Severity: Warning
Message: file_get_contents(https://...@gmail.com&api_key=61f08fa0b96a73de8c900d749fcb997acc09): Failed to open stream: HTTP request failed! HTTP/1.1 429 Too Many Requests
Filename: helpers/my_audit_helper.php
Line Number: 143
Backtrace:
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 143
Function: file_get_contents
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 209
Function: simplexml_load_file_from_url
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 994
Function: getPubMedXML
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 3134
Function: GetPubMedArticleOutput_2016
File: /var/www/html/application/controllers/Detail.php
Line: 574
Function: pubMedSearch_Global
File: /var/www/html/application/controllers/Detail.php
Line: 488
Function: pubMedGetRelatedKeyword
File: /var/www/html/index.php
Line: 316
Function: require_once
Purpose: Manual and automatic blood sampling at different time intervals is considered the gold standard to determine the arterial input function (AIF) in dynamic positron emission tomography (PET). However, blood sampling is characterized by poor time resolution and is an invasive procedure. The aim of this study was to characterize the scintillating fibers used to develop a non-invasive positron detector.
Methods: The detector consists of a scintillating fiber coupled at each end to transmission fiber-optic cables that are connected to photo multiplier tubes in a dual readout setup. The detector is designed to be wrapped around the wrist of the patient undergoing dynamic PET. The attenuation length and bending losses were measured with excitation from gamma radiation (Cs) and ultraviolet (UV) light. The response to positron-emitting radio-tracers was evaluated with F and C.
Results: The attenuation length for a 3.0 m and 1.5 m long scintillating fiber both coincides with the attenuation length given by the manufacturer when excited with the Cs source, but not with the UV source due to the differences in scintillation mechanisms. The bending losses are smaller than the measurement uncertainty for the Cs source irradiation, and increase when the bending radius decrease for the UV source irradiation. The signal-to-noise ratio for F and C solutions are 1.98 and 22.54 respectively. The measured decay constant of C agrees with its characteristic value.
Conclusion: The performed measurements in the dual readout configuration suggest that scintillating fibers may be suitable to determine the AIF non-invasively.
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Source |
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http://dx.doi.org/10.1016/j.ejmp.2019.08.009 | DOI Listing |
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