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43 results on '"Osorio, Eliana Vasquez"'

1. New rectum dose surface mapping methodology to identify rectal subregions associated with toxicities following prostate cancer radiotherapy

Author

Bouzaki, Artemis, Green, Dylan, van Herk, Marcel, Shortall, Jane, Puri, Tanuj, Kerns, Sarah, Azria, David, Farcy-Jacquet, Marrie-Pierre, Chang-Claude, Jenny, Choudhury, Ananya, Dunning, Alison, Lambrecht, Maarten, Avuzzi, Barbara, Ruysscher, Dirk De, Seibold, Petra, Sperk, Elena, Talbot, Christopher, Vega, Ana, Veldeman, Liv, Webb, Adam, Rosenstein, Barry, West, Catharine M., Gioscio, Eliana, Rancati, Tiziana, Osorio, Eliana Vasquez, and McWilliam, Alan

Published
2025
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2. Contour Generation with Realistic Inter-observer Variation

Author

Osorio, Eliana Vásquez, Shortall, Jane, Robbins, Jennifer, and van Herk, Marcel

Subjects
Physics - Medical Physics
Abstract

Contours are used in radiotherapy treatment planning to identify regions to be irradiated with high dose and regions to be spared. Therefore, any contouring uncertainty influences the whole treatment. Even though this is the biggest remaining source of uncertainty when daily IGRT or adaptation is used, it has not been accounted for quantitatively in treatment planning. Using probabilistic planning allows to directly account for contouring uncertainties in plan optimisation. The first step is to create an algorithm that can generate many realistic contours with variation matching actual inter-observer variation. We propose a methodology to generate random contours, based on measured spatial inter-observer variation, IOV, and a single parameter that controls its geometrical dependency: alpha, the width of the 3D Gaussian used as point spread function (PSF). We used a level set formulation of the median shape, with the level set function defined as the signed distance transform. To create a new contour, we added the median level set and a noise map which was weighted with the IOV map and then convolved with the PSF. Thresholding the level set function reconstructs the newly generated contour. We used data from 18 patients from the golden atlas, consisting of five prostate delineations on T2-w MRI scans. To evaluate the similarity between the contours, we calculated the maximum distance to agreement to the median shape (maxDTA), and the minimum dose of the contours using an ideal dose distribution. We used the two-sample Kolmogorov-Smirnov test to compare the distributions for maxDTA and minDose between the generated and manually delineated contours. Only alpha=0.75cm produced maxDTA and minDose distributions that were not significantly different from the manually delineated structures. Accounting for the PSF is essential to correctly simulate inter-observer variation., Comment: Paper originally presented in: The International Conference on the Use of Computers in Radiation Therapy June 17-21, 2019 Montreal, Canada http://iccr-mcma.org/ http://iccr-mcma.org/ICCR_MCMA_AbstractDocs.pdf

Published
2022

3. Hounsfield-based Automatic Evaluation of Volumetric Breast Density on Radiotherapy CT-Scans

Author

Akuoko, Deborah E. M., Osorio, Eliana Vasquez, Van Herk, Marcel, and Aznar, Marianne

Subjects
Physics - Medical Physics
Abstract

Radiotherapy is an integral part of treatment for many patients with breast cancer. However, side effects can occur, Example fibrosis or erythema. If patients at higher risks of radiation induced side effects could be identified before treatment, they could be given more individual information about the risks and benefits of radiotherapy. We hypothesise that breast density is correlated with the risk of side effects and present a novel method for automatic evaluation based on radiotherapy planning CT scans.

Published
2021

4. Contouring variation affects estimates of normal tissue complication probability for breast fibrosis after radiotherapy

Author

Jaikuna, Tanwiwat, Osorio, Eliana Vasquez, Azria, David, Chang-Claude, Jenny, De Santis, Maria Carmen, Gutiérrez-Enríquez, Sara, van Herk, Marcel, Hoskin, Peter, Lambrecht, Maarten, Lingard, Zoe, Seibold, Petra, Seoane, Alejandro, Sperk, Elena, Symonds, R Paul, Talbot, Christopher J., Rancati, Tiziana, Rattay, Tim, Reyes, Victoria, Rosenstein, Barry S., de Ruysscher, Dirk, Vega, Ana, Veldeman, Liv, Webb, Adam, West, Catharine M.L., and Aznar, Marianne C.

Published
2023
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8. Multi-centre evaluation of variation in cumulative dose assessment in reirradiation scenarios

Author

Hardcastle, Nicholas, primary, Osorio, Eliana Vasquez, additional, Jackson, Andrew, additional, Mayo, Charles, additional, Aarberg, Anja Einebærholm, additional, Ayadi, Myriam, additional, Belosi, Francesca, additional, Ceylan, Cemile, additional, Davey, Angela, additional, Dupuis, Pauline, additional, Handley, Julia-Claire, additional, Hemminger, Theresa, additional, Hoffmann, Lone, additional, Kelly, Colin, additional, Michailidou, Chrysanthi, additional, Muscat, Sarah, additional, Murrell, Donna H., additional, Pérez-Alija, Jaime, additional, Palmer, Catherine, additional, Placidi, Lorenzo, additional, Popovic, Marija, additional, Rønde, Heidi S., additional, Selby, Adam, additional, Skopidou, Theodora, additional, Solomou, Natasa, additional, Stroom, Joep, additional, Thompson, Christopher, additional, West, Nicholas S, additional, Zaila, Ali, additional, and Appelt, Ane L, additional

Published
2024
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14. 1461: Prostate cancer patients with lower muscle mass have increased late toxicities post-radiotherapy.

Author

McWilliam, Alan, Shortall, Jane, Puri, Tanuj, Osorio, Eliana Vasquez, van Herk, Marcel, Choudhury, Ananya, Hoskin, Peter, Kerns, Sarah, Azria, David, Farcy-Jacquet, Marie-Pierre, Chang-Claude, Jenny, Dunning, Alison, Lambrecht, Maarten, Avuzzi, Barbara, de Ruysscher, Dirk, Seibold, Petra, Sperk, Elena, Talbot, Chris, Webb, Adam, Vega, Ana, Veldeman, Liv, Rosenstein, Barry, West, Catharine, and McSweeney, Donal

Published
2024
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15. 1242: Sensitivity of dose-response mapping model parameters at the bladder and rectum in prostate cancer

Author

Puri, Tanuj, van Herk, Marcel, osorio, Eliana Vasquez, Morros, Andrew P., Shortall, Jane, Kerns, Sarah L., Azria, David, Farcy-Jacquet, Marie-Pierre, Chang-Claude, Jenny, Dunning, Alison, Lambrecht, Maarten, Avuzzi, Barbara, de Ruysscher, Dirk, Seibold, Petra, Sperk, Elena, Talbot, Christopher, Vega, Ana, Veldeman, Liv, Webb, Adam, Rancati, Tiziana, Rosenstein, Barry, West, Catharine, Choudhury, Ananya, Hoskin, Peter, and McWilliam, Alan

Published
2024
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24. Dose outside of the prostate is associated with improved outcomes for high-risk prostate cancer patients treated with brachytherapy boost.

Author

Shortall, Jane, Osorio, Eliana Vasquez, Green, Andrew, McWilliam, Alan, Elumalai, Thriaviyam, Reeves, Kimberley, Johnson-Hart, Corinne, Beasley, William, Hoskin, Peter, Choudhury, Ananya, and van Herk, Marcel

Subjects
PROSTATE cancer patients, RADIOISOTOPE brachytherapy, INTENSITY modulated radiotherapy, PROSTATE, SEMINAL vesicles
Abstract

Background: One in three high-risk prostate cancer patients treated with radiotherapy recur. Detection of lymph node metastasis and microscopic disease spread using conventional imaging is poor, and many patients are under-treated due to suboptimal seminal vesicle or lymph node irradiation. We use Image Based Data Mining (IBDM) to investigate association between dose distributions, and prognostic variables and biochemical recurrence (BCR) in prostate cancer patients treated with radiotherapy. We further test whether including dose information in risk-stratification models improves performance. Method: Planning CTs, dose distributions and clinical information were collected for 612 high-risk prostate cancer patients treated with conformal hypofractionated radiotherapy, intensity modulated radiotherapy (IMRT), or IMRT plus a single fraction high dose rate (HDR) brachytherapy boost. Dose distributions (including HDR boost) of all studied patients were mapped to a reference anatomy using the prostate delineations. Regions where dose distributions significantly differed between patients that did and did-not experience BCR were assessed voxel-wise using 1) a binary endpoint of BCR at four-years (dose only) and 2) Cox-IBDM (dose and prognostic variables). Regions where dose was associated with outcome were identified. Cox proportionalhazard models with and without region dose information were produced and the Akaike Information Criterion (AIC) was used to assess model performance. Results: No significant regions were observed for patients treated with hypofractionated radiotherapy or IMRT. Regions outside the target where higher dose was associated with lower BCR were observed for patients treated with brachytherapy boost. Cox-IBDM revealed that dose response was influenced by age and T-stage. A region at the seminal vesicle tips was identified in binaryand Cox-IBDM. Including the mean dose in this region in a risk-stratification model (hazard ratio=0.84, p=0.005) significantly reduced AIC values (p=0.019), indicating superior performance, compared with prognostic variables only. The region dose was lower in the brachytherapy boost patients compared with the external beam cohorts supporting the occurrence of marginal misses. Conclusion: Association was identified between BCR and dose outside of the target region in high-risk prostate cancer patients treated with IMRT plus brachytherapy boost. We show, for the first-time, that the importance of irradiating this region is linked to prognostic variables. [ABSTRACT FROM AUTHOR]

Published
2023
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25. 443 Exploring Impact of Dose Deposition and Breast Composition on Acute Breast Oedema after Radiotherapy

Author

Jaikuna, Tanwiwat, Azria, David, Chang-Claude, Jenny, De Santis, Maria Carmen, Gutiérrez-Enríque, Sara, van Herk, Marcel, Hoskin, Peter, Lambrecht, Maarten, Seibold, Petra, Seoane, Alejandro, Sperk, Elena, Symonds, R. Paul, Talbot, Christopher J., Rancati, Tiziana, Rattay, Tim, Reyes, Victoria, Rosenstein, Barry S., de Ruysscher, Dirk, Vega, Ana, Veldeman, Liv, Webb, Adam, West, Catharine M.L., Osorio, Eliana Vasquez, and Aznar, Marianne C.

Published
2024
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26. In Reply to Ebert et al.

Author

Shortall, Jane, primary, Palma, Giuseppe, additional, Mistry, Hitesh, additional, Osorio, Eliana Vasquez, additional, McWilliam, Alan, additional, Choudhury, Ananya, additional, Aznar, Marianne, additional, van Herk, Marcel, additional, and Green, Andrew, additional

Published
2022
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33. Identification of modes of tumor regression in non‐small cell lung cancer patients during radiotherapy.

Author

Amugongo, Lameck Mbangula, Green, Andrew, Cobben, David, van Herk, Marcel, McWilliam, Alan, and Osorio, Eliana Vasquez

Subjects
IMAGE registration, NON-small-cell lung carcinoma, CONE beam computed tomography, CANCER patients
Abstract

Purpose: Observed gross tumor volume (GTV) shrinkage during radiotherapy (RT) raises the question of whether to adapt treatment to changes observed on the acquired images. In the literature, two modes of tumor regression have been described: elastic and non‐elastic. These modes of tumor regression will affect the safety of treatment adaptation. This study applies a novel approach, using routine cone‐beam computed tomography (CBCT) and deformable image registration to automatically distinguish between elastic and non‐elastic tumor regression. Methods: In this retrospective study, 150 locally advanced non‐small cell lung cancer patients treated with 55 Gray of radiotherapy were included. First, the two modes of tumor regression were simulated. For each mode of tumor regression, one timepoint was simulated. Based on the results of simulated data, the approach used for analysis in real patients was developed. CBCTs were non‐rigidly registered to the baseline CBCT using a cubic B‐spline algorithm, NiftyReg. Next, the Jacobian determinants were computed from the deformation vector fields. To capture local volume changes, 10 Jacobian values were sampled perpendicular to the surface of the GTV, across the lung‐tumor boundary. From the simulated data, we can distinguish elastic from non‐elastic tumor regression by comparing the Jacobian values samples between 5 and 12.5 mm inside and 5 and 12.5 mm outside the planning GTV. Finally, morphometric results were compared between tumors of different histologies. Results: Most patients (92.3%) in our cohort showed stable disease in the first week of treatment and non‐elastic shrinkage in the later weeks of treatment. At week 2, 125 patients (88%) showed stable disease, three patients (2.1%) disease progression, and 11 patients (8%) regression. By treatment completion, 91 patients (64%) had stable disease, one patient (0.7%) progression and 46 patients (32%) regression. A slight difference in the mode of tumor change was observed between tumors of different histologies. Conclusion: Our novel approach shows that it may be possible to automatically quantify and identify global changes in lung cancer patients during RT, using routine CBCT images. Our results show that different regions of the tumor change in different ways. Therefore, careful consideration should be taken when adapting RT. [ABSTRACT FROM AUTHOR]

Published
2022
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37. Learning from every patient treated

Author

Van Herk, Marcel, primary, Mcwilliam, Alan, additional, Green, Andrew, additional, osorio, Eliana Vasquez, additional, Beasley, William, additional, Choudhury, Ananya, additional, and Faivre-Finn, Corinne, additional

Published
2018
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39. An individualized strategy to estimate the effect of deformable registration uncertainty on accumulated dose in the upper abdomen

Author

Wang, Yibing, Petit, Steven F., Osorio, Eliana Vasquez, Gupta, Vikas, Romero, Alejandra Mendez, Heijmen, Ben, Wang, Yibing, Petit, Steven F., Osorio, Eliana Vasquez, Gupta, Vikas, Romero, Alejandra Mendez, and Heijmen, Ben

Abstract

In the abdomen, it is challenging to assess the accuracy of deformable image registration (DIR) for individual patients, due to the lack of clear anatomical landmarks, which can hamper clinical applications that require high accuracy DIR, such as adaptive radiotherapy. In this study, we propose and evaluate a methodology for estimating the impact of uncertainties in DIR on calculated accumulated dose in the upper abdomen, in order to aid decision making in adaptive treatment approaches. Sixteen liver metastasis patients treated with SBRT were evaluated. Each patient had one planning and three daily treatment CT-scans. Each daily CT scan was deformably registered 132 times to the planning CT-scan, using a wide range of parameter settings for the registration algorithm. A subset of realistic registrations was then objectively selected based on distances between mapped and target contours. The underlying 3D transformations of these registrations were used to assess the corresponding uncertainties in voxel positions, and delivered dose, with a focus on accumulated maximum doses in the hollow OARs, i.e. esophagus, stomach, and duodenum. The number of realistic registrations varied from 5 to 109, depending on the patient, emphasizing the need for individualized registration parameters. Considering for all patients the realistic registrations, the 99th percentile of the voxel position uncertainties was 5.6 +/- 3.3 mm. This translated into a variation (difference between 1st and 99th percentile) in accumulated Dmax in hollow OARs of up to 3.3 Gy. For one patient a violation of the accumulated stomach dose outside the uncertainty band was detected. The observed variation in accumulated doses in the OARs related to registration uncertainty, emphasizes the need to investigate the impact of this uncertainty for any DIR algorithm prior to clinical use for dose accumulation. The proposed method for assessing on an individual patient basis the impact of uncertainties in DIR on acc, Funding Agencies|Elekta AB, Stockholm, Sweden; Dutch Cancer Society [KWF EMCR 2014-6667]

Published
2018
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40. A WebGL based visual proton delivery simulator

Author

Osorio, Eliana Vasquez

Abstract

Introduction. Planning proton therapy is complicated because setup, organ motion, and range uncertainties affect dose delivery, dependent on beam directions and optimization. For robustness evaluation of plans, e.g. for training, a fast delivery simulator would be beneficial. For ease of use and access is should be web-based. The purpose of this project is to develop such a simulator. Material and methods. A full calculation is impractical, but using as core assumption that individual beams can move relative to each other, extremely rapid calculation of treatment scenarios is possible, that correctly render delivery variation at depth. We chose to implement the system on the GPU, using WebGL, where calculation is provided as C-like shader program, integrated in the web page code, that is evaluated massively parallel for every pixel on the screen. Input data (CT, contours and individual beam doses), are provided as a few large texture images (e.g. Fig. 1). Sliders allow setting the delivery and error parameters.Results. The core of the shader program is only 50 lines. WebGL runs about 100 times faster than Javascript. Figure 2 shows a mock proton plan in the resulting web page; dose inhomogeneity due to range uncertainties per fraction is simulated. Calculation speed is high, even on a low end integrated graphic card, a 20 fraction treatment is simulated in 60 fps, allowing immediate feedback on a change of parameters. Conclusions. Using WebGL it is possible to provide a realistic simulation of proton delivery. Evaluation of the simulation accuracy remains to be done.

Published
2017

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