Sharma Amandeep, Singh Mohinderpal, Singh Bhajan, Sandhu Balvir S
Department of Physics, Punjabi University, Patiala-147002, India.
J Med Phys. 2009 Jul;34(3):182-7. doi: 10.4103/0971-6203.54855.
The aim of present study is to investigate the feasibility of gamma ray scattering for measurements of mandibular bone density and stable iodine content of tissue. Scattered spectra from solutions of K(2)HPO(4) in distilled water (a phantom simulating the mandibular bone) and KI in distilled water filled in a thin plastic vial (a phantom simulating the kinetics of thyroid iodine) are recorded for 59.54 and 145 keV incident gamma rays, respectively. A high-purity germanium detector is placed at various angular positions to record the scattered spectra originating from interactions of incident gamma rays with the phantom. The measured intensity ratio of coherent to incoherent scattered gamma rays, corrected for photo-peak efficiency of HPGe detector, absorption of gamma rays in air column present between phantom and detector, and self-absorption in the phantom, is found to be increasing linearly with increase in concentration of K(2)HPO(4) and KI in distilled water within experimental estimated error of <6%. The regression lines, obtained from experimental data for intensity ratio, provide the bone density and stable iodine contents of thyroid. The present non-destructive technique has the potential for a measure of mandibular bone density and stable iodine contents of thyroid.
本研究的目的是探讨利用伽马射线散射测量下颌骨密度和组织中稳定碘含量的可行性。分别记录了59.54 keV和145 keV入射伽马射线照射下，装在薄塑料瓶中的磷酸氢二钾蒸馏水（模拟下颌骨的体模）溶液和碘化钾蒸馏水（模拟甲状腺碘动力学的体模）的散射光谱。将高纯锗探测器置于不同角度位置，记录入射伽马射线与体模相互作用产生的散射光谱。在校正了HPGe探测器的光电峰效率、体模与探测器之间气柱对伽马射线的吸收以及体模中的自吸收后，测得的相干散射伽马射线与非相干散射伽马射线的强度比，在实验估计误差<6%的范围内，随蒸馏水中磷酸氢二钾和碘化钾浓度的增加呈线性增加。由强度比实验数据得到的回归线可得出甲状腺的骨密度和稳定碘含量。这种非破坏性技术有潜力用于测量下颌骨密度和甲状腺稳定碘含量。
