Closed-loop control of an x-ray pulse chain generated by means of a linear accelerator system

Patent metadata

Field	Value
Publication number	US-2022151051-A1
Application number	US-202117517106-A
Country	US
Kind code	A1
Filing date	Nov 2, 2021
Priority date	Nov 10, 2020
Publication date	May 12, 2022
Grant date	—

Abstract

A method is for closed-loop control of an X-ray pulse chain generated via a linear accelerator system. In an embodiment, the method includes modulating a first electron beam within a first radio-frequency pulse duration, wherein the first multiple amplitude X-ray pulse is produced on modulating the first electron beam; measuring time-resolved actual values of the first multiple amplitude X-ray pulse; adjusting at least one pulse parameter as a function of a comparison of the specified multiple amplitude X-ray pulse profile and the measured time-resolved actual values; and modulating a second electron beam within a second radio-frequency pulse duration as a function of the at least one adjusted pulse parameter for production of the second multiple amplitude X-ray pulse, so the X-ray pulse chain is controlled.

First claim

What is claimed is:

1 . A method for closed-loop control of an X-ray pulse chain generated via a linear accelerator system, with a first multiple amplitude X-ray pulse and a second multiple amplitude X-ray pulse, the method comprising:
modulating a first electron beam produced via an electron source of the linear accelerator system within a first radio-frequency pulse duration as a function of a specified multiple amplitude X-ray pulse profile, the first multiple amplitude X-ray pulse being produced by modulating the first electron beam; measuring time-resolved actual values of the first multiple amplitude X-ray pulse via a measuring unit; adjusting at least one pulse parameter via a closed-loop control unit as a function of a comparison of the specified multiple amplitude X-ray pulse profile and the time-resolved actual values measured, to produce at least one adjusted pulse parameter; and modulating a second electron beam produced via the electron source within a second radio-frequency pulse duration as a function of the at least one adjusted pulse parameter to produce the second multiple amplitude X-ray pulse, for closed-loop control of an X-ray pulse chain.

2 . The method of claim 1 , wherein the time-resolved actual values measured, describe a dose measure distribution of the first multiple amplitude X-ray pulse.

3 . The method of claim 2 , wherein the measuring unit for measurement of the dose measure distribution is an ionization chamber, a photo-scintillator or a direct conversion semiconductor.

4 . The method of claim 1 , wherein the time-resolved actual values describe an energy value distribution of the first multiple amplitude X-ray pulse.

5 . The method of claim 4 , wherein the measuring unit for measurement of the energy value distribution is an ammeter connected to a target of the linear accelerator system or a measuring transformer surrounding an electron beam path of the X-ray pulse chain.

6 . The method of claim 1 , wherein a radio-frequency power value is varied by a staggered switching-on, initiated via the closed-loop control unit, of at least one stage of a Marx generator of the radio-frequency source.

7 . The method of claim 6 , wherein an impedance of a capacitance element, wired parallel to a magnetron of the radio-frequency source, on reaching the magnetron trigger voltage, is set at a ratio not equal to 1 in relation to an impedance of the magnetron, so that a high-voltage value of the magnetron increases or decreases as a function of staggered switching-on of the at least one stage.

8 . The method of claim 1 , wherein the time-resolved actual values of the first multiple amplitude X-ray pulse are measured with a time resolution of less than 1 μs.

9 . The method of claim 8 , wherein the time resolution is less than 10 ns.

10 . The method of claim 1 , wherein the multiple amplitude X-ray pulse profile has a continuous and variable amplitude profile for an energy value distribution with at least one of increasing and decreasing energy values.

11 . The method of claim 1 , wherein the multiple amplitude X-ray pulse profile has at least two separate intrapulses.

12 . A linear accelerator system, comprising:
an electron source to modulate a first electron beam produced within a first radio-frequency pulse duration as a function of a specified multiple amplitude X-ray pulse profile, the first multiple amplitude X-ray pulse being produced by modulating the first electron beam; a measuring device to measure time-resolved actual values of the first multiple amplitude X-ray pulse; a closed-loop controller to carry out at least
adjusting at least one pulse parameter as a function of a comparison of the specified multiple amplitude X-ray pulse profile and the time-resolved actual values measured, to produce at least one adjusted pulse parameter, and
modulating a second electron beam, produced via the electron source, within a second radio-frequency pulse duration as a function of the at least one adjusted pulse parameter to produce the second multiple amplitude X-ray pulse, for closed-loop control of an X-ray pulse chain; and
a target to generate the X-ray pulse chain.

13 . A non-transitory computer program product, directly loadable into a storage device of an arithmetic unit, storing program code segments to carry out the method of claim 1 when the computer program product is run in the arithmetic unit.

14 . The method of claim 2 , wherein a radio-frequency power value is varied by a staggered switching-on, initiated via the closed-loop control unit, of at least one stage of a Marx generator of the radio-frequency source.

15 . The method of claim 14 , wherein an impedance of a capacitance element, wired parallel to a magnetron of the radio-frequency source, on reaching the magnetron trigger voltage, is set at a ratio not equal to 1 in relation to an impedance of the magnetron, so that a high-voltage value of the magnetron increases or decreases as a function of staggered switching-on of the at least one stage.

16 . The method of claim 2 , wherein the time-resolved actual values of the first multiple amplitude X-ray pulse are measured with a time resolution of less than 1 μs.

17 . The method of claim 16 , wherein the time resolution is less than 10 ns.

18 . The method of claim 2 , wherein the multiple amplitude X-ray pulse profile has a continuous and variable amplitude profile for an energy value distribution with at least one of increasing and decreasing energy values.

19 . The method of claim 2 , wherein the multiple amplitude X-ray pulse profile has at least two separate intrapulses.

20 . A non-transitory computer program product, directly loadable into a storage device of an arithmetic unit, storing program code segments to carry out the method of claim 2 when the computer program product is run in the arithmetic unit.

Assignees

• Siemens Healthcare Gmbh

Inventors

• Mueller Sven
• Koschmieder Martin
• Moeller Marvin
• Cyliax Benno
• Willing Stefan

Classifications

• H05G1/30

  Controlling · CPC title

• H05G1/20

  with high-frequency AC; with pulse trains {(pulse generators in general H03K3/00, H03K4/00)} · CPC title

• H01J35/045

  Electrodes for controlling the current of the cathode ray, e.g. control grids · CPC title

• H01J35/04 Primary

  Electrodes {; Mutual position thereof; Constructional adaptations therefor} · CPC title

• H05H7/22

  Details of linear accelerators, e.g. drift tubes (H05H7/02 - H05H7/20 take precedence) · CPC title