Radiological evaluation of childhood abdominal masses in Ilorin, Nigeria

Background: The presentation of a child with an abdominal mass is a source of concern to the Paediatricians, Paediatric Surgeons and the parents, and it poses a diagnostic challenge. Due to the low socio-economic status of the patients in this setting, cost-effective approach in evaluating these patients is necessary.Objective: This was to determine the common causes and the most costeffective radiological examination to diagnose abdominal mass in children.Design: This was a retrospective cross sectional descriptive study.Setting: University of Ilorin Teaching Hospital, Ilorin. Nigeria.Subjects: Paediatric patients with abdominal masses seen in the Radiology Department of UITH, Ilorin over a period of 5 years (2011-2015)Analysis: Statistical analysis was carried out using the Statistical Package for the Social Sciences version 20.0 (SPSS Inc; Chic; Il.).Result: A total of 172 patients were seen, including 98(57%) males. All patients seen (100%) had abdominal ultrasound followed by plain radiography 161 (93.6%) and 44(25.5%) patients had histological confirmation. The Kidneys 53 (30.8%) was the most affected organ followed by liver 48(27.9%) and spleen 30(17.4%). Burkitt’s lymphoma 15 (34.1%) was the commonest histological diagnosis followed by nephroblastoma 14 (31.8%).Conclusion: Ultrasonography was the most common imaging modality used for evaluation of children with abdominal masses in this setting. The kidney was the most affected organ and Burkitt’s lymphoma was the most prevalent histological diagnosis followed by nephroblastoma in this study

Recent advances in silica glass optical fiber for dosimetry applications

In this paper, we review the highly promising silica glass, fabricated as doped and undoped optical fiber for intended use in radiation dosimetry. The dosimetry techniques reviewed here, underpinned by intrinsic and extrinsic defects in silica glass, focus on Thermoluminescence (TL), Optically Stimulated Luminescence (OSL) and Radioluminescence (RL), with occasional references to the much more established Radiation Induced Attenuation (RIA). The other focus in this review is on the various materials that have been reported earlier as dopants and modifiers used in silica glass optical fiber radiation dosimeters. This article also elaborates on recently reported optical fiber structures, namely, cylindrical fibers, photonic crystal fibers and flat fibers, as well as dimensions and shapes used for optimization of dosimeter performance. The various types of optical fiber radiation dosimeters are subsequently reviewed for various applications ranging from medical dosimetry such as in external beam radiotherapy, brachytherapy and diagnostic imaging, as well as in industrial processing and space dosimetry covering a dynamic dose range from μGy to kGy. Investigated dosimetric characteristics include reproducibility, fading, dose response, reciprocity between luminescence yield to dose-rate and energy dependence. The review is completed by a brief discussion on limitations and future developments in optical fiber radiation dosimetry

Implications of serial measurements of natriuretic peptides in heart failure: insights from BIOSTAT‐CHF

No abstract available

Effects of hydroxyl content in pure silica optical fiber exposed to kGy electron beams

We present a study on the effect of high dose (kGy) electron beams on pure silica core fibers through examining the following phenomena within the fibers: radioluminescence (RL), radiation induced attenuation (RIA), and recovery. The objective is to identify the relevant characteristics of these fibers having favourable radiation response, that can be utilized in the development of dose measurement systems for high dose (kGy) environments. Two types of 20 m long pure silica optical fiber samples have been used, differing in their concentrations of hydroxyl (OH) content. Segments of 3.5 m length from each fiber were wound into coils of radius ~25 cm and exposed to consecutive irradiation doses, in the order of tens of kGy (10 kGy through 70 kGy in individual exposures), leading to a cumulative dose of some 300 kGy. The low-OH fiber showed saturation of response at the shorter wavelengths of the RL spectrum for doses of 30 kGy and above, resulting from presence of Oxygen Defect Centers (ODC). At the longer wavelengths the RL response of the low-OH optical fibers is observed to increase with dose, attributed to various bonding structural defects of silica nanoclusters. The saturation effect at shorter wavelengths is less prominent in the high-OH samples, where a monotonic increase is observed up to ~60 kGy indicating the formation of radiation induced ODC beyond this point. For cumulative dose of ~70 kGy, the highest RIA losses were registered at 550 nm (12.74 dB/m) for low-OH sample, and at 460 nm (4.75 dB/m) for high-OH sample. The high-OH sample showed much faster recovery post-irradiation, making it more suitable for repeated usage. Both the RL and RIA phenomena observed herein show the feasibility of pure silica optical fibers for dose measurement in high dose (kGy) environments up to individual dose of ~70 kGy

Determination of Radiation Delivery Parameters of Medical Linear Accelerators using Data Analytics Pipeline

Radiotherapy treatments involve the delivery of sharp radiation pulses of 2 to 4 microseconds duration over typical total periods of 30 to 300 seconds at a rate of up to 400 pulses per second. Recent developments in optical fiber-based radioluminescence/scintillator systems offer radiation-sensing capabilities that capture signals from individual pulses. Each of these signals has unique characteristics which provide insights into the parameters of radiation delivery. Current data acquisition methods commonly rely on hardware-based charge integration methods for radiation dose calculations and have limited utilization of the acquired data for further insights or applications. In this paper, a data analytics pipeline for the extraction and processing of data from a Ge-doped real-time dosimetry system is presented. The data, as obtained for an Elekta Synergy radiotherapy system, is then analyzed for dose distribution, dose-rates determination, and signal clustering. The gathering and processing of such time-resolved data would enable applications such as fault analysis, auto-calibration, and equipment fault prediction in medical radiation facilities in addition to enhancing the routine QA process

Real-time germanium-doped optical fibers for clinical computed tomography dosimetry

In studies focusing on the practice of clinical computed tomography (CT) a particular concern has been that of delivering unnecessary dose to patients and with it the added risk for radiation-induced cancers. For a CT system, present work has investigated the dosimetric characteristics of a Ge-doped optical fiber real-time dosimetry system (model LS-2000, Lumisyns), measuring beam quality, exposure linearity and exposure duration accuracy. For comparison, the study has used a RaySafe X2 test device (Unfors RaySafe) and a Black Piranha (RTI) QA meter. Irradiations were made using a Somatom Definition Flash dual-source 128-slice CT scanner (Siemens Healthcare). The LS-2000, RaySafe X2, and Black Piranha sensors were exposed to beams energized at accelerating potentials ranging from 80 to 140 kVp, with tube current-time products from 50 to 300 mA, and exposure durations from 750 to 2000 ms. Constant signal responses from the LS-2000 have been obtained, measured in respect of beam quality, exposure linearity, and time accuracy. In respect of accuracy of beam quality, the RaySafe X2 and Black Piranha maximum deviations were 1% and 5%, respectively; the coefficients of linearity of RaySafe, Black Piranha and LS-2000 are 1%, 0.4% and 1.4%, respectively; the maximum deviation for the time accuracy test for the three sensors are 0.5%, 2% and 1.3%, respectively. Evaluation of the LS-2000 real-time dosimetry system with a Ge-doped optical fiber scintillator points to potential for its use in clinical CT dosimetry

Real-time radiation dosimetry using P-doped silica optical fiber

Radiation dosimetry applications related to radiotherapy have clear importance in determining the accurate and safe delivery of patient prescribed doses. Versatile yet robust, high spatial resolutions, wide dynamic range real-time forms of dosimetry are called for. Doped silica optical fibers of sub-mm spatial resolution exhibit useful radioluminescence (RL) properties when exposed to ionizing radiation. In this study, primary investigations have been carried out on phosphorus-doped silica optical-fiber. High-energy clinical X-ray beams (6 MV and 10 MV) were used to irradiate the optical fiber, RL response being recorded for six dose-rates (between 100 MU/min and 600 MU/min) delivered by a Varian 2100 C/D linear accelerator. The P-doped optical-fiber showed linear RL response, with minimal observable memory and afterglow and plateau effects. The results indicate the P-doped optical-fiber dosimeter to have strong potential for use in radiotherapy applications

Time-resolved radiation dosimetry using a cerium and terbium co-doped YAG crystal scintillator

Time-resolved radiation dosimetry is an important factor in ensuring dose delivery during radiotherapy is within the prescribed doses for treatment. One method for time-resolved radiation dosimetry is by radioluminescence (RL) measurement technique using doped-silica optical fibre scintillators. The benefits of RL measurement technique include the capability to measure in real-time, high spatial resolution, and greater adaptability. Additionally, time-resolved dosimetry can be achieved by employing suitable scintillators with short rise and decay time. Silica optical fibre scintillators when doped with suitable dopants, provides the temporal resolution required for pulse-by-pulse dosimetry. Yttrium Aluminium Garnet (YAG) crystal optical fiber doped with Cerium and Terbium are discussed as a possible scintillator for time-resolved radiation dosimetry. The Cerium and Terbium co-doped YAG crystal scintillator samples are irradiated under a 6 MV photon beam from a Elekta Synergy® LINAC. The irradiation doses ranged from 100 cGy/min to 600 cGy/min. The measurements were made using an RL system with a gating time of 1μs. Linear RL response to dose of the irradiated scintillator samples was shown with minimal detectable memory, no afterglow or plateau effects. A rise time of 189.3 ns and a decay time of 260 ns were recorded, indicating promising potential for time-resolved radiation dosimetry.</p