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Coherent and incoherent scatterings for measurement of mandibular bone density and stable iodine content of tissue.

Sharma A, Singh M, Singh B, Sandhu BS - J Med Phys (2009)

Bottom Line: 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 present non-destructive technique has the potential for a measure of mandibular bone density and stable iodine contents of thyroid.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics, Punjabi University, Patiala-147002, India.

ABSTRACT
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.

No MeSH data available.


Related in: MedlinePlus

Experimental set-up
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Figure 0001: Experimental set-up

Mentions: Two separate experiments, one for madibular bone density using 59.54 keV gamma rays and the other for stable iodine content of tissue using 145 keV gamma rays, are performed simultaneously. Figure 1 shows narrow beam geometry used in the present measurements to observe simultaneously the coherent and incoherent scattered gamma ray flux. A well-collimated beam of 59.54 keV gamma rays from 241Am radioactive source (strength 7.4 GBq, T1/2 = 458 years) irradiates the phantom simulating mandibular bone. This source is chosen because its low gamma ray energy favours coherent scattering and at the same time this energy is not so low as to cause severe gamma ray losses due to phantom (simulating mandibular bone) attenuation. 241Am does not emit other photons in the region of 59.54 keV or above; thus, coherent and other peaks can be distinguished without interference from other emissions. In addition, 241Am has a long half-life and it is readily available. Bone phantoms are prepared using K2HPO4 and distilled water. Aqueous solutions of K2HPO4 in the concentration range 0-30 g in steps of 6 g in 100 mL of water are used to simulate the bone density ranging from 1000 to 1200 kg/m3. The solutions are filled in plastic containers (diameter 43, 65 and 82 mm for central, middle and outer containers, respectively) positioned at the center of rotation of the source and detector assemblies. For measurement of iodine content of tissue, a well-collimated beam of 145 keV gamma rays from 141Ce source of strength 0.74 GBq irradiates the phantom. The sample (phantom) is in the form of KI of different amounts ranging from 2 to 10 g in step of 2 g in 10 mL of distilled water filled in a plastic vial (10 mm diameter) kept in a stand with screw to adjust its height.


Coherent and incoherent scatterings for measurement of mandibular bone density and stable iodine content of tissue.

Sharma A, Singh M, Singh B, Sandhu BS - J Med Phys (2009)

Experimental set-up
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2807686&req=5

Figure 0001: Experimental set-up
Mentions: Two separate experiments, one for madibular bone density using 59.54 keV gamma rays and the other for stable iodine content of tissue using 145 keV gamma rays, are performed simultaneously. Figure 1 shows narrow beam geometry used in the present measurements to observe simultaneously the coherent and incoherent scattered gamma ray flux. A well-collimated beam of 59.54 keV gamma rays from 241Am radioactive source (strength 7.4 GBq, T1/2 = 458 years) irradiates the phantom simulating mandibular bone. This source is chosen because its low gamma ray energy favours coherent scattering and at the same time this energy is not so low as to cause severe gamma ray losses due to phantom (simulating mandibular bone) attenuation. 241Am does not emit other photons in the region of 59.54 keV or above; thus, coherent and other peaks can be distinguished without interference from other emissions. In addition, 241Am has a long half-life and it is readily available. Bone phantoms are prepared using K2HPO4 and distilled water. Aqueous solutions of K2HPO4 in the concentration range 0-30 g in steps of 6 g in 100 mL of water are used to simulate the bone density ranging from 1000 to 1200 kg/m3. The solutions are filled in plastic containers (diameter 43, 65 and 82 mm for central, middle and outer containers, respectively) positioned at the center of rotation of the source and detector assemblies. For measurement of iodine content of tissue, a well-collimated beam of 145 keV gamma rays from 141Ce source of strength 0.74 GBq irradiates the phantom. The sample (phantom) is in the form of KI of different amounts ranging from 2 to 10 g in step of 2 g in 10 mL of distilled water filled in a plastic vial (10 mm diameter) kept in a stand with screw to adjust its height.

Bottom Line: 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 present non-destructive technique has the potential for a measure of mandibular bone density and stable iodine contents of thyroid.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics, Punjabi University, Patiala-147002, India.

ABSTRACT
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.

No MeSH data available.


Related in: MedlinePlus