Development and Optimization of Surface and Volume Radiofrequency Coils Suitable for Fast-Field-Cycling Magnetic Resonance Imaging (FFC-MRI)

  Objective: To evaluate a modelling and design methodology employed in constructing and optimizing radiofrequency (RF) coils suitable for use with the whole-body fast-field-cycling Magnetic Resonance Imaging (FFC-MRI). It is also aimed at comparing the sensitivity and the signal-to-noise ratio (SNR) of the various types of surface RF coils constructed at the initial and final stages of this research. Methodology: An experimental study carried out at Biomedical MRI Laboratory at University of Aberdeen. Various designs of RF coil were constructed, optimized and tested with network/signal analyser for use with an experimental FFC - MRI scanner, operating at a detection magnetic field of 0.2 T (proton Larmor frequency of 8.5 MHz). The coils comprised circular loop (CL) RF – receive surface coil and a birdcage RF – transmit volume coil.  The intrinsic parameters of the CL coils were measured using a search-coil field probe and a network/signal analyser. Results: The CL surface coil constructed with copper wire had resonant frequency of 8.46 MHz and Quality factor (Q – factor) of 47.1 while the resonant frequency of the one constructed with litz wire was 8.54 MHz and Q - factor of 85.4 MHz. The intrinsic parameter of the birdcage volume coil was 8.48 MHz and Q - factor of 102. Conclusion: Bench testing of the coils showed promise as receiver and transmit coils for the FFC-MRI system &nbsp

X-Ray Film Reject Analysis as a Quality Indicator in a Tertiary Health Centre in Northwestern Nigeria

Objective: To assess the rate of rejects in routine radiography as a quality control measure.   Methods: Retrospective study was carried out on radiographs obtained from two conventional diagnostic rooms of the Radiology Department at Usmanu Danfodiyo University Teaching Hospital, Sokoto, for a period of six months (July-December 2016). All rejected radiographs were analyzed under uniform viewing conditions. All images with good diagnostic quality, those carried out for special examination and mammograms were excluded. Data were collected and entered into database for analysis.   Results: The overall reject rate was found to be 16.4% with chest contributing the (7.1%). The major cause of reject was inappropriate collimation (18.1%).   Conclusion: A total of 16.4% reject was noted in the study conducted, which was above the recommended level given by World Health Organization (WHO).   &nbsp