bluuebunny/crossref_metadata_2025_split huggingface dataset:
SU‐G‐IeP1‐10: Permeability Evaluation of Interstitial Cystitis by DCE‐MRI of the Bladder
Authors: Wu D , Vo J , North J , Towner R , Hurst R 
Published: July 2016

Purpose:Interstitial cystitis (IC) is a chronic and painful condition that can lead to bladder pain syndrome (BPS) in women. IC and BPS have been known to manifest after physiological changes after giving birth. In this project, we pioneered and advanced a new clinical utility using DCE‐MRI to assess bladder permeability. At first IC/BPS perfusion methods were with ratio signal evaluation, we now incorporate pharmacokinetics techniques to allow for further assessment.Methods:In this pilot study, female patients and volunteers (IC=4, Control=3) underwent imaging with a clinical GE 3T 750W MRI system. This project was approved by the OUHSC IRB. Multiple TR Images series were acquired. Images were analyzed in the coronal plane at 0‐, 3‐, 6‐, 9‐, 12‐, 15‐, 20‐, 25‐, and 30‐minute intervals. We used a three‐compartmental pharmacokinetic model with these data. The compartments included: a) bladder interior site of injection, b) bladder wall, and c) external psoas muscle. The signal was transformed and corrected for T1‐relaxation based on a multi‐TR exponential regression before pharmacokinetic analysis.Results:Significant differences (p<0.05) were detected with relative means for T1 concentration changes (IC/BPS=0.0107, control=0.616) on the outflow between the k13 transfer coefficient, which represents the injection leakage to the external parenchyma. Trend differences (p<0.1) were found in permeability between the bladder injection site to the rim. We also found changes in the kurtosis of the histograms of regional perfusion. No detectable changes were found in the reverse directions for the above compartments (k21, k31).Conclusion:We report clinical changes in this pilot study. This study illustrates early detectable evidence for a possible DCE‐MRI tool that can detect permeability differences with pharmacokinetics measurement of k13. These techniques are intended to advance quantitative imaging methods for IC/BPS, per the goals/objectives of the Quantitative Imaging Biomarker Alliance (QIBA) and other AAPM and RSNA initiatives.
SU‐G‐JeP1‐04: Characterization of a High‐Definition Optical Patient Surface Tracking System Across Five Installations
Authors: Smith T , Ayan A , Cochran E , Woollard J , Gupta N 
Published: July 2016

Purpose:To assess the performance of Varian's real‐time, Optical Surface Monitoring System (OSMS) by measuring relative regular and irregular surface detection accuracy in 6 degrees of motion (6DoM), across multiple installations.Methods:Varian's Intracranial SRS Package includes OSMS, which utilizes 3 HD camera/projector pods to map a patient surface, track intra‐fraction motion, and gate the treatment beam if motion exceeds a threshold. To evaluate motion‐detection accuracy of OSMS, we recorded shifts of a cube‐shaped phantom on a single Varian TrueBeam linear accelerator as known displacements were performed incrementally across 6DoM. A subset of these measurements was repeated on identical OSMS installations. Phantom motion was driven using the TrueBeam treatment couch, and incremented across ±2cm in steps of 0.1mm, 1mm, and 1cm in the cardinal planes, and across ±40° in steps of 0.1°, 1°, and 5° in the rotational (couch kick) direction. Pitch and Roll were evaluated across ±2.5° in steps of 0.1° and 1°. We then repeated this procedure with a frameless SRS setup with a head phantom in a QFix Encompass mask.Results:Preliminary data show OSMS is capable of detecting regular‐surfaced phantom displacement within 0.03±0.04mm in the cardinal planes, and within 0.01±0.03° rotation across all planes for multiple installations. In a frameless SRS setup, OSMS is accurate to within 0.10±0.07mm and 0.04±0.07° across 6DoM. Additionally, a reproducible “thermal drift” was observed during the first 15min of monitoring each day, and characterized by recording displacement of a stationary phantom each minute for 25min. Drift settled after 15min to an average delta of 0.26±0.03mm and 0.38±0.03mm from the initial capture in the Y and Z directions, respectively.Conclusion:For both regular surfaces and clinical SRS situations, OSMS exceeds quoted detection accuracy. To reduce error, a warm‐up period should be employed to allow camera/projector pod thermal stabilization.
SU‐G‐TeP2‐10: Feasibility of Newly Designed Applicator for High Dose Rate Brachytherapy Treatment of Patients with Vaginal Vault Recurrence
Authors: Lee V , Huang X , Wong M , Chan M , Chui E , Cheung S , Leung R , Lee K , Law G , Leung K , Tung S , Kwong D 
Published: July 2016

Purpose:To compare the dose of an in‐house 3D‐printed gynecology applicator (TMHGA) for vaginal vault recurrence of corpus cancer patients after operation for high dose rate brachytherapy treatment with commercially available applicators.Methods:A newly designed applicator is made from 3D‐printing methods using ABSM30i. The isodose of the applicator is compared with Elekta multi‐channel (MC) applicator and titanium Rotterdam applicator with coupling central tube and vaginal cylinder (RC). Three plans are created using three applicators in a CT set of water phantom. The applicators are anchored using the applicator library and implant library in the Elekta Oncentra treatment planning system (ver.4.5). The rectum is mimicked by creating a 2cm diameter cylinder, with a distance 1mm posteriorly away from the high risk CTV (HR‐CTV). Similarly, the bladder is replicated by a 6cm diameter cylinder with distance 1mm anteriorly from the HR‐CTV. Three plans are all normalized 1.5cm superior, 0.5cm anterior and 0.5cm posterior of the applicator surface. By fixing D90 of HR‐CTV to 6Gy, the D2cc of rectum and bladder of three plans are compared.Results:The D2cc of the bladder for using TMHGA is lower than MC and RC by 14.0% and 11.9% respectively. While the D2cc of the rectum for using TMHGA is lower than MC and RC by 18.9% and 12.4% respectively. The total treatment time of TMHGA plan is shorter than MC and RC by 11.2% and 12.9%.Conclusion:The applicator created via 3D printing delivers a lower dose to the bladder and the rectum while keeping the same coverage to HR‐CTV as other commercially available applicators. Additionally, the new applicator resulted in a reduction of treatment time, which is always welcome.
SU‐G‐TeP2‐11: Initial Evaluation of a Novel Split‐Filter Dual‐Energy CT for Use in Radiation Oncology
Authors: Miller J , Huang J , Szczykutowicz T , Bayouth J 
Published: July 2016

Purpose:To perform an initial evaluation of a novel split‐filter dual‐energy CT (DECT) system with the goal of understanding the clinical utility and limitations of the system for radiation therapy.Methods:Several phantoms were imaged using the split‐filter DECT technique on the Siemens Edge CT scanner using a range of clinically‐relevant doses. The optimum‐contrast reconstruction, the mixed reconstruction, and the monoenergetic reconstructions (ranging from 40 keV to 190 keV) were evaluated. Each image was analyzed for CT number accuracy, uniformity, noise, low‐contrast visibility (LCV), spatial resolution and geometric distortion. For comparison purposes, all parameters were evaluated on 120 kVp single‐energy CT (SECT) scans used for treatment planning, as well as, a sequential‐scan DECT technique for corresponding doses.Results:For all DECT reconstructions no observable geometric distortion was found. Both the optimal‐contrast and mixed images demonstrated slight improvements in LCV and noise when compared to the SECT, and slight reductions in CT number accuracy and spatial resolution. The CT numbers trended as expected for the monoenergetic reconstructions, with CT number accuracy within 50 HU for materials of density <2 g/cm3. Spatial resolution increased with energy, and for monoenergetic reconstructions >70 keV the spatial resolution exceeded that of the SECT. The noise in the monoenergetic reconstructions increased with decreasing energy. Thus, the image uniformity, signal‐to‐noise ratio and LCV were diminished at lower energies (70 keV). Applying iterative reconstruction techniques to the low‐energy images reduced noise and improved LCV. The signal‐to‐noise ratio was stable for energies >100 keV.Conclusion:The initial commissioning of the novel split‐filter DECT technology demonstrated favorable results for clinical implementation. The mixed reconstruction showed potential as a replacement for the treatment planning SECT. The image parameters for the monoenergetic reconstructions varied appropriately with energy. This work provides an initial understanding of the limitations and potential applications for monoenergetic imaging.
SU‐G‐TeP2‐13: Patient‐Specific Reduction of Range Uncertainties in Proton Therapy by Proton Radiography with a Multi‐Layer Ionization Chamber
Authors: Deffet S , Farace P , Righetto R , Macq B , Vander Stappen F 
Published: July 2016

Purpose:The conversion from Hounsfield units (HU) to stopping powers is a major source of range uncertainty in proton therapy (PT). Our contribution shows how proton radiographs (PR) acquired with a multi‐layer ionization chamber in a PT center can be used for accurate patient positioning and subsequently for patient‐specific optimization of the conversion from HU to stopping powers.Methods:A multi‐layer ionization chamber was used to measure the integral depth‐dose (IDD) of 220 MeV pencil beam spots passing through several anthropomorphic phantoms. The whole area of interest was imaged by repositioning the couch and by acquiring a 45×45 mm2 frame for each position. A rigid registration algorithm was implemented to correct the positioning error between the proton radiographs and the planning CT. After registration, the stopping power map obtained from the planning CT with the calibration curve of the treatment planning system was used together with the water equivalent thickness gained from two proton radiographs to generate a phantom‐specific stopping power map.Results:Our results show that it is possible to make a registration with submillimeter accuracy from proton radiography obtained by sending beamlets separated by more than 1 mm. This was made possible by the complex shape of the IDD due to the presence of lateral heterogeneities along the path of the beam. Submillimeter positioning was still possible with a 5 mm spot spacing. Phantom specific stopping power maps obtained by minimizing the range error were cross‐verified by the acquisition of an additional proton radiography where the phantom was positioned in a random but known manner.Conclusion:Our results indicate that a CT‐PR registration algorithm together with range‐error based optimization can be used to produce a patient‐specific stopping power map.Sylvain Deffet reports financial funding of its PhD thesis by Ion Beam Applications (IBA) during the confines of the study and outside the submitted work.Francois Vander Stappen reports being employed by Ion Beam Applications (IBA) during the confines of the study and outside the submitted work.
SU‐G‐TeP2‐14: Universal Function Form for Photon Open Field In‐Water Output Ratio
Authors: Zhou S , Wu Q , Fan Q , Lei Y , Li S , Li X , Ma R , Wang S , Wang X , Zheng D , Zhu X , Enke C 
Published: July 2016

Purpose:In‐Water‐Output‐Ratio (IWOR) plays a significant role in linac‐based radiotherapy treatment planning, linking MUs to delivered radiation dose. For an open rectangular field, IWOR depends on both its width and length, and changes rapidly when one of them becomes small. In this study, a universal functional form is proposed to fit the open field IWOR tables in Varian TrueBeam representative datasets for all photon energies.Methods:A novel Generalized Mean formula is first used to estimate the Equivalent Square (ES) for a rectangular field. The formula's weighting factor and power index are determined by collapsing all data points as much as possible onto a single curve in IWOR vs. ES plot. The result is then fitted with a novel universal function IWOR=1+b*Log(ES/10cm)/(ES/10cm)^c via a least‐square procedure to determine the optimal values for parameters b and c. The maximum relative residual error in IWOR over the entire two‐dimensional measurement table with field sizes between 3cm and 40cm is used to evaluate the quality of fit for the function.Results:The two‐step fitting strategy works very well in determining the optimal parameter values for open field IWOR of each photon energies in the Varian data‐set. Relative residual error ≤0.71% is achieved for all photon energies (including Flattening‐Filter‐Free modes) with field sizes between 3cm and 40cm. The optimal parameter values change smoothly with regular photon beam quality.Conclusion:The universal functional form fits the Varian TrueBeam open field IWOR measurement tables accurately with small relative residual errors for all photon energies. Therefore, it can be an excellent choice to represent IWOR in absolute dose and MU calculations. The functional form can also be used as a QA/commissioning tool to verify the measured data quality and consistency by checking the IWOR data behavior against the function for new photon energies with arbitrary beam quality.
SU‐G‐IeP3‐07: High‐Resolution, High‐Sensitivity Imaging and Quantification of Intratumoral Distributions of Gold Nanoparticles Using a Benchtop L‐Shell XRF Imaging System
Authors: Manohar N , Reynoso F , Diagaradjane P , Krishnan S , Cho S 
Published: July 2016

Purpose:To demonstrate the ability to perform high‐resolution imaging and quantification of sparse distributions of gold nanoparticles (GNPs) within ex vivo tumor samples using a highly‐sensitive benchtop L‐shell x‐ray fluorescence (XRF) imaging system.Methods:An optimized L‐shell XRF imaging system was assembled using a tungsten‐target x‐ray source (operated at 62 kVp and 45 mA). The x‐rays were filtered (copper: 0.08 mm & aluminum: 0.04 mm) and collimated (lead: 5 cm thickness, 3 cm aperture diameter) into a cone‐beam in order to irradiate small samples or objects. A collimated (stainless steel: 4 cm thickness, 2 mm aperture diameter) silicon drift detector, capable of 2D translation, was placed at 90° with respect to the beam to acquire XRF/scatter spectra from regions of interest. Spectral processing involved extracting XRF signal from background, followed by attenuation correction using a Compton scatter‐based normalization algorithm. Calibration phantoms with water/GNPs (0 and 0.00001–10 mg/cm3) were used to determine the detection limit of the system at a 10‐second acquisition time. The system was then used to map the distribution of GNPs within a 12×11×2 mm3 slice excised from the center of a GNP‐loaded ex vivo murine tumor sample; a total of 110 voxels (2.65×10−3 cm3) were imaged with 1.3‐mm spatial resolution.Results:The detection limit of the current cone‐beam benchtop L‐shell XRF system was 0.003 mg/cm3 (3 ppm). Intratumoral GNP concentrations ranging from 0.003 mg/cm3 (3 ppm) to a maximum of 0.055 mg/cm3 (55 ppm) and average of 0.0093 mg/cm3 (9.3 ppm) were imaged successfully within the ex vivo tumor slice.Conclusion:The developed cone‐beam benchtop L‐shell XRF imaging system can immediately be used for imaging of ex vivo tumor samples containing low concentrations of GNPs. With minor finetuning/optimization, the system can be directly adapted for performing routine preclinical in vivo imaging tasks. Supported by NIH/NCI grant R01CA155446This investigation was supported by NIH/NCI grant R01CA155446.
SU‐G‐IeP3‐08: Image Reconstruction for Scanning Imaging System Based On Shape‐Modulated Point Spreading Function
Authors: Wang Ruixing , Yang LV , Xu Kele , Zhu Li 
Published: July 2016

Purpose:Deconvolution is a widely used tool in the field of image reconstruction algorithm when the linear imaging system has been blurred by the imperfect system transfer function. However, due to the nature of Gaussian‐liked distribution for point spread function (PSF), the components with coherent high frequency in the image are hard to restored in most of the previous scanning imaging system, even the relatively accurate PSF is acquired. We propose a novel method for deconvolution of images which are obtained by using shape‐modulated PSF.Methods:We use two different types of PSF ‐ Gaussian shape and donut shape ‐ to convolute the original image in order to simulate the process of scanning imaging. By employing deconvolution of the two images with corresponding given priors, the image quality of the deblurred images are compared. Then we find the critical size of the donut shape compared with the Gaussian shape which has similar deconvolution results. Through calculation of tightened focusing process using radially polarized beam, such size of donut is achievable under same conditions.Results:The effects of different relative size of donut and Gaussian shapes are investigated. When the full width at half maximum (FWHM) ratio of donut and Gaussian shape is set about 1.83, similar resolution results are obtained through our deconvolution method. Decreasing the size of donut will favor the deconvolution method. A mask with both amplitude and phase modulation is used to create a donut‐shaped PSF compared with the non‐modulated Gaussian PSF. Donut with size smaller than our critical value is obtained.Conclusion:The utility of donutshaped PSF are proved useful and achievable in the imaging and deconvolution processing, which is expected to have potential practical applications in high resolution imaging for biological samples.
SU‐G‐IeP3‐12: Preliminary Report On the Experience of Patient Radiation Dose Monitoring and Tracking Systems; PEMNET, Radimetrics and DoseWatch
Authors: Lin P , Corwin F , Ghita M 
Published: July 2016

Purpose:Three patient radiation dose monitoring and tracking (PRDMT) systems have been in operation at this institution for the past 6 months. There are useful information that should be disseminated to those who are considering installation of PRDMT programs. In addition, there are “problems” uncovered in the process of estimating fluoroscopic “peak” skin dose (PSD), especially, for those patients who received interventional angiographic studies and in conjunction with surgical procedures.Methods:Upon exporting the PRDMT data to Microsoft Excel program, the peak skin dose can be estimated by applying various correction factors including; attenuation due to the tabletop and examination mattress, table height, tabletop translation, backscatter, etc. A procedure was established to screen and divide the PRDMT reported radiation dose and estimated PSD to three different levels of threshold to assess the potential skin injuries, to assist patient follow‐up, risk management and provide radiation dosimetry information in case of “Sentinel Event”.Results:The Radiation Dose Structured Report (RDSR) was found to be the prerequisite for the PRDMT systems to work seamlessly. And, the geometrical parameters (gantry and table orientation) displayed by the equipment are not necessarily implemented in the “patient centric” manner which could result in a large error in the PSD estimation. Since, the PRDMT systems obtain their pertinent data from the DICOM tags including the polarity (+ and − signs), the geometrical parameters need to be verified.Conclusion:PRDMT systems provide a more accurate PSD estimation than previously possible as the air‐kerma‐area dose meter become widely implemented. However, care should be exercised to correctly apply the geometrical parameters in estimating the patient dose. In addition, further refinement is necessary for these software programs to account for all geometrical parameters such as the tabletop translation in the z‐direction in particular.
SU‐G‐IeP3‐13: Real‐Time Patient and Staff Dose Monitoring in Fluoroscopy Guided Interventions
Authors: Vergoossen L , Sailer A , Paulis L , Wildberger J , Jeukens C 
Published: July 2016

Purpose:Interventional radiology procedures involve the use of X‐rays, which can pose a large radiation burden on both patients and staff. Although some reports on radiation dose are available, most studies focus on limited types of procedures and only report patient dose. In our cathlabs a dedicated real‐time patient and staff monitoring system was installed in November 2015. The aim of this study was to investigate the patient and staff dose exposure for different types of interventions.Methods:Radiologists involved in fluoroscopy guided interventional radiology procedures wore personal dose meters (PDM, DoseAware, Philips) on their lead‐apron that measured the personal dose equivalent Hp(10), a measure for the effective dose (E). Furthermore, reference PDMs were installed in the C‐arms of the fluoroscopy system (Allura XPer, Philips). Patient dose‐area‐product (DAP) and PDM doses were retrieved from the monitoring system (DoseWise, Philips) for each procedure. A total of 399 procedures performed between November 2015 and February 2016 were analyzed with respect to the type of intervention. Interventions were grouped by anatomy and radiologist position.Results:The mean DAP for the different types of interventions ranged from 2.86±2.96 Gycm2 (percutaneous gastrostomy) to 147±178 Gycm2 (aortic repair procedures). The radiologist dose (E) ranged from 5.39±7.38 µSv (cerebral interventions) to 84.7±106 µSv (abdominal interventions) and strongly correlated with DAP (R2=0.83). The E normalized to DAP showed that the relative radiologist dose was higher for interventions in larger body parts (e.g. abdomen) compared to smaller body parts (e.g. head).Conclusion:Using a real‐time dose monitoring system we were able to assess the staff and patient dose revealing that the relative staff dose strongly depended on the type of procedure and patient anatomy. This could be explained by the position of the radiologist with respect to the patient and X‐ray tube.To facilitate this study L Vergoossen received a scholarship from Philips Medical Systems.
SU‐G‐IeP3‐14: Updating Tools for Radiographic Technique Charts
Authors: Walz‐Flannigan A , Lucas J , Buchanan K , Schueler B 
Published: July 2016

Purpose:Manual technique selection in radiography is needed for imaging situations where there is difficulty in proper positioning for AEC, prosthesis, for non‐bucky imaging, or for guiding image repeats. Basic information about how to provide consistent image signal and contrast for various kV and tissue thickness is needed to create manual technique charts, and relevant for physicists involved in technique chart optimization. Guidance on technique combinations and rules‐of‐thumb to provide consistent image signal still in use today are based on measurements with optical density of screen‐film combinations and older generation x‐ray systems. Tools such as a kV‐scale chart can be useful to know how to modify mAs when kV is changed in order to maintain consistent image receptor signal level. We evaluate these tools for modern equipment for use in optimizing proper size scaled techniques.Methods:We used a water phantom to measure calibrated signal change for CR and DR (with grid) for various beam energies. Tube current values were calculated that would yield a consistent image signal response. Data was fit to provide sufficient granularity of detail to compose technique‐scale chart. Tissue thickness approximated equivalence to 80% of water depth.Results:We created updated technique‐scale charts, providing mAs and kV combinations to achieve consistent signal for CR and DR for various tissue equivalent thicknesses. We show how this information can be used to create properly scaled size‐based manual technique charts.Conclusion:Relative scaling of mAs and kV for constant signal (i.e. the shape of the curve) appears substantially similar between film‐screen and CR/DR. This supports the notion that image receptor related differences are minor factors for relative (not absolute) changes in mAs with varying kV. However, as demonstrated creation of these difficult to find detailed technique‐scales are useful tools for manual chart optimization.