Varian Medical Systems International Ag

Varian Medical Systems, Inc.

Sami P Siljamaki

Janne Ilmari Nord

Laura Kristiina Korhonen

Tuomas Erik Torsti

Esa Kuusela

Janne Iimari Nord

Stanley Mansfield

Juha Kauppinen

Michelle Marie Svatos

Christopher Boylan

Marko Rusanen

Jarmo Ruohonen

Viljo Petaja

Ari Harju

Katja Marika Pesola

Petri Hiltunen

Petri Kokkonen

Antti Karjalainen

Timo Ikonen

Corey E Zankowski

A method of calculating radiation dose includes dosimetric projection of a collimator geometry. The method includes defining a three-dimensional (3D) geometry of a collimating device which defines an aperture configured to allow a radiation beam passing through, projecting the collimating device along the radiation beam into a two-dimensional (2D) geometry in a plane, calculating dosimetric opacity values of the collimating device at locations adjacent to the aperture based on the 3D geometry of the collimating device, and calculating transport of the radiation beam through the collimating device based on the 2D geometry projected in the plane and using the dosimetric opacity values of the collimating device at the locations adjacent to the aperture.

Dosimetric projection of collimator geometry

A method of determining a treatment parameter, includes determining an accumulated dose at a target region that undergoes motion, determining an accumulated dose at a critical region, and determining the treatment parameter based on the determined accumulated dose at the target region and the determined accumulated dose at the critical region, wherein the act of determining the treatment parameter is performed during a treatment session. A method of determining a treatment parameter, includes tracking a position of a target, delivering radiation to the target based on the tracked position, and compensating for an inaccuracy of the tracked position by using information regarding a delivered dose to determine a treatment parameter for a next beam delivery.

Real time treatment parameter algorithm for moving targets

To overcome the difficulties inherent in conventional proton therapy systems, new techniques are described herein for synchronizing the application of proton radiation with the periodic movement of a target area. In an embodiment, a method is provided that combines multiple rescans of a spot scanning proton beam while monitoring the periodic motion of the target area, and aligning the applications of the proton beam with parameters of the periodic motion. For example, the direction(s) and frequency of the periodic motion may be monitored, and the timing, dose rate, and/or scanning direction and spot sequence of the beam can be adjusted to align with phases in the periodic motion.

Beam limiting device for intensity modulated proton therapy

Systems and methods for developing a treatment plan for irradiating a treatment volume within a patient are disclosed. In accordance with the present invention, control points used to calculate a dose of radiation delivered to the treatment volume may be combined to result in a smaller number of control points. The smaller number of control points may allow more efficient calculation of dose distributions resulting in a treatment plan that can be delivered to the patient earlier or may allow additional iterations of treatment plan optimization resulting in a more accurate dose distribution being delivered to the patient.

Dose calculation method for multiple fields

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.

Method for calculating head scatter phase space for radiation treatment using a multi-leaf collimator with dynamic jaws

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.

Leaf sequencing algorithm for moving targets

The present invention provides an intensity modulated radiation therapy (IMRT) method for treating a target region that minimizes the tongue and groove effect. By minimizing that effect, striping in the final delivered fluence is reduced, which improves the overall quality of the radiation delivery. In the method, compensating functions C(x) are added to leaf coordinates a(x) and b(x) for all of the leaf pairs i in a leaf sequence algorithm, where C(x) is chosen to match the mechanical limitations of the MLC and to minimize non-weighted or weighted sums of the tongue and groove effects, where the weighting is time-dependent, position-dependent, or time- and position-dependent, or to minimize the total treatment time, changes to the original MLC sequence, or the tongue and groove effect distribution variance in spatial or temporal coordinates.

Method for minimizing the tongue and groove effect in intensity modulated radiation delivery

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Vantaa, Finland

Sami P Siljamaki