider is directly transmitted to the linear member, and the aperture leaf is driven a specific amount due to the load.

Abstract: A stacked conformation radiotherapy system capable of homogenizing a radiation dose distribution, including an irradiation head and irradiation control means. The irradiation head projects a particle beam accelerated by an accelerator, toward an object to-be-irradiated, and it includes wobbler electromagnets for deflecting and scanning the particle beam. In carrying out stacked conformation radiotherapy by deflecting and scanning the particle beam, the irradiation control means subjects the wobbler electromagnets to magnetization controls so that the particle beam may depict a one-stroke revolving orbit which begins with a start point and returns to the start point, and it performs a control so that the irradiation period of the particle beam to be outputted from the irradiation head may become integral times a wobbler cycle which is required for the particle beam to make one revolution of the revolving orbit.

Abstract: Methods and apparatus are provided for planning and delivering radiation treatments by modalities which involve moving a radiation source along a trajectory relative to a subject while delivering radiation to the subject. In some embodiments the radiation source is moved continuously along the trajectory while in some embodiments the radiation source is moved intermittently. Some embodiments involve the optimization of the radiation delivery plan to meet various optimization goals while meeting a number of constraints. For each of a number of control points along a trajectory, a radiation delivery plan may comprise: a set of motion axes parameters, a set of beam shape parameters and a beam intensity.

Abstract: A multi-leaf collimator for a radiotherapy apparatus comprises at least one array of laterally-spaced elongate leaves, each leaf being driven by an associated motor connected to the leaf via a drive means so as to extend or retract the leaf in its longitudinal direction, the drive means comprising a sub-frame on which at least a subset of the motors are mounted, the sub-frame being mounted at a location spaced from the leaf array in a direction transverse to the lateral and longitudinal directions, and including a plurality of threaded drives disposed longitudinally, each being driven by a motor and being operatively connected to a leaf thereby to drive that leaf.

Abstract: Methods and apparatus are provided for planning and delivering radiation treatments by modalities which involve moving a radiation source along a trajectory relative to a subject while delivering radiation to the subject. In some embodiments the radiation source is moved continuously along the trajectory while in some embodiments the radiation source is moved intermittently. Some embodiments involve the optimization of the radiation delivery plan to meet various optimization goals while meeting a number of constraints. For each of a number of control points along a trajectory, a radiation delivery plan may comprise: a set of motion axes parameters, a set of beam shape parameters and a beam intensity.

Abstract: A light blocking device includes a deformable member deformable in a first direction and elongating in a second direction intersecting with the first direction, a plurality of light blocking plates arrayed along the second direction, each of the plurality of light blocking plates being connected to the deformable member, so that adjoining blocking plates of the plurality of light blocking plates partly overlap with each other, and a plurality of actuators arrayed along the second direction and which cause deformation of the deformable member. At least one of the plurality of light blocking plates is tiltable independently from the other light blocking plates in response to deformation of the deformable member. A light blocking region is thereby defined, based on edges of the plurality of light blocking plates.

Abstract: A radiation therapy apparatus has a multi-leaf collimator device having a pair of collimator components which respectively comprise a plurality of leaves arranged close to one another such that the leaves face one another across an irradiation axis, and configured to set a desired irradiation field by individually moving the leaves. One of the collimator components is arranged with an offset with respect to the other collimator component, within a range of a leaf-width.

Abstract: A collimator (1) primarily adapted for usage in a narrow scanned pencil beam radiation therapy system (100) includes adjacent pairs (5) of collimator leaves (10, 20). An inner portion (12) of a collimator leaf (10) facing the opposite leaf (20) of a pair (5) is made of a first material having high linear radiation attenuation. The remaining, major portion (14) of the leaf (10) is made of a second material having a comparatively low density, weight and radiation attenuation. The collimator (1) provides effective penumbra trimming of a radiation beam (60), while simultaneously protecting healthy tissue around a tumor in an irradiated patient (80) from the radiation. The new design results in a significantly more compact, lighter and less expensive collimator (1) as compared to traditional collimators.

Abstract: To reduce X-ray exposure, an area of interest is selected in the image. The image of the selected area is updated frequently, comparable to rate of updates used today for the whole image. The rest of the image is updated at a significantly lower rate. Since the area of interest normally is a small part of the overall area, the total exposure is reduced significantly. A movable X-ray shield placed near the X-ray source blocks the radiation from areas outside the area of interest. The shield automatically retracts when the complete image is updated. The area of interest can be selected by the user or automatically selected based on activity in the image.

Abstract: The invention relates to a multileaf collimator having a plurality of leaves mounted displaceably in an adjusting direction for establishing a contour of a beam path. Each displaceably mounted leaf is assigned at least one linear drive having at least one piezoelectric actuator for displacing the leaf in the adjusting direction. Because the piezoelectric actuator can be driven precisely, an improved radiation therapy can be achieved, particularly in the case of a radiation therapy device having a multileaf collimator of said kind, owing to precise establishing of the contour.

Abstract: A multi-leaf collimator for use in a radiotherapeutic apparatus comprises a plurality of elongate narrow leaves arranged side-by side and supported in a frame, the frame having upper and lower formations for guiding each leaf into which extend ridges on the upper and lower edges of the leaves, thereby to allow the leaves to move in a longitudinal direction, the upper and lower formations being aligned so that the sides of the leaves when fitted are at a non-zero angle to the beam direction, the upper and lower ridges being located on the upper and lower edges of the leaves so that a line joining their centres is at a non-zero angle to the sides of the leaf, tilted relative to the sides in a sense opposite to that of the beam. An outer face of the upper and/or lower ridges can be aligned with a side face of the leaf, for ease of manufacture.

Abstract: Radiation may be delivered in a number of segments shaped by a multi-leaf collimator. The collimator may be at different angles of rotation for the different segments. A method for planning radiation treatment involves obtaining an optimized set of collimator configurations by a direct aperture optimization method that takes into account collimator rotation. In some embodiments, area constraints are applied to the optimization. Methods according to embodiments of the invention can generate efficient treatment plans.

Abstract: The supporter supports a patient and is disposed movably along the body axis direction of said patient. The imaging part includes an X-ray-generator and an X-ray-detector. The X-ray-generator irradiates X-rays while rotating around the body axis. The X-ray-detector detects the X-rays that have permeated the patient. The collimator changes the irradiation field of the X-rays to be irradiated. The scan controller controls the movement of the supporter and the imaging part. The image-reconstructing part reconstructs image data based on the X-rays that have been detected by the X-ray detector. The movement amount-detector detects the amount of movement of the patient by the supporter. The collimator controller controls so as to change the size of the opening of the collimator based on the amount of movement.

Abstract: A shutter mechanism for collimating x-rays has two parallel drive shafts and two parallel guide shafts orthogonal to the drive shafts to define a rectangular aperture. Two flexible bands moving around a generally rectangular path about the aperture independently control the positions of each set of shutters. Two cams on the drive shafts control the positions of the flexible bands and shutters. A pair of transverse shutters made of an x-ray opaque material are held in sliding engagement between the drive shafts. One end of each transverse shutter is attached to the first flexible band adjacent to the drive shafts. Similarly, a pair of longitudinal shutters are held in sliding engagement between the drive shafts. One end of each longitudinal shutter is attached to the second flexible band adjacent to the guide shafts.

Abstract: A method of providing intensity modulated radiation therapy to a moving target is disclosed. The target moves periodically along a trajectory that is projected onto a multi-leaf collimator (MLC) plane. The MLC plane is divided into thin slices parallel to the movement of the target. The present invention optimizes the leaf sequence such that, within each slice, if a point receives radiation, all other points in that slice that receive the same amount or more fluence are also receiving radiation at the same time.

Abstract: Systems and methods of controlling the leaves of an aperture in radiation treatment are disclosed. In some embodiments, these systems and methods allow the delivery of different radiation fluences to different parts of a treatment volume in a single rotation of the aperture around the treatment volume. In some embodiments, different radiation fluences are achieved by radiating different parts of the treatment volume from opposing positions of the aperture around the treatment volume. In some embodiments, different radiation fluences are achieved by assigning different leaf pairs to radiate different parts of the treatment volume.

Abstract: A collimator (1) primarily adapted for usage in a narrow scanned pencil beam radiation therapy system (100) includes adjacent pairs (5) of collimator leaves (10, 20). An inner portion (12) of a collimator leaf (10) facing the opposite leaf (20) of a pair (5) is made of a first material having high linear radiation attenuation. The remaining, major portion (14) of the leaf (10) is made of a second material having a comparatively low density, weight and radiation attenuation. The collimator (1) provides effective penumbra trimming of a radiation beam (60), while simultaneously protecting healthy tissue around a tumor in an irradiated patient (80) from the radiation. The new design results in a significantly more compact, lighter and less expensive collimator (1) as compared to traditional collimators.

Abstract: A multi-leaf collimator that narrows a radiation field to a predetermined shape is provided with leaf blocks movable in the direction of the radiation field and having pattern images drawn along the direction of movement on a predetermined surface, and detection part acquiring an image of fixed-point via fixed-point observation in the direction of that predetermined surface and for detecting displacement of said leaf blocks based on the arranged locations of the pattern images existing in this image of fixed-point. Moreover, it is provided with detection part acquiring an image of fixed-point via fixed-point observation in the direction of that predetermined surface and for detecting the locations of the leaf blocks based on the arranged locations of the pattern images existing in this image of fixed-point.

Abstract: A multi-leaf collimator for a radiotherapy apparatus comprises at least one array of laterally-spaced elongate leaves, each leaf being driven by an associated motor connected to the leaf via a drive means so as to extend or retract the leaf in its longitudinal direction, the drive means comprising a sub-frame on which at least a subset of the motors are mounted, the sub-frame being mounted at a location spaced from the leaf array in a direction transverse to the lateral and longitudinal directions, and including a plurality of leadscrews disposed longitudinally, each being driven by a motor and being operatively connected to a leaf thereby to drive that leaf.

Abstract: A multi-leaf collimator comprises an elongate leaf moveable in a longitudinal direction, and having an associated toothed rack driven by a pinion, wherein the rack is carried on an elongate actuator section, having a transversely extending link section, the leaf being connected to the link section and thereby being spaced from the actuator section.

Abstract: A concentrated irradiation type radiotherapy apparatus comprises a radiation source, a multi-channeled radiation detector, a rotating mechanism, an image reconstruction unit, a multi-leaf collimator disposed between the radiation source and the subject to trim the radioactive rays in arbitrary shapes and including a plurality of first leaves and a plurality of second leaves each disposed to be individually movable forwards/backwards and each having a strip shape and in which types of the first leaves are different from those of the second leaves.

Abstract: Provision is made for a particle-beam treatment system in which, even during particle-beam irradiation, the shape of a multileaf collimator is monitored. The particle-beam treatment system, in which multi-layer conformal irradiation is performed while the setting of the shape of the multileaf collimator in an irradiation head is changed during particle-beam irradiation, is provided with an optical shape-monitoring unit mounted attachably and detachably in the snout portion at the downstream side of the multileaf collimator, the optical shape-monitoring unit having a shape-monitoring mirror, opposing the multileaf collimator, for monitoring the shape of the multileaf collimator; a video camera for shooting the multileaf-collimator shape reflected by the shape-monitoring mirror; and an image monitor for displaying an image of the video camera that shoots the shape of the multileaf collimator.

Abstract: A method and associated system 300 for delivering intensity-modulated radiation therapy (IMRT) uses variable feathering field splitting for intensity modulated fields of large size. A processor controls a beam-shaping device that splits the radiation beam into a plurality of radiation fields delivered to a patient. The processor in cooperation with the beam-shaping device implements a variable feathering method which includes providing an intensity matrix for the treatment of a patient, the intensity matrix having a plurality of rows and columns for spanning a prescribed radiation field including a prescribed field width. The prescribed width is compared to a maximum field width provided by the radiation treatment system.

Abstract: A multileaf collimator includes a first leaf block group including plural leaf blocks, a second leaf block group including plural leaf blocks arranged in the same direction as the first leaf block group and disposed opposite the leaf blocks of the first leaf block group, plural magnetic layers located on the respective leaf blocks of the first and second leaf block groups so as to be positioned on faces of the leaf blocks along a moving direction of the leaf blocks, plural magnetic sensors mounted on the respective leaf blocks and varying output signals when the respective leaf blocks are moved in an oncoming direction or a departing direction, and a control device controlling drive mechanisms according to the output signals delivered by the respective magnetic sensors so that spacing between the leaf blocks of the first and second leaf blocks is adjusted into a target configuration.

Abstract: A multileaf collimator is provided. The multileaf collimator may be used for radiotherapy. The multileaf collimator may include a plurality of leaves that are adjustable along a displacement direction for the absorption of rays propagated along a direction of radiation, with opposing leaves relative to the displacement direction with front faces oriented toward each other being displaceable into a closed position. The multileaf collimator may also include a shielding-intensifying planar shape, which in closed position, is characterized by an at least partial overlapping of the front faces relative to the direction of radiation.

Abstract: A multi-leaf collimator includes a number of independently adjustable leaves. Adjacent leaves overlap to prevent an incident beam of radiation from passing through a gap between them. The overlapping portions of the leaves are made of a first material, while the non-overlapping portions of the leaves are made of a second, different material.

Abstract: The present invention refers to a radiation system (1) comprising an excentric gantry (100) arranged in connection with multiple treatment rooms (61-68) separated by radiation-shielding separating members (71-78). A movable rotation head (120) is connected to the gantry (100) and is able to move between, and direct a radiation beam (110) into, the treatment rooms (61-68). A simulator head (200-1 to 200-8) is preferably arranged together with the radiation system so it can be used in each respective treatment room (61-68). In such a case, while a first subject (40-1) is being irradiated in a first room (61), a treatment set-up procedure, including correct positioning of subjects (40-2 to 40-8) and irradiation simulation, can simultaneously take place for the other subjects (40-2 to 40-8) in the other treatment rooms (62 to 68).

Abstract: A system and method are provided for a high resolution radiation treatment system which provide for projecting a field of radiation energy at targeted patient tissue. The system uses a multi-leaf collimator, which is positioned such that a significant clearance is provided between the multi-leaf collimator and the isocenter plane where the targeted tissue is located. The leaves of the multi-leaf collimator are designed to provide for high step resolution in the projected radiation energy shape. Additionally, an embodiment of the system and method herein can provide for a high step resolution in the projected radiation energy shape, and for a dose calculation matrix which has matrix units which coincide with the high step resolution in the projected radiation shape.

Abstract: A collimator for adjusting an X-ray beam includes: an up-and-down adjustment mechanism; a left-and-right adjustment mechanism, a supporting member; and an adjusting plate connected with the supporting member. The up-and-down adjustment mechanism comprises first rotating nuts, up-and-down moving leading screws threadedly connected with the first rotating nuts, and upper and lower sliding stops located in the supporting member. Each of the leading screws is connected with the upper and lower sliding stops to drive the upper and lower sliding stops, respectively, to vertically move. The left-and-right adjustment mechanism comprises second rotating nuts, horizontally moving leading screws connected with second rotating nuts, and left and right sliding stops located in the supporting member. Each of the horizontally moving leading screws are connected with the left and right sliding stops to drive the left and right sliding stops, respectively, to horizontally move.

Abstract: The invention relates to a collimator (1) for limiting a beam of high-energy radiation (2) which, starting from an essentially point-shaped radiation source (3), is directed onto an object (4) to be treated and which is used especially for stereotactic, conformal radiation therapy of tumors, wherein the collimator (1) has an iris diaphragm (5) as a beam-limiting means.

Abstract: The invention relates to a multileaf collimator having a plurality of leaves mounted displaceably in an adjusting direction for establishing a contour of a beam path. Each displaceably mounted leaf is assigned at least one linear drive having at least one piezoelectric actuator for displacing the leaf in the adjusting direction. Because the piezoelectric actuator can be driven precisely, an improved radiation therapy can be achieved, particularly in the case of a radiation therapy device having a multileaf collimator of said kind, owing to precise establishing of the contour.

Abstract: A method of delivering a radiation therapy treatment plan to a treatment area of a patient. The treatment plan is delivered using a radiation therapy system including a moveable support for supporting a patient, and a gantry moveable relative to the support. The gantry supports a radiation source, a set of jaws having a jaw width and a multi-leaf collimator for modulating the radiation during delivery of the treatment plan. The support is moved during delivery of the treatment plan to the treatment area, and the width of the jaws is dynamically adjusted during delivery of the treatment plan to the treatment area.