Gamma knife radiotherapy dose acquisition device

Abstract

The utility model relates to a gamma knife radiotherapy dose acquisition device. The gamma knife radiotherapy dose acquisition device comprises a beam outlet, the beam outlet is arranged on a tungsten cover of a gamma knife, the gamma knife radiotherapy dose acquisition device further comprises two finger-type ionization chambers, and the two finger-type ionization chambers are arranged on two sides of the beam outlet of the gamma knife and are distributed at an angle of 180 degrees. According to the utility model, the dose at the beam outlet of the gamma knife is detected in real time, the dose monitoring value in the treatment process is used as a closed-loop feedback of the opening angle of the collimator, the risk of pulse loss of the position feedback encoder of the collimator is detected and identified in real time, the accuracy of the treatment dose each time is ensured, and the treatment accuracy of equipment is improved.

Description

Technical Field

[0001] The utility model relates to the field of medical equipment, in particular to a gamma knife radiotherapy dose acquisition device. Background Art

[0002] A gamma knife is a gamma ray stereotactic radiotherapy system that integrates stereotactic technology and radiosurgery technology. It is a large-scale radiotherapy device mainly used to treat head and body tumors. Its treatment principle is to adjust the focus of the gamma rays generated by the radiation source, so that the ray beams cross and overlap to obtain a high dose in the lesion area, while the normal tissues passed by each beam receive a relatively low dose. The high-dose gamma rays after focusing destroy the biological tissues of the patient's tumor site to achieve the treatment purpose of destroying the lesion, while ensuring the safety of normal tissues. The gamma knife usually combines a mechanical structure with a radiation source of known activity and type. At present, the dose control in the gamma knife treatment process usually adopts the configuration of collimators and the control of the open source time. The opening angle of the collimator configured during the treatment is executed by the set angle of the servo motor, and the closed-loop feedback depends on the encoder signal of the control system. However, there is a risk of pulse loss in the encoder pulse signal under the conditions of mechanical vibration and electromagnetic interference. This risk will lead to inaccurate dose rate during the gamma knife treatment process and affect the treatment effect of the gamma knife.

[0003] Therefore, it is necessary to provide a new technical solution to solve the risk that the position feedback encoder of the collimator loses pulses and is not easy to detect, and to be able to detect and identify the risk of dose in real time during each treatment process to ensure the accuracy of the dose during the treatment process. Summary of the Utility Model

[0004] To solve the above technical problems in the background art, the utility model provides a gamma knife radiotherapy dose acquisition device, which can detect the dose at the beam outlet of the gamma knife in real time, use the dose monitoring value during the treatment process as a closed-loop feedback of the collimator opening angle, detect and identify the risk that the position feedback encoder of the collimator loses pulses in real time, ensure the accuracy of each treatment dose, and improve the accuracy of equipment treatment.

[0005] The technical solution of the utility model is: the utility model is a gamma knife radiotherapy dose acquisition device, including a beam outlet, and the beam outlet is arranged on the tungsten cover of the gamma knife. The special feature is that the gamma knife radiotherapy dose acquisition device further includes two finger ionization chambers, and the two finger ionization chambers are arranged on both sides of the beam outlet of the gamma knife and are distributed at 180°.

[0006] Furthermore, the gamma knife radiotherapy dose acquisition device further includes an ionization chamber instrument, and the two finger ionization chambers are respectively connected to the ionization chamber instrument, and the ionization chamber instrument mainly plays a counting role.

[0007] Further, the sensitive volume Φ of the finger ionization chamber is 18 mm, and the response range is 10 Sv / h - 100 μSv / h.

[0008] A gamma knife radiotherapy dose acquisition device provided by the present utility model takes dose monitoring as a closed-loop feedback for precise dose control during radiotherapy, monitors the accuracy of the dose in real time during the treatment process, identifies the dose risk during the treatment process and automatically gives an alarm prompt. The present utility model can detect and identify risks for the dose of each treatment process in real time, ensure the accuracy of the dose during the treatment process, and improve the accuracy of equipment treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is a schematic structural diagram of the present utility model;

[0010] Figure 2 is a collection flow chart of the present utility model.

[0011] The description of the reference numerals in the drawings is as follows:

[0012] 1, tungsten cover; 2, first finger ionization chamber; 3, beam outlet; 4, second finger ionization chamber. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0013] The following further describes the present utility model in detail with reference to the drawings and specific embodiments.

[0014] Refer to Figure 1 The structure of the specific embodiment of the present utility model includes two finger ionization chambers: the first finger ionization chamber 2 and the second finger ionization chamber 4. The two finger ionization chambers are arranged on both sides of the beam outlet 3 of the gamma knife, distributed at 180°, and the beam outlet 3 is arranged on the tungsten cover 1 of the gamma knife.

[0015] The present utility model uses two finger ionization chambers to collect data on the dose output by the equipment during radiotherapy. The two finger ionization chambers need to be calibrated for the absolute dose value, consistency detection, stability test, etc. before use. Among them, the sensitive volume Φ of the finger ionization chamber is 18 mm, and the response range is 10 Sv / h - 100 μSv / h. The two finger ionization chambers are distributed on both sides of the beam outlet of the gamma knife, distributed at 180°. The collected data is transmitted to the gamma knife control system (the gamma knife control system is an existing system) through the ionization chamber instrument. After processing such as noise reduction and background subtraction, the collected data is compensated according to the calibration value, and finally the real-time display of the dose rate and the total absorbed dose is completed. During each radiotherapy process, the dose rate is detected in real time. If the deviation of the dose rate is greater than the allowable value, an alarm prompt is triggered.

[0016] Refer to Figure 2 The specific collection process of the present utility model is as follows:

[0017] 1) Calibrate the absolute dose value; the calibration of the absolute dose value is completed by establishing the relationship between the scattered dose level and the absolute dose, and the absolute dose is obtained through the nominal absorbed dose rate and the exponential decay relationship;

[0018] The calibration of the absolute dose value is achieved by establishing the relationship between the scattered dose level and the absolute dose, that is, by obtaining a large amount of data through actual measurement and then using data fitting to obtain the relationship between the scattered dose level and the absolute dose.

[0019] 2) Collect data on the dose output by the device during radiotherapy through two finger ionization chambers. The two finger ionization chambers need to undergo consistency and stability tests, both of which are completed during the calibration phase in step 1). The consistency and stability are verified by measuring the readings of the two finger ionization chambers when the beam is output at the same time and through multiple measurements.

[0020] 3) Process the data collected in step 2): including signal preprocessing, peak detection, and peak determination; among them, signal preprocessing includes noise reduction, filtering, or data normalization. The method of peak detection uses the threshold method, and peak determination involves analyzing the amplitude, duration, and shape of the peak.

[0021] 4) Denoise and background subtract the data processed in step 3); due to the limitation of the statistical duration, the collected data has poor statistics. To meet the accuracy of data analysis, the process of noise and background subtraction of the data is required. Specifically, the least squares method is used for denoising, and the SNIP method is used to complete the background subtraction.

[0022] 5) Compensate the collected data according to the calibration value in step 1);

[0023] 6) Display the dose rate and the total absorbed dose; among them, the dose rate shows the change of the real-time dose, and the total dose is the total beam output dose within the statistical time.

[0024] 7) During each radiotherapy process, the dose rate is detected in real time. If the deviation of the dose rate is greater than the allowable value (judged by setting the dose deviation threshold), an alarm prompt is triggered.

[0025] The technical content not specifically described in the content of the present utility model and the above embodiments is the same as the prior art.

[0026] The above is only the specific implementation manner disclosed by the present utility model, but the protection scope disclosed by the present utility model is not limited thereto. The protection scope disclosed by the present utility model shall be subject to the protection scope of the claims.

Claims

1. A gamma knife radiotherapy dose acquisition device, including a beam output port, the beam output port is arranged on the tungsten cover of the gamma knife, and is characterized in that: The gamma knife radiotherapy dose acquisition device further includes two finger ionization chambers, which are arranged on both sides of the gamma knife beam outlet and are distributed at 180°.

2. The gamma knife radiotherapy dose acquisition device according to claim 1, characterized in that: The gamma knife radiotherapy dose acquisition device further includes an ionization chamber instrument, and the two finger ionization chambers are respectively connected to the ionization chamber instrument.

3. The gamma knife radiotherapy dose acquisition device according to claim 1 or 2, characterized in that: The sensitive volume Φ of the finger ionization chamber is 18 mm, and the response range is 10 Sv / h - 100 μSv / h.

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