scholarly journals Impact of respiratory motion on breast tangential radiotherapy using the field-in-field technique compared to irradiation using physical wedges

2014 ◽  
Vol 48 (1) ◽  
pp. 94-98 ◽  
Author(s):  
Hidekazu Tanaka ◽  
Shinya Hayashi ◽  
Kazuhiro Ohtakara ◽  
Hiroaki Hoshi
Keyword(s):  
Respiratory Motion ◽  
Early Stage ◽  
Free Breathing ◽  
Ct Images ◽  
Data Set ◽  
Acceptable Range ◽  
Treatment Plans ◽  
Prescription Dose ◽  
Ct Data ◽  
The Impact

Abstract Background. This study aimed to evaluate whether the field-in-field (FIF) technique was more vulnerable to the impact of respiratory motion than irradiation using physical wedges (PWs). Patients and methods. Ten patients with early stage breast cancer were enrolled. Computed tomography (CT) was performed during free breathing (FB). After the FB-CT data set acquisition, 2 additional CT scans were obtained during a held breath after light inhalation (IN) and light exhalation (EX). Based on the FB-CT images, 2 different treatment plans were created for the entire breast for each patient and copied to the IN-CT and EX-CT images. The amount of change in the volume of the target receiving 107%, 95%, and 90% of the prescription dose (V107%, V95%, and V90%, respectively), on the IN-plan and EX-plan compared with the FB-plan were evaluated. Results. The V107%, V95%, and V90% were significantly larger for the IN-plan than for the FB-plan in both the FIF technique and PW technique. While the amount of change in the V107% was significantly smaller in the FIF than in the PW plan, the amount of change in the V95% and V90% was significantly larger in the FIF plan. Thus, the increase in the V107% was smaller while the increases in the V95% and V90% were larger in the FIF than in the PW plan. Conclusions. During respiratory motion, the dose parameters stay within acceptable range irrespective of irradiation technique used although the amount of change in dose parameters was smaller with FIF technique.

Computer-assisted Diagnosis for Early Stage Pleural Mesothelioma

2007 ◽  
Vol 46 (03) ◽  
pp. 324-331 ◽  
Author(s):  
P. Jäger ◽  
S. Vogel ◽  
A. Knepper ◽  
T. Kraus ◽  
T. Aach ◽  
...  
Keyword(s):  
Early Stage ◽  
Computation Time ◽  
Hounsfield Unit ◽  
Computer Assisted ◽  
Clinical Test ◽  
Pleural Mesothelioma ◽  
Data Sets ◽  
Data Set ◽  
Average Computation Time ◽  
Ct Data

Summary Objectives: Pleural thickenings as biomarker of exposure to asbestos may evolve into malignant pleural mesothelioma. Foritsearly stage, pleurectomy with perioperative treatment can reduce morbidity and mortality. The diagnosis is based on a visual investigation of CT images, which is a time-consuming and subjective procedure. Our aim is to develop an automatic image processing approach to detect and quantitatively assess pleural thickenings. Methods: We first segment the lung areas, and identify the pleural contours. A convexity model is then used together with a Hounsfield unit threshold to detect pleural thickenings. The assessment of the detected pleural thickenings is based on a spline-based model of the healthy pleura. Results: Tests were carried out on 14 data sets from three patients. In all cases, pleural contours were reliably identified, and pleural thickenings detected. PC-based Computation times were 85 min for a data set of 716 slices, 35 min for 401 slices, and 4 min for 75 slices, resulting in an average computation time of about 5.2 s per slice. Visualizations of pleurae and detected thickeningswere provided. Conclusion: Results obtained so far indicate that our approach is able to assist physicians in the tedious task of finding and quantifying pleural thickenings in CT data. In the next step, our system will undergo an evaluation in a clinical test setting using routine CT data to quantifyits performance.

Does Social Similarity Pay Off? Homophily and Venture Capitalists’ Deal Valuation, Downside Risk Protection, and Financial Returns in India

2020 ◽  
Vol 31 (3) ◽  
pp. 576-603 ◽  
Author(s):  
Kim Claes ◽  
Balagopal Vissa
Keyword(s):  
Early Stage ◽  
Qualitative Interviews ◽  
Downside Risk ◽  
Venture Capitalists ◽  
Data Set ◽  
Start Up ◽  
Risk Protection ◽  
Regional Similarity ◽  
Post Hoc ◽  
The Impact

We ask how social similarity between start-up founders and venture capitalists (VCs) influences VCs’ pricing decisions and returns on investments. We conceptualize how regional and caste similarity, two salient aspects of social similarity in India, affect two distinct aspects of deal pricing: premoney valuation and investors’ downside risk protection in the Indian venture capital market. We theorize that VCs reflect the benefits and costs of social similarity by setting higher premoney valuation when investing in companies led by socially similar founders while also minimizing their downside risks in these investments. We expect that social similarity’s impact on pricing is amplified when VCs face greater subjective uncertainty, such as for early-stage deals or if the VCs lack expertise in the start-up company’s product market. Finally, we claim that VCs achieve superior returns on investments when their deal pricing accurately reflects the impact of social similarity. We tested our conceptual model using both parametric and nonparametric methods on a hand-collected data set of all deals that occurred during 2005–2012, and we supplemented our analyses with in-depth, qualitative interviews that contextualize our findings. The pattern of findings on regional similarity are consistent with our model, but the effects of caste in our data are theoretically anomalous. Post hoc analyses to resolve the anomaly suggest an “intrinsic quality” mechanism, whereby higher-caste VCs set higher valuations when matching with lower-caste founders that signal high quality. Overall, our findings offer evidence that VCs incorporate social attributes into deal pricing in nuanced yet boundedly rational ways.

scholarly journals Assessing and accounting for the impact of respiratory motion on FDG uptake and viable volume for liver lesions in free-breathing PET using respiration-suspended PET images as reference

2014 ◽  
Vol 41 (9) ◽  
pp. 091905 ◽  
Author(s):  
Guang Li ◽  
C. Ross Schmidtlein ◽  
Irene A. Burger ◽  
Carole A. Ridge ◽  
Stephen B. Solomon ◽  
...  
Keyword(s):  
Respiratory Motion ◽  
Free Breathing ◽  
Liver Lesions ◽  
Fdg Uptake ◽  
The Impact

scholarly journals Breast Cancer Among the Oldest Old: Tumor Characteristics, Treatment Choices, and Survival

2010 ◽  
Vol 28 (12) ◽  
pp. 2038-2045 ◽  
Author(s):  
Mara A. Schonberg ◽  
Edward R. Marcantonio ◽  
Donglin Li ◽  
Rebecca A. Silliman ◽  
Long Ngo ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Early Stage ◽  
Oldest Old ◽  
Age Groups ◽  
Breast Conserving Surgery ◽  
Stage I ◽  
Tumor Characteristics ◽  
Data Set ◽  
Younger Women ◽  
The Impact

Purpose Few data are available on breast cancer characteristics, treatment, and survival for women age 80 years or older. Patients and Methods We used the linked Surveillance, Epidemiology and End Results-Medicare data set from 1992 to 2003 to examine tumor characteristics, treatments (mastectomy, breast-conserving surgery [BCS] with radiation therapy or alone, or no surgery), and outcomes of women age 80 years or older (80 to 84, 85 to 89, ≥ 90 years) with stage I/II breast cancer compared with younger women (age 67 to 79 years). We used Cox proportional hazard models to examine the impact of age on breast cancer–related and other causes of death. Analyses were performed within stage, adjusted for tumor and sociodemographic characteristics, treatments received, and comorbidities. Results In total, 49,616 women age 67 years or older with stage I/II disease were included. Tumor characteristics (grade, hormone receptivity) were similar across age groups. Treatment with BCS alone increased with age, especially after age 80. The risk of dying from breast cancer increased with age, significantly after age 80. For stage I disease, the adjusted hazard ratio of dying from breast cancer for women age ≥ 90 years compared with women age 67 to 69 years was 2.6 (range, 2.0 to 3.4). Types of treatments received were significantly associated with age and comorbidity, with age as the stronger predictor (26% of women age ≥ 80 years without comorbidity received BCS alone or no surgery compared with 6% of women age 67 to 79 years). Conclusion Women age ≥ 80 years have breast cancer characteristics similar to those of younger women yet receive less aggressive treatment and experience higher mortality from early-stage breast cancer. Future studies should focus on identifying tumor and patient characteristics to help target treatments to the oldest women most likely to benefit.

Evaluation of Integral Dose in Cranio-spinal Axis (CSA) Irradiation with Conventional and Helical Delivery

2005 ◽  
Vol 4 (6) ◽  
pp. 683-689 ◽  
Author(s):  
José A. Peñagarícano ◽  
Chengyu Shi ◽  
Vaneerat Ratanatharathorn
Keyword(s):  
Pediatric Population ◽  
Healthy Tissue ◽  
Whole Body ◽  
Secondary Malignancies ◽  
Data Set ◽  
Integral Dose ◽  
Dose Comparison ◽  
Spinal Axis ◽  
Ct Data ◽  
The Impact

In cranio-spinal axis (CSA) irradiation, patients are usually treated in the prone position with junctions between cranial and spinal fields. Collimator angle and pedestal rotations are introduced to obtain coplanar alignment of the matched junction. Furthermore, daily moving junctions are commonly used to feather out the junctional dose as additional safe-guards to avoid radiation myelopathy. Helical tomotherapy integrates linear accelerator and CT technology capable of delivering CSA treatment without geometric matches or feathering of junctions. The patient is treated with helical beams in the supine position. Since CSA is used mainly in the pediatric population, the potential increase in integral dose to structures or the whole body from linac- or tomotherapy-based IMRT raises concerns of increased rates of secondary malignancies. In this study, we will present an integral dose comparison between conventional CSA (3D) and helical delivery to the CSA (TOMO) utilizing the Tomotherapy Hi-ART system for three pediatric patients. Integral dose was calculated for organ at risk (OAR), two targets (PTV-BRAIN and PTV-SPINE), entire planning CT data set and to the healthy tissue (entire CT-DATA SET minus the PTV). Overall integral dose was 8% higher in the TOMO plans for Patients #1 and #3, but 2% lower in Patient #2. DVH analysis shows that TOMO plans give lower doses to larger volumes and higher doses to smaller volumes of tissue in all three cases. The advantages of the TOMO plans are minimization of matched junctions and better sparing of most OARs. With increased computational and memory power in the tomotherapy planning station, the excess integral dose to the healthy tissue can be re-distributed within the patient and in turn the total integral dose can be same or lower than in conventional delivery. The impact of a small increase in overall integral dose and the associated risks of secondary malignancies are unknown. Long-term follow-up is needed to answer this question.

scholarly journals Automated incisional hernia characterization by non-rigid registration of CT images – a pilot study

2020 ◽  
Vol 6 (3) ◽  
pp. 91-94
Author(s):  
Samuel Voß ◽  
Philipp D. Lösel ◽  
Vincent Heuveline ◽  
Sylvia Saalfeld ◽  
Philipp Berg ◽  
...  
Keyword(s):  
Incisional Hernia ◽  
Clinical Observation ◽  
Valsalva Maneuver ◽  
Incisional Hernia Repair ◽  
Ct Images ◽  
Software Framework ◽  
Maximum Displacement ◽  
Data Set ◽  
Fully Automatic ◽  
Ct Data

AbstractIncisional hernia repair makes use of prosthetic meshes to re-establish a biomechanically stable abdominal wall. Mesh sizing and fixation have been found to be essential for the clinical outcome. Comparative CT images a) under rest versus b) under Valsalva maneuver (exhalation against closed airways) provide useful information for hernia characterization. However, this process incorporates several manual measurements, which led to observer variability. The present study suggests using an image registration approach of the CT data to reliably and reproducibly extract hernia quantities. The routine is implemented in the software framework MATLAB and works fully automatic. After CT data import, slice by slice undergo non-rigid B-spline grid registration. Local displacement and strain are extracted from the transformation field. The qualitative results correspond to the clinical observation. Maximum displacement of 3.5 cm and maximum strain of 25 % are calculated for one patient’s data set. Current approaches do not provide this type of information. Further research will focus on validation and possibilities to include this new kind of knowledge into the design process of prosthetic meshes.

Competing mortality (CM) risk in patients with resected stage I and II non-small cell lung cancer (NSCLC): A Surveillance, Epidemiology, and End Results (SEER) analysis.

2013 ◽  
Vol 31 (15_suppl) ◽  
pp. 7563-7563
Author(s):  
Gayathri Nagaraj ◽  
Janakiraman Subramanian ◽  
Feng Gao ◽  
Siddhartha Devarakonda ◽  
Ramaswamy Govindan
Keyword(s):  
Risk Factors ◽  
Lung Cancer ◽  
Clinical Trials ◽  
Sample Size ◽  
Cumulative Incidence ◽  
Early Stage ◽  
Stage I ◽  
Data Set ◽  
Early Stage Nsclc ◽  
The Impact

7563 Background: CM risk has been identified as a potential confounder in the interpretation of treatment effects in head and neck cancer (Rose et al. J Clin Oncol. 2011). Lung cancer patients (pts) are at considerable risk for CM due to their advanced age at diagnosis and smoking related chronic diseases. We plan to identify risk factors for CM in pts with early stage NSCLC and develop a statistical model to estimate the effect of CM on power calculation for lung cancer clinical trials. Methods: Using SEER registry we identified 32104 pts who had undergone surgical resection with or without radiation for stage I and II NSCLC between 1994 and 2006. The data set was split into two groups: training set (75%) and testing set (25%). Risk factors for lung cancer-specific mortality (LCSM) and CM were identified using training data by Gray’s sub-distribution regression of competing risk. Pts from the testing data were then stratified according to CM risk and the impact of this risk on power loss was evaluated. Results: The 5-year cumulative incidence of death from lung cancer, other causes and overall mortality was 32.7%, 14.2% and 46.9% respectively. Risk factors for CM were: age (hazard ratio [HR] 1.05), male gender (HR 1.43), divorced (HR 1.30), widowed (HR 1.23) or single (HR 1.29) marital status, squamous (HR 1.40) or not-otherwise-specified (HR 1.22) histology, stage I NSCLC (HR 1.27) and sublobar resection (HR 1.23). The 5-year cumulative incidence of CM in low, mid and high-risk tertiles was 7%, 14% and 21% respectively. Sample size calculations based on all-cause mortality (ACM) result in over-estimation of power as the risk for CM increases. In order to restore the underestimated power in LCSM, 19% and 35% more pts are required in the mid and high CM risk groups respectively (Table). Conclusions: Our findings indicate that conventional sample size calculation methods can result in significant loss of power and incorporating CM risk models in power estimation should be considered for clinical trials involving early stage NSCLC pts. [Table: see text]

Management of Melanoma during Pregnancy: A Case Series of 11 Women Treated at NYU Langone Health

Oncology ◽  
2020 ◽  
Vol 98 (12) ◽  
pp. 847-852
Author(s):  
Amelia E. Sawyers ◽  
Anna C. Pavlick ◽  
Jeffrey S. Weber ◽  
Iman Osman ◽  
Jennifer A. Stein
Keyword(s):  
Early Stage ◽  
Case Series ◽  
Advanced Stage ◽  
Early Stage Disease ◽  
Melanoma Diagnosis ◽  
Stage Disease ◽  
Treatment Plans ◽  
Melanoma Patients ◽  
The Impact

<b><i>Objectives:</i></b> Melanoma is one of the most common malignancies diagnosed during pregnancy. This study examined the impact of pregnancy on management decisions of melanoma patients treated at NYU Langone Health (NYULH). <b><i>Methods:</i></b> We analyzed data for patients who were pregnant at initial or recurrent melanoma diagnosis at NYULH from 2012 to 2019 with prospective protocol-driven follow-up. <b><i>Results:</i></b> Of the 900 female patients accrued during this period, 11 women in the childbearing range were pregnant at melanoma diagnosis. Six patients presented with early (stage 0 or I) disease and five with advanced (stage III or IV) melanoma. Women with early stage disease had normal deliveries and minimal changes to their treatment timeline and regimen. However, patients with more advanced stage disease opted for either termination of the pregnancy or early delivery and altered treatment timelines because of pregnancy. <b><i>Conclusion:</i></b> Both melanoma stage and gestational age at diagnosis contribute to the differences in the therapeutic management of melanoma in pregnant women. Given the complexity and variety of each case of melanoma during pregnancy, informed discussion between patients and physicians allows for individualized treatment plans that address each patient’s unique situation.

Dosimetric comparison of flattened and flattening filter-free beams for liver stereotactic body irradiation in deep inspiration breath hold, and free breathing conditions

2019 ◽  
Vol 18 (02) ◽  
pp. 169-174
Author(s):  
N. Munirathinam ◽  
P. N. Pawaskar
Keyword(s):  
Free Breathing ◽  
Target Volume ◽  
Conformity Index ◽  
Breath Hold ◽  
Deep Inspiration ◽  
Deep Inspiration Breath Hold ◽  
Flattening Filter Free ◽  
Treatment Plans ◽  
Flattening Filter ◽  
Prescription Dose

AbstractAimThe aim of this study is to evaluate the influence of flattened and flattening filter-free (FFF) beam 6 MV photon beam for liver stereotactic body radiation therapy by using volumetric modulated arc therapy (VMAT) technique in deep inspiration breath hold (DIBH) and free breathing condition.Materials and methodsEight liver metastasis patients (one to three metastasis lesions) were simulated in breath hold and free breathing condition. VMAT-based treatment plans were created for a prescription dose of 50 Gy in 10 fractions, using a 230° coplaner arc and 60° non-coplanar arc for both DIBH and free breathing study set. Treatment plans were evaluated for planning target volume (PTV) dose coverage, conformity and hot spots. Parallel and serial organs at risk were compared for average and maximum dose, respectively. Dose spillages were evaluated for different isodose volumes from 5 to 80%.ResultMean D 98% (dose received by 98% target volume) for FFF in DIBH, flattened beam in DIBH, FFF in free breathing and flatten beam in free breathing dataset were 48·9, 47·81, 48·5 and 48·3 Gy, respectively. D 98% was not statistically different between FFF and flatten beam (p = 0·34 and 0·69 for DIBH and free breathing condition). PTV V 105% (volume receiving 105% dose) for the same set were 3·76, 0·25, 1·2 and 0·4%, respectively. Mean heterogeneity index for all study sets and beam models varies between 1·05 and 1·07. Paddik conformity index using unflattened and flattened beam in DIBH at 98% prescription dose were 0·91 and 0·79, respectively. Maximum variation of isodose volume was observed for I-5%, which was ranging between 2288·8 and 2427·2 cm3. Increase in isodose value shows a diminishing difference in isodose volumes between different techniques. DIBH yields a significant reduction in the chest wall dose compared with free breathing condition. Average monitor units for FFF beam in DIBH, flattened beam in DIBH, FFF beam in free breathing CT dataset and flattened beam in free breathing CT dataset were 1318·6 ± 265·1, 1940·3 ± 287·6, 1343·3 ± 238·1 and 2192·5 ± 252·6 MU.ConclusionDIBH and FFF is a good combination to reduce the treatment time and to achieve better tumour conformity. No other dosimetric gain was observed for FFF in either DIBH or free breathing condition.

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