An example particle therapy system may include: a synchrocyclotron to produce a particle beam; a scanner to move the particle beam in one or more dimensions relative to an irradiation target; and an energy degrader that is between the scanner and the irradiation target. The energy degrader may include multiple plates that are movable relative to a path of the particle beam, with the multiple plates each being controllable to move while in the path of the particle beam and during movement of the particle beam. An aperture may be between the energy degrader and the irradiation target. The aperture being may be to trim the particle beam prior to the particle beam reaching the irradiation target.

A cryogenic magnet structure includes at least two superconducting coils that are substantially symmetric about a central axis and on opposite sides of a median plane. At least one cryostat contains the superconducting coils; and a magnetic yoke surrounds the superconducting coils and contains at least a portion of a chamber, wherein the median plane extends through the chamber. At least one integral maintenance boot assembly is in thermal contact with the superconducting coils and is configured to preserve a sealed vacuum in the cryostat; and a cryogenic refrigerator is in thermal contact with the maintenance boot assembly and is configured to cool the superconducting coils below their critical superconducting temperatures and is configured for removal from thermal contact with the integral maintenance boot assembly without breaking the sealed vacuum in the cryostat.

Radiation treatment planning includes determining a number of beams to be directed into a target, determining directions (e.g., gantry angles) for the beams, and determining an energy level for each of the beams. The number of beams, the directions of the beams, and the energy levels are determined such that the beams do not overlap outside the target and the prescribed dose will be delivered across the entire target.

A dose distribution calculation device of the invention is characterized by including: a beam information storing unit (a measured energy storing unit, a measured electric-charge storing unit, a measured beam-central axis storing unit), in which, when particle beam information of a particle beam generated by a particle beam therapy system is measured by a measuring device in confirmative radiation in which the particle beam is radiated to a phantom as a substitute for a treatment target, the thus-measured particle beam information is stored; and a total dose calculation unit for calculating a radiation dose distribution (a total dose distribution) on the basis of the measured particle beam information (a measured energy, a measured beam quantity (a measured number of electric charges), a measured position of beam central axis).

Systems and methods for radiation treatment planning in proton therapy using pencil beam scanning (PBS) are described. More particularly, the systems and methods described in the present disclosure related to quantifying the output from a proton therapy system implementing PBS. The systems and methods described in the present disclosure can therefore be implemented when commissioning a new proton therapy system, or when performing quality assurance (QA) on a proton therapy system. A spot delivery pattern that includes a spiral out pattern is used for beam delivery. A number of control points along the spot delivery pattern define a beam pause time during which delivery of the proton beam is paused. Radiation measurements are obtained at the control points and at the end of the spot delivery pattern, and these radiation measurements are used to compute field size factors for field sized associated with the segments of the spot delivery pattern.

An example particle therapy system includes a particle accelerator to output a particle beam having a spot size; a scanning system for the particle accelerator to scan the particle beam in two dimensions across at least part of a treatment area of an irradiation target; and an adaptive aperture between the scanning system and the irradiation target. The adaptive aperture includes structures that are movable relative to the irradiation target to approximate a shape to trim part of the treatment area. The part of the treatment area has a size that is based on an area of the spot size.

According to a first aspect, it is presented a method for determining a treatment plan comprising a distribution of spots for use with ion beam therapy for providing the spots in a target volume. The method comprises the steps of: selecting energy layers to be used in the treatment plan; determining a number of spot sizes to use; generating, for each energy layer, one copy of the energy layer for each spot size to use and populating each copy with spots of the spot size for that copy; optimizing spots of all copies of all energy layers, by repeatedly varying a weight of at least a subset of the spots and calculating an effect on a performance measurement, wherein the performance measurement is calculated by combining a plurality of evaluation criteria, comprising a first criterion related to total treatment time and a second criterion related to a desired dose distribution.

A method of optimizing a radiation treatment plan of ion treatment, in which the optimization procedure is interrupted, some but not all low-weight spots are discarded and the optimization procedure is resumed with a reduced set of spots. The weight of one or more remaining spots may be increased before resuming the optimization procedure, for example by adding the spot weight of one or more of the discarded spots to one or more of the remaining spots.

A method is proposed for evaluating the robustness of a radiotherapy treatment plan. The method comprises, defining a number of scenarios, each comprising one or more errors for each fraction of the plan, including interfractional and/or intrafractional errors, and calculating a dose distribution resulting from the scenario; The robustness of the plan is then evaluated based at least one of the following i. the probability of fulfilling a set of clinical goals estimated as the clinical goal fulfillment over the scenarios ii. the range of DVH values over the scenarios iii. dose statistics for dose distributions defined as voxel-wise aggregates over the scenario doses

A particle therapy system includes a particle accelerator for generating a charged particle beam, a beam delivery device, a beam transport system for transporting the beam from the particle accelerator to the beam delivery device, and a supporting device for supporting a subject. The beam delivery device is rotatable around the target and with respect to the supporting device, so as to be able to deliver the beam to the target according to a plurality of irradiation angles. The system also includes a controller configured to make the beam delivery device rotate at a beam-on speed and meanwhile to irradiate the target with the beam. The controller is configured to make the beam delivery device rotate at at least two different beam-on speeds with respect to the supporting device, a first speed corresponding to a first irradiation angle and a second speed corresponding to a second irradiation angle.