An evaluation of the stability of image quality parameters of Varian on-board imaging (OBI) and EPID imaging systems

Purpose: Quality assurance of the image quality for image guided localization systems is crucial to ensure accurate visualization and localization of target volumes. In this study, the stability of selected image parameters was assessed and evaluated for CBCT mode, planar radiographic kV mode and the radiographic MV EPID mode.Methods and Materials: The CATPHAN, QckV-1 and QC-3 phantoms were used to evaluate the image quality parameters. The planar radiographic images were analyzed in PIPSpro™ with spatial resolution (f30, f40, f50) being recorded. For OBI CBCT, High quality head Full-Fan acquisition and Pelvis Half-Fan acquisition modes were evaluated for Uniformity, Noise, Spatial Resolution, HU constancy and geometric distortion. Dose and kVp for the OBI were recorded using the Unfors RaySafe Xi system with the R/F High Detector for planar kV and the CT detector for CBCT. Dose for the MV EPID was recorded using a PTW975 Semiflex Ion Chamber, webline electrometer and 1cm SolidWater™.Results: For each metric, values were normalized to the mean and the standard deviations were recorded. Table 1 shows the standard deviation for all results. Using this, tolerances can be reported as a warning threshold of 1σ and an action threshold of 2σ. Table 2 shows the warning and action tolerances for the planar radiographic modalities while Table 3 and 4 show tolerance levels for the Full-Fan and Half-Fan, respectively.Conclusion: A study was performed to assess the stability of the basic image quality parameters recommended by TG-142 for the Varian OBI and EPID Imaging systems. The two systems show consistent imaging and dosimetric properties over the evaluated time frame.----------------------------Cite this article as: Stanley DN, Papanikolaou N, Gutierrez AN. An evaluation of the stability of image quality parameters of Varian on-board imaging (OBI) and EPID imaging systems. Int J Cancer Ther Oncol 2014; 2(2):020236. DOI: 10.14319/ijcto.0202.3

An evaluation of the stability of image quality parameters of Varian on-board imaging (OBI) and EPID imaging systems

Purpose: Quality assurance of the image quality for image guided localization systems is crucial to ensure accurate visualization and localization of target volumes. In this study, the stability of selected image parameters was assessed and evaluated for CBCT mode, planar radiographic kV mode and the radiographic MV EPID mode.Methods and Materials: The CATPHAN, QckV-1 and QC-3 phantoms were used to evaluate the image quality parameters. The planar radiographic images were analyzed in PIPSpro™ with spatial resolution (f30, f40, f50) being recorded. For OBI CBCT, High quality head Full-Fan acquisition and Pelvis Half-Fan acquisition modes were evaluated for Uniformity, Noise, Spatial Resolution, HU constancy and geometric distortion. Dose and kVp for the OBI were recorded using the Unfors RaySafe Xi system with the R/F High Detector for planar kV and the CT detector for CBCT. Dose for the MV EPID was recorded using a PTW975 Semiflex Ion Chamber, webline electrometer and 1cm SolidWater™.Results: For each metric, values were normalized to the mean and the standard deviations were recorded. Table 1 shows the standard deviation for all results. Using this, tolerances can be reported as a warning threshold of 1σ and an action threshold of 2σ. Table 2 shows the warning and action tolerances for the planar radiographic modalities while Table 3 and 4 show tolerance levels for the Full-Fan and Half-Fan, respectively.Conclusion: A study was performed to assess the stability of the basic image quality parameters recommended by TG-142 for the Varian OBI and EPID Imaging systems. The two systems show consistent imaging and dosimetric properties over the evaluated time frame.----------------------------Cite this article as: Stanley DN, Papanikolaou N, Gutierrez AN. An evaluation of the stability of image quality parameters of Varian on-board imaging (OBI) and EPID imaging systems. Int J Cancer Ther Oncol 2014; 2(2):020236. DOI: 10.14319/ijcto.0202.36</p

Comparison of low contrast sensitivity among multi-slice CT units using various mAs setting for the potential benefit of non-MRI compatible, stereotactic radiosurgery (SRS) patients

Purpose: To evaluate the low contrast detectability sensitivity among 4-slice, 8-slice and 16-slice CT units using various mAs settings. Findings of the study may elucidate the most optimal imaging parameter for stereotactic radiosurgery (SRS) patients who are not MRI compatible.Methods and Materials: Low contrast targets in the CATPHAN phantom (model: CTP 504, The Phantom Laboratory) were imaged on a 4-slice LightSpeed Advantage™ GE CT scanner (GE Healthcare, WI) and a 16- slice LightSpeed Advantage™ GE CT scanner (GE Healthcare, WI) in 8-slice and 16-slice mode. The CATPHAN CTP515 low contrast targets of size 15, 9, 8, 7, 6, 5, 4, 3 and 2 mm for each contrast difference of 1%, 0.5% and 0.3% from the water-equivalent background was imaged using a SRS protocol. Two image sets per setting were acquired for mAs parameters of 300, 350 and 440. Images were evaluated in a blind study by three independent reviewers.Results: Using 300,350 and 440mAs settings on the 4-slice scanner, the average smallest diameters recorded at 1% contrast were 5 ± 1 mm, 5 ± 1 mm and 5 ± 0 mm and at 0.5% were 7 ± 2 mm, 7 ± 1 mm and 6 ± 1 mm. For the 8 - slice scanner, the average smallest diameters recorded at 1% contrast were 7 ± 0 mm, 6 ± 0 mm and 5 ± 0 mm, and at 0.5% were 12 ± 3 mm, 9 ± 1 mm and 6 ± 1 mm. For the 16 - slice scanner, the average smallest diameters recorded at 1% contrast were 7 ± 1 mm, 7 ± 1 mm and 6 ± 1 mm, and at 0.5% were 11 ± 3 mm, 8 ± 1 mm and 8 ± 1 mm. A difference was observed between the 4 and 8 - slice scanners at 300mAs (p &lt; 0.01) for each contrast level as well as the 4 and 16 slice at 440 (p &lt; 0.01) and 350 (p &lt; 0.01) mAs. Additionally, a difference was observed between each mAs for the 8 slice at 1% (p &lt; 0.01) and 0.5% (p &lt; 0.01) contrast.Conclusion: Results demonstrate consistently improved low contrast detectability as mAs was increased. CT simulation imaging parameters can be optimized to improve low contrast sensitivity for non MRI compatible SRS patients.----------------Cite this article as: Stanley D, Narayanasamy G, Breton C, Papanikolaou N, Gutierrez AN. Comparison of low contrast sensitivity among multi-slice CT units using various mAs setting for the potential benefit of non-MRI compatible, stereotactic radiosurgery (SRS) patients. Int J Cancer Ther Oncol 2014; 2(2):020237. DOI: 10.14319/ijcto.0202.37</p

Comparison of low contrast sensitivity among multi-slice CT units using various mAs setting for the potential benefit of non-MRI compatible, stereotactic radiosurgery (SRS) patients

Purpose: To evaluate the low contrast detectability sensitivity among 4-slice, 8-slice and 16-slice CT units using various mAs settings. Findings of the study may elucidate the most optimal imaging parameter for stereotactic radiosurgery (SRS) patients who are not MRI compatible.Methods and Materials: Low contrast targets in the CATPHAN phantom (model: CTP 504, The Phantom Laboratory) were imaged on a 4-slice LightSpeed Advantage™ GE CT scanner (GE Healthcare, WI) and a 16- slice LightSpeed Advantage™ GE CT scanner (GE Healthcare, WI) in 8-slice and 16-slice mode. The CATPHAN CTP515 low contrast targets of size 15, 9, 8, 7, 6, 5, 4, 3 and 2 mm for each contrast difference of 1%, 0.5% and 0.3% from the water-equivalent background was imaged using a SRS protocol. Two image sets per setting were acquired for mAs parameters of 300, 350 and 440. Images were evaluated in a blind study by three independent reviewers.Results: Using 300,350 and 440mAs settings on the 4-slice scanner, the average smallest diameters recorded at 1% contrast were 5 ± 1 mm, 5 ± 1 mm and 5 ± 0 mm and at 0.5% were 7 ± 2 mm, 7 ± 1 mm and 6 ± 1 mm. For the 8 - slice scanner, the average smallest diameters recorded at 1% contrast were 7 ± 0 mm, 6 ± 0 mm and 5 ± 0 mm, and at 0.5% were 12 ± 3 mm, 9 ± 1 mm and 6 ± 1 mm. For the 16 - slice scanner, the average smallest diameters recorded at 1% contrast were 7 ± 1 mm, 7 ± 1 mm and 6 ± 1 mm, and at 0.5% were 11 ± 3 mm, 8 ± 1 mm and 8 ± 1 mm. A difference was observed between the 4 and 8 - slice scanners at 300mAs (p &lt; 0.01) for each contrast level as well as the 4 and 16 slice at 440 (p &lt; 0.01) and 350 (p &lt; 0.01) mAs. Additionally, a difference was observed between each mAs for the 8 slice at 1% (p &lt; 0.01) and 0.5% (p &lt; 0.01) contrast.Conclusion: Results demonstrate consistently improved low contrast detectability as mAs was increased. CT simulation imaging parameters can be optimized to improve low contrast sensitivity for non MRI compatible SRS patients.----------------Cite this article as: Stanley D, Narayanasamy G, Breton C, Papanikolaou N, Gutierrez AN. Comparison of low contrast sensitivity among multi-slice CT units using various mAs setting for the potential benefit of non-MRI compatible, stereotactic radiosurgery (SRS) patients. Int J Cancer Ther Oncol 2014; 2(2):020237. DOI: 10.14319/ijcto.0202.3

Quality Control Report of Drugs Analyzed in the Drug Analysis and Research Unit during the Period 2011-2015

During the period 2011-2015, the Drug Analysis and Research Unit (DARU) analyzed 1972 drug samples. The samples consisted of 21.5% locally manufactured and 78.2% imported products while the origin of 0.3% of products was indeterminate. Samples were subjected to compendial and/or in-house analytical specifications. The overall non-compliance rate was 4.5% comprising 2.5% local products and 2.0% imports. High failure rates were recorded for uterotonics (37.5%), hemostatics (33%), anthelmintics (17%) and anticancers (10.5%) while ophthalmic, immunomodulatory, musculoskeletal and endocrine drugs all complied with the quality acceptance criteria. Erectile dysfunction drugs, received by the laboratory for the first time, all complied with specifications. The results obtained demonstrate an improvement in the quality of samples submitted to DARU when compared to previous performance

Malaria entomological profile in Tanzania from 1950 to 2010: a review of mosquito distribution, vectorial capacity and insecticide resistance

In Sub Saharan Africa where most of the malaria cases and deaths occur, members of the Anopheles gambiae species complex and Anopheles funestus species group are the important malaria vectors. Control efforts against these vectors in Tanzania like in most other Sub Saharan countries have failed to achieve the set objectives of eliminating transmission due to scarcity of information about the enormous diversity of Anopheles mosquito species and their susceptibility status to insecticides used for malaria vector control. Understanding the diversity and insecticide susceptibility status of these vectors and other factors relating to their importance as vectors (such as malaria transmission dynamics, vector biology, ecology, behaviour and population genetics) is crucial to developing a better and sound intervention strategies that will reduce man-vector contact and also manage the emergency of insecticide resistance early and hence a success in malaria control. The objective of this review was therefore to obtain the information from published and unpublished documents on spatial distribution and composition of malaria vectors, key features of their behaviour, transmission indices and susceptibility status to insecticides in Tanzania. All data available were collated into a database. Details recorded for each data source were the locality, latitude/longitude, time/period of study, species, abundance, sampling/collection methods, species identification methods, insecticide resistance status, including evidence of the kdr allele, and Plasmodium &nbsp;falciparum sporozoite rate. This collation resulted in a total of 368 publications, encompassing 806,273 Anopheles mosquitoes from 157 geo-referenced locations being collected and identified across Tanzania from 1950s to 2010. Overall, the vector species most often reported included An. gambiae complex (66.8%), An. funestus complex (21.8%), An. gambiae s.s. (2.1%) and An. arabiensis (9%). A variety of sampling/collection and species identification methods were used with an increase in molecular techniques in recent decades. Only 32.2% and 8.4% of the data sets reported on sporozoite analysis and entomological inoculation rate (EIR), respectively which highlights the paucity of such important information in the country. Studies demonstrated efficacy of all four major classes of insecticides against malaria vectors in Tanzania with focal points showing phenotypic resistance. About 95% of malaria entomological data was obtained from north- eastern Tanzania. This shows the disproportionate nature of the available information with the western part of the country having none. Therefore it is important for the country to establish entomological surveillance system with state of the art to capture all vitally important entomological indices including vector bionomics in areas of Tanzania where very few or no studies have been done. This is vital in planning and implementing evidence based malaria vector control programmes as well as in monitoring the current malaria control interventions

Value co-creation through multiple shopping channels: the interconnections with social exclusion and wellbeing

This study examines consumers’ value co-creation via several shopping channels including a traditional out-of-home shopping channel and “smart” channels where consumers use a computer, a mobile phone or social media. It focuses on the effect that value co-creation has on consumers’ shopping behaviour as well as on the perceived contribution of a shopping channel to their wellbeing, with a focus on individuals who perceive themselves as being socially excluded, particularly by mobility disability. The project was carried out in the USA using an online survey (n=1220). Social exclusion has a positive statistically significant effect on respondents’ self-connection with all channels; for many socially excluded respondents the shopping channel has an important role in their lives. Self-connection with the channel has a positive effect on value co-creation and there is a positive relationship between value co-creation and the perceived contribution of the channel on wellbeing. When consumers help other individuals in their decision making they not only create value for the retailer and for other customers but also contribute positively to their own wellbeing. Importantly, for smart shopping channels where consumers use a computer or a mobile phone, the impact of value co-creation on the perceived contribution of these channels to consumer wellbeing are stronger for shoppers with a mobility disability than for those without such a disability

Loss and Recovery of Mgat3 and GnT-III Mediated E-cadherin N-glycosylation Is a Mechanism Involved in Epithelial-Mesenchymal-Epithelial Transitions

BACKGROUND: N-acetylglucosaminyltransferase-III (GnT-III) is a glycosyltransferase encoded by Mgat3 that catalyzes the addition of β1,4-bisecting-N-acetylglucosamine on N-glycans. GnT-III has been pointed as a metastases suppressor having varying effects on cell adhesion and migration. We have previously described the existence of a functional feedback loop between E-cadherin expression and GnT-III-mediated glycosylation. The effects of GnT-III-mediated glycosylation on E-cadherin expression and cellular phenotype lead us to evaluate Mgat3 and GnT-III-glycosylation role during Epithelial-Mesenchymal-Transition (EMT) and the reverted process, Mesenchymal-Epithelial-Transition (MET). METHODOLOGY/PRINCIPAL FINDINGS: We analyzed the expression profile and genetic mechanism controlling Mgat3 expression as well as GnT-III-mediated glycosylation, in general and specifically on E-cadherin, during EMT/MET. We found that during EMT, Mgat3 expression was dramatically decreased and later recovered when cells returned to an epithelial-like phenotype. We further identified that Mgat3 promoter methylation/demethylation is involved in this expression regulation. The impact of Mgat3 expression variation, along EMT/MET, leads to a variation in the expression levels of the enzymatic product of GnT-III (bisecting GlcNAc structures), and more importantly, to the specific modification of E-cadherin glycosylation with bisecting GlcNAc structures. CONCLUSIONS/SIGNIFICANCE: Altogether, this work identifies for the first time Mgat3 glycogene expression and GnT-III-mediated glycosylation, specifically on E-cadherin, as a novel and major component of the EMT/MET mechanism signature, supporting its role during EMT/MET

Evaluation of the limitations and methods to improve rapid phage-based detection of viable Mycobacterium avium subsp. paratuberculosis in the blood of experimentally infected cattle

Background Disseminated infection and bacteraemia is an underreported and under-researched aspect of Johne’s disease. This is mainly due to the time it takes for Mycobacterium avium subsp. paratuberculosis (MAP) to grow and lack of sensitivity of culture. Viable MAP cells can be detected in the blood of cattle suffering from Johne’s disease within 48 h using peptide-mediated magnetic separation (PMMS) followed by bacteriophage amplification. The aim of this study was to demonstrate the first detection of MAP in the blood of experimentally exposed cattle using the PMMS-bacteriophage assay and to compare these results with the immune response of the animal based on serum ELISA and shedding of MAP by faecal culture. Results Using the PMMS-phage assay, seven out of the 19 (37 %) MAP-exposed animals that were tested were positive for viable MAP cells although very low numbers of MAP were detected. Two of these animals were positive by faecal culture and one was positive by serum ELISA. There was no correlation between PMMS-phage assay results and the faecal and serum ELISA results. None of the control animals (10) were positive for MAP using any of the four detection methods. Investigations carried out into the efficiency of the assay; found that the PMMS step was the limiting factor reducing the sensitivity of the phage assay. A modified method using the phage assay directly on isolated peripheral blood mononuclear cells (without PMMS) was found to be superior to the PMMS isolation step. Conclusions This proof of concept study has shown that viable MAP cells are present in the blood of MAP-exposed cattle prior to the onset of clinical signs. Although only one time point was tested, the ability to detect viable MAP in the blood of subclinically infected animals by the rapid phage-based method has the potential to increase the understanding of the pathogenesis of Johne’s disease progression by warranting further research on the presence of MAP in blood