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CN-122017922-A - FLASH radiotherapy ray dose calorimeter and method

CN122017922ACN 122017922 ACN122017922 ACN 122017922ACN-122017922-A

Abstract

A radiation dose calorimeter for FLASH radiotherapy and a method thereof are provided, wherein the calorimeter comprises a calorimeter core, a jacket layer and a shielding layer. The calorimetric core is an absorber of FLASH radiotherapy rays, is nested in a first space inside the jacket layer in a mode of being in a first interval with the jacket layer and not in contact with each other, is nested in a second space inside the shielding layer in a mode of being in a second interval with the shielding layer and not in contact with each other, and no non-gas filler exists in the first interval and the second interval. The calorimeter is arranged in such a way, and aims to adapt to the strict requirements of ultra-high dose rate and millisecond irradiation of FLASH radiotherapy rays, avoid the defects of heat transfer resistance and heat capacity increase of solid fillers in the prior art, reduce heat loss and heat conduction hysteresis through the design of three layers of non-contact and non-solid filling, concentrate heat on a calorimetric core, reduce the whole heat capacity, ensure millisecond thermal response speed and ensure high accuracy and traceability of dose measurement.

Inventors

  • HUANG JI
  • WANG KUN
  • ZHANG GUOLONG

Assignees

  • 中国计量科学研究院

Dates

Publication Date
20260512
Application Date
20260316

Claims (10)

  1. 1. A calorimeter for FLASH radiotherapy rays, characterized in that the calorimeter (100) comprises a calorimeter core (101), a jacket layer (102) and a shielding layer (103); The calorimetric core (101) is an absorber of FLASH radiotherapy rays, and the calorimetric core (101) is nested in a first space inside the jacket layer (102) in a mode of having a first interval with the jacket layer (102) and not contacting each other; The jacket layer (102) is nested in a second space inside the shielding layer (103) in a manner of being in a second interval with the shielding layer (103) and not contacting each other; no non-gaseous filler is present within the first and second spaces.
  2. 2. The calorimeter of claim 1, wherein the first wall portion of the jacket layer (102) is provided with at least two first holes (108) for penetrating the suspension wires (105); The heat measuring core (101) is pulled from at least two directions by a suspension wire (105) in a mode of penetrating through a first hole (108) on a first wall part of the jacket layer (102) and is in a suspended state in a first space, and meanwhile, the jacket layer (102) is in a suspended state in a second space of the shielding layer (103) under the suspension action of the suspension wire (105), so that the heat measuring core (101), the jacket layer (102) and the shielding layer (103) are not contacted with each other; one end of the suspension wire (105) is connected with the calorimetric core (101), and the other end of the suspension wire is connected with the second wall part of the shielding layer (103).
  3. 3. The calorimeter of claim 1 or 2, wherein the first interval is equidistant from the second interval.
  4. 4. A calorimeter as claimed in any one of claims 1 to 3, wherein the calorimetric core (101), the jacket layer (102) and the shielding layer (103) are nested with each other in an isocentric manner to achieve stable thermal isolation.
  5. 5. The calorimeter of any one of claims 1-4, wherein the calorimeter core (101) is pulled by a suspension wire (105) from three directions in a manner of penetrating a first hole (108) on a first wall portion of the jacket layer (102) and is in a suspended state in a first space; Wherein the three directions are in the same plane and have the same angle with each other, so that the calorimetric core (101) is stably fixed.
  6. 6. The calorimeter of any one of claims 1-5, wherein a gas is present in the first and/or second intervals; Or the first interval and/or the second interval is a vacuum environment.
  7. 7. The calorimeter of any one of claims 1-6, wherein the calorimeter core (101) is provided with a miniature temperature sensor (106) for acquiring the temperature of the calorimeter core (101).
  8. 8. The calorimeter of any one of claims 1-7, further comprising a constant temperature die body (200) for providing a quasi-adiabatic environment, the temperature of the liquid within the constant temperature die body (200) approaching a quasi-isothermal state; When the calorimeter (100) is fixed in a specified depth range below the liquid surface, a temperature sensor (106) on the calorimeter core (101) outputs temperature data of the calorimeter core (101) after FLASH radiotherapy rays are applied to the calorimeter (100).
  9. 9. The calorimeter of any one of claims 1 to 8, wherein an incident window (204) for the radiation of FLASH radiotherapy is provided on the constant temperature die body (200), so that an ultra-high dose rate electron beam of the radiation of FLASH radiotherapy is intensively irradiated through the incident window (204) of the constant temperature die body (200), and the radiation of FLASH radiotherapy is accurately irradiated onto the calorimeter (100).
  10. 10. A method for using amount of radiation for FLASH radiotherapy, which is characterized by comprising the following steps: Adjusting the liquid in the constant temperature die body (200) to approach a quasi-constant temperature state; Fixing the calorimeter (100) at a specified depth range below the liquid surface of the constant temperature die body (200); -applying FLASH radiation to the calorimeter (100); A temperature sensor (106) on the calorimetric core (101) outputs temperature data of the calorimetric core (101) of the calorimeter (100); Wherein the calorimeter (100) comprises a calorimeter core (101), a jacket layer (102) and a shielding layer (103); The calorimetric core (101) is an absorber of FLASH radiotherapy rays, and the calorimetric core (101) is nested in a first space inside the jacket layer (102) in a mode of having a first interval with the jacket layer (102) and not contacting each other; The jacket layer (102) is nested in a second space inside the shielding layer (103) in a manner of being in a second interval with the shielding layer (103) and not contacting each other; no non-gaseous filler is present within the first and second intervals; the heat measuring core (101) is provided with a miniature temperature sensor (106) for collecting the temperature of the heat measuring core (101).

Description

FLASH radiotherapy ray dose calorimeter and method Technical Field The invention relates to the technical field of radiotherapy dose measurement, in particular to a FLASH radiotherapy ray dose calorimeter and a method. Background Malignant tumors are serious diseases that seriously threaten human life and health. In clinical treatment of tumors, radiation therapy is one of its central approaches, and it is statistically about 70% of tumor patients need radiation therapy at different stages of disease progression. In conventional radiotherapy (Conventional Radiotherapy, CONV), the average dose rate is typically in the range of 1-5 Gy/min, and a single irradiation often needs to last for several minutes. Although conventional radiotherapy can play a role in killing tumor cells, it inevitably causes radioactive damage to normal tissues around the tumor during irradiation. Therefore, how to effectively reduce the Normal Tissue Complication Probability (NTCP) while maintaining or improving the Tumor Control Probability (TCP) is always a core scientific problem to be solved in the radiotherapy field. In recent years, FLASH radiation therapy has received widespread attention as a novel radiotherapy technique. The technology is characterized by Ultra-High Dose Rate (UHDR), the definition of the Dose Rate is usually not lower than 40 Gy/s, and the Dose Rate is improved by more than three orders of magnitude compared with that of conventional radiotherapy. FLASH radiotherapy is capable of achieving high dose radiation in a timescale on the order of sub-milliseconds to milliseconds. The existing animal model research and preliminary clinical research show that the technology can induce a unique FLASH effect, namely, can obviously reduce the radiation damage of irradiated normal tissues on the premise of keeping the tumor killing efficiency equivalent to that of conventional radiotherapy. The characteristic provides a new physical and biological basis for realizing a radiation therapy mode with high curative effect and low toxicity, and has great clinical application potential and research value. However, while FLASH radiotherapy has shown great potential for clinical application, its physical properties of ultra-high dose rate also present a serious challenge for accurate measurement of absorbed dose. Because FLASH rays need to finish large-dose deposition in a very short time scale of the order of submilliseconds to milliseconds, the existing conventional dose monitoring means are difficult to meet the requirements of high dynamic response and high precision. In particular, conventional active dosimeters (such as ionization chambers and the like) commonly used in clinic at present are extremely easy to generate obvious collection efficiency loss and serious response nonlinearity problems due to aggravation of compound effects when facing to ultra-high pulse dose rates, and cannot accurately acquire dose parameters in real time. While passive dosimeters such as alanine, film and a thermoluminescent dosimeter (TLD) have weak dependence on dose rate, the measurement process is complex and cannot realize real-time measurement, so that the real-time quality control requirement of FLASH radiotherapy in clinic and research is difficult to support. The basic principle of the calorimeter is that the temperature rise effect generated after the medium absorbs the ionizing radiation energy is utilized, and the quantity value reproduction is directly realized through the traceable temperature or electrical quantity. Because its detection mechanism is theoretically unaffected by the radiation, energy spectrum and dose rate, calorimetry is considered to be an ideal technical approach to solve the problem of dosimetry traceability under ultra-high dose rate conditions. Therefore, aiming at the special working conditions of ultra-high instantaneous dose and extremely-short irradiation time of FLASH radiotherapy, the heat measuring device with high sensitivity, high reliability and metering traceability is developed, and has extremely important technical significance for establishing an ultra-high dose rate absorption dose quantity value traceability system and guaranteeing the clinical application safety of FLASH radiotherapy and the accuracy of dosimetry research. However, the existing calorimeter technical scheme still has obvious technical bottlenecks when dealing with extreme physical working conditions such as ultra-high dose rate of FLASH radiotherapy rays, millisecond-level transient irradiation and the like. For example, CN216848160U discloses a graphite calorimeter suitable for measuring multi-energy electron beam absorption dose, comprising a graphite absorber set, a heat insulation layer, a graphite shell, a temperature control system and an aluminum shell, wherein the graphite absorber set comprises a graphite absorber layer and a foaming polystyrene filling layer, a thermistor is embedded in the graphite absorber layer,