Adaptive-predictive organ localization (a-POLO) in the clinic: Updated results in hypofractionated bladder radiotherapy.

2011 ◽  
Vol 29 (7_suppl) ◽  
pp. 282-282
Author(s):  
F. McDonald ◽  
S. Lalondrelle ◽  
H. Taylor ◽  
V. Harris ◽  
V. Hansen ◽  
...  
Keyword(s):  
Treatment Plan ◽  
Cone Beam Ct ◽  
Outcome Data ◽  
Target Coverage ◽  
Independent Observer ◽  
Distant Relapse ◽  
Plan Selection ◽  
The Mean ◽  
Set Up ◽  
Muscle Invasive

282 Background: The A-POLO strategy allows the optimal 'plan of the day' to be selected online for radiotherapy (RT) delivery. The methodology is implemented in a phase II study of patients with muscle-invasive bladder cancer who are not suitable for cystectomy/daily RT and are receiving hypofractionated RT. Methods: Planning scans were performed at 0 and 30 minutes post void (CT0 and CT30). Three conformal plans were created (small, intermediate, large) ( Table ). Patients were prescribed 6Gy weekly for 5–6 weeks. A pre-RT cone beam CT (CBCT) scan and online set-up correction were performed. The plan giving the optimal target coverage was selected by 2 observers. Offline plan selection was also carried out by an independent observer. A post-RT CBCT was acquired to calculate the percentage of the CTV covered by 95% of the dose (V95). The mean A- POLO volume was compared to our previous institutional standard PTV (1.5cm isotropic margins) (PTViso). Outcome data were collected. Results: A total of 77 RT fractions were delivered to 14 patients. The small plan was delivered for 38 (49%) fractions and the large for 6 (8%) fractions. The concordance rate between online and offline plan selection was 71/77 (92%). The mean CTV V95 was 99% (patient mean range 97–100%). The mean time between the pre- and post-treatment CBCT was 15 minutes. The mean reduction between PTViso and mean A-POLO PTV was 42% (range 16– 59%). 2 patients had grade (G) 3 (CTCv3.0) treatment-related acute toxicity. There have been no treatment-related G4 acute or G3 late toxicities. With a median follow-up of 7.3 months 10 patients are alive with 8 disease free (1 local and 1 distant relapse). Conclusions: Implementation of A-POLO RT is feasible, well tolerated, and associated with good concordance in 'plan of the day' selection. An individualized treatment plan can be delivered with each fraction to achieve a reduction in PTV compared to PTViso with maintenance of target coverage. [Table: see text] No significant financial relationships to disclose.

The Y-shaped trabecular bone structure in the odontoid process of the axis: a CT scan study in 54 healthy subjects and biomechanical considerations

2019 ◽  
Vol 30 (5) ◽  
pp. 585-592 ◽  
Author(s):  
Nicola Montemurro ◽  
Paolo Perrini ◽  
Vittoriano Mangini ◽  
Massimo Galli ◽  
Andrea Papini
Keyword(s):  
Ct Scan ◽  
Healthy Subjects ◽  
Bone Structure ◽  
Cone Beam Ct ◽  
Odontoid Process ◽  
Trabecular Structure ◽  
Anatomical Entity ◽  
Significant Difference ◽  
Axial Ct ◽  
The Mean

OBJECTIVEOdontoid process fractures are very common in both young and geriatric patients. The axial trabecular architecture of the dens appears to be crucial for physiological and biomechanical function of the C1–2 joint. The aim of this study is to demonstrate the presence of a Y-shaped trabecular structure of the dens on axial CT and to describe its anatomical and biomechanical implications.METHODSFifty-four C2 odontoid processes in healthy subjects were prospectively examined for the presence of a Y-shaped trabecular structure at the odontocentral synchondrosis level with a dental cone beam CT scan. Length, width, and axial area of the odontoid process were measured in all subjects. In addition, measurements of the one-third right anterior area of the Y-shaped structure were taken.RESULTSThe Y-shaped trabecular structure was found in 79.6% of cases. Length and width of the odontoid process were 13.5 ± 0.6 mm and 11.2 ± 0.9 mm, respectively. The mean area of the odontoid process at the odontocentral synchondrosis was 93.5 ± 4.3 mm2, whereas the mean one-third right anterior area of the odontoid process at the same level was 29.3 ± 2.5 mm2. The mean area of the odontoid process and its length and width were similar in men and women (p > 0.05). No significant difference was found in the mean area of the odontoid process in people older than 65 years (94 ± 4.2 mm2) compared to people younger than 65 years (93.3 ± 4.4 mm2; p > 0.05).CONCLUSIONSThe authors identified a new anatomical entity, named the Y-shaped trabecular structure of the odontoid process, on axial CT scans. This structure appears to be the result of bone transformation induced by the elevated dynamic loading at the C1–2 level. The presence of the Y-shaped structure provides new insights into biomechanical responses of C2 under physiological loading and traumatic conditions.

scholarly journals Comprehensive Perspective for Lung Cancer Characterisation Based on AI Solutions Using CT Images

2020 ◽  
Vol 10 (1) ◽  
pp. 118
Author(s):  
Tania Pereira ◽  
Cláudia Freitas ◽  
José Luis Costa ◽  
Joana Morgado ◽  
Francisco Silva ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Targeted Therapies ◽  
Treatment Plan ◽  
Personalised Medicine ◽  
Growth Factor Receptor ◽  
Accurate Diagnosis ◽  
Cancer Development ◽  
Thoracic Computed Tomography ◽  
Plan Selection ◽  
Ct Image Analysis

Lung cancer is still the leading cause of cancer death in the world. For this reason, novel approaches for early and more accurate diagnosis are needed. Computer-aided decision (CAD) can be an interesting option for a noninvasive tumour characterisation based on thoracic computed tomography (CT) image analysis. Until now, radiomics have been focused on tumour features analysis, and have not considered the information on other lung structures that can have relevant features for tumour genotype classification, especially for epidermal growth factor receptor (EGFR), which is the mutation with the most successful targeted therapies. With this perspective paper, we aim to explore a comprehensive analysis of the need to combine the information from tumours with other lung structures for the next generation of CADs, which could create a high impact on targeted therapies and personalised medicine. The forthcoming artificial intelligence (AI)-based approaches for lung cancer assessment should be able to make a holistic analysis, capturing information from pathological processes involved in cancer development. The powerful and interpretable AI models allow us to identify novel biomarkers of cancer development, contributing to new insights about the pathological processes, and making a more accurate diagnosis to help in the treatment plan selection.

Tissue Ki67 proliferative index expression and pathological changes in hemodialysis arteriovenous fistulae: Preliminary single-center results

2021 ◽  
pp. 112972982110154
Author(s):  
Raffaella Mauro ◽  
Cristina Rocchi ◽  
Francesco Vasuri ◽  
Alessia Pini ◽  
Anna Laura Croci Chiocchini ◽  
...  
Keyword(s):  
Morphological Changes ◽  
Hot Spot ◽  
Wall Thickening ◽  
Proliferating Cells ◽  
Ki 67 ◽  
Group A ◽  
The Mean ◽  
Set Up ◽  
Group B

Background: Arteriovenous fistula (AVF) for hemodialysis integrates outward remodeling with vessel wall thickening in response to drastic hemodynamic changes. Aim of this study is to determine the role of Ki67, a well-established proliferative marker, related to AVF, and its relationship with time-dependent histological morphologic changes. Materials and methods: All patients were enrolled in 1 year and stratified in two groups: (A) pre-dialysis patients submitted to first AVF and (B) patients submitted to revision of AVF. Morphological changes: neo-angiogenesis (NAG), myointimal thickening (MIT), inflammatory infiltrate (IT), and aneurysmatic fistula degeneration (AD). The time of AVF creation was recorded. A biopsy of native vein in Group A and of arterialized vein in Group B was submitted to histological and immunohistochemical (IHC) analysis. IHC for Ki67 was automatically performed in all specimens. Ki67 immunoreactivity was assessed as the mean number of positive cells on several high-power fields, counted in the hot spots. Results: A total of 138 patients were enrolled, 69 (50.0%) Group A and 69 (50.0%) Group B. No NAG or MIT were found in Group A. Seven (10.1%) Group A veins showed a mild MIT. Analyzing the Group B, a moderate-to-severe MIT was present in 35 (50.7%), IT in 19 (27.5%), NAG in 37 (53.6%); AD was present in 10 (14.5%). All AVF of Group B with the exception of one (1.4%) showed a positivity for Ki67, with a mean of 12.31 ± 13.79 positive cells/hot spot (range 0–65). Ki67-immunoreactive cells had a subendothelial localization in 23 (33.3%) cases, a myointimal localization in SMC in 35 (50.7%) cases. The number of positive cells was significantly correlated with subendothelial localization of Ki67 ( p = 0.001) and with NA ( p = 0.001). Conclusions: Native veins do not contain cycling cells. In contrast, vascular cell proliferation starts immediately after AVF creation and persists independently of the time the fistula is set up. The amount of proliferating cells is significantly associated with MIT and subendothelial localization of Ki67-immunoreactive cells, thus suggesting a role of Ki-67 index in predicting AVF failure.

scholarly journals The Sankara Nethralaya Tamil Nadu Essilor Myopia (STEM) Study—Defining a Threshold for Non-Cycloplegic Myopia Prevalence in Children

2021 ◽  
Vol 10 (6) ◽  
pp. 1215
Author(s):  
Aparna Gopalakrishnan ◽  
Jameel Rizwana Hussaindeen ◽  
Viswanathan Sivaraman ◽  
Meenakshi Swaminathan ◽  
Yee Ling Wong ◽  
...  
Keyword(s):  
Open Field ◽  
Tamil Nadu ◽  
Mean Difference ◽  
School Vision ◽  
Elite School ◽  
Prevalence Estimates ◽  
The Mean ◽  
Clinically Significant ◽  
Set Up ◽  
Definition Of

The aim of this study was to investigate the agreement between cycloplegic and non-cycloplegic autorefraction with an open-field auto refractor in a school vision screening set up, and to define a threshold for myopia that agrees with the standard cycloplegic refraction threshold. The study was conducted as part of the Sankara Nethralaya Tamil Nadu Essilor Myopia (STEM) study, which investigated the prevalence, incidence, and risk factors for myopia among children in South India. Children from two schools aged 5 to 15 years, with no ocular abnormalities and whose parents gave informed consent for cycloplegic refraction were included in the study. All the children underwent visual acuity assessment (Pocket Vision Screener, Elite school of Optometry, India), followed by non-cycloplegic and cycloplegic (1% tropicamide) open-field autorefraction (Grand Seiko, WAM-5500). A total of 387 children were included in the study, of whom 201 were boys. The mean (SD) age of the children was 12.2 (±2.1) years. Overall, the mean difference between cycloplegic and non-cycloplegic spherical equivalent (SE) open-field autorefraction measures was 0.34 D (limits of agreement (LOA), 1.06 D to −0.38 D). For myopes, the mean difference between cycloplegic and non-cycloplegic SE was 0.13 D (LOA, 0.63D to −0.36D). The prevalence of myopia was 12% (95% CI, 8% to 15%) using the threshold of cycloplegic SE ≤ −0.50 D, and was 14% (95% CI, 11% to 17%) with SE ≤ −0.50 D using non-cycloplegic refraction. When myopia was defined as SE of ≤−0.75 D under non-cycloplegic conditions, there was no difference between cycloplegic and non-cycloplegic open-field autorefraction prevalence estimates (12%; 95% CI, 8% to 15%; p = 1.00). Overall, non-cycloplegic refraction underestimates hyperopia and overestimates myopia; but for subjects with myopia, this difference is minimal and not clinically significant. A threshold of SE ≤ −0.75 D agrees well for the estimation of myopia prevalence among children when using non-cycloplegic refraction and is comparable with the standard definition of cycloplegic myopic refraction of SE ≤ −0.50 D.

scholarly journals Enamel interproximal reduction during treatment with clear aligners: digital planning versus OrthoCAD analysis

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Giuseppina Laganà ◽  
Arianna Malara ◽  
Roberta Lione ◽  
Carlotta Danesi ◽  
Simonetta Meuli ◽  
...  
Keyword(s):  
Treatment Plan ◽  
End Of Treatment ◽  
The Mean ◽  
The Difference ◽  
Dependent Sample ◽  
University Of Rome ◽  
The University ◽  
Enamel Reduction ◽  
Lower Arch

Abstract Background The aim of the study was to compare the amount of interproximal enamel reduction (IPR) provided on ClinCheck software with the amount of IPR carried out by the orthodontist during treatment with clear aligners. Methods 30 subjects (14 males, 16 females; mean age of 24.53 ± 13.41 years) randomly recruited from the Invisalign account of the Department of Orthodontics at the University of Rome “Tor Vergata” from November 2018 to October 2019, were collected according to the following inclusion criteria: mild to moderate dento-alveolar discrepancy (1.5–6.5 mm); Class I canine and molar relationship; full permanent dentition (excluding third molars); both arches treated only using Comprehensive Package by Invisalign system; treatment plan including IPR. Pre- (T0) and post-treatment (T1) digital models (.stl files), created from an iTero scan, were collected from all selected patients. The OrthoCAD digital software was used to measure tooth mesiodistal width in upper and lower arches before (T0) and at the end of treatment (T1) before any refinement. The widest mesio-distal diameter was measured for each tooth excluding molars by “Diagnostic” OrthoCAD tool. The total amount of IPR performed during treatment was obtained comparing the sum of mesio-distal widths of all measured teeth at T0 and T1. Significant T1–T0 differences were tested with dependent sample t-test (P < 0.05). Results In the upper arch, IPR was digitally planned on average for 0.62 mm while in the lower arch was on average for 1.92 mm. As for the amount of enamel actually removed after IPR performing, it was on average 0.62 mm in the maxillary arch. In the mandibular arch, the mean of IPR carried out was 1.93 mm. The difference between planned IPR and performed IPR is described: this difference was on average 0.00 mm in the upper arch and 0.01 in the lower arch. Conclusions The amount of enamel removed in vivo corresponded with the amount of IPR planned by the Orthodontist using ClinCheck software.

scholarly journals A Method to Improve Electron Density Measurement of Cone-Beam CT Using Dual Energy Technique

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Kuo Men ◽  
Jian-Rong Dai ◽  
Ming-Hui Li ◽  
Xin-Yuan Chen ◽  
Ke Zhang ◽  
...  
Keyword(s):  
Electron Density ◽  
Cone Beam Ct ◽  
Density Measurement ◽  
Dual Energy ◽  
Cone Beam ◽  
Imaging Method ◽  
Basis Material ◽  
X Ray ◽  
Dual Energy Imaging ◽  
Set Up

Purpose. To develop a dual energy imaging method to improve the accuracy of electron density measurement with a cone-beam CT (CBCT) device.Materials and Methods. The imaging system is the XVI CBCT system on Elekta Synergy linac. Projection data were acquired with the high and low energy X-ray, respectively, to set up a basis material decomposition model. Virtual phantom simulation and phantoms experiments were carried out for quantitative evaluation of the method. Phantoms were also scanned twice with the high and low energy X-ray, respectively. The data were decomposed into projections of the two basis material coefficients according to the model set up earlier. The two sets of decomposed projections were used to reconstruct CBCT images of the basis material coefficients. Then, the images of electron densities were calculated with these CBCT images.Results. The difference between the calculated and theoretical values was within 2% and the correlation coefficient of them was about 1.0. The dual energy imaging method obtained more accurate electron density values and reduced the beam hardening artifacts obviously.Conclusion. A novel dual energy CBCT imaging method to calculate the electron densities was developed. It can acquire more accurate values and provide a platform potentially for dose calculation.

Experiments on the flow of heat in liquid helium below 0.7 °K

1958 ◽  
Vol 246 (1246) ◽  
pp. 390-405 ◽  
Keyword(s):  
Thermal Conductivity ◽  
Liquid Helium ◽  
Free Path ◽  
Empirical Relation ◽  
Mean Free Path ◽  
Series Of Experiments ◽  
The Mean ◽  
Set Up ◽  
Low Pressures ◽  
Measured Thermal Conductivity

A series of experiments has been performed to study the steady flow of heat in liquid helium in tubes of diameter 0.05 to 1.0 cm at temperatures between 0.25 and 0.7 °K. The results are interpreted in terms of the flow of a gas of phonons, in which the mean free path λ varies with temperature, and may be either greater or less than the diameter of the tube d . When λ ≫ d the flow is limited by the scattering of the phonons at the walls, and the effect of the surface has been studied, but when λ ≪ d viscous flow is set up in which the measured thermal conductivity is increased above that for wall scattering. This behaviour is very similar to that observed in the flow of gases at low pressures, and by applying kinetic theory to the problem it can be shown that the mean free path of the phonons characterizing viscosity can be expressed by the empirical relation λ = 3.8 x 10 -3 T -4.3 cm. This result is inconsistent with the temperature dependence of λ as T -9 predicted theoretically by Landau & Khalatnikov (1949).

scholarly journals Human Mesiodistal Tooth Width Measurements and Comparison with Dental Cast in a Bangladeshi Population

2015 ◽  
Vol 16 (4) ◽  
pp. 299-303 ◽  
Author(s):  
Mohammad Khursheed Alam ◽  
Fazal Shahid ◽  
Kathiravan Purmal ◽  
MA Sikder ◽  
Mohammed Saifuddin
Keyword(s):  
Direct Measurement ◽  
Treatment Plan ◽  
Tooth Size ◽  
Human Teeth ◽  
Tooth Width ◽  
The Mean ◽  
Width Measurements ◽  
Bangladeshi Population ◽  
Plaster Model ◽  
Dental Cast

ABSTRACT Aim This analysis was aimed to determine the mesiodistal tooth width of human teeth and to compare with the measurements on plaster model in a Bangladeshi population. Materials and methods The samples of 2,892 teeth of Bangladeshi subjects were collected for this purpose. This article presents mesiodistal tooth width measurements made on all types of teeth and compares with the mesiodistal tooth width measurements of dental cast collected from Bangladeshi subjects between the ages of 18 and 24 years. The mesiodistal dimension was recorded, involving the maximum mesiodistal dimension of each tooth when measurement was rendered parallel to the occlusal and labial surfaces. Descriptive and comparative statistics were applied. Results The mean, standard deviation and 95% confidence interval of mesiodistal tooth width measurements were determined and have been with the mesiodistal tooth width measurements of dental cast. Significant differences have been observed between mesiodistal tooth size of direct measurement on tooth (DMT) and measurement on plaster model (MPM) for the maxillary first molar (p < 0.001) and mandibular incisors to first premolar (p < 0.001). Conclusion These data should prove to be helpful to the practitioner for performing successful orthodontic treatment in Bangladeshi population. Clinical significance Direct measurement of mesiodistal tooth width and individual variation of maxillary and mandibular permanent central incisor to first molar of the Bangladeshi individuals showed some distinguishable features, which will certainly help an orthodontist for diagnosis and treatment plan of an orthodontic case. How to cite this article Alam MK, Shahid F, Purmal K, Sikder MA, Saifuddin M. Human Mesiodistal Tooth Width Measurements and Comparison with Dental Cast in a Bangladeshi Population. J Contemp Dent Pract 2015;16(4):299-303.

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