Quality Assurance Parameters Research Articles

Establishment of Quality Standards of Abrus precatorius Linn. Seeds

Standardization of herbal formulations is an important aspect while considering the quality of the herbal drug, consistency in active principle content and therapeutic efficacy. The seeds of Abrus precatorius Linnaeus, a well-established medicinal plant belonging to the family Fabaceae is commonly known as Gunja or Rati. In view of its medicinal importance the present study was conducted to standardize the crude drug according to the standard laboratory methods and to define pharmacopoeial standards for the seeds of this species. Qualitative phytochemical analysis and physiochemical studies of the powdered drug using various methods including organoleptic analysis, ash value, extractive value, thin-layer chromatography, loss on drying, and fluorescence analysis were performed to establish quality standards of the herb, which would help in identification as well as develop quality assurance parameters for herbal formulations containing this herbal product as an active component.

A preliminary investigation on long-term consistency of MPC as a quick daily QA application

Purpose: The purpose of this study was to establish Machine performance check (MPC) application as a comprehensive daily QA program in a clinical setting for a True Beam 2.0 system and investigate the first ten months (195 days) daily QA data generated by the MPC. Methods: An automated daily quality assurance (QA) application named machine performance check (MPC) was recently launched by Varian Medical Systems with their TrueBeam 2.0 linear accelerator (linac) system. MPC performs all the essential machine tests such as Beam Constancy Check, and Geometry Check with the use of an IsoCal phantom. There is no systematic published study on long-term consistency and validation of MPC in a clinical set-up for its acceptance as an alternative QA application. In the present study, we collected data with the MPC for over ten months (195 days) on a TrueBeam 2.0 system. The data was analysed for reproducibility and also compared with the data collected with other statndard QA devices at the time of commissioning of the TrueBeam system for validation. Results: The results showed that the reproducibility of MPC was at least an order of magnitude less than the tolerance values for the respective parameters and also the average measured values for all QA parameters studied. The MPC measured isocenter accuracy, and output values were close to the Winston-Lutz test (within 0.1 mm) and the ion-chamber measurements (within 0.1%), respectively. Conclusion: With our long term result, it is evident that the MPC could be an alternative daily QA tool. A comprehensive and long-term validation of the MPC measured values with the other standard QA methods over the ten month period will be needed before accepting MPC as a reliable QA tool.

A Feasibility Study on Incorporating Clinical Trial Quality Assurance Parameters into Outcome Prediction in Head and Neck Radiation Therapy Treatment

A Feasibility Study on Incorporating Clinical Trial Quality Assurance Parameters into Outcome Prediction in Head and Neck Radiation Therapy Treatment

Buccal swab genomic DNA fragmentation predicts likelihood of successful HLA genotyping by next-generation sequencing

Many clinical human leukocyte antigen (HLA) laboratories are adopting next-generation sequencing (NGS) technology for HLA genotyping. There have been several reports of the cost-benefit and reduction in turn-around-time provided by NGS. Ninety-six percent of buccal swabs and peripheral blood samples had reportable HLA genotyping by NGS. The HLA loci most likely to fail genotyping from buccal swabs were DQB1, DPB1, and DPA1. Successful buccal swab samples had significantly less genomic DNA fragmentation compared to buccal swab samples that were unsuccessful. Increasing sequencing depth of coverage for heavily fragmented samples rescued HLA genotyping. This information provides laboratories with a quality assurance parameter that reduces the amount of repeat NGS needed to achieve high-resolution HLA genotyping. This information should further reduce laboratory and patient costs for HLA genotyping.

Beam focal spot position: The forgotten linac QA parameter. An EPID-based phantomless method for routine Stereotactic linac QA.

Modern day Stereotactic treatments require high geometric accuracy of the delivered treatment. To achieve the required accuracy the IGRT imaging isocenter needs to closely coincide with the treatment beam isocenter. An influence on this isocenter coincidence and on the spatial positioning of the beam itself is the alignment of the treatment beam focal spot with collimator rotation axis. The positioning of the focal spot is dependent on the linac beam steering and on the stability of the monitor chamber and beam steering servo system. As such, there is the potential for focal spot misalignment and this should be checked on a regular basis. Traditional methods for measuring focal spot position are either indirect, inaccurate, or time consuming and hence impractical for routine use. In this study a novel, phantomless method has been developed using the EPID (Electronic Portal Imaging Device) that utilizes the different heights of the MLC and jaws. The method has been performed on four linear accelerators and benchmarked against an alternate ion chamber‐based method. The method has been found to be reproducible to within ±0.012 mm (1 SD) and in agreement with the ion chamber‐based method to within 0.001 ± 0.015 mm (1 SD). The method could easily be incorporated into a departmental routine linac QA (Quality Assurance) program.

天然气中H<sub>2</sub>S快速定量检测研究进展

H2S对天然气的运输、贮存及使用安全会产生破坏性的影响，其含量是天然气检测必不可少的项目，快速准确测定其含量具有极其重要的意义。本文对天然气中H2S检测所用到的国内国际标准进行了总结分析。在此基础上，综述了满足快速定量检测H2S的半导体氧化物、电化学和光学传感器研究进展，比较各种H2S检测传感器的操作标准(如操作原理、检测限、响应时间、检测浓度范围)。最后，探讨各种传感器的不足并指出今后的发展方向。 H2S has great effect on the transportation, storage and use safety of natural gas. It is an absolutely necessary measuring project for natural gas quality control. So it has important significance to quickly and precisely monitor H2S content. The summary is made about the present national and international standard test method for H2S in natural gas. Based on these, sensor-based type for quantifying H2S including semiconductor metal oxide, electrochemical and optical sensor are re-viewed. Different quality-assurance parameters (e.g., operating principles, limit of detection, re-sponse time and common operating range of concentration) are evaluated and compared. Finally, the limitations and the future prospects of these sensor-based methods are highlighted.

Tropical Fruit Pulps: Processing, Product Standardization and Main Control Parameters for Quality Assurance

ABSTRACT Fruit pulp is the most basic food product obtained from fresh fruit processing. Fruit pulps can be cold stored for long periods of time, but they also can be used to fabricate juices, ice creams, sweets, jellies and yogurts. The exploitation of tropical fruits has leveraged the entire Brazilian fruit pulp sector due mainly to the high acceptance of their organoleptic properties and remarkable nutritional facts. However, several works published in the last decades have pointed out unfavorable conditions regarding the consumption of tropical fruit pulps. This negative scenario has been associated with unsatisfactory physico-chemical and microbiological parameters of fruits pulps as outcomes of little knowledge and improper management within the fruit pulp industry. There are protocols for delineating specific identity and quality standards (IQSs) and standardized good manufacturing practices (GMP) for fruit pulps, which also embrace standard operating procedures (SOPs) and hazard analysis and critical control points (HACCP), although this latter is not considered mandatory by the Brazilian legislation. Unfortunately, the lack of skilled labor, along with failures in complying established protocols have impaired quality of fruit pulps. It has been necessary to collect all information available with the aim to identify the most important hazards within fruit pulp processing lines. Standardizing methods and practices within the Brazilian fruit pulp industry would assurance high quality status to tropical fruit pulps and the commercial growth of this vegetal product towards international markets.

Changes in the Physicochemical Quality Characteristics of Cabbage Kimchi with respect to Storage Conditions

In this study, the changes in pH, organic acid content, acidity, and salinity of kimchi prepared at 0 days, stored 1–8 weeks at 4 and 10°C, and stored at room temperature for two days were analyzed. Organic acids content was analyzed by using analytical technique of high-performance liquid chromatography (HPLC). This method was also validated using quality assurance parameters of linearity, limits of detection and quantification (LOD and LOQ), precision, and spike recovery experiments. In the analysis of organic acids content (mg/kg), it was found that the kimchi stored for 1–8 weeks at 4 and 10°C showed gradual increase in the organic acids content during storage period. The order of organic acids was lactic acid > acetic acid > citric acid > malic acid > succinic acid > oxalic acid > fumaric acid. The pH values of kimchi stored at 4°C, 10°C, and 25°C were 4.1, 3.6–3.7, and 4.1, respectively.

Current State of Bedside Glucose Meter Testing.

As arguably the most measured analyte in clinical chemistry, glucose remains a topic of great discussion. The measurement of glucose is relatively straightforward and robust in the central laboratories, whereby glucose in plasma or serum and other body fluids is quantified using enzymatic-spectrophotemetric–based methods. At the bedside, glucose is most routinely assessed with handheld meters using test strips that measure whole blood glucose in an enzymatic-electrochemical manner. Test strip methods have come a long way since the early days; current generation glucose meters provide rapid measurement (<10 seconds) of glucose, in small volumes of whole blood (<10 μL), using a variety of specimen types (arterial, venous, capillary, and neonatal heel-stick whole blood). The operation of the device is purposefully designed to be intuitive and simple. Meter features such as operator management, wireless connectivity to the laboratory/hospital information system, and QC testing features are all important quality assurance parameters characteristic of today's hospital glucose meters. Historically, glucose meter testing did not start in the hospital; it started in physicians' offices around 1970 with the Ames Reflectance Meter. Over time, the glucose meter evolved in both design and technology, finding its way into the hands of patients, quickly becoming a very useful tool for the self-management of diabetes. Eventually, these glucose meters migrated into …

Effective energy measurement using radiochromic film: application of a mobile scanner

Abstract The effective energy calculated using the half-value layer (HVL) is an important parameter for quality assurance (QA) and quality control (QC). However constant monitoring has not been performed because measurements using an ionization chamber (IC) are time-consuming and complicated. To solve these problems, a method using radiochromic film (GAFCHROMIC EBT2 dosimetry film (GAF-EBT2) with slight energy dependency errors), a mobile scanner and step-shaped aluminum (SSAl) filter is developed. The results of the method using a mobile scanner were compared with those of the recommended method using an IC in order to evaluate its applicability. The difference ratios of the effective energies by each method using a mobile scanner with GAF-EBT2 were less than 5% compared with results of an IC. It is considered that this method offers a simple means of determining HVL for QA and QC consistently and quickly without the need for an IC dosimeter.

Identification and quantification of adulteration in Garcinia cambogia commercial products by chromatographic and spectrometric methods

ABSTRACTSpecies of genus Garcinia are rich sources of bioactive constituents with antimicrobial, anticancer, anti-inflammatory, hepatoprotective and anti-HIV activities. Commercial products of Garcinia cambogia are used as anti-obesity drugs with increasing market demand. Because of the high price of its products, it can be adulterated with similar lower-priced species. This study was designed to develop and validate an accurate and efficient method for the detection of any adulteration (G. indica) in G. cambogia products. For this purpose, high performance liquid chromatography (HPLC) was used to analyse the ethanolic fruit rind extracts of G. cambogia and G. indica, their formulations of 0.5, 1, 2, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90 and 95% G. indica with G. cambogia, and 11 G. cambogia commercial products. The analytical methods were validated by quality assurance parameters of linearity, sensitivity, precision and accuracy. Two marker peaks were detected in G. indica fruit extract, whereas G. cambogia did not show these peaks. The detected peaks were identified as anthocyanins; cyanidin-3-O-sambubioside and cyanidin-3-O-glucoside. In the study to determine the effect of pH and temperature on the stability of its anthocyanin content, HPLC analysis of G. indica extract showed the highest content at pH 1 and 50°C. Using two different mobile phases, the limits of detection (LOD) for cyanidin-3-O-sambubioside and cyanidin-3-O-glucoside were 0.036 and 0.059, and 0.022 and 0.033 mg kg–1, respectively. Furthermore, the inter-day precision (< 3.2%) confirmed that the applied analytical method fulfils the required criteria of Association of Official Analytical Chemists (AOAC). From this study, it was found that the HPLC method used for the detection of adulteration in G. cambogia products is rapid and accurate.

Impacts of aggregate geometrical features on the rheological properties of asphalt mixtures during compaction and service stage

To study the influence of aggregates geometrical features on the rheological properties of asphalt mixtures during compaction and service stage, asphalt mixtures with partially substituted aggregates were compacted by Superpave gyratory compaction (SGC), and their properties in service were measured by creep and dynamical modulus tests. The relation between rheological properties of mixtures and aggregate geometrical features was studied by gray relational analysis method. Results show that the rheological properties of mixtures during compaction and service stage are more sensitive to sieving diameter and shape index, but are less sensitive to angularity. The results indicate potential for using these parameters for quality control and quality assurance of asphalt mixture during production.

Geographical origin authentication of pork using multi-element and multivariate data analyses

In the recent years, consumers have become increasingly concerned about the authenticity and labeling claims associated with meat and meat based products. In this study, investigating geographical origin authenticity of pork, 323 samples of pork belly were collected from Korea, USA, Germany, Austria, Netherlands and Belgium. These were analyzed for twenty-nine macro and trace elements using inductively coupled plasma-optical emission spectroscopy (ICP-OES), and ICP-mass spectrometry (MS). The applied analytical techniques were validated by quality assurance parameters in which the values of correlation coefficient, limits of detection and quantification, precision, and spiking recovery confirmed that the methods were well efficient and in accordance to the criteria set by the Association of Official Analytical Chemists (AOAC) for metals analysis. From the results of multivariate analyses, it was found that the trace elements are promising constituents which could be used to accurately determine the inter-continental provenance of pork.

TU-FG-BRB-12: Real-Time Visualization of Discrete Spot Scanning Proton Therapy Beam for Quality Assurance

Purpose: With the growing adoption of proton beam therapy there is an increasing need for effective and user-friendly tools for performing quality assurance (QA) measurements. The speed and versatility of spot-scanning proton beam (PB) therapy systems present unique challenges for traditional QA tools. To address these challenges a proof-of-concept system was developed to visualize, in real-time, the delivery of individual spots from a spot-scanning PB in order to perform QA measurements. Methods: The PB is directed toward a custom phantom with planar faces coated with a radioluminescent phosphor (Gd2O2s:Tb). As the proton beam passes through the phantom visible light is emitted from the coating and collected by a nearby CMOS camera. The images are processed to determine the locations at which the beam impinges on each face of the phantom. By so doing, the location of each beam can be determined relative to the phantom. The cameras are also used to capture images of the laser alignment system. The phantom contains x-ray fiducials so that it can be easily located with kV imagers. Using this data several quality assurance parameters can be evaluated. Results: The proof-of-concept system was able to visualize discrete PB spots with energies ranging from 70 MeV to 220 MeV. Images were obtained with integration times ranging from 20 to 0.019 milliseconds. If not limited by data transmission, this would correspond to a frame rate of 52,000 fps. Such frame rates enabled visualization of individual spots in real time. Spot locations were found to be highly correlated (R2=0.99) with the nozzle-mounted spot position monitor indicating excellent spot positioning accuracy Conclusion: The system was shown to be capable of imaging individual spots for all clinical beam energies. Future development will focus on extending the image processing software to provide automated results for a variety of QA tests.

Thermochromic tissue-mimicking phantom for optimisation of thermal tumour ablation

Purpose The purpose of this study was to (1) develop a novel tissue-mimicking thermochromic (TMTC) phantom that permanently changes colour from white to magenta upon heating above ablative temperatures, and (2) assess its utility for specific applications in evaluating thermal therapy devices.Materials and methods Polyacrylamide gel mixed with thermochromic ink was custom made to produce a TMTC phantom that changes its colour upon heating above biological ablative temperatures (> 60 °C). The thermal properties of the phantom were characterised, and compared to those of human tissue. In addition, utility of this phantom as a tool for the assessment of laser and microwave thermal ablation was examined.Results The mass density, thermal conductivity, and thermal diffusivity of the TMTC phantom were measured as 1033 ± 1.0 kg/m3, 0.590 ± 0.015 W/m.K, and 0.145 ± 0.002 mm2/s, respectively, and found to be in agreement with reported values for human soft tissues. Heating the phantom with laser and microwave ablation devices produced clearly demarcated regions of permanent colour change geographically corresponding to regions with temperature elevations above 60 °C.Conclusion The TMTC phantom provides direct visualisation of ablation dynamics, including ablation volume and geometry as well as peak absolute temperatures within the treated region post-ablation. This phantom can be specifically tailored for different thermal therapy modalities, such as radiofrequency, laser, microwave, or therapeutic ultrasound ablation. Such modality-specific phantoms may enable better quality assurance, device characterisation, and ablation parameter optimisation, or optimise the study of dynamic heating parameters integral to drug device combination therapies relying upon heat.

Practice Patterns Analysis of Ocular Proton Therapy Centers: The International OPTIC Survey

To assess the planning, treatment, and follow-up strategies worldwide in dedicated proton therapy ocular programs. Ten centers from 7 countries completed a questionnaire survey with 109 queries on the eye treatment planning system (TPS), hardware/software equipment, image acquisition/registration, patient positioning, eye surveillance, beam delivery, quality assurance (QA), clinical management, and workflow. Worldwide, 28,891 eye patients were treated with protons at the 10 centers as of the end of 2014. Most centers treated a vast number of ocular patients (1729 to 6369). Three centers treated fewer than 200 ocular patients. Most commonly, the centers treated uveal melanoma (UM) and other primary ocular malignancies, benign ocular tumors, conjunctival lesions, choroidal metastases, and retinoblastomas. The UM dose fractionation was generally within a standard range, whereas dosing for other ocular conditions was not standardized. The majority (80%) of centers used in common a specific ocular TPS. Variability existed in imaging registration, with magnetic resonance imaging (MRI) rarely being used in routine planning (20%). Increased patient to full-time equivalent ratios were observed by higher accruing centers (P=.0161). Generally, ophthalmologists followed up the post-radiation therapy patients, though in 40% of centers radiation oncologists also followed up the patients. Seven centers had a prospective outcomes database. All centers used a cyclotron to accelerate protons with dedicated horizontal beam lines only. QA checks (range, modulation) varied substantially across centers. The first worldwide multi-institutional ophthalmic proton therapy survey of the clinical and technical approach shows areas of substantial overlap and areas of progress needed to achieve sustainable and systematic management. Future international efforts include research and development for imaging and planning software upgrades, increased use of MRI, development of clinical protocols, systematic patient-centered data acquisition, and publishing guidelines on QA, staffing, treatment, and follow-up parameters by dedicated ocular programs to ensure the highest level of care for ocular patients.

Quality Assurance for Accuracy of Anthropometric Measurements in Clinical and Epidemiological Studies: [Errare humanum est = to err is human

Anthropometry involves the external measurement of morphologic traits of human beings. High quality anthropometric measurements are fundamental to clinical and epidemiological research. The measurements for each method have inherent variations, either due to biologic variation or due to error in measurement. Errors in measurement cannot be avoided completely but they can be minimized to a large extent. We define methods to estimate measurement error in anthropometry, offer guidelines for acceptable error, and suggest ways to minimize measurement error; thereby improving anthropometry quality in health assessments. We propose that special attention be paid to the following six key parameters for quality assurance of anthropometric measurements: (i) Identification of certified lead anthropometrist and trainer, (ii) manual of standard operating procedures, (iii) choice of robust equipment, (iv) equipment calibration, (v) standardization training and certification, and (vi) measurements resampling.

Flattening filter free beams from TrueBeam and Versa HD units: Evaluation of the parameters for quality assurance.

Flattening filter free (FFF) beams generated by medical linear accelerators are today clinically used for stereotactical and non-stereotactical radiotherapy treatments. Such beams differ from the standard flattened beams (FF) in the high dose rate and the profile shape peaked on the beam central axis. Definition of new parameters as unflatness and slope for FFF beams has been proposed based on a renormalization factor for FFF profiles. The present study aims to assess the dosimetric differences between FFF beams generated by linear accelerators from different vendors, and to provide renormalization and parameter data of the two kinds of units. Dosimetric data from two Varian TrueBeam and two Elekta Versa HD linear accelerators, all with 6 and 10 MV nominal accelerating potentials, FF and FFF modes have been collected. Renormalization factors and related fit parameters according to Fogliata et al. ["Definition of parameters for quality assurance of flattening filter free (FFF) photon beams in radiation therapy," Med. Phys. 39, 6455-6464 (2012)] have been evaluated for FFF beams of both units and energies. Unflatness and slope parameters from profile curves were evaluated. Dosimetric differences in terms of beam penetration and near-the-surface dose were also assessed. FFF profile parameters have been updated; renormalization factors and unflatness from the Varian units are consistent with the published data. Elekta FFF beam qualities, different from the Varian generated beams, tend to express similar behaviour as the FF beam of the corresponding nominal energy. TPR20,10 for 6 and 10 MV FF and FFF TrueBeam beams are 0.665, 0.629 (6 MV) and 0.738, 0.703 (10 MV). The same figures for Versa HD units are 0.684, 0.678 (6 MV) and 0.734, 0.721 (10 MV). Renormalization factor and unflatness parameters evaluated from Varian and Elekta FFF beams are provided, in particular renormalization factors table and fit parameters.

Can knowledge-based DVH predictions be used for automated, individualized quality assurance of radiotherapy treatment plans?

BackgroundTreatment plan quality assurance (QA) is important for clinical studies and for institutions aiming to generate near-optimal individualized treatment plans. However, determining how good a given plan is for that particular patient (individualized patient/plan QA, in contrast to running through a checklist of generic QA parameters applied to all patients) is difficult, time consuming and operator-dependent. We therefore evaluated the potential of RapidPlan, a commercial knowledge-based planning solution, to automate this process, by predicting achievable OAR doses for individual patients based on a model library consisting of historical plans with a range of organ-at-risk (OAR) to planning target volume (PTV) geometries and dosimetries.MethodsA 90-plan RapidPlan model, generated using previously created automatic interactively optimized (AIO) plans, was used to predict achievable OAR dose-volume histograms (DVHs) for the parotid glands, submandibular glands, individual swallowing muscles and oral cavities of 20 head and neck cancer (HNC) patients using a volumetric modulated (RapidArc) simultaneous integrated boost technique. Predicted mean OAR doses were compared with mean doses achieved when RapidPlan was used to make a new plan. Differences between the achieved and predicted DVH-lines were analyzed. Finally, RapidPlan predictions were used to evaluate achieved OAR sparing of AIO and manual interactively optimized plans.ResultsFor all OARs, strong linear correlations (R2 = 0.94–0.99) were found between predicted and achieved mean doses. RapidPlan generally overestimated the amount of achievable sparing for OARs with a large degree of OAR-PTV overlap. RapidPlan QA using predicted doses alone identified that for 50 % (10/20) of the manually optimized plans, sparing of the composite salivary glands, oral cavity or composite swallowing muscles could be improved by at least 3 Gy, 5 Gy or 7 Gy, respectively, while this was the case for 20 % (4/20) AIO plans. These predicted gains were validated by replanning the identified patients using RapidPlan.ConclusionsStrong correlations between predicted and achieved mean doses indicate that RapidPlan could accurately predict achievable mean doses. This shows the feasibility of using RapidPlan DVH prediction alone for automated individualized head and neck plan QA. This has applications in individual centers and clinical trials.

Quality of life, psychological distress, and social outcomes after radical prostatectomy. Results from a urology competence center for rehabilitation

Quality of life is an important parameter for quality assurance of the results. After radical prostatectomy, quality of life is often limited. The degree of urinary incontinence correlates significantly with quality of life. Oncological and functional results are significantly decreased with the age of the patients. On the other hand, the psychological distress of younger patients is significantly greater than in the elderly. In the relative short period of 3-4 weeks of an inpatient rehabilitation in our urology competence center for rehabilitation, the mean decrease of urinary loss (24-h pad test) was 44.4 %. Psychological distress also decreased significantly as measured by the questionnaire on psychological distress FBK-R10 (p < 0.001). With this, quality of life significantly increased in all function and symptom scales of the QLQ-C30. Thus, this makes reintegration into social life easier. The return to work rate of employed persons after our specific urological rehabilitation program following radical prostatectomy was 87 %.