bluuebunny/crossref_metadata_2025_split huggingface dataset:
SU‐F‐J‐226: Structural Similarity‐Based Ultrasound Image Similarity Measurement
Authors: Zhu Li , Wang Ruixing , Xu Kele 
Published: July 2016

Purpose:We explore a method to measure the global ultrasound image similarity measurement, with the aim to facilitate abnormal region detection and automatic tracking failure re‐initialization in the ultrasound image sequences.Methods:Structural similarity is used in our similarity measurement framework. The classical structural similarity assesses the visual impact of three characteristics of the ultrasound imaging region from three aspects: luminance, contrast and structure. Unlike the approach to calculate the local means, standard deviations and cross‐covariance for adjacent two ultrasound images directly, we propose to compute the three aspects based on the local speckle statistics, in which locally adaptive Nakagami distribution‐based measurements are used, resulting in significantly increasing the robustness against the speckle noise.Results:As the tongue can stay in the rest position for long duration and it's easy to conduct the experiment, the proposed similarity measurement is firstly tested on the ultrasound tongue image. The performance demonstrates that the proposed method can provide an accurate similarity description between the frames. Moreover, the potential application of the similarity measurement‐based automatic contour tracking failure re‐initialization is also explored in our experiment. And the results show that using the proposed similarity‐based automatic tracking failure re‐initialization method can improve the accuracy of the tracking. And the tracking error reduce from about 2–3 mm to about 1.5 mm using Euclidean distance measurement.Conclusion:The performance demonstrates that the proposed method can provide an accurate similarity description between the frames. And, the potential applications of the similarity measurement seem evident in several aspects.
SU‐F‐T‐01: Optimization of the Accelerated Partial Breast Brachytherapy Fractionation with Consideration of Physical Doses to Tumor and Organ at Risk
Authors: Fu W , Huq M 
Published: July 2016

Purpose:The accelerated partial breast irradiation (APBI) with brachytherapy prescribes 34Gy to be delivered in 10 fractions over 5 consecutive working days without considering the physical dose to the target and organs at risk (OARs) for an individual patient. The purpose of this study is to optimize the fractionation scheme by evaluating the radiation effect on tumor and OARs with a modified linear‐quadratic (LQ) model based on dose‐volume histograms (DVHs).Methods:Five breast patients treated with multilumen balloon brachytherapy were selected. The minimum skin and rib spacing were ranged from 2.5mm to 14.3mm and from 1.0mm to 25.0mm, respectively. The LQ model parameters were set as: (1) breast: α=0.08, β=0.028, doubling time Tpot=14.4 days, and starting time Tk=21days; (2) skin: acute reaction α=0.101, β=0.009; late reaction α=0.064, β=0.029; (3) rib: α=0.3, β=0.12. Boundary dose Dt was 6 Gy for both target and OARs. The relation between radiation effects on the tumor (ET) and OARs (EOAR) were plotted for fraction number from 1 to 20.Results:The value of radiation effect from routine 3.4Gyx10 fractions was used as reference, ETref and EOARref. If set ET=ETref, the fractionation that results in minimum EOAR values correspond to the optimal fractionation. For these patients, the optimal numbers are 10 fractions for skin acute reaction, 18 fractions for skin and rib late reaction while the doses per fraction are 3.4Gy and 2.05–2.10Gy, respectively. If set EOAR=EOARref, the fractionation that results in a maximum ET value corresponds to the optimal fractionation. The optimal fractionation is 3.4Gyx10 fractions for skin acute reaction, and 2.10–2.25Gyx18 fractions for skin late reaction and rib.Conclusion:For APBI brachytherapy, the routine 3.4Gyx10 fractions is optimal fractionation for skin acute reaction, while 2.05–2.25Gyx18 fractions is optimal fractionation for late reaction of skin and rib.
SU‐F‐T‐05: Dosimetric Evaluation and Validation of Newlydeveloped Well Chamber for Use in the Calibration of Brachytherapy Sources
Authors: Saminathan S , Godson H , Ponmalar R , Manickam R , Mazarello J 
Published: July 2016

Purpose:To evaluate the dosimetric characteristics of newly developed well type ionization chamber and to validate the results with the commercially available calibrated well chambers that are being used for the calibration of brachytherapy sources.Methods:The newly developed well type ionization chamber (BDS 1000) has been designed for the convenient use in brachytherapy which is open to atmospheric condition. The chamber has a volume of 240 cm3 and weight of 2.5 Kg. The calibration of the radioactive source with activities from 0.01 mCi to 20 Ci can be carried out using this chamber. The dosimetric parameters such as leakage current, stability, scattering effect, ion collection efficiency, reference air kerma rate and nominal response with energy were carried out with the BDS 1000 well type ion chamber. The evaluated dosimetric characteristics of BDS1000 well chamber were validated with two other commercially available well chambers (HDR 1000 plus and BTC/3007).Results:The measured leakage current observed was negligible for the newly developed BDS 1000 well type ion chamber. The ion collection efficiency was close to 1 and the response of the chamber was found to be very stable. The determined sweet spot was at 42 mm from bottom of the chamber insert. The reference air kerma rate was found to be 4.634 × 105 Gym2hr‐1A‐1 for the BDS 1000 well chamber. The overall dosimetric characteristics of BDS 1000 well chamber was in good agreement with the dosimetric properties of other two well chambers.Conclusion:The dosimetric study shows that the newly developed BDS 1000 well type ionization chamber is high sensitive and reliable chamber for reference air kerma strength calibration. The results obtained confirm that this chamber can be used for the calibration of HDR and LDR brachytherapy sources.
SU‐F‐T‐12: Monte Carlo Dosimetry of the 60Co Bebig High Dose Rate Source for Brachytherapy
Authors: Campos L T , de Almeida C E V 
Published: July 2016

Purpose:The purpose of this work is to obtain the dosimetry parameters in accordance with the AAPM TG‐43U1 formalism with Monte Carlo calculations regarding the BEBIG 60Co high‐dose‐rate brachytherapy. The geometric design and material details of the source was provided by the manufacturer and was used to define the Monte Carlo geometry.Methods:The dosimetry studies included the calculation of the air kerma strength Sk, collision kerma in water along the transverse axis with an unbounded phantom, dose rate constant and radial dose function. The Monte Carlo code system that was used was EGSnrc with a new cavity code, which is a part of EGS++ that allows calculating the radial dose function around the source. The XCOM photon cross‐section library was used. Variance reduction techniques were used to speed up the calculation and to considerably reduce the computer time. To obtain the dose rate distributions of the source in an unbounded liquid water phantom, the source was immersed at the center of a cube phantom of 100 cm3.Results:The obtained dose rate constant for the BEBIG 60Co source was 1.108±0.001 cGyh‐1U‐1, which is consistent with the values in the literature. The radial dose functions were compared with the values of the consensus data set in the literature, and they are consistent with the published data for this energy range.Conclusion:The dose rate constant is consistent with the results of Granero et al. and Selvam and Bhola within 1%. Dose rate data are compared to GEANT4 and DORZnrc Monte Carlo code. However, the radial dose function is different by up to 10% for the points that are notably near the source on the transversal axis because of the high‐energy photons from 60Co, which causes an electronic disequilibrium at the interface between the source capsule and the liquid water for distances up to 1 cm.
SU‐F‐T‐19: The Consistency Dosimetric Analysis of the Accelerated Breast Brachytherapy
Authors: Pinder J , Chandrasekara S , Pella S 
Published: July 2016

Purpose:To assess the best approach in accept a treatment plan for APBI Savi patients. Should we run a treatment verification test prior to delivering it to the patient? Should we check each CT scan in regards to the initial one in dosimetrical terms? Do we need deformable registration and adaptive planning for each fraction? These are the questions we want to answer running a dosimetric analysis of the dose variances for APBI treatments who receive 10 fractions and no re‐planning has been done being considered unnecessary with today's means of assessment.Methods:A retrospective analysis of 30 patients treated with SAVI applicators were considered for this study. The CT scans taken before each treatment were imported in the treatment planning system and registered with the initial CT scan. The images were fused together with respective to the applicator, using landmark registration. Dosimetric evaluations were performed. Dose received by skin, ribs and PTV on CT images with respect to the initial treatment plan were recorded including maximum, average and minimum doseResults:All the structures displayed changes in volume over the 10 fractions of treatment. The cavities reduction in volume was considerable with a maximum reduction of over 10%. The PTV‐eval is covered better due to this fact while the critical organs manifest an increase in the total and maximum dose delivered. Ribs and skin surface that are required by B39 protocol to be monitored can acquire maximum doses of 20% to 30% respectively.Conclusion:A dosimetric evaluation prior to the initial treatment and prior to each of the 10 fractions is proven to be necessary. Deformable registration and adaptive planning have to be studied more and eventually implemented for every patient who received more than one fraction of any type of brachytherapy treatment. Immobilization ad localization methods must be improved and studied further
SU‐F‐T‐22: Clinical Implications When Using TG‐186 (ACE) Heterogeneity Software
Authors: Likhacheva A , Grade E , Sadeghi A , Sokolowski T 
Published: July 2016

Purpose:The purpose of this study is to compare dosimetric calculations using traditional TG‐43 formalism and Oncentra Brachy Advanced Collapsed cone Engine (ACE) TG‐186 calculation algorithm in clinical setting.Methods:We analyzed dosimetry of four patients treated with accelerated partial breast irradiation using a multi‐channel intracavitary device (SAVI). All patients were treated to 34 Gy in 10 fractions using a high‐dose‐rate (192) Ir source. The plans were designed and treated using the TG‐43 model. ACE was used to assess the effect heterogeneity correction on various dosimetric parameters. Mass density was estimated using Hounsfield units.Results:Compared to TG‐43 formalism, ACE estimated lower doses to targets and organs at risk. The mean difference was 19.8% (range 15.3–24.1%) for PTV_eval V200, 12.0% (range 9.7–17.7%) for PTV_eval V150, 4.3% (range 3.3–6.5%) for PTV_eval D95, 3.3% (range 1.4–5.4%) for PTV_eval D90, 5.4% (range 2.9–9.9%) for maximum rib dose, and 5.7% (2.4–7.4%) for maximum skin dose. There was no correlation between the magnitude of the difference and the PTV_eval volume, air volume, or tissue‐applicator conformance.Conclusion:Based on our preliminary study, the TG‐43 algorithm appears to overestimate the dose to targets and organs at risk when compared to the ACE TG‐186 software. We hypothesize that air adjacent to the SAVI struts contributes to lack of scatter thereby contributing a significant difference in dose calculation when using ACE. We believe that ACE calculation provides a more realistic isodose distribution than TG‐43. We plan to further investigate the impact of heterogeneity correction on brachytherapy planning for a wide variety of clinical scenarios, include skin, cervix/uterus, prostate, and lung
SU‐F‐T‐29: The Important of Each Fraction Image‐Guided Planning for Postoperative HDR‐Brachytherapy in Endometrial Carcinoma
Authors: Piriyasang D , Pattaranutaporn P , Manokhoon K 
Published: July 2016

Purpose:Cylindrical applicators are often used for postoperative HDRbrachytherapy in endometrial carcinoma. It has been considered that dosimetric variation between fractions for this treatment is minimal and might not be necessary to perform treatment planning for every fractions. At our institute, it is traditional to perform treatment planning with CT simulation on the first fraction and uses this plan for the rest of treatment. This study was aim to evaluate the errors of critical structure doses between the fractions when simulation and planning were done for first fraction only.Methods:Treatment plans of 10 endometrial carcinoma patients who received postoperative HDR‐brachytherapy and underwent CT‐simulation for every HDR‐fractions at our department were retrospectively reviewed. All of these patients were treated with cylindrical applicator and prescribed dose 15Gy in 3 fractions to 0.5cm from vaginal surface. The treatment plan from the first fraction was used to simulate in second and third CT‐simulation. Radiation dose for critical structures in term of Dose‐to‐2cc (D2cc) were evaluated and compared between planning CT.Results:The D2cc for bladder and rectum were evaluated. For bladder, the mean error of D2cc estimation for second and third fractions was 7.6% (0.1–20.1%, SD=5.7). And the mean error for D2cc of rectum was 8.5% (0.1–29.4%, SD=8.5).Conclusion:The critical structure doses could be significant difference between fractions which may affects treatment outcomes or toxicities. From our data, image‐guided brachytherapy at least with CT‐Simulation should be done for every treatment fractions.
SU‐F‐T‐39: Comparing Nomograms for Ordering of Palladium‐103 Seeds for Dynamic Intraoperative Prostate Seed Implantation
Authors: Taylor P , Wang L , Riegel A 
Published: July 2016

Purpose:Several nomograms exist for the purpose of ordering palladium‐ 103 seeds for permanent prostate seed implants. Excess seeds pose additional radiation safety risks and increase the cost of care. This study compared three seed ordering nomograms with seed counts from dynamic intra‐operative PSI to determine (1) the cause of excess seeds and (2) the optimal nomogram for our institution.Methods:Pre‐operative and intra‐operative clinical data were collected for 100 Gy (n=151) and 125 Gy (n=224) prostate seed implants. The number of implanted seeds which would have given D90=100% was normalized to that criteria and seed strength of 2U. This was plotted against intra‐operative prostate volume and compared to two previously published nomograms and an in‐house nomogram. A linear fit was produced and confidence intervals were calculated. The causes of excess seeds were assessed by comparing pre‐ and intra‐operative prostate volumes, variability of D90 around 100%, and variance of seed strength from 2U.Results:Of the 375 total cases, 97.6% had excess seeds. On average, 27.17±12.91% of ordered seeds were wasted. Of this percentage, 6.98±5.47% of excess seeds were due to overestimation of pre‐operative prostate volume, 1.10±0.88% were due to D90<100%, 1.17±0.67% were due to seed strength over 2U, and 17.36±7.79% could not be directly attributed to a specific reason. The latter percentage may be due to overestimation of the in‐house nomogram. Two of three nomograms substantially overestimated the number of seeds required. The third nomogram underestimated the required seed number for smaller prostate treatment volume. A linear fit to the clinical data was derived and 99.9% confidence intervals were calculated.Conclusion:Over 85% of clinical cases wasted over 15% of ordered seeds. Two of three nomograms overestimated the required number of seeds. The upper 99.9% C.I. of the clinical data may provide a more reasonable nomogram for Pd‐103 seed ordering.
SU‐F‐T‐41: 3D MTP‐TRUS for Prostate Implant
Authors: Yan P 
Published: July 2016

Purpose:Prostate brachytherapy is an effective treatment for early prostate cancer. The current prostate implant is limited to using 2D transrectal ultrassound (TRUS) or machenical motor driven 2D array either in the end or on the side. Real‐time 3D images can improve the accuracy of the guidance of prostate implant. The concept of our system is to allow realtime full visualization of the entire prostate with the multiple transverse scan.Methods:The prototype of 3D Multiple‐Transverse‐Plane Transrectal Ultrasound probe (MTP‐TRUS) has been designed by us and manufactured by Blatek inc. It has 7 convex linear arrays and each array has 96 elements. It is connected to cQuest Fire bird research system (Cephasonics inc.) which is a flexible and configurable ultrasound‐development platform. The size of cQuest Firebird system is compact and supports the real‐time wireless image transferring. A relay based mux board is designed for the cQuest Firebird system to be able to connect 672 elements.Results:The center frequency of probe is 6MHz±10%. The diameter of probe is 3cm and the length is 20cm. The element pitch is 0.205 mm. Array focus is 30mm and spacing 1.6cm. The beam data for each array was measured and met our expectation. The interface board of MTP‐TURS is made and able to connect to cQuest Firebird system. The image display interface is still under the development. Our real‐time needle tracking algorithm will be implemented too.Conclusion:Our MTP‐TRUS system for prostate implant will be able to acquire real‐time 3D images of prostate and do the real‐time needle segmentation and tracking. The system is compact and have wireless function.
SU‐F‐T‐47: MRI T2 Exclusive Based Planning Using the Endocavitary/interstitial Gynecological Benidorm Applicator: A Proposed TPS Library and Preplan Efficient Methodology
Authors: Richart J , Otal A , Rodriguez S , Santos M , Perez‐Calatayud J 
Published: July 2016

Purpose:ABS and GEC‐ESTRO have recommended MRI T2 for image guided brachytherapy. Recently, a new applicator (Benidorm Template, TB) has been developed in our Department (Rodriguez et al 2015). TB is fully MRI compatible because the Titanium needles and it allows the use of intrauterine tandem. Currently, TPS applicators library are not currently available for non‐rigid applicators in case of interstitial component as the TB.The purpose of this work is to present the development of a library for the TB, together with its use on a pre‐planning technique. Both new goals allow a very efficient and exclusive T2 MRI based planning clinical TB implementation.Methods:The developed library has been implemented in Oncentra Brachytherapy TPS, version 4.3.0 (Elekta) and now is being implemented on Sagiplan v 2.0 TPS (Eckert&Ziegler BEBIG). To model the TB, free and open software named FreeCAD and MeshLab have been used. The reconstruction process is based on three inserted A‐vitamin pellets together with the data provided by the free length. The implemented preplanning procedure is as follow: 1) A MRI T2 acquisition is performed with the template in place just with the vaginal cylinder (no uterine tube nor needles). 2) The CTV is drawn and the required needles are selected using a developed Java based application and 3) A post‐implant MRI T2 is performed.Results:This library procedure has been successfully applied by now in 25 patients. In this work the use of the developed library will be illustrated with clinical examples. The preplanning procedure has been applied by now in 6 patients, having significant advantages: needle depth estimation, needle positions and number are optimized a priori, time saving, etcConclusion:TB library and pre‐plan techniques are feasible and very efficient and their use will be illustrated in this work.
SU‐F‐T‐49: Dosimetry Parameters and TPS Commissioning for the CivaSheet Directional Pd‐103 Brachytherapy Source
Authors: Rivard MJ 
Published: July 2016

Purpose:The CivaSheet is a new LDR Pd‐103 brachytherapy device offering directional‐radiation for preferentially irradiating malignancies with healthy‐tissue sparing. Observations are presented on dosimetric characterization, TPS commissioning, and evaluation of the dosesuperposition‐ principle for summing individual elements comprising a planar CivaSheetMethods:The CivaSheet comprises individual sources (CivaDots, 0.05cm thick and 0.25cm diam.) inside a flexible bioabsorbable substrate with a 0.8cm center‐to‐center rectangular array. All non‐radioactive components were measured to ensure accuracy of manufacturer‐provided dimensional information. The Pd spatial distribution was gleaned from radioactive and inert samples, then modeled with the MCNP6 radiation‐transport‐code. A 6×6 array CivaSheet was modeled to evaluate the dose superposition principle for treatment planning. Air‐kerma‐strength was estimated using the NIST WAFAC geometry. Absorbed dose was estimated in water with polar sampling covering 0.05≤r≤15cm in 0.05cm increments and 0°≤θ≤180° in 1° increments. These data were entered into VariSeed9.0 and tested for the dose‐superposition‐principle.Results:The dose‐rate‐constant was 0.579 cGy/h/U with g(r) determined along the rotational‐axis of symmetry (0°) instead of 90°. gP(r) values at 0.1, 0.5, 2, 5, and 10cm were 1.884, 1.344, 0.558, 0.088, and 0.0046. F(r,θ) decreased between 0° and 180° by factors of 270, 23, and 5.1 at 0.1, 1, and 10cm. The highest dose‐gradient was at 92°, changing by a factor of 3 within 1° due to Au‐foil shielding. TPS commissioning from 0.1≤r≤11cm and 0°≤θ≤180° demonstrated 2% reproducibility of input data except at the high‐dose‐gradient where interpolations caused 3% differences. Dose superposition of CivaDots replicated a multi‐source CivaSheet array within 2% except where another CivaDot was present. Following implantation, the device is not perfectly planar. TPS accuracy utilizing the dose‐superposition‐principle through geometric repositioning of CivaDots supersedes TPS limitations of intersource shielding effectsConclusion:Dosimetric characterization, source commissioning, and evaluation of the dose‐superposition‐principle with VariSeed9.0 permits treatment planning for the CivaSheet brachytherapy device.Research supported in part by CivaTech Oncology, Inc.