Background
There currently exists no widespread high dose‐rate (HDR) brachytherapy afterloader quality assurance (QA) tool for simultaneously assessing the afterloader's positional, temporal, transit ...velocity and air kerma strength accuracy.
Purpose
The purpose of this study was to develop a precise and rigorous technique for performing daily QA of HDR brachytherapy afterloaders, incorporating QA of: dwell position accuracy, dwell time accuracy, transit velocity consistency and relative air kerma strength (AKS) of an Ir‐192 source.
Method
A Sharp ProGuide 240 mm catheter (Elekta Brachytherapy, Veenendaal, The Netherlands) was fixed 5 mm above a 256 channel epitaxial diode array ‘dose magnifying glass’ (DMG256) (Centre for Medical and Radiation Physics, University of Wollongong). Three dwell positions, each of 5.0 s dwell times, were spaced 13.0 mm apart along the array with the Flexitron HDR afterloader (Elekta Brachytherapy, Veenendaal, The Netherlands). The DMG256 was connected to a data acquisition system (DAQ) and a computer via USB2.0 link for live readout and post‐processing. The outputted data files were analyzed using a Python script to provide positional and temporal localization of the Ir‐192 source by tracking the centroid of the detected response. Measurements were repeated on a weekly basis, for a period of 5 weeks to determine the consistency of the measured parameters over an extended period.
Results
Using the DMG256 for relative AKS measurements resulted in measured values within 0.6%–3.0% of the expected activity over a 7‐week period. The sub‐millisecond temporal accuracy of the device allowed for measurements of the transit velocity with an average of (10.88 ± 1.01) cm/s for 13 mm steps. The dwell position localization for 1, 2, 3, 5, and 10 mm steps had an accuracy between 0.1 and 0.3 mm (3σ), with a fixed temporal accuracy of 10 ms.
Conclusion
The DMG256 silicon strip detector allows for clinics to perform rigorous daily QA of HDR afterloader dwell position and dwell time accuracy with greater precision than the current standard methodology using closed circuit television and a stopwatch. Additionally, DMG256 unlocks the ability to perform measurements of transit velocity/time and relative AKS, which are not possible using current standard techniques.
Nem tudjuk biztosan, hogy kik és mikor készítettek nagyításra alkalmas eszközöket először, de amikor észrevették az emberek egyes természeti jelenségek ilyen hatását, majd ezek mintájára a megfelelő ...eszközt elő is tudták állítani, a végtelenül nagy, távoli és végtelenül kicsi világok csodáira vonatkozó emberi kíváncsiság ezen a területen is hihetetlen technikai fejlődést eredményezett. Jelen munkában csak a közelmúltig, az 1800-as évek végéig vázolom fel ezt a folyamatot a 4–5000 évvel ezelőtti, egyszerű hegyikristályból, üvegből vagy vízzel teli edény segítségével készített lencséktől az egyszerűbb, majd egyre bonyolultabb és egyre szebb képet adó mikroszkópokig. Eljutunk a polarizációs mikroszkóp és a petrográfia térhódításához és a legnagyobb magyar geológusok, Hantken Miksa, Szabó József és Zsigmondy Vilmos mikroszkóppal kapcsolatos tevékenységéhez.
The origin of introduced Nile tilapia stocks in sub-Saharan Africa is largely unknown. In this study, the potential of monogeneans as a biological tag and magnifying glass is tested to reveal their ...hosts' stocking history. The monogenean gill community of different Nile tilapia populations in sub-Saharan Africa was explored, and a phylogeographic analysis was performed based on the mitogenomes of four dactylogyrid species (Cichlidogyrus halli, C. sclerosus, C. thurstonae, and Scutogyrus longicornis). Our results encourage the use of dactylogyrids as biological tags. The magnifying glass hypothesis is only confirmed for C. thurstonae, highlighting the importance of the absence of other potential hosts as prerequisites for a parasite to act as a magnifying glass. With the data generated here, we are the first to extract mitogenomes from individual monogeneans and to perform an upscaled survey of the comparative phylogeography of several monogenean species with unprecedented diagnostic resolution.
•Parasites are helpful to explore Nile tilapia introductions in sub-Saharan Africa.•Monogeneans are used as biological tag and magnifying glass of Nile tilapia host.•Phylogeography is performed based on mitogenomes of four dactylogyrid species.•Mitogenomes are extracted from individual monogeneans for the first time.•Parasites need to be host specific to act as a magnifying glass.
Abstract The aim of this study was to evaluate the effect of magnification during post space preparation on root cleanness and on fiber post bond strength. Methods: Thirty human central upper ...incisors with similar root canal in size and shape were selected, decoronated to 15 mm and endodontically filled. The teeth were assigned into 3 groups (n=10), according to the method of magnification during post space preparation inspection: Control, using naked eye; loupe, using a dental surgical 3x magnifying glass; surgical microscope, using a 6x surgical microscope. The roots were scanned by using micro-CT before and after post space preparation for residue remnants evaluation. Fiber posts were cemented using self-adhesive resin cement (Rely X U200, 3M-ESPE). Two 1-mm-thick slices from the cervical, medium and apical thirds were submitted to a push-out test (PBS). Failures modes were classified. PBS data were analyzed by using two-way ANOVA with repeated measurement and the Tukey test. The significance level was set at 5%. The method of visualization had no effect on PBS (p=0.556). The cervical region had higher values than apical region irrespective of the inspection method (p=0.012). Adhesive failure between the resin cement and dentin was the prevalent failure mode for all groups. Micro-CT analysis showed no difference on root cleanness into the root canal after post space preparation. The use of magnification devices as loupe and microscope while performing post space do not improve the PBS and did not affect sealer remain of decoronated anterior teeth.
Resumo Avaliar o efeito do método de visualização durante o preparo do espaço do pino sobre o remanescente de material obturador endodôntico e sobre a resistência adesiva do pino de fibra de vidro. Trinta incisivos centrais superiores humanos com canal radicular circular foram selecionados, foram desobstruídos a 15 mm e obturados. Os dentes foram divididos em 3 grupos (n=10), de acordo com o método de ampliação utilizado para inspeção do preparo: Controle, usando olho nu; lupa, usando uma lupa cirúrgica 3x cirúrgica; microscópio cirúrgico, usando um microscópio cirúrgico 6x. As raízes foram digitalizadas usando micro-CT antes e após a preparação do espaço para avaliação de resíduos remanescentes. Os pinos de fibra foram cimentados com cimento resinoso autoadesivo (RelyX U200, 3M-ESPE). Duas fatias de 1 mm de espessura dos terços cervical, médio e apical foram submetidas ao teste push-out (PBS). Os padrões de falhas foram classificados. Os dados de PBS foram analisados usando análise de variância em dois fatores com medição repetida e o teste de Tukey. O nível de significância foi estabelecido em 5%. Resultados: O método de visualização não teve efeito no PBS (p=0,556). A região cervical apresentou valores maiores que a região apical, independentemente do método de inspeção (p=0,012). A falha adesiva entre o cimento resinoso e a dentina foi o modo de falha prevalente para todos os grupos. A análise de micro-CT não mostrou diferença na limpeza da raiz no canal radicular após a preparação do espaço do pino. Conclusão: O uso de dispositivos de ampliação como lupas e microscópios durante a realização de preparo não melhora o PBS e não afetou a permanência do material obturador remanescente de dentes anteriores.
We reported two Japanese patients with phonological dyslexia. In both patients, reading with a magnifying glass improved performance of a reading aloud task of Kana non-words, and enabled the ...patients to feel facility at reading sentences. On the reading aloud task of Kana non-words, both patients scored significantly better when they used a magnifying glass than when reading without one. We consider the mechanism of the effect as follows: Reading with a magnifying glass generates a mental set to focus on and read letters one by one on the reading aloud task. In both patients, the mental set may partially compensate for the fragility of phonological representation and impaired processing of phonological sequencing, and reduce misreading of Kana non-words. Use of a magnifying glass may reduce misreading of general sentences as well as non-words in Japanese patients with phonological dyslexia because of the agglutinative nature of the Japanese language.
Traditional magnifying glasses can give magnified virtual images with diffraction‐limited resolution, that is, detailed information is lost. Here, a novel magnifying glass by transformation optics, ...referred to as a “superresolution magnifying glass” (SMG) is designed, which can produce magnified virtual images with a predetermined magnification factor and resolve subwavelength details (i.e., light sources with subwavelength distances can be resolved). Based on theoretical calculations and reductions, a metallic plate structure to produce the reduced SMG in microwave frequencies, which gives good performance verified by both numerical simulations and experimental results, is proposed and realized. The function of SMG is to create a superresolution virtual image, unlike traditional superresolution imaging devices that create real images. The proposed SMG will create a new branch of superresolution imaging technology.
Superresolution magnifying glass, which can achieve a superresolution optical illusion, is designed by transformation optics. Traditional magnifying glasses can give magnified virtual images where the detailed subwavelength information are lost. A super‐magnifying glass can produce magnified virtual images with subwavelength details, which is different from traditional methods for superresolution imaging (often produce a real image with subwavelength details).
Coronary angiography and percutaneous coronary intervention are frequently and increasingly performed worldwide. Although catheters for coronary angiography are considered as single-use devices, some ...people still question this decision. This study evaluated the structural characteristics and thermal stability of new and reprocessed catheters.
Five catheters (Judkins left) of the same brand and manufacturer were selected for each analysis. We evaluated: new catheters, catheters reprocessed once (first), twice (second), thrice (third), and seven times (seventh). The optical analyses of the proximal, middle and distal parts of the catheters were performed by magnifying glass. Besides, thermogravimetric analyses were done.
After reprocessing, the crushing, color changes, folds, dents, deformations, and lumen narrowing were observed; the stainless-steel framework, the external tortuosity, the interlaced mesh of stainless-steel wires and loss of polymeric material were visualized. Thermogravimetric analysis showed lost of mass of the catheters.
This study demonstrated that the structural integrity and mass of catheters are lost with reprocessing. These findings may be caused by several steps of reprocessing; however, regardless of which step or steps were responsible, the presence of structural integrity loss leads to the recommendation of not reusing this type of device.
Purpose:
Helical tomotherapy is a complex delivery technique, integrating CT image guidance and intensity modulated radiotherapy in a single system. The integration of the CT detector ring on the ...gantry not only allows patient position verification but is also often used to perform various QA procedures. This convenience lacks the rigor of a machine-independent QA process.
Methods:
In this article, a Si strip detector, known as the Dose Magnifying Glass (DMG), was used to perform machine-independent QA measurements of the multileaf collimator alignment, leaf open time threshold, and leaf fluence output factor (LFOF).
Results:
The DMG measurements showed good agreements with EDR2 film for the MLC alignment test while the CT detector agrees well with DMG measurements for leaf open time threshold and LFOF measurements. The leaf open time threshold was found to be approximately 20 ms. The LFOF measured with the DMG agreed within error with the CT detector measured LFOF.
Conclusions:
The DMG with its 0.2 mm spatial resolution coupled to TERA ASIC allowed real-time high temporal resolution measurements of the tomotherapy leaf movement. In conclusion, DMG was shown to be a suitable tool for machine-independent QA of a tomotherapy unit.
Background
At present, no ideal diagnostic tools exist in the market to excise cancer tissue with the required safety margins and to achieve optimal aesthetic results using tissue-conserving ...techniques.
Objectives
In this prospective study, confocal laser endomicroscopy (CLE) and the traditional gold standard of magnifying glasses (MG) were compared regarding the boundaries of in vivo basal cell carcinoma and squamous cell carcinoma.
Materials & methods
Tumour diameters defined by both methods were measured and compared with those determined by histopathological examination. Nineteen patients were included in the study.
Results
The CLE technique was found to be superior to excisional margins based on MG only. Re-excision was required in 68% of the cases following excision based on MG evaluation, but only in 27% of the cases for whom excision margins were based on CLE.
Conclusion
Our results are promising regarding the distinction between tumour and healthy surrounding tissue, and indicate that presurgical mapping of basal cell carcinoma and squamous cell carcinoma is possible. The tool itself should be developed further with special attention to early detection of skin cancer.
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