Shielding optimization in an in vivo activation analysis setup

Moghaddam, Yasaman Rezaei; Rafat-Motavalli, Laleh; Hakimabad, Seyyed Hashem Miri

doi:10.1007/s10967-012-1978-5

Cited by 5 publications

(3 citation statements)

References 13 publications

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“…The geometry of the sample was constructed with four major parts: (i) an elliptical cylinder representing the trunk and arm; (ii) a half ellipsoid placed on top of an elliptical cylinder as a head; (iii) another elliptical cylinder between the head and trunk representing the neck; and (iv) two truncated circular cones that represent the legs and feet [17]. The elemental composition and density of three major body tissues (skeletal, lung and soft tissue) were chosen from Table A-1 of ORNL/TM8381 [27].…”

Section: Methodsmentioning

confidence: 99%

“…This situation can be simulated when photon production is turned on only in the phantom. The evaluated spectrum can be analyzed and calibrated to measure the precise amount of sample elements [17]. If the energy of the secondary photons that were produced inside the different components of the facility lie in the region of interest (ROI), distinguishing the ideal peak will be difficult.…”

Section: Methodsmentioning

confidence: 99%

“…Using fast neutrons to improve uniformity, the dose delivered to the body increases [5, 16]. In addition, the activation of materials used in the facility may affect detector spectrum [17]. Thus, uniformity, absorbed dose and gamma spectrum should be inspected simultaneously.…”

Section: Introductionmentioning

confidence: 99%

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Facility optimization to improve activation rate distributions during IVNAA

Khankook

Rafat-Motavalli

Hakimabad

2013

Journal of Radiation Research

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Currently, determination of body composition is the most useful method for distinguishing between certain diseases. The prompt-gamma in vivo neutron activation analysis (IVNAA) facility for non-destructive elemental analysis of the human body is the gold standard method for this type of analysis. In order to obtain accurate measurements using the IVNAA system, the activation probability in the body must be uniform. This can be difficult to achieve, as body shape and body composition affect the rate of activation. The aim of this study was to determine the optimum pre-moderator, in terms of material for attaining uniform activation probability with a CV value of about 10% and changing the collimator role to increase activation rate within the body. Such uniformity was obtained with a high thickness of paraffin pre-moderator, however, because of increasing secondary photon flux received by the detectors it was not an appropriate choice. Our final calculations indicated that using two paraffin slabs with a thickness of 3 cm as a pre-moderator, in the presence of 2 cm Bi on the collimator, achieves a satisfactory distribution of activation rate in the body.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%