# US 2021/0275831 A1 · System, process and apparatus to determine linac isocenter > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0275831 A1 - Document ID: US20210275831A1 - Status: Published application - Kind: A1 - Application number: 16/999,693 - Filed: 2020-08-21 - Published: 2021-09-09 - Earliest claimed: 2020-03-09 - Assignees: Aktina Corp. - Applicants: Aktina Corp. - Inventors: Nicholas Zacharopoulos; Milan Markovic; David Fenyes - Web page: https://patentgrep.com/patent/US20210275831A1 ## CPC - A61N 5/1049: {for verifying the position of the patient with respect to the radiation beam} - A61N 5/1075: {for testing, calibrating, or quality assurance of the radiation treatment apparatus} - A61N 5/1081: {Rotating beam systems with a specific mechanical construction, e.g. gantries} - A61N 2005/1051: {using an active marker} - A61N: ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY (measurement of bioelectric currents A61B; surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body A61B18/00; anaesthetic apparatus in general A61M; incandescent lamps H01K; infrared radiators for heating H05B) ## Abstract A system to determine the isocenter of a LINAC includes apparatus and processes. One embodiment does this by determining the axis of rotation for the collimator, the gantry, and may include the couch. In another embodiment only determining the axis of the rotation of the collimator is required. The system and apparatus enable the tracking of the translation-rotation of mechanical components attached to the LINAC to compute the axis of rotation of gantry, collimator and couch. Based on the data collected related to these axes the LINAC isocenter is determined. The primary apparatus utilized in the system includes a single emitter module, a signal receiver module, and a positioning module. The system also includes an isocenter target module and a gravity module to determine a gravity vector relative to the signal receiver. ## Claims ### Claim 1 A LINAC mechanical isocenter determination process comprising: mounting a signal emitter module on a collimator; mounting a signal receiver module at a location with an unobstructed view of the signal emitter module; determining an axis rotation for a gantry by rotating the gantry while the signal receiver module acquires signal emitter module positions; determining an axis of rotation for the collimator by rotating the collimator while the signal receiver module acquires signal emitter module positions during the collimator rotation; and determining the LINAC mechanical isocenter by processing signal emitter module positions during the collimator rotation and the gantry rotation. ### Claim 2 (depends on 1) A LINAC mechanical isocenter determination process according to claim 1, wherein the signal receiver module is mounted on a couch, further comprising determining an axis of rotation for the couch by rotating the couch while the signal receiver module acquires signal emitter module positions during the couch rotation and determining the LINAC mechanical isocenter by processing the signal emitter module positions for the axis of rotation for the gantry, the collimator, and the couch. ### Claim 3 (depends on 1) The LINAC mechanical isocenter determination process according to claim 1 wherein the signal emitter module emits light signals and the signal receiver module receives the light signals. ### Claim 4 (depends on 3) The LINAC mechanical isocenter determination process according to claim 3 wherein the signal emitter module comprises a minimum of one marker reflecting or emitting light at a specific frequency optimized for the signal receiver module. ### Claim 5 (depends on 4) The LINAC mechanical isocenter determination process according to claim 4 wherein the signal receiver module is a camera pod. ### Claim 6 (depends on 5) The LINAC mechanical isocenter determination process according to claim 5 wherein the camera pod is comprised of at least 2 cameras capable of acquiring time synchronized images for computer analysis. ### Claim 7 (depends on 1) The LINAC mechanical isocenter determination process according to claim 1 further comprising mounting an isocenter target module on a positioning module and positioning the isocenter target module at the LINAC isocenter using at least one emitter marker on the isocenter target module. ### Claim 8 (depends on 7) The LINAC mechanical isocenter determination process according to claim 7 wherein the isocenter target module includes a radiation opaque marker inside a target body. ### Claim 9 (depends on 8) The LINAC mechanical isocenter determination process according to claim 8 wherein the isocenter target module includes crosshairs on an outside of the target body. ### Claim 10 (depends on 9) The LINAC mechanical isocenter determination process according to claim 9 wherein the positioning module includes controls for an X position, a Y position, and a Z position. ### Claim 11 (depends on 1) The LINAC mechanical isocenter determination process according to claim 1 further comprising utilizing a processor to collect data and process it utilizing software. ### Claim 12 A LINAC radiation isocenter determination process comprising: mounting a signal emitter module on a collimator; mounting a signal receiver module in a location with an unobstructed view of the signal emitter module; rotating the collimator with a gantry positioned at a first angle while the signal receiver module acquires signal emitter module positions; determining a calculated collimator axis of rotation from the signal emitter module positions acquired with the gantry positioned at the first angle; rotating the collimator with the gantry positioned at a second angle while the signal receiver module captures the signal emitter module positions; determining a calculated collimator axis of rotation from the signal emitter module positions acquired with the gantry positioned at the second angle; and determining LINAC radiation isocenter using the calculated collimator axis of rotation with the gantry positioned at the first angle and the calculated collimator axis of rotation with the gantry positioned at the second angle. ### Claim 13 (depends on 12) The LINAC radiation isocenter determination process according to claim 12 further comprising rotating the collimator with the gantry positioned at a minimum of one additional angle while the signal receiver module captures the signal emitter module positions. ### Claim 14 (depends on 12) The LINAC radiation isocenter determination process according to claim 12 wherein the signal emitter module emits light signals and the signal receiver module receives the light signals. ### Claim 15 (depends on 12) The LINAC radiation isocenter determination process according to claim 12 wherein the signal receiver module is mounted on a couch. ### Claim 16 (depends on 12) The LINAC radiation isocenter determination process according to claim 12 further comprising rotating a couch and determining LINAC radiation isocenter using the computed collimator and coach axes. ### Claim 17 A LINAC gantry axis of rotation determination process comprising: mounting a signal emitter module on a collimator; mounting a signal receiver module at a location with an unobstructed view of the signal emitter module; and determining the gantry axis rotation by rotating the gantry while the signal receiver module acquires signal emitter module positions. ### Claim 18 A LINAC collimator axis of rotation determination process comprising: mounting a signal emitter module on a collimator; mounting a signal receiver module at a location with an unobstructed view of the signal emitter module; and determining the collimator axis rotation by rotating the collimator while the signal receiver module acquires signal emitter module positions. ### Claim 19 A LINAC couch axis of rotation determination process comprising: mounting a signal emitter module on a collimator; mounting a signal receiver module at a location with an unobstructed view of the signal emitter module; and determining the collimator axis rotation by rotating the couch while the signal receiver module acquires signal emitter module positions. ### Claim 20 A gravity vector determination process comprising mounting a gravity module on a collimator; mounting a camera pod in a location with an unobstructed view of the gravity module; and using the camera pod to acquire images of a location of the gravity module to determine a direction of a gravity vector relative to an internal coordinate system of the camera pod. ### Claim 21 A collimator axis walkout determination process comprising: mounting a signal emitter module on a collimator; mounting a signal receiver module at a location with an unobstructed view of the signal emitter module; determining a path through space of the signal emitter module during the collimator rotation by analyzing signal emitter module positions; fitting the computed signal emitter module positions to a three-dimensions circle in space; and computing an error vector between each position and a nearest point to the fit three-dimensional circle. ### Claim 22 A couch axis walkout determination process comprising: mounting a signal emitter module on a collimator; mounting a signal receiver module at a location with an unobstructed view of the signal emitter module; determining a path through space of the signal emitter module during couch rotation by analyzing signal emitter module positions; fitting the computed signal emitter module positions to a three-dimensions circle in space; and computing an error vector between each position and a nearest point to the fit three-dimensional circle.