Multifunctional ionization chamber and its electronic path for use on the medical accelerator Prometeus

The article describes the proposed new multifunctional ionization chamber (MIC) designed to measure dose profiles when the medical accelerator Prometheus is operating in the scanning “pencil beam” mode. A digital image acquisition detector (DIDE) with a tissue-equivalent water phantom is used to calibrate the accelerator before a radiation therapy session. The application of the CPPI on the beam of a proton accelerator operating in the mode of beam splitting into spots with a scanning beam is considered. The CDPI detector allows for a few accelerator pulses in on-line mode to see how the energy release of each spot is distributed over the area of the irradiated target, which is the actual calibration of the accelerator before the proton therapy session. During the proton therapy session, it is planned to install the MIC directly in front of the patient. The MIC chamber contains two ionization chambers operating simultaneously — a pad chamber (PC) operating on gas or “warm liquid” and a strip ionization chamber operating only on gas (SC). At the accelerator Prometheus it is proposed to use a MIC, which will be used in the mode of operation by the method of active scanning with a “pencil” proton beam. The use of the MIC operation is intended to control the density of the beam intensity during the irradiation of the “target” in the patient during the proton therapy session. In case of violation of the planned operating mode of the accelerator and the beam goes beyond the parameters preset before the session, the deviation detection control system (SDMS) will turn off the accelerator. The device of the readout electronics (SE) of the MIC and SKOO cameras is described. This proposed detector, including the MIC and SKOO camera and the reading electronics serving it, will improve the quality of the therapeutic beam supply, due to the accurate determination of the absorbed dose density supplied by the scanning beam to each spot of the irradiated target, and therefore the generated high dose distribution field will correspond to the irradiated volume of the patient and will increase the safety and control of patient exposure to the target. The PC included in the MIC is designed on a “warm liquid” (or gas) and is a high-precision ionization chamber with coordinate sensitivity over the width of the irradiated target. The SC included in the MIC operates on gas and controls the direction of the incident beam to a given spot in the target. A version of the charge-sensitive preamplifier (QCD) and the SE system designed for experimental verification of the MIC prototype has been developed. The SCOO circuit working in conjunction with the MIC camera allows you to control the predetermined parameters of the irradiation of the patient’s target boundaries and turns off the accelerator if these parameters deviate from the initially specified ones.

1. Siksin V. V. Ways to improve the TV-type detector. Bull. Lebedev Phys. Inst., 2019, vol. 46, no. 1, pp. 19—22. DOI: 10.3103/S1068335619010068

2. Siksin V. V. Measurement of the Bragg peak profiles by the TTD. Bull. Lebedev Phys. Inst., 2019, vol. 46, no. 2. pp. 47—52. (In Russ.)

3. Siksin V. V. Pilot installation for the purificationof the “warm liquid” of tetramethylsilane and conducting “non-accelerating experiments”. Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, 2019, vol. 22, no. 2, pp. 118—127. (In Russ.). DOI: 10.17073/1609-3577-2019-2-118-127

4. Pyramid Technical Consultants, Inc. URL: www.ptcusa.com

5. Siksin V. V. “Warm liquid” detector for measuring dose profi les from ionizing radiation. Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, 2019, vol. 22, no. 3, pp. 228—236. (In Russ.). DOI: 10.17073/1609-3577-2019-3-228-236

6. Dorokhov D. V., Kuper E. A. System for measuring ionization chamber currents in experiments with synchrotron radiation. Optoelectron. Instrument. Proc., 2015, vol. 51, no. 1, pp. 76—80. DOI: 10.3103/S8756699015010124

7. Siksin V. V. Pulsed X-Ray source (PXS) for calibrating microdosimeters based on “warm liquids” and testings of television type detectors. Bull. Lebedev Phys. Inst., 2018, vol. 45, no. 7, pp. 199—203. DOI: 10.3103/S1068335618070023

8. Patent 1338154 (SU). Sposob kontrolya parametrov puchka v protsesse protonnoy terapii [Method for controlling the beam parameters during proton therapy]. E. A. Damaskinsky, D. L. Karlin, O. E. Prokofiev, V. S. Samsonenkov, 1988. (In Russ.)

9. Patent 2684567 (RU). Sposob rekonstruktivnogo dozimetricheskogo kontrolya v protonnoy terapii skaniruyushchim luchom [Method of reconstructive dosimetric control in proton therapy with a scanning beam]. A. E. Chernukha, O. G. Lepilina, S. E. Ulyanenko et al., 2018. (In Russ.)

10. Patent 2704012 (RU). Sposob avtoregulirovaniya i stabilizatsii intensivnosti sinkhrotsiklotrona pri protonno-luchevom obluchenii bol’nykh i ustroystvo dlya yego osushchestvleniya [A method of automatic regulation and stabilization of the synchrocyclotron intensity during proton-beam irradiation of patients and a device for its implementation]. E. M. Ivanov V. I., Maksimov, G. F. Mikheev, 2019. (In Russ.)

11. PTW. The Dosimetry Company: OCTAVIUS Detector 1500XDR. URL: https: //www/ptwdisimetry.com/en/products/octavius-detector-1500xdr/

12. Kudashkin I. V. Development and creation of devices for diagnostic and monitoring systems for internal and extracted beams of the Nuclotron accelerator: Dis. … Cand. Sci. (Phys.-Math.). Moscow, 2015. 88 p. (In Russ.)

13. Baldin A. A., Berlev A. I., Kudashkin I. V., Fedorov A. N. Detector based on microchannel plates for monitoring space-time characteristics of a circulating beam at Nuclotron. Phys. Part. Nuclei Lett., 2014, vol. 11, pp. 121—126. DOI: 10.1134/S1547477114020137

14. Baldin A., Feofilov G., Gavrilov Yu., Tsvinev A., Valiev F. Proposals for a new type of microchannel-plate-based vertex detector. Nucl. Instr. Meth. A, 1992, vol. 323, no. 1–2, pp. 439—444. DOI: 10.1016/0168-9002(92)90329-3

15. Butenko A. V. Acceleration of heavy ion beams with a mass number of more than 100 in the superconducting synchrotron Nuclotron: Dis. ... Cand. Sci. (Eng.). Dubna, JINR, 2012. 101 p. (In Russ.)

16. Barnes P. G., Cross G. M., Drumm B. S., Fisher S. A., Payne S. J., Pertica A., Wilcox C. C. A micro-channel plate based gas ionization profile monitor with shaping field electrodes for the ISIS H-injector. Proc. IPAC. San Sebastián (Spain), 2011. URL: https://accelconf.web.cern.ch/IPAC2011/papers/tupc147.pdf

17. Connolly R., Fite J., Jao S., Tepikian S., Trabocchi C. Residual-gas-ionization beam profile monitors in RHIC. Proc. BIW10. Santa Fe (New Mexico, US), 2010. URL: https://accelconf.web.cern.ch/BIW2010/papers/tupsm010.pdf

18. Teterev Yu. G., Kaminski G., Huong P. T., Kozik E. Ionization beam profile monitor for operation under hard environmental conditions. Nucl. Phys. Atomic Energy, 2011, vol. 12, no. 1, pp. 98—103.

19. Quinteros T., DeWitt D. R., Paál A., Schuch R. Three-dimensional ion beam-profile monitor for storage rings. Nucl. Instrum. Methods Phys. Res. A. 1996, vol. 378, no. 1–2, pp. 35—39. DOI: 10.1016/0168-9002(96)00278-1

20. Mezhdunarodnye prakticheskie rekomendatsii po dozimetrii, osnovannye na etalonakh edinitsy pogloshchennoi dozy v vode [International practical recommendations on dosimetry based on standards for absorbed dose units in water. With support from IAEA, WHO, PAHO and ESTRO]. Technical Report Series No. 398. Vienna: International Atomic Energy Agency, 2004. (In Russ.). URL: https://www-pub.iaea.org/mtcd/publications/pdf/trs398r_web.pdf