scholarly journals The Effect of Contrast Agents on Dose Calculations of Volumetric Modulated Arc Radiotherapy Plans for Critical Structures

2021 ◽  
Vol 11 (18) ◽  
pp. 8355
Author(s):  
A. A. Elawadi ◽  
Safa AlMohsen ◽  
Reham AlGendy ◽  
Hosam Allazkani ◽  
Reham A. Mohamed ◽  
...  
Keyword(s):  
Contrast Agents ◽  
Volumetric Modulated Arc Therapy ◽  
Dose Calculation ◽  
Radiotherapy Planning ◽  
Dose Calculations ◽  
Gamma Analysis ◽  
Significant Difference ◽  
Target Volumes ◽  
The Difference ◽  
Clinically Significant

Radiotherapy dose calculation requires accurate Computed Tomography (CT) imaging while tissue delineation may necessitate the use of contrast agents (CA). Acquiring these two sets is a common practice in radiotherapy. This study aims to evaluate the effect of CA on the dose calculations. Two hundred and twenty-six volumetric modulated arc therapy (VMAT) patients that had planning CT with contrast (CCT) and non-contrast CT (NCCT) of different cancer sites (e.g., brain, head, and neck (H&N), chest, abdomen, and pelvis) were evaluated. Treatment plans were recalculated using CCT, then compared to NCCT. The variation in Hounsfield units (HU) and dose distributions for critical structures and target volumes were analyzed using mean HU, mean and maximum relative dose values, D2%, D98%, and 3D gamma analysis. HU variations were statistically significant for most structures. However, this was not clinically significant as the difference in mean HU values was within 30 HU for soft tissue and 50 HU for lungs. Variation in target volumes’ D2% and D98% were insignificant for all sites except brain and nasopharynx. Dose maximum differences were within 2% for the majority of critical structures and target volumes. 3D gamma analysis results revealed that majority of plans satisfied the 2% and 2 mm criteria. CCT may be acquired for VMAT radiotherapy planning purposes instead of NCCT, since there is no clinically significant difference in dose calculations based on either image set.

scholarly journals The effect on tumour control probability of using AXB algorithm in replacement of AAA for SBRT of hepatocellular carcinoma located at lung–liver boundary region

BJR|Open ◽  
2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Michael Lok Man Cheung ◽  
Monica WK Kan ◽  
Vanessa TY Yeung ◽  
Darren MC Poon ◽  
Michael KM Kam ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Volumetric Modulated Arc Therapy ◽  
Boundary Region ◽  
Volume Data ◽  
Worst Case ◽  
Tumour Control ◽  
Tumour Control Probability ◽  
Significant Difference ◽  
Target Volumes ◽  
The Difference

Objective: To retrospectively analyze the clinical impact on stereotactic body radiation therapy (SBRT) for hepatocellular carcinoma (HCC) located at lung–liver boundary due to the use of Acuros XB algorithm (AXB) in replacement of anisotropic analytical algorithm (AAA). Methods: 23 SBRT volumetric modulated arc therapy (VMAT) plans for HCC located at lung–liver boundary were calculated using AAA and AXB respectively with the same treatment parameters. The dose–volume data of the planned target volumes (PTVs) were compared. A published tumour control probability (TCP) model was used to calculate the effect of dosimetric difference between AAA and AXB on tumour control probability. Results: For dose calculated by AXB (Dose to medium), the D95% and D98% of the PTV were on average 2.4 and 3.1% less than that calculated by AAA. For dose calculated by AXB (dose to water), the D95% and D98% of the PTV were on average 1.8%, and 2.7% less than that calculated by AAA. Up to 5% difference in D95% and 8% difference in D98% were observed in the worst cases. The significant decrease in D95% calculated by AXB compared to AAA could result in a % decrease in 2 year TCP up to 8% in the worst case (from 46.8 to 42.9%). Conclusion: The difference in dose calculated by AAA and AXB could lead to significant difference in TCP for HCC SBRT located at lung–liver boundary region. Advances in knowledge: The difference in calculated dose and tumour control probability for HCC SBRT between AAA and AXB algorithm at lung–liver boundary region was compared.

4971Blood viscosity and its relevance to the diagnosis and management of pulmonary hypertension: a new elephant in the cathlab

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
A Kempny ◽  
K Dimopoulos ◽  
A E Fraisse ◽  
G P Diller ◽  
L C Price ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Cardiac Catheterization ◽  
Clinical Decision Making ◽  
Clinical Decision ◽  
Pulmonary Vasculature ◽  
Pulmonary Vascular Disease ◽  
Significant Difference ◽  
The Difference ◽  
Clinically Significant ◽  
The Relationship

Abstract Background Pulmonary vascular resistance (PVR) is an essential parameter assessed during cardiac catheterization. It is used to confirm pulmonary vascular disease, to assess response to targeted pulmonary hypertension (PH) therapy and to determine the possibility of surgery, such as closure of intra-cardiac shunt or transplantation. While PVR is believed to mainly reflect the properties of the pulmonary vasculature, it is also related to blood viscosity (BV). Objectives We aimed to assess the relationship between measured (mPVR) and viscosity-corrected PVR (cPVR) and its impact on clinical decision-making. Methods We assessed consecutive PH patients undergoing cardiac catheterization. BV was assessed using the Hutton method. Results We included 465 patients (56.6% female, median age 63y). The difference between mPVR and cPVR was highest in patients with abnormal Hb levels (anemic patients: 5.6 [3.4–8.0] vs 7.8Wood Units (WU) [5.1–11.9], P<0.001; patients with raised Hb: 10.8 [6.9–15.4] vs. 7.6WU [4.6–10.8], P<0.001, respectively). Overall, 33.3% patients had a clinically significant (>2.0WU) difference between mPVR and cPVR, and this was more pronounced in those with anemia (52.9%) or raised Hb (77.6%). In patients in the upper quartile for this difference, mPVR and cPVR differed by 4.0WU [3.4–5.2]. Adjustment of PVR required Conclusions We report, herewith, a clinically significant difference between mPVR and cPVR in a third of contemporary patients assessed for PH. This difference is most pronounced in patients with anemia, in whom mPVR significantly underestimates PVR, whereas in most patients with raised Hb, mPVR overestimates it. Our data suggest that routine adjustment for BV is necessary.

Attention Deficit Hyperactivity Disorder, Creativity, and the Effects of Methylphenidate

PEDIATRICS ◽  
1993 ◽  
Vol 91 (4) ◽  
pp. 816-819
Author(s):  
Jeanne B. Funk ◽  
John B. Chessare ◽  
Michael T. Weaver ◽  
Anita R. Exley
Keyword(s):  
Attention Deficit Hyperactivity Disorder ◽  
Attention Deficit ◽  
Repeated Measures ◽  
Creative Thinking ◽  
Adhd Group ◽  
Hyperactivity Disorder ◽  
Significant Difference ◽  
Quasi Experimental ◽  
The Difference ◽  
Clinically Significant

Given that children with attention deficit hyperactivity disorder (ADHD) are more impulsive than peers, this study explored whether they are correspondingly more creative, and whether creativity declines when impulsivity is decreased through methylphenidate (Ritalin) therapy. A repeated-measures quasi-experimental design was used to compare the performance of 19 boys with previously diagnosed ADHD and 21 comparison boys aged 8 through 11 on two administrations of alternate forms of the Torrance Tests of Creative Thinking-Figural (nonverbal). Boys with ADHD received prescribed methylphenidate only for the first session. Overall, mean Torrance summary scores for comparison boys (mean = 115.1, SD = 16.1) were higher than for boys with ADHD (mean = 107.6, SD = 12.7). However, the difference between means was small (7%) and did not meet the 25% criterion for a clinically significant difference. No changes in performance over time (comparison group) or medication state (ADHD group) were observed. These data suggest that, when measured nonverbally, the creative thinking performance of boys with ADHD is not superior to that of peers who do not have ADHD. Regarding the effects of methylphenidate, prescribed therapy did not influence performance on this measure of creative thinking.

scholarly journals A Comparison Between Two Types of Radiographic Film for Accuracy of Measurements of Approximal Osseous Defects

2006 ◽  
Vol 7 (3) ◽  
pp. 22-29
Author(s):  
Farah Masood ◽  
Christos Angelopoulos ◽  
Alan Glaros
Keyword(s):  
Bone Loss ◽  
Ground Truth ◽  
Radiographic Film ◽  
Radiographic Images ◽  
Accuracy Of Measurements ◽  
Significant Difference ◽  
Molar Teeth ◽  
The Difference ◽  
Clinically Significant ◽  
Osseous Defects

Abstract Aim The purpose of this study was to compare two types of conventional radiographic film: Ekta-speed plus and Insight (Eastman Kodak Co, Rochester NY, USA) for accuracy of measurements of approximal bone loss. Methods and Materials Four dried human mandibles with complete dentition were selected. Radiographic images were made with a standardized technique. Mesial and distal bone levels on the mandibular premolar and molar teeth were measured on the two types of radiographs (Ekta-speed plus and Insight) by nine observers. The data obtained by the observers were compared with the primary investigators’ corresponding measurements, which served as “the ground truth” for this study. Results The results of the analysis of variance (ANOVA) demonstrated a significant difference for the Ektaspeed plus film (p = .001), but the difference was not clinically significant. The level of intra-rater reliability was high for the observers (0.969 to 0.990). Conclusion Performance of Ekta-speed plus and Insight films was found to be similar. Citation Masood F, Angelopoulos C, Glaros A. A Comparison Between Two Types of Radiographic Film for Accuracy of Measurements of Approximal Osseous Defects. J Contemp Dent Pract 2006 July;(7)3:022-029.

Radiotherapy planning study comparing volumetric modulated arc therapy (VMAT) with intensity modulated radiotherapy (IMRT) in the treatment of bladder and pelvic lymph nodes.

2012 ◽  
Vol 30 (5_suppl) ◽  
pp. 320-320
Author(s):  
Victoria Harris ◽  
Karole Warren-Oseni ◽  
Robert Anthony Huddart
Keyword(s):  
Low Dose ◽  
Treatment Time ◽  
Statistical Significance ◽  
Volumetric Modulated Arc Therapy ◽  
Radiotherapy Planning ◽  
Rank Test ◽  
Attractive Alternative ◽  
Planning Study ◽  
Significant Difference ◽  
3D Crt

320 Background: VMAT is increasingly used as an alternative to IMRT and has been shown to reduce treatment time and monitor units delivered. We report a radiotherapy (RT) planning study of bladder and pelvic lymph node (LN) RT comparing dosimetric outcomes of VMAT and IMRT techniques. Methods: 8 patients with/at high risk of LN+ bladder cancer were treated with bladder/pelvic LN IMRT. 4 clinical target volumes (CTVs) were defined: Whole bladder (CTV1), Pelvic LN (CTV2), Involved Bladder (CTV3) and Involved LNs (CTV4). Margins were applied to create 4 corresponding PTVs. IMRT plans were compared with VMAT plans in order to assess planning target volume (PTV) and organ at risk (OAR) coverage. The same PTV/OAR volumes and doses were used for each technique. Results: The mean dose statistics were compared for each dosimetric parameter for both techniques. The Wilcoxon signed-rank test was used to compare techniques with statistical significance assumed as p<0.05. Both techniques met prescription goals for PTV coverage. Comparison of conformity indices revealed no significant difference between techniques. VMAT achieved significantly better homogeneity in coverage of PTV2, although this finding was not replicated in the other PTVs (Table). Homogeneity index (HI) was defined as HI = 100x(D2-D98)/ Dp, where Dp = prescribed dose. VMAT resulted in significantly larger volumes of bowel (4.7%) and rectum (4.8%) receiving low dose radiation (15 Gy) than IMRT, although there was no significant difference seen at higher dose levels. Comparison with 3D conformal radiotherapy (3D-CRT) showed that both techniques resulted in a large reduction in bowel irradiation to 45Gy (IMRT = 123cc, VMAT = 145cc and 3D-CRT = 218cc). Conclusions: VMAT offers an attractive alternative to IMRT with similar conformality. Whilst increased low dose RT to OARs was seen with VMAT, it is of doubtful significance relative to the higher doses received by these structures. [Table: see text]

scholarly journals Evaluation of Pupils’ Knowledge about Kidney Health

2021 ◽  
Vol 18 (23) ◽  
pp. 12811
Author(s):  
Theodore Vassilikopoulos ◽  
Athena Kalokairinou ◽  
Georgia Kourlaba ◽  
Eirini Grapsa
Keyword(s):  
Renal Function ◽  
General Education ◽  
Knowledge Score ◽  
Cross Sectional Study ◽  
The Body ◽  
Cross Sectional ◽  
Convenience Sample ◽  
Significant Difference ◽  
The Difference ◽  
Clinically Significant

The purpose of this study was to investigate the level of renal function knowledge of primary school pupils in Greece. We conducted a cross-sectional study with a convenience sample of 220 pupils, coming from the 5th and 6th grades of general education schools. A questionnaire consisting of 11 questions was developed from scratch. However, based on an analysis of Cronbach’s alpha values obtained when individual questions were deleted, two questions were removed from the analysis, and only nine remained for analysis and participated in the calculation of the knowledge score. Moreover, the gender and daily habits of pupils regarding water consumption and frequency of urination were recorded. Pupils had a high percentage of correct knowledge about the number of kidneys (95.2%), whether a child may have problems with the kidneys (85.5%) and whether a person can survive with one kidney (68.5%). Low levels of knowledge were observed in the function and role of the kidneys (36.4%), as well as the part of the body where the kidneys are located (30.9%). The median (interquartile range (IQR)) total knowledge score was 6 (5–7), with no difference detected between genders (p = 0.135). A statistically significant difference between pupils of 5th and 6th grades was found but the difference did not seem to be clinically significant (p = 0.035). The present research demonstrates that pupils’ knowledge of renal function and the protection of their kidneys needs improvement.

Accurate Gleason Grading of Prostatic Adenocarcinoma in Prostate Needle Biopsies by General Pathologists

2003 ◽  
Vol 127 (8) ◽  
pp. 1007-1008 ◽  
Author(s):  
Andrew A. Renshaw ◽  
Delray Schultz ◽  
Kerri Cote ◽  
Marian Loffredo ◽  
David E. Ziemba ◽  
...  
Keyword(s):  
Gleason Score ◽  
Prostatic Adenocarcinoma ◽  
Gleason Grading ◽  
Prostate Biopsies ◽  
Tumor Focus ◽  
Significant Difference ◽  
Appropriate Therapy ◽  
The Difference ◽  
Clinically Significant ◽  
Over Time

Abstract Context.—Gleason grading of prostatic adenocarcinoma in core needle biopsies is important for predicting prognosis and selecting appropriate therapy. Previous studies have shown that Gleason scores assigned by general pathologists have a low correlation with those assigned by urologic pathologists, and that general pathologists tend to undergrade prostate carcinoma. Objective.—To determine if the performance of general pathologists grading prostate needle biopsies has changed over time. Design.—Four hundred sixteen prostate biopsies from men treated at a single community-based institution between 1987 and 2000 were reviewed by one urologic pathologist (A.A.R.). The correlation between the original Gleason score and the reviewer's score was determined over time. Results.—Cases were divided into those performed and originally interpreted in the first half of the study (1987–1996) and those performed and originally interpreted in the second half (1996–2000). Overall concordance for exact Gleason score was 59% (244/416). The exact concordance of the Gleason score assigned by the original pathologist and the reviewer during the first half of the study was 51%, whereas in the second half of the study the concordance was significantly greater (66.3%, P = .002). However, when grouped into score categories of 6 or less, 7, and 8 or greater, there was no significant difference in the exact concordance between the first half of the study (78.3%) and the second half (78.4%). Fifty-five percent of the cases in which there was discordance were graded as 7 by the reference pathologist and 6 or less by the original pathologist. There was no correlation between concordance in Gleason score and the percentage of tissue involved by carcinoma. Conclusion.—The concordance between general pathologists' Gleason grading and that of a reference pathologist in this study is much higher than that in previously reported studies. Although exact concordance has significantly improved over time, concordance by clinically significant groups has remained high throughout the study, is dominated by the difference between Gleason score 7 and 6 or less, and is unrelated to the size of the tumor focus.

scholarly journals Should All Steps Count When Using a Pedometer as a Measure of Physical Activity in Older Adults?

2007 ◽  
Vol 4 (3) ◽  
pp. 305-314 ◽  
Author(s):  
Alison L. Marshall
Keyword(s):  
Older Adults ◽  
Feedback Condition ◽  
Daily Step ◽  
Step Counts ◽  
Telephone Interviews ◽  
Significant Difference ◽  
Daily Step Count ◽  
Steps Per Day ◽  
The Difference ◽  
Clinically Significant

Purpose:The aim of this study was to determine if feedback on step counts from a pedometer encourages participants to increase walking.Methods:Randomly recruited older adults (n = 105) were asked to wear a pedometer for 2 wk. Half the participants were asked to monitor and record daily step counts during week 1 (feedback), then seal the pedometer shut during week 2 (no feedback). Half completed the study in reverse order. Self-reported walking was assessed via telephone interviews.Results:Significantly more steps were recorded per day (approximately 400 steps per day) when participants (n = 103, 63% women; mean BMI 25 ± 4) monitored their daily step count [t (102) = –2.30, P = 0.02)] compared to the no feedback condition. There was no statistically significant difference in self-reported walking (P = 0.31) between feedback conditions.Conclusion:The difference in daily step counts observed between conditions, while statistically significant, may not be considered clinically significant. Further, the non-significant difference in self-reported walking between conditions suggests that feedback on daily step counts from a pedometer does not encourage participants to increase their walking.

Prevalence of Impaired Orthostasis after Concussion Injury

Neurology ◽  
2020 ◽  
Vol 95 (20 Supplement 1) ◽  
pp. S1.3-S2
Author(s):  
Michael F. La Fountaine ◽  
Asante Hohn ◽  
Caroline Leahy ◽  
Anthony Testa
Keyword(s):  
Collegiate Athletes ◽  
Transient State ◽  
Incidence Rates ◽  
Control Group ◽  
Clinical Approach ◽  
Male Age ◽  
Significant Difference ◽  
The Difference ◽  
Clinically Significant ◽  
A Prospective Study

ObjectiveTo determine the prevalence of orthostatic hypotension (OHypo) and hypertension (OHTN), respectively after a concussion in collegiate athletes.BackgroundOrthostasis causes a gravity-dependent redistribution of blood volume to the lower extremities. The baroreflex coordinates the cardiovascular autonomic nervous system to mitigate aberrant changes in systolic blood pressure (SBP). In autonomic dysfunction (AD), impaired accommodation may lead to a clinically significant? SBP decreases (OHypo: SBP fall = 20 mm Hg) or paradoxical increases (OHTN: SBP rise = 20 mm Hg) within 3 minutes of assuming the standing (STND) posture. Concussion injuries may induce a transient state of AD. A clinical approach to surveil this state has yet to be defined.Design/MethodsA prospective study was performed in 36 concussed (gender: 23 female, 13 male; age: 20 ± 1 years; height: 1.75 ± 0.12 meters; weight: 73 ± 14 kilograms) and 20 non-concussed athletes (gender: 12 female, 8 male; age: 21 ± 2 years; height: 1.74 ± 0.15 meters; weight: 72 ± 18 kilograms). Continuous beat-to-beat SBP was collected for 10-minutes in a resting supine position (SUP) and then for 3-minutes in the STND position within 48 hours (48H) of concussion. The average SBP was computed from the difference between SUP and the final 15 seconds of STND. SBP were then categorized: Normal (NR: SBP -15 to +15 mm Hg); Borderline OHypo (BordOHypo: SBP −16 to −19 mm Hg) and OHTN (BordOHTN: SBP +16 to +19 mm Hg); OHypo; and, OHTN.ResultsIn concussed athletes, the SBP prevalence rates were 42% NR, 31% OHypo, 11% OHTN, 11% BordOHTN, and 6% BordOHypo compared to 90% NR, 5% OHypo and 5% OHTN in the non-concussed athletes. ?2 test revealed a significant difference in this distribution (p = 0.012).ConclusionsWithin 48H of concussion injury, a combined 42% of injured athletes had an abnormal SBP response to orthostasis and a further 6% had borderline responses that warrant re-evaluation. The incidence rates for each circumstance exceeded the control group.

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