【摘要】：目的 INTRABEAM系統(tǒng)是一款使用低能X射線的術(shù)中放射治療(intra-operative radiotherapy,IORT)專用設(shè)備,其低能X射線特性平板和針形施用器相關(guān)劑量學(xué)研究較少。本研究測試低能光子線術(shù)中放射治療系統(tǒng),分析低能X射線源和球形、平板、針形三種施用器的劑量學(xué)特點并對其潛在臨床應(yīng)用進行初步探討。方法采用專用水箱、平行板電離室和靜電計等測量儀器,測量X射線源在不同管電壓/管電流下的劑量特性,以及3種施用器的深度劑量率、各向同性、劑量重復(fù)性,并與系統(tǒng)數(shù)據(jù)進行比對。結(jié)果40和50kV X射線的深度劑量率測量值與系統(tǒng)數(shù)據(jù)偏差分別為(-1.56±1.29)%和(-2.16±1.36)%,不同管電流下的深度劑量率測量值與理論值偏差為-2.3%~1.7%。不同施用器的劑量梯度不同,直徑越小,表面劑量越高,劑量梯度越大。施用器的轉(zhuǎn)換系數(shù)隨施用器種類、大小和測量深度而變化;不同直徑球形施用器轉(zhuǎn)換系數(shù)測量值與系統(tǒng)值偏差均值為-2.6%~2.4%,針形施用器轉(zhuǎn)換系數(shù)偏差均值為-3.8%。重復(fù)測量結(jié)果表明,X射線源和3種施用器的深度劑量率、各向同性的重復(fù)性較好。結(jié)論低能X射線源在不同管電壓/管電流下的測量值與系統(tǒng)數(shù)據(jù)一致性較好,其劑量分布隨施用器的種類、大小和測量深度變化較大,臨床應(yīng)用時應(yīng)充分考慮。
[Abstract]:Objective INTRABEAM system is a special equipment for intra-operative radiotherapytherapy (IORT) using low energy X ray. The dosimetry of low energy X ray characteristic plate and needle applicator is less. In this study, the low energy photon line intraoperative radiotherapy system was tested, and the dosimetric characteristics of the low energy X-ray source and three applicators, spherical, flat and needle, were analyzed and their potential clinical applications were discussed. Methods the dose characteristics of X-ray sources under different tube voltages / tube currents were measured with special water tank, parallel plate ionization chamber and electrometer, and the depth dose rate, isotropy and dose repeatability of the three applicators were measured. And compared with the system data. Results the depth dose rate measurements of 40 and 50kV X-rays were (-1.56 鹵1.29)% and (-2.16 鹵1.36)%, respectively. The deviation between the depth dose rate measurements at different tube currents and the theoretical values was -2.3% and 1.7%, respectively. The dose gradient of different applicators is different, the smaller the diameter, the higher the surface dose and the larger the dose gradient. The conversion coefficient of the applicator varies with the type, size and depth of the applicator, and the mean deviation between the measured value of the conversion coefficient and the system value of the spherical applicator with different diameters is -2.6 and 2.4, and the mean deviation of the conversion coefficient of the needle applicator is -3.8. The results of repeated measurement showed that the depth dose rate and isotropic repeatability of X-ray source and three applicators were good. Conclusion the measured values of low energy X-ray sources under different tube voltages / tube currents are in good agreement with the system data, and the dose distribution varies greatly with the type, size and depth of the applicator, which should be fully considered in clinical application.
【作者單位】： 中山大學(xué)附屬第一醫(yī)院放射治療科;
【分類號】：R730.55
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本文編號：2159122