bluuebunny/crossref_metadata_2025_split huggingface dataset:
MO‐DE‐210‐04: Repositioning and Monitoring of Prostate Cancer Radiotherapy with a New 4D Ultrasound Intra‐Modality IGRT Device
Authors: Fargier‐Voiron M , Guillet L , Pommier P , Sarrut D , Biston M 
Published: June 2015

Purpose:We report our clinical experience using a non‐invasive transperineal (TP) ultrasound (US) probe dedicated to pre‐positioning and monitoring of prostate cancer patients. The accuracy of pre‐treatment positioning was compared to CBCT for prostate and post‐prostatectomy patients. Intrafraction motions were recorded for both localizations. The dosimetric impact of these displacements was finally investigated on prostate patients.Methods:Differences between CBCT/CT and TP‐US/TP‐US registrations were analyzed on 427 and 453 sessions for 13 prostate and 14 post‐prostatectomy patients, respectively. Ten prostate patients’ dosimetries were retrospectively planned using 2 different protocols: 80Gy in 40 fractions and 36.25Gy in 5 fractions with a 5mm CTV‐ to‐ PTV margin. The delivery time was measured in order to analyze ranges of intrafraction motions related to each protocol. Mean prostate displacements were calculated for each patient and applied to the treatment isocenter coordinates to evaluate the dosimetric impact of these motions.Results:CBCT and TP‐US shifts agreements at ±5mm were 76.6%, 95.1%, 96.3% and 90.3%, 85.0%, 97.6% in anterior‐ posterior, superior‐ inferior and left‐right directions, for prostate and post‐prostatectomy patients, respectively. Intrafraction motions were analyzed considering delivery times of 140 and 290s with an additional time of 120s for patient installation for doses of 2 and 7.25Gy, respectively. Intrafraction motions were patient‐dependent and were larger as the irradiation time increased. Larger displacements were observed for prostate compared to post‐prostatectomy localizations. Shifts above 3mm were observed on 17.6% and 4.5% of the 2Gy sessions against 30.6% and 7.3% of the 7.25Gy sessions in the anterior‐posterior direction for prostate and post‐prostatectomy localizations, respectively. Preliminary dosimetric results showed that intrafraction motions mainly impact the PTV coverage.Conclusion:4D TP‐US modality is a promising alternative to irradiating and/or invasive IGRT modalities for both inter and intrafraction motions management. Preliminary dosimetric results show that intrafraction monitoring is mandatory especially for hypofractionated treatments.M Fargier‐Voiron was supported by a PhD grant from Elekta
MO‐DE‐210‐05: Improved Accuracy of Liver Feature Motion Estimation in B‐Mode Ultrasound for Image‐Guided Radiation Therapy
Authors: O'shea T , Bamber J , Harris E 
Published: June 2015

Purpose:In similarity‐measure based motion estimation incremental tracking (or template update) is challenging due to quantization, bias and accumulation of tracking errors. A method is presented which aims to improve the accuracy of incrementally tracked liver feature motion in long ultrasound sequences.Methods:Liver ultrasound data from five healthy volunteers under free breathing were used (15 to 17 Hz imaging rate, 2.9 to 5.5 minutes in length). A normalised cross‐correlation template matching algorithm was implemented to estimate tissue motion. Blood vessel motion was manually annotated for comparison with three tracking code implementations: (i) naive incremental tracking (IT), (ii) IT plus a similarity threshold (ST) template‐update method and (iii) ST coupled with a prediction‐based state observer, known as the alpha‐beta filter (ABST).Results:The ABST method produced substantial improvements in vessel tracking accuracy for two‐dimensional vessel motion ranging from 7.9 mm to 40.4 mm (with mean respiratory period: 4.0 ± 1.1 s). The mean and 95% tracking errors were 1.6 mm and 1.4 mm, respectively (compared to 6.2 mm and 9.1 mm, respectively for naive incremental tracking).Conclusions:High confidence in the output motion estimation data is required for ultrasound‐based motion estimation for radiation therapy beam tracking and gating. The method presented has potential for monitoring liver vessel translational motion in high frame rate B‐mode data with the required accuracy.This work is support by Cancer Research UK Programme Grant C33589/A19727.
MO‐DE‐210‐06: Development of a Supercompounded 3D Volumetric Ultrasound Image Guidance System for Prone Accelerated Partial Breast Irradiation (APBI)
Authors: Chiu T , Hrycushko B , Zhao B , Jiang S , Gu X 
Published: June 2015

Purpose:For early‐stage breast cancer, accelerated partial breast irradiation (APBI) is a cost‐effective breast‐conserving treatment. Irradiation in a prone position can mitigate respiratory induced breast movement and achieve maximal sparing of heart and lung tissues. However, accurate dose delivery is challenging due to breast deformation and lumpectomy cavity shrinkage. We propose a 3D volumetric ultrasound (US) image guidance system for accurate prone APBIMethods:The designed system, set beneath the prone breast board, consists of a water container, an US scanner, and a two‐layer breast immobilization cup. The outer layer of the breast cup forms the inner wall of water container while the inner layer is attached to patient breast directly to immobilization. The US transducer scans is attached to the outer‐layer of breast cup at the dent of water container. Rotational US scans in a transverse plane are achieved by simultaneously rotating water container and transducer, and multiple transverse scanning forms a 3D scan. A supercompounding‐technique‐based volumetric US reconstruction algorithm is developed for 3D image reconstruction. The performance of the designed system is evaluated with two custom‐made gelatin phantoms containing several cylindrical inserts filled in with water (11% reflection coefficient between materials). One phantom is designed for positioning evaluation while the other is for scaling assessment.Results:In the positioning evaluation phantom, the central distances between the inserts are 15, 20, 30 and 40 mm. The distances on reconstructed images differ by −0.19, −0.65, −0.11 and −1.67 mm, respectively. In the scaling evaluation phantom, inserts are 12.7, 19.05, 25.40 and 31.75 mm in diameter. Measured inserts’ sizes on images differed by 0.23, 0.19, −0.1 and 0.22 mm, respectively.Conclusion:The phantom evaluation results show that the developed 3D volumetric US system can accurately localize target position and determine target volume, and is a promising image‐guidance tool for prone APBI.
MO‐E‐BRD‐01: Is Non‐Invasive Image‐Guided Breast Brachytherapy Good?
Authors: Hiatt J. 
Published: June 2015

Is Non‐invasive Image‐Guided Breast Brachytherapy Good? – Jess Hiatt, MSNon‐invasive Image‐Guided Breast Brachytherapy (NIBB) is an emerging therapy for breast boost treatments as well as Accelerated Partial Breast Irradiation (APBI) using HDR surface breast brachytherapy. NIBB allows for smaller treatment volumes while maintaining optimal target coverage. Considering the real‐time image‐guidance and immobilization provided by the NIBB modality, minimal margins around the target tissue are necessary.Accelerated Partial Breast Irradiation in brachytherapy: is shorter better? ‐ Dorin Todor, PhD VCUA review of balloon and strut devices will be provided together with the origins of APBI: the interstitial multi‐catheter implant. A dosimetric and radiobiological perspective will help point out the evolution in breast brachytherapy, both in terms of devices and the protocols/clinical trials under which these devices are used. Improvements in imaging, delivery modalities and convenience are among the factors driving the ultrashort fractionation schedules but our understanding of both local control and toxicities associated with various treatments is lagging. A comparison between various schedules, from a radiobiological perspective, will be given together with a critical analysis of the issues.

to review and understand the evolution and development of APBI using brachytherapy methods
to understand the basis and limitations of radio‐biological ‘equivalence’ between fractionation schedules
to review commonly used and proposed fractionation schedules
Intra‐operative breast brachytherapy: Is one stop shopping best?‐ Bruce Libby, PhD. University of VirginiaA review of intraoperative breast brachytherapy will be presented, including the Targit‐A and other trials that have used electronic brachytherapy. More modern approaches, in which the lumpectomy procedure is integrated into an APBI workflow, will also be discussed.Learning Objectives:

To review past and current clinical trials for IORT
To discuss lumpectomy‐scan‐plan‐treat workflow for IORT
MO‐E‐BRD‐02: Accelerated Partial Breast Irradiation in Brachytherapy: Is Shorter Better?
Authors: Todor D. 
Published: June 2015

Is Non‐invasive Image‐Guided Breast Brachytherapy Good? – Jess Hiatt, MSNon‐invasive Image‐Guided Breast Brachytherapy (NIBB) is an emerging therapy for breast boost treatments as well as Accelerated Partial Breast Irradiation (APBI) using HDR surface breast brachytherapy. NIBB allows for smaller treatment volumes while maintaining optimal target coverage. Considering the real‐time image‐guidance and immobilization provided by the NIBB modality, minimal margins around the target tissue are necessary.Accelerated Partial Breast Irradiation in brachytherapy: is shorter better? ‐ Dorin Todor, PhD VCUA review of balloon and strut devices will be provided together with the origins of APBI: the interstitial multi‐catheter implant. A dosimetric and radiobiological perspective will help point out the evolution in breast brachytherapy, both in terms of devices and the protocols/clinical trials under which these devices are used. Improvements in imaging, delivery modalities and convenience are among the factors driving the ultrashort fractionation schedules but our understanding of both local control and toxicities associated with various treatments is lagging. A comparison between various schedules, from a radiobiological perspective, will be given together with a critical analysis of the issues.

to review and understand the evolution and development of APBI using brachytherapy methods
to understand the basis and limitations of radio‐biological ‘equivalence’ between fractionation schedules
to review commonly used and proposed fractionation schedules
Intra‐operative breast brachytherapy: Is one stop shopping best?‐ Bruce Libby, PhD. University of VirginiaA review of intraoperative breast brachytherapy will be presented, including the Targit‐A and other trials that have used electronic brachytherapy. More modern approaches, in which the lumpectomy procedure is integrated into an APBI workflow, will also be discussed.Learning Objectives:

To review past and current clinical trials for IORT
To discuss lumpectomy‐scan‐plan‐treat workflow for IORT
MO‐DE‐210‐07: Investigation of Treatment Interferences of a Novel Robotic Ultrasound Radiotherapy Guidance System with Clinical VMAT Plans for Liver SBRT Patients
Authors: Gong R , Bruder R , Schweikard A , Schlosser J , Hristov D 
Published: June 2015

Purpose:To evaluate the proportion of liver SBRT cases in which robotic ultrasound image guidance concurrent with beam delivery can be deployed without interfering with clinically used VMAT beam configurations.Methods:A simulation environment incorporating LINAC, couch, planning CT, and robotic ultrasound guidance hardware was developed. Virtual placement of the robotic ultrasound hardware was guided by a target visibility map rendered on the CT surface. The map was computed on GPU by using the planning CT to simulate ultrasound propagation and attenuation along rays connecting skin surface points to a rasterized imaging target. The visibility map was validated in a prostate phantom experiment by capturing live ultrasound images of the prostate from different phantom locations. In 20 liver SBRT patients treated with VMAT, the simulation environment was used to place the robotic hardware and ultrasound probe at imaging locations indicated on the visibility map. Imaging targets were either entire PTV (range 5.9–679.5 ml) or entire GTV (range 0.9–343.4 ml). Presence or absence of mechanical collisions with LINAC, couch, and patient body as well as interferences with treated beams were recorded.Results:For PTV targets, robotic ultrasound guidance without mechanical collision was possible in 80% of the cases and guidance without beam interference was possible in 60% of the cases. For the smaller GTV targets, these proportions were 95% and 85% correspondingly. GTV size (1/20), elongated shape (1/20), and depth (1/20) were the main factors limiting the availability of non‐interfering imaging positions.Conclusion:This study indicates that for VMAT liver SBRT, robotic ultrasound tracking of a relevant internal target would be possible in 85% of cases while using treatment plans currently deployed in the clinic. With beam re‐planning in accordance with the presence of robotic ultrasound guidance, intra‐fractional ultrasound guidance may be an option for 95% of the liver SBRT cases.This project was funded by NIH Grant R41CA174089.
MO‐FG‐BRD‐04: Real‐Time Imaging and Tracking Techniques for Intrafractional Motion Management: MR Tracking
Authors: Low D. 
Published: June 2015

Intrafraction target motion is a prominent complicating factor in the accurate targeting of radiation within the body. Methods compensating for target motion during treatment, such as gating and dynamic tumor tracking, depend on the delineation of target location as a function of time during delivery. A variety of techniques for target localization have been explored and are under active development; these include beam‐level imaging of radio‐opaque fiducials, fiducial‐less tracking of anatomical landmarks, tracking of electromagnetic transponders, optical imaging of correlated surrogates, and volumetric imaging within treatment delivery. The Joint Imaging and Therapy Symposium will provide an overview of the techniques for real‐time imaging and tracking, with special focus on emerging modes of implementation across different modalities. In particular, the symposium will explore developments in 1) Beam‐level kilovoltage X‐ray imaging techniques, 2) EPID‐based megavoltage X‐ray tracking, 3) Dynamic tracking using electromagnetic transponders, and 4) MRI‐based soft‐tissue tracking during radiation delivery.Learning Objectives:

Understand the fundamentals of real‐time imaging and tracking techniques
Learn about emerging techniques in the field of real‐time tracking
Distinguish between the advantages and disadvantages of different tracking modalities
Understand the role of real‐time tracking techniques within the clinical delivery work‐flow
MO‐FG‐BRB‐03: Addressing the Cancer Challenge: International Cancer Experts Corps
Authors: Coleman N. 
Published: June 2015

The global burden of cancer is growing rapidly with an estimated 15 million new cases per year worldwide in 2015, growing to 19 million by 2025 and 24 million by 2035. The largest component of this growth will occur in low‐to‐middle income countries (LMICs). About half of these cases will require radiation treatment. The gap for available cancer treatment, including radiation therapy, between high‐income countries (HICs) and LMICs is enormous. Accurate data and quantitative models to project the needs and the benefits of cancer treatment are a critical first step in closing the large cancer divide between LMICs and HICs. In this context, the Union for International Cancer Control (UICC) has developed a Global Task Force on Radiotherapy for Cancer Control (GTFRCC) with a charge to answer the question as to what it will take to close the gap between what exists today and reasonable access to radiation therapy globally by 2035 and what the potential clinical and economic benefits are for doing this. The Task Force has determined the projections of cancer incidence and the infrastructure required to provide access to radiation therapy globally. Furthermore it has shown that appropriate investment not only yields improved clinical outcomes for millions of patients but that it also provides an overall economic gain throughout all the income settings where this investment is made. This symposium will summarize the facets associated with this global cancer challenge by reviewing the cancer burden, looking at the requirements for radiation therapy, reviewing the benefits of providing such therapy both from a clinical and economic perspective and finally by looking at what approaches can be used to aid in the alleviation of this global cancer challenge. The speakers are world renowned experts in global public health issues (R. Atun), medical physics (D. Jaffray) and radiation oncology (N. Coleman).Learning Objectives:

To describe the global cancer challenge and the corresponding potential benefits of addressing this challenge.
To describe what radiation therapy infrastructure, in terms of facilities, equipment and personnel, will be required to address this challenge.
To describe models of addressing personnel and infrastructure mobilization and capacity building within regions where significant cancer treatment disparities exist.
MO‐FG‐BRA‐01: Development of An Image‐Guided Dosimetric Planning System for Injectable Brachytherapy Using ELP Nanoparticles
Authors: Lafata K , Schaal J , Liu W , Cai J 
Published: June 2015

Purpose:To develop, validate, and evaluate a methodology for determining dosimetry for intratumoral injections of elastin‐like‐polypeptide (ELP) brachytherapy nanoparticles. These organic‐polymer‐based nanoparticles are injectable, biodegradable, and genetically tunable. We present a genetically encoded polymer‐solution, composed of novel radiolabeled‐ELP nanoparticles that are custom‐designed to self‐assemble into a local source upon intratumoral injection. Our preliminary results of a small animal study demonstrate 100% tumor response, effective radionuclide retention‐rates, strong in vivo stability, and no polymer‐induced toxicities. While our approach is therefore highly promising for improved brachytherapy, the current workflow lacks a dosimetry framework.Methods:We are developing a robust software framework that provides image‐guided dosimetric‐planning capabilities for ELP brachytherapy. The user graphically places ELP injection sites within a µCT‐planning‐image, and independently defines each injection volume, concentration, and radioisotope to be used. The resulting internal dosimetry is then pre‐determined by first modeling post‐injection ELP advection‐diffusion, and then calculating the resulting dose distribution based on a point‐ dose‐kernel‐convolution algorithm. We have experimentally measured ELP steady‐state concentrations via µSPECT acquisition, and validated our dose calculation algorithm against Monte Carlo simulations of several radioactivity distributions. Finally, we have investigated potential advantages and limitations of various ELP injection parameters.Results:The µSPECT results demonstrated inhomogeneous steady‐state distributions of ELP in tissue, and Monte Carlo radioactivity distributions were designed accordingly. Our algorithm yielded a root‐mean‐square‐error of less than 2% for each distribution tested (average root‐mean‐square‐error was 0.73%). Dose‐Volume‐Histogram analysis of five different plans showed how strategic injection placement, and an injection volume‐tapering technique, could be used to achieve D95% target coverage.Conclusion:We have preliminarily developed a novel planning framework for ELP brachytherapy. Its dosimetry accuracy has been validated against Monte Carlo, and we have started to investigate the potential advantages of injection‐based planning. This system, once fully developed, will serve as the technical foundation for our novel approach.
MO‐FG‐303‐08: PET‐Detectable Bimetallic (Zn@Au) Nanoparticles for Radiotherapy and Molecular Imaging Applications
Authors: Cho J , Wang M , Gonzalez‐Lepera C , Zubarev E , Cho S 
Published: June 2015

Purpose:A technical challenge in clinical translation of GNP‐mediated radiotherapy is lack of in‐vivo imaging tools for monitoring biodistribution of GNPs. While several modalities (x‐ray fluorescence, photoacoustic, etc.) are investigated, we propose a potentially more effective technique based on PET imaging. We developed Zn@Au NPs whose Zn core acts as positron emitters when activated by protons, while the Au shell plays the original role for GNP‐mediated radiosensitization.Methods:Spherical Zn NPs (∼7nm diameter) were synthesized and then coated with ∼7nm thick Au layer to make Zn@Au NPs (∼20nm diameter). A water slurry containing 29mg of Zn@Au NPs was deposited (<10µm thickness) on a thin cellulose target and subsequently baked to remove the water. The cellulose matrix was placed in an aluminum target holder and irradiated with 14.5MeV protons from a GE PETtrace cyclotron with 4µA for 5min. After irradiation the cellulose matrix with the NPs was placed in a dose calibrator to assay radioactivity. Gamma spectroscopy using a HPGe detector was conducted on a very small fraction (<1mg) of the irradiated NPs.Results:We measured 158µCi of activity 32min after end of bombardment (EOB) using 66Ga setting on the dose calibrator (contribution from the cellulose matrix is negligible) which decreased to 2µCi over a 24hrs period. A gamma spectrum started one hour after EOB on the small fraction and acquired for 700sec showed a strong peak at 511keV (∼40,000 counts) with several other peaks (highest peak <1200 counts) of smaller magnitude.Conclusion:Strong 511keV gamma emission from proton‐activated Zn cores can potentially be utilized to image the biodistribution of Zn@Au NPs using a PET scanner. The developed Zn@Au NPs are expected to retain radiosensitizing capability similar to solid GNPs, while observable through PET imaging for human‐sized objects. Moreover, bioconjugated PET‐detectable GNPs would allow a new option to perform molecular imaging.
MO‐FG‐204‐06: A New Algorithm for Gold Nano‐Particle Concentration Identification in Dual Energy CT
Authors: Chen L , Shen C , Ng M , Zeng T , Lou Y , Jia X 
Published: June 2015

Purpose:Gold nano‐particle (GNP) has recently attracted a lot of attentions due to its potential as an imaging contrast agent and radiotherapy sensitiser. Imaging the GNP at its low contraction is a challenging problem. We propose a new algorithm to improve the identification of GNP based on dual energy CT (DECT).Methods:We consider three base materials: water, bone, and gold. Determining three density images from two images in DECT is an under‐determined problem. We propose to solve this problem by exploring image domain sparsity via an optimization approach. The objective function contains four terms. A data‐fidelity term ensures the fidelity between the identified material densities and the DECT images, while the other three terms enforces the sparsity in the gradient domain of the three images corresponding to the density of the base materials by using total variation (TV) regularization. A primal‐dual algorithm is applied to solve the proposed optimization problem. We have performed simulation studies to test this model.Results:Our digital phantom in the tests contains water, bone regions and gold inserts of different sizes and densities. The gold inserts contain mixed material consisting of water with 1g/cm3 and gold at a certain density. At a low gold density of 0.0008 g/cm3, the insert is hardly visible in DECT images, especially for those with small sizes. Our algorithm is able to decompose the DECT into three density images. Those gold inserts at a low density can be clearly visualized in the density image.Conclusion:We have developed a new algorithm to decompose DECT images into three different material density images, in particular, to retrieve density of gold. Numerical studies showed promising results.