bluuebunny/crossref_metadata_2025_split huggingface dataset:
SU‐FF‐T‐361: Planning Study of Intensity‐Modulated and 3D Conformal Radiotherapy of Whole Pelvis Including Inguinal Lymphatics: Radiobiological Considerations for Designing New Fractionation Schemes
Authors: Ahmad M , Song H , Lund M , Niemierko A , Moran M , Weidhaas J , Higgins S , Chen Z , Deng J , Nath R 
Published: July 2006

Purpose: To examine the possibility of using “simultaneous integrated boost” intensity‐modulated radiotherapy (SIB‐IMRT), for the management of pelvic malignancies, with potential clinical advantage for simultaneous delivery of high doses to the primary disease and lower doses to the subclinical disease or electively treated regions.Method and Materials: For this study, a sample patient diagnosed with anal cancer was randomly selected from our database. Four treatment plans were developed: (1) the 3D conformal plan for initial pelvis/inguinal node irradiation and subsequent conventional 3D boost to the primary tumor, (2) conventional 3D initial pelvis/inguinal node irradiation and subsequent IMRT boost plan, (3) Two‐phase IMRT plan for initial pelvis/inguinal node irradiation and subsequent IMRT boost plan, (4) A single‐phase SIB‐IMRT plan to deliver simultaneous boost. DVHs for the target volumes were transformed into equivalent uniform dose (EUD) using the LQ model to evaluate relative merits of these plans using tumor control probability (TCP), and normal tissue complication probability (NTCP) for normal tissues.Results: We have found that dose distributions for SIB‐IMRT are similar in conformality to dose distributions when IMRT is divided into a large‐field phase and a boost phase. As shown in Fig. 1(a–d), both techniques produce significantly superior dose distributions compared to those obtained with 3DCRT as well as to dose distributions obtained using conventional beams for the large‐field phase followed by IMRT boost phase. We also found that normal tissues outside the target volume receive significantly lower dose due to higher dose conformality of IMRT plans (Table 1). Conclusions: SIB‐IMRT offers unique ability to produce highly conformal dose distributions with better sparing of organs at risk, with more efficient delivery, and shorter treatment duration. This new modality also facilitates the prospect of dose escalation to highly advanced tumors for better radiobiological effectiveness potentially leading to improved outcome.
SU‐FF‐T‐375: Quality Contra Complexity in IVD. A Comparative Study Between Three Semiconductor Detectors
Authors: Rikner G , Grusell E 
Published: July 2006

Semiconductor detectors have frequently been used in vivo dosimetry (IVD) to confirm the dose given to a patient in external radiotherapy, due to the high mechanical stability, small size, high signal and no need of external bias. As it is important that the complexity of these measurements should be as low as possible, semiconductor detectors from three different manufactures have been compared with respect to the need of correction factors, where effects of radiation damage has been studied.Detectors from Sun Nuclear (SN), PTW and Scanditronix Wellhöfer (SW) have been investigated in 15 MV x‐rays. The sensitivity drop, dose rate linearity, the sensitivity variation with temperature (SVWT) and “dark current” have been studied after different doses of irradiation. Parameters, which are related to the mechanical construction, the field size and directional dependence have also been studied.It was shown that the SW and SN detectors showed small variations in the sensitivity drop and the linearity properties did not change after moderate doses, about 1 kGy of 15 MV x‐rays. PTW, however, showed a three times larger sensitivity drop and an increasingly non‐linear response. The SVWT was stable for the SW, 0,2% per centigrade, and for the SN detectors, 0,5 % respectively. The PTW detector showed a low value in the beginning, but increased after irradiation. Also the “dark current” changed after irradiation, and was in favour for the SW detector.The directional dependence was about the same for all detectors, but the field size dependence deviated for the PTW detector.To obtain an accuracy better than 1,5% in each parameter the complexity is rather low for the SW and SN, except for the temperature dependence for SN. It is, however, rather complicated for the PTW detector, as large corrections must be applied for some parameters.“Research sponsored by Scanditronix‐Wellhoepher corporation.”
SU‐FF‐T‐378: Radiation Transport Software for Medical Physics Studies
Authors: Kirk B , Haghigat A , Jeraj R , Newhauser W , Rivard M , Goorley J T 
Published: July 2006

Purpose: To present a summary of radiation transport software for medical physics applications. Method and Materials: The Radiation Safety Information Computational Center (RSICC), a center at Oak Ridge National Laboratory (ORNL), is the Department of Energy software center for radiation transport and safety software. The center houses over 1600 software packages and nuclear cross section data of importance to nuclear science applications. The different software packages have been applied to the following topics:• Dosimetry calculations for radiation therapy• Treatment planning in radiation oncology• Design of photon and secondary neutron shielding for therapy rooms• Evaluating and estimating patient and staff radiation dose• Electron beam transport and energy deposition• Secondary neutron and gamma transport and energy deposition• Cancer brachytherapy dosimetry• Medical diagnostic imaging applications, including SPECT, PET, and x‐ray imaging• Error evaluations for accelerator particle delivery systems• Modalities of treatment and exploration of alternatives• Licensing and safety analysis for medical radiation facilities• Medical diagnostics and therapyExamples of software in the RSICC collection include MCNP/MCNPX, ITS, ANISN, TORT, EGS4, PARTISN, SERA, and PENELOPE. There are other software packages (not available through RSICC), which have been applied to the above topics ‐ for example, PENTRAN, A3MCNP, ATTILA, COMET, EGSnrc, TransMED, EVENT, FLUKA, PEREGRINE. Results: Studies on selected software is presented, particularly on the above applications. Conclusion: As the field of medical physics advances, computer software technology continues on the road to improvement and efficiency. Conflict of Interest: Work was supported by the Department of Energy under contract DE‐AC05‐00OR22725.
SU‐FF‐T‐379: Radiochromic Film Dosimetry for a New Type of I‐125 Seed: Determination of TG43 Parameters
Authors: Chiu‐Tsao S , Munro J , Harrison L 
Published: July 2006

Purpose: A new prototype of I‐125 seed was studied using radiochromic EBT film in solid water for the dose distributions from 0.06cm out to 5cm. The high activity seed was designed for intravascular brachytherapy of lesions in peripheral arteries. The active source core was produced with Xenon ion implantation into a solid quartz core (without silver marker) and then encapsulated in titanium to form a sealed source.Materials and methods: A multiple film technique was employed. Each film (EBT lot #35076) was in contact geometry with the seed at the center of a solid water phantom, 30×30×20 cm. Totally 46 films were separately exposed to 12 seeds, with the product of activity and exposure time between 8 and 4910 mCi‐hr. The seed activity ranged from 12.5 to 2.4 mCi during the experimental runs. 30 calibration films were exposed to one seed at 0.5 cm above or below the seed. All experimental, calibration and background films were scanned (pixel resolution 0.2mm) using a PeC CCD100 densitometer, with red and green light sources at least one day after exposures. Conversion from optical densities to doses was achieved based on the calibration curve established for each light source used in scanning. The 2‐d dose values in cylindrical coordinates were converted to polar coordinates, and the TG43 parameters were generated. Results: The radial dose function and anisotropy function were plotted. Compared with the Implant Sciences model 3500 seed, the anisotropy function values are similar, while the radial dose function values (at distances > 1cm) are higher, possibly due to the absence of silver fluorescent x‐rays. An interim value of dose rate constant was determined. Conclusion: TG43 parameters for a new type of high activity I‐125 seed have been obtained using radiochromic EBT film for distances from 0.06 to 5 cm in solid water phantom.
SU‐FF‐T‐385: Reproducibility of the Optical CT‐Based Polymer Gel Dosimetry
Authors: Xu Y , Wuu C S 
Published: July 2006

Purpose: To study the reproducibility of the reconstructed dose distributions from optical CT scanning of polymer gel dosimeters with variation of time between irradiation and scanning using phantoms of the same and different geometry. Method and Materials: The commercial BANG®3 polymer gels from the same batch were housed in cylindrical phantoms of 3 types: a) PET bottles of 15 cm diameter and 20 cm height; b) Barex cylinders of 17 cm diameter and 15 cm height; c) Acrylic cylinders of 25 cm diameter and 25 cm height. Four PET and Acrylic gel phantoms were irradiated with a 5 field IMRT and a 3DCRT once each. Six Barex cylinders were irradiated with the same IMRT and 3DCRT plans three times each. One additional Barex gel phantom was irradiated with a 6 cm × 6cm, 12 MeV electron field for calibration purpose.The gel phantoms were scanned using the OCTOPUS™ optical scanner one day after irradiation. One Barex phantom irradiated with IMRT fields was scanned 1 and 8 weeks later. All reconstructed images were calibrated using the dose response curve from the electron field irradiation. Root mean square of the pixel dose differences in a cylindrical region of 10 cm diameter and 10 cm height were compared for each pair of phantoms irradiated with the same plan. Results: The reconstructed dose distributions from scanning the same IMRT gel phantom 8 weeks apart change less than 1%. The root mean square dose difference among the 3 different kinds of phantoms irradiated with the IMRT and 3DCRT plans are all less than 3%. Conclusion: The optical CT‐based polymer gel dosimetry is reproducible within the experimental uncertainty (3%) when different gel phantoms are irradiated and scanned at different time after irradiation.This work was supported by MGS research Inc. (Madison, CT; www.mgsresearch.com).
SU‐FF‐T‐389: Sensitivity of Document Scanners Used for Radiochromic Film Dosimetry
Authors: Wang Y , Lewis D , Poon E , Verhaegen F , Podgorsak E , Devic S 
Published: July 2006

Purpose: The use of color CCD‐based document scanners, having an ability to perform scans in the transmission mode, has been suggested as an inexpensive option in the process of radiochromic film dosimetry. These scanners allow acquisition of transmission scans in up to a 48‐bit red‐greenblue (RGB) mode. Since the absorption spectrum of the radiochromic film exhibits a maximum in the red region of the visible spectrum, extraction of the red channel from the RGB image improves document scanner sensitivity when used in combination with radiochromic films. However; transmission scanners use a linear CCD array that suffers from a difference in response along the array. In this work, we present our measurements of the spatial response of an AGFA Arcus II document scanner used for radiochromic film dosimetry.Method and Materials: To create various pixel value levels, we employed 5 neutral density filters and their combinations. The profiles were fitted with the sixth order polynomial and consequently used for image correction. The sensitivity curves have been created by normalizing their values to the central profile value.Results: In the regions close to scanner bed edges, the non‐uniformity of the raw pixel data depends on the pixel level detected by the CCD array and can be as large as 15%. Over the 80% of the scanning region, the uniformity is of the order of 2% after corrections are applied. However in areas close to the left and right edges of the scan deviations can reach 5% even after the correction. Conclusions: We have demonstrated that in transmission scanners, using linear CCD array detectors, a considerable change in sensitivity may occur along the detector array direction. If not properly corrected for, this spatial sensitivity may obscure a 2D accuracy of the radiochromic film dosimetry. Conflict of interests: Research is sponsored by ISP.
SU‐FF‐T‐400: Supine Craniospinal Irradiation Using Electronic Portal Imaging
Authors: Heaton R , Guscott H , Lau M 
Published: July 2006

Purpose: The traditional prone patient position for craniospinal irradiation [CSI] is not suitable for paediatric patients requiring anaesthetics. A new supine CSI technique was developed to implement crucial features of the prone technique—the ability to palpate the spine and pre‐treatment verification of junctions. Methods and Material: Fourteen patients have been treated using a custom treatment board, which indexes to the CT and Varian Exact™ couch. Patient were immobilized with a thermoplastic head‐and‐shoulder mask secured to the board. Three‐dimensional CT based plans were developed with the collimator of lateral opposed cranial fields rotated to match the beam divergence of the posterior spine field. The fields junction along a common line running through the mid‐sagittal plane.The junction was confirmed using a 2 mm radio‐opaque marker placed daily on the anterior surface of patient's mask at the intersection of inferior border of cranial fields. Pre‐treatment electronic portal images of the lateral cranial and posterior spinal field borders were captured and assessed to confirm the position of the field junction, with discrepancies greater than 2.0mm corrected prior to treatment delivery. Results: This new supine CSI technique has improved patient comfort, treatment set‐up reproducibility and stability. It mirrors the prone technique in matching field junctions and maintaining the ability to palpate the spine. Standard EPI measuring tools facilitate the assessment of marker position relative to the field edge and patient anatomy. Conclusion: Supine CSI has increased patient safety through improved airway access in the event of respiratory distress. Supine positioning facilitates alternative distraction devices, such as video entertainment, reducing the need for anaesthetics in the paediatric population. The couch indexing system has allowed a more accurate monitoring of treatment set‐up, as demonstrated by a decrease in postplanning shielding modifications. The supine technique is preferred for patient comfort, precise junction match, and demonstrated reproducibility.
SU‐FF‐T‐406: Testing of ATC Method 2 for Supporting QA of Cooperative Group Advanced Technology Clinical Trials Requiring Digital Data Submission
Authors: Bosch W , O'Leary S , Matthews J , Frouhar V , Palta J , Field G , Pho L , Purdy J 
Published: July 2006

Purpose: To test the readiness of a system of software (“ATC Method 2‐v.2.3”) developed by the Resource Center for Emerging Technologies (RCET) for supporting QA of cooperative group clinical trials within the Advanced Technology QA Consortium (ATC). Method and Materials: ATC Method 2‐v.2.3 includes WebSys client and server for secure data upload/download/archiving of volumetric imaging and radiotherapy treatment planning data, a web‐based Rapid Image Viewer (RIV) tool, and web‐based tools for server administration. The software was implemented on a test server at the Image‐guided Therapy QA Center (ITC), and underwent rigorous testing by ITC personnel. Tests conducted included examination of user interface behavior, as well as systematic comparison of submitted/retrieved copies of 16 representative test data sets (in DICOM and RTOG Data Exchange format) from nine different treatment planning system vendors. Results: Evaluation tests of version 2.3 of the ATC Method 2 software identified improvements in the usability of software over the previous version, and provided general suggestions for further improvement. These tests also identified specific input that led to failure of the WebSys client, usability issues in the RIV tool, database changes needed to support case identifiers in ATC trails, and corrections needed in handling certain DICOM objects. These test results have contributed to improvements in version 2.4 of this software in preparation for its use to support clinical trials. Version 2.4 is expected to be ready for testing beginning March 2006. The National Cancer Institute of Canada (NCIC) Clinical Trials Group (CTG) will participate in the new round of testing. Conclusion: Since this software is intended to play a major role in QA of data submitted for future ATC‐supported clinical trials, rigorous testing is essential to its ongoing development. Future testing is expected to benefit from collaborative efforts of NCIC CTG.Supported by NIH U24 Grant CA81647.
SU‐FF‐T‐407: Testing the Accuracy and Usefulness of the Portal Vision Dosimetry System for Large‐Volume and Complex‐Geometry IMRT
Authors: Nalichowski A , Rosca F , Kadam D , Zygmanski P 
Published: July 2006

Purpose: To test a commercial EPID dosimetry system for the accuracy and usefulness for head&neck, whole‐pelvis, mesothelioma IMRT QA.Materials and Methods: Portal Vision (PV) dosimetry system was configured and experimentally used as intended by the manufacturer (Varian) for 6MV 2100Ex. Additional data analysis software was developed. Collimator angle=90deg and the smallest possible SDD=105cm and were selected to maximize the functional area of the EPID. EPID responses were calculated by Eclipse and compared to the experimentally determined responses in two ways: by comparing individual images and 3D‐response reconstructions for cumulative plans (home‐built software).To account for the PV arm sag during gantry rotation, and the need to shift the detector, raw PV images were automatically magnified and registered with calculated images. 3D‐response reconstructions for the measured and calculated images were performed by: backprojecting the images and applying attenuation and phantom scatter in a homogeneous virtual patient. Patient beam configuration and depths to isocenter were used. Results: PV dosimetry for large/complex targets is difficult and time‐consuming due to practical limitations (detector size, arm sag, manual shifting). Experimental response images show strong tongue&groove effects and elevated values outside of the field edges compared to Eclipse. Response discrepancies inside treatment fields cause (±2–3%) discrepancies in cumulative plan. Discrepancies outside of field edges cause systematic shift up to (5–7%) in cumulative plan, because fluences are split into 2–3 narrower subfields in the delivery. The observed discrepancies are consistent with but stronger than ion chamber measurements in solid water. The reason may be the small 1cm‐buildup and therefore larger PV sensitivity to MLC scatter and T&G. Conclusions: Neither MLC scatter nor T&G are modeled in Eclipse. Their contributions may be significant for large/complex IMRT due to the increased MLC blockage. PV dosimetry may capture these effects, but caution is indicated in interpretation.
SU‐FF‐T‐409: The Computational Environment for Radiotherapy Research: New Tools for Multi‐Modality Imaging, Treatment Plan Comparisons, and Plan Evaluations
Authors: Deasy J , Khullar D , Apte A , Hope A , Alaly J , Clark V , El Naqa I , Spezi E 
Published: July 2006

Purpose: CERR (a Computational Environment for Radiotherapy Research) is an open‐source Matlab‐based set of tools for conducting radiotherapy research which has been available for several years. In order to make CERR as useful as possible to radiotherapy researchers, we have added multi‐modality imaging support as we as new dosimetric and radiobiological plan review tools. Method: The existing DICOM Import tool box in CERR was upgraded with capability to import PET, MR and SPECT DICOM images. While MR and PET are single frame image sets, CERR seamlessly imports multiframe SPECT DICOM. Automated and interactive registration tools were developed. A new metric selection GUI provides user ability to select a variety of metrics and save a ‘plan evaluation set' for later use. When adding an individual metric, the user can select applicable parameters as well as information about criteria, including passing and marginal values, and priority. The metrics can then be compared on a graphical display or a report can be generated which lists passed/marginal/failed for all criteria and displays a score for each dose distribution. Several new dose comparison tools have been added, including: (1) side‐by‐side dose comparison views, (2) dose subtraction views for up to three dose distributions compared to a reference distribution, and (3) a 3‐D slicer view which paints differences on coordinate system or transparent anatomic structure surfaces. Results: CERR continues to undergo continuous development to provide a wide range of tools for image‐guided research. The latest release can be downloaded from www.radium.wustl.edu/cerr. CERR can be used freely only for research work. Conclusions: New CERR tools can facilitate research in adaptive and 4‐D treatment planning.This research was partially supported by NIH grant CA85181 and a grant from TomoTherapy, Inc.
SU‐FF‐T‐410: The Credentialing Process for the NSABP B‐39/RTOG 0413 Partial Breast Irradiation Trial
Authors: Lowenstein J , Davis C , Roll J , Harris I , Hall F , Followill D , Ibbott G 
Published: July 2006

Purpose: Develop a credentialing process for the NSABP B‐39/RTOG 0413 Partial Breast Irradiation (PBI) trial. Method: NSABP B‐39/RTOG 0413, a Phase III trial comparing whole breast irradiation versus PBI (3D conformal radiation therapy (3D‐CRT), MammoSite® and multi‐catheter brachytherapy). For each PBI technique, an institution, radiation oncologist and physicist team must be credentialed. The credentialing verifies that all personnel involved with treatment planning have read the protocol prior to enrolling patients to limit the number of deviations. Credentialing also allows feedback to the team prior to patient treatment to correct any mistakes. Each institution must complete online the knowledge assessment and facility questionnaires and download a PBI technique CT benchmark case. Results: Teams at 308 distinct institutions have submitted applications for credentialing for at least one PBI technique. 733 radiation oncologists applied for 3D‐CRT credentialing, 490 radiation oncologists for MammoSite® and 151 radiation oncologists for multicatheter. Of those applications, 79% became credentialed for 3D‐CRT, 69% for MammoSite®, and 56% for multi‐catheter. Reasons for which a radiation oncologist failed to become credentialed included; incomplete application, incorrect answers on knowledge assessment, treatment planning system could not submit data electronically, and the CT benchmark was not planned per protocol. The first patient enrolled by each institution received a rapid review prior to patient treatment. The next 4 cases received a timely review. These reviews included a dosimetric and clinical review. Currently, this protocol has accrued 880 patients, of which 328 treated with 3D‐CRT, 82 treated with MammoSite, and 31 treated with multi‐catheter brachytherapy. Of the 441 patients treated to date on the PBI arm there have been no dosimetric deviations. Conclusion: The PBI credentialing process has been successful in educating participating facilities and helping to minimize dosimetry errors.Work was supported by PHS grants CA10953 and CA081647 awarded by NCI.