Simulation of in-vivo measurement of ^<90>Sractivity in bone by detecting bremsstrahlung x-rays

通过检测轫致辐射 X 射线模拟骨中 ^<90>Sractivity 的体内测量

• 批准号: 06680511
• 负责人: UEHARA Shuzo
• 金额: $ 0.77万
• 依托单位: KYUSHU UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1994
• 资助国家: 日本
• 起止时间: 1994 至 1995
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06680511/
• 关键词: In-vivo measurement; ^<90>Sr in bone; Beta-ray emitter; Bremsstrahlung; Body phantom; Photon detector; Monte Carlo Simulation

1) Since 1960's there are a number of experimental works on the external measurement of ^<90>Sr+^<90>Y bremsstrahlung generated by their beta-rays using the whole-body counter installed NaI (Tl) crystal. Quantitative evaluation of the bremsstrahlung yield of ^<90>Sr+^<90>Y has been undertaken using an in-house Monte Carlo code SR90. The optimum organ and the condition for the external measurement of bremsstrahlung using a single detector was investigated under more realistic environment contaminated by the other sources such as ^<137>Cs and ^<40>K.2) Body organs consisted of a large volume bone and also thin skin such as leg, waist and head are considered to be the candidates for the present purpose. As the results of calculations, waist and head were inappropriate because they contain large volume inner soft tissue. Leg phantom approximated by the coaxial cylinder consisted of bone and skin was investigated varying the bone diameter and skin thickness.3) The photon spectrum entering the detector window having 200 mm diameter was obtained. A factor, signal-to-noise ratio s/n, was introduced to judge quantitatively the optimum condition for in-vivo measurements.s/n = <@D7I(<@D190@>D1Sr[1])(/)I(<@D1137@>D1Cs[1]+<@D140@>D1K[70])@>D7in which I means the intensity between 30 and 160 keV in the calculated spectrum for the sources with activities in units of Bq kg^<-1> designated in the bracket. In comparison with s/n ratio for various conditions of leg phantom, the best value was obtained for the case of large bone (50 mm diameter) covered with thin skin (1 mm).4) A possibility of a new and simple method for in-vivo measurement of beta-emitter is suggested by combining the present calculations with the conventional measurements.

1)自20世纪60年代以来，利用安装在NaI （Tl）晶体上的全身计数器，对其β射线产生的^<90>Sr+^<90>Y轫致辐射进行了大量的外部测量实验。使用内部蒙特卡罗代码SR90，对^<90>Sr+^<90 >y的轫致应变产率进行了定量评价。在^<137>Cs和^<40 >k污染的较为真实的环境下，研究了单探测器外测轫致辐射的最佳器官和条件。2)由大量骨骼和薄皮肤组成的身体器官，如腿、腰和头，被认为是目前目的的候选人。从计算结果来看，腰部和头部由于含有大量的内部软组织，是不合适的。研究了由骨和皮肤组成的共轴圆柱体近似的腿模，改变骨直径和皮肤厚度。3)得到了进入直径为200mm的探测器窗口的光子光谱。引入信噪比s/n因子定量判断体内测量的最佳条件。s/n = <@ d7i (<@ d190 @>D1Sr[1])(/)I(<@ d1137 @>D1Cs[1]+<@ d140 @>D1K[70])@> d7其中，我是指在计算光谱中，以Bq kg^<-1>为单位的源的强度在30至160 keV之间。对不同情况下腿肢的s/n比进行比较，在大骨（直径50 mm）覆盖薄皮肤（1 mm）的情况下获得最佳值。4)结合现有的计算方法和传统的测量方法，提出了一种新的、简单的体内β -发射器测量方法的可能性。

项目成果

Shuzo Uehara: "Simulation of in-vivo measurement of ^<90>Sr activity in bone by detecting bremsstrahlung x-rays (II)" Journal of Radiation Research. 36. 308- (1995)

Shuzo Uehara：“通过检测轫致辐射X射线模拟体内测量骨中^ 90 Sr活性（II）”辐射研究杂志。

Shuzo Uehara: "Simulation of in-vivo measurement of ^<90>Sr activity in bone by detecting bremsstrahlung x-rays" Journal of Radiation Research. 35. 341- (1994)

Shuzo Uehara：“通过检测轫致辐射X射线模拟体内测量骨中^ 90 Sr活性”辐射研究杂志。

上原 周三: "骨中^<90>Sr放射能による制動X線検出の可能性" 第5回放射線計測研究会論文集. 6-12 (1994)

Shuzo Uehara：“利用骨骼中的 ^<90>Sr 放射性检测轫致辐射 X 射线的可能性”第五辐射测量研究组的会议记录 6-12 (1994)。

Shuzo Uehara: "Simulation of in-vivo measurement of ^<90>Sr activity in bone by detecting bremsstrahlung x-rays" 35. 341 (1994)

Shuzo Uehara：“通过检测轫致辐射 X 射线模拟骨中 ^<90>Sr 活性的体内测量”35. 341 (1994)

S.Uehara and M.Hoshi: "Monte Carlo simulation of in-vivo measurements of ^<90>Sr + ^<90>Y bremsstrahlung" Health Physics.(submitted).

S.Uehara 和 M.Hoshi：“^<90>Sr ^<90>Y 轫致辐射体内测量的蒙特卡罗模拟”健康物理学。（已提交）。