bluuebunny/crossref_metadata_2025_split huggingface dataset:
SU‐E‐T‐240: Design and Implement of An Electronic Records Function for Treatment Plan Checked Meeting
Authors: Wu Q 
Published: June 2015

Purpose:To replace the paper records, we designed an electronic records function for plan checked meeting in our in‐house developed radiotherapy information management system(RTIMS).Methods:Since 2007, the RTIMS has been developed on a database and web service of Apache+PHP+MySQL, and almost all computers and smartphones could access the RTIMS through IE browser, to input, search, count, and print the data. In 2012, we also established an radiation therapy case conference multi‐media system(RTCCMMS) based on Windows Remote Desktop feature. Since 2013, we have carried out the treatment plan checked meeting of the physics division in every afternoon for about half an hour. In 2014, we designed an electronic records function, which includes a meeting information record and a checked plan record. And the meeting record includes the following items: meeting date, name, place, length, status, attendee, content, etc. The plan record includes the followings: meeting date, meeting name, patient ID, gender, age, patient name, course, plan, purpose, position, technique, CTsim type, plan type, primary doctor, other doctor, primary physicist, other physicist, difficulty, quality, score, opinion, status, note, etc.Results:In the past year, the electronic meeting records function has been successfully developed and implemented in the division, and it could be accessed from an smartphone. Almost all items have the corresponding pull‐down menu selection, and each option would try to intelligently inherit default value from the former record or other form. According to the items, we could do big data mining to the input data. It also has both Chinese and English two versions.Conclusion:It was demonstrated to be user‐friendly and was proven to significantly improve the clinical efficiency and quality of treatment plan. Since the RTIMS is an in‐house developed system, more functions can be added or modified to further enhance its potentials in research and clinical practice.Project supported by the National Natural Science Foundation of China (Grant No.81101694).
SU‐E‐T‐242: Design of a Novel Afterloader Clearance QA Device for Biliary HDR Therapy
Authors: Mullins JP , Deufel CL 
Published: June 2015

Purpose:Bile duct cancer affects 2–3 thousand people annually in the United States. Radiation therapy has been shown to double median survival, with combined external beam and intraluminal high dose‐rate (HDR) brachytherapy being most effective. Endoscopic retrograde cholangiopancreatography (ERCP) biliary HDR, a less‐invasive alternative to trans‐hepatic brachytherapy, is delivered through a catheter that travels a tortuous path from nose to bile duct, requiring wire drive force and dexterity beyond typical afterloader performance specifications. Thus, specific afterloader quality assurance(QA) is recommended for this procedure. Our aim was to create a device and process for Varisource afterloader clearance QA with objectives that it be quantitative and can monitor afterloader performance over time, compare performance between two distinct afterloaders and potentially Result in a predictive nomogram for patient‐specific clearance.Methods:Based on retrospective reconstruction of 20 ERCP patient anatomies, we designed a phantom to test afterloader ability to drive the source wire along an intended treatment path. The ability of the afterloader to fully extend the intended treatment path is a function of number and diameters of turns. We have determined experimentally that relative position of the turns does not impact performance.Results:Both patient and QA paths involve three common turns/loops: a large turn representing the stomach(10.8cm±2.0cm), an elliptical loop representing the duodenum(7.3cm±1.5cmx4.8cm±0.7cm), and a final turn at the end of the bile duct that may be tight for some patient‐specific anatomies and absent in others(3.7cm±0.7cm, where present). Our phantom design uses anatomical average turn diameters for the stomach and duodenum then terminates in a turn of quantitatively selectable diameter. The smallest final turn diameter that an afterloader can pass is recorded as the QA parameter.Conclusion:With this device and QA process, we have the ability to quantitatively evaluate and track our afterloader performance for a technically challenging ERCP brachytherapy procedure.
SU‐E‐T‐243: Design of a Novel Testing Port for Radiation Protection and Shielding Measurements
Authors: Tanny S , Harrell D , Chopra M , Noller J , Parsai E 
Published: June 2015

Purpose:The majority of radiation shielding research utilizes Monte Carlo simulation because of the difficulty in eliminating secondary radiations from measurements. We have designed a test port into a primary barrier of our newest vault to allow for shielding measurements while ensuring adequate protection to the public and staff during normal machine operation. This port allows for measurement of attenuation values of shielding materials, differential dose albedos, and radiation scatter fractions.Methods:The vault design utilized the maze as part of a compound primary barrier. The test port is contained within the maze and is centered along isocenter. The inner 30 cm has a 20×20 cm2 opening, while the remaining length has a 30×30 cm2 opening. The block that contains the port has a density of 200 pcf to minimize internal scatter. The 30×30 cm2 opening is occupied by removable 215 pcf concrete blocks. The innermost and outermost blocks activate an interlock wired into the beam‐enable loop. This disallows beam‐on in treatment mode if the interlock isn't closed. The interlock can be overridden in service mode, or by‐passed via an override switch in case of circuit failure.Results:The test port was installed in August. The beam is disabled when the interlock is tripped. Measurements taken when the primary beam is not incident on the port are indistinguishable from background. Ambient dose levels surrounding the vault with the designed shielding blocks in place are all within allowable limits for occupational workers.Conclusions:We have designed and installed a unique testing port for radiation protection and shielding measurements. This port is appropriately interlocked and designed to mitigate any risks of incidental exposure to staff or members of the public. The test port design allows measurements with “good geometry” and efficient removal of contaminating sources of radiation present in many shielding measurements.Daniel Harrell and Jim Noller are employees of Shielding Construction Solutions, Inc, the shielding construction company that built the vault discussed in this abstract. Manjit Chopra is an employee of Universal Minerals International, Inc, the company that provided the aggregates for the high density concretes used in the vault construction.
SU‐E‐T‐246: Detector Selection for Small Field Measurements, a Comparative Study
Authors: Sigler M , Pavord D , Irwin J , Kriminski S 
Published: June 2015

Purpose:To compare commercially available detectors for small field dosimetry.Methods:PTW (Freiburg, Germany) diode E, PTW microDiamond, and SunNuclear (Melbourne, FL) Edge detector were used to measure output factors, PDD, and profiles on a Varian iX linear accelerator (Varian Medical Systems, Palo Alto, CA) using 6MV and 18MV photon beams. The water tank was set to 100cm SSD. Centering profiles at 5cm and 20cm depth confirmed an offset <0.1mm. High resolution PDD (0.1mm) aligned the collecting volume at water surface. For setup and linearity verification, PDD and profiles were matched to annual measurements, which were performed with an A1SL ion chamber.Scans were taken for 6X and 18X, for 10cmx10cm, 10cmx2cm, 10cmx1cm, and 10cmx0.5cm fields. Profiles were measured at Dmax (6X=1.5cm, 18X=3.5cm), 5cm, 10cm, and 20cm depths. All fields used 10cmx10cm jaws with the MLC defining the field in the X‐direction. PDDs used 2mm step size and 0.2s discrete collecting time. Profiles used 1mm step size and a 0.4s discrete collecting time.Results:The PTW diode E and Edge detector exhibit centering stability, but all detectors require vertical shifts from Vendor defined vertical alignment. Output factor measurements reveal good agreement between detectors. The Edge detector demonstrates the sharpest penumbra and the closest consistent match to ion chamber measurements in the out of field regions for 6MV (3.2%). Each detector provides comparable curve quality for PDDs, with a maximum difference across detectors giving a standard deviation of 0.6% at 30cm depth, 18X, and 10cmx0.5cm. Profiles match closely across all detectors, depths, energies, and field sizes. The microDiamond detector produces the largest penumbra width, largest deviation from ion chamber dose in the tail region for 6MV, and exhibits centering instability.Conclusion:Based on our findings, the Edge detector was chosen for stereotactic measurements. The PTW diode E is an acceptable alternative.
SU‐E‐T‐247: Determinations of the Optimal Phase for Respiratory Gated Radiotherapy From Statistical Analysis Using a Visible Guidance System
Authors: Oh S , Yea J , Kang M , Lee H , Kim S 
Published: June 2015

Purpose:Respiratory gated radiation therapy (RGRT) is used to minimize the radiation dose to normal tissue in lung cancer patients. Determination of the optimal point in the respiratory phase of a patient is important in RGRT but it is not easy. The goal of the present study was to see if a visible guidance system is helpful in determining the optimal phase in respiratory gated therapy.Methods:The breathing signals of 23 lung cancer patients were recorded with a Real‐time Position Management (RPM) respiratory gating system (Varian, USA). The patients underwent breathing training with our visible guidance system, after which their breathing signals were recorded during 5 min of free breathing and 5 min of guided breathing. The breathing signals recorded between 3 and 5 min before and after training were compared. We performed statistical analysis of the breathing signals to find the optimal duty cycle in guided breathing for RGRT.Results:The breathing signals aided by the visible guidance system had more regular cycles over time and smaller variations in the positions of the marker block than the free breathing signals. Of the 23 lung cancer patients, 19 showed statistically significant differences by time when the values obtained before and after breathing were compared (p < 0.05); 30% and 40% of the duty cycle, respectively, was determined to be the most effective, and the corresponding phases were 30 60% (duty cycle, 30%; p < 0.05) and 30 70% (duty cycle, 40%; p < 0.05).Conclusion:Respiratory regularity was significantly improved with the use of the RPM with our visible guiding system; therefore, it would help improve the accuracy and efficiency of RGRT.
SU‐E‐T‐314: Dosimetric Effect of Smooth Drilling On Proton Compensators in Prostate Patients
Authors: Reyhan M , Yue N , Zou J 
Published: June 2015

Purpose:To evaluate the dosimetric effect of smooth drilling of proton compensators in proton prostate plans when compared to typical plunge drilling settings.Methods:Twelve prostate patients were planned in Eclipse treatment planning system using three different drill settings Smooth, Plunge drill A, and Plunge drill B. The differences between A and B were: spacing X[cm]: 0.4(A), 0.1(B), spacing Y[cm]: 0.35(A), 0.1(B), row offset [cm]: 0.2(A), 0(B). Planning parameters were kept consistent between the different plans, which utilized two opposed lateral beams arrangement. Mean differences absolute dosimetry in OAR constraints are presented.Results:The smooth drilled compensator based plans yielded equivalent target coverage to the plans generated with drill settings A and B. Overall, the smooth compensators reduced dose to the majority of organs at risk compared to settings A and B. Constraints were reduced for the following OAR: Rectal V75 by 2.12 and 2.48%, V70 by 2.45 and 2.91%, V65 by 2.85 and 3.37%, V50 by 2.3 and 5.1%, Bladder V65 by 4.49 and 3.67%, Penial Bulb mean by 3.7 and 4.2Gy, and the maximum plan dose 5.3 and 7.4Gy for option A vs smooth and option B vs smooth respectively. The femoral head constraint (V50<5%) was met by all plans, but it was not consistently lower for the smooth drilling plan.Conclusion:Smooth drilled compensators provide equivalent target coverage and overall slightly cooler plans to the majority of organs at risk; it also minimizes the potential dosimetric impacts caused by patient positioning uncertainty.
SU‐E‐T‐317: Dosimetric Evaluation of Acuros XB Advanced Dose Calculation Algorithm in Head and Neck Patients
Authors: Faught A , Wu Q 
Published: June 2015

Purpose:The Acuros XB photon dose calculation algorithm is a newly implemented calculation technique within the Eclipse treatment planning system using deterministic solutions to the linear Boltzmann transport equations. The goal of this study is to assess the clinical impact of dose differences arising from a retrospective comparison of calculations performed using the Analytical Anisotropic Algorithm (AAA) and Acuros XB on patients.Methods:Ten head and neck patients receiving intensity modulated radiation therapy were selected as a pilot study. Initial evaluation was based on the percentage of the planning target volume (PTV) covered by the prescription dose, minimum dose within the PTV, and dose differences in critical structures. For patients receiving boost plans, dosimetric evaluations were performed on the plan sum of the primary and boost plans.Results:Among the ten patients there were a total of 21 PTVs corresponding to primary and boost volumes. Using the same normalization within Eclipse, the average percentage of the PTVs receiving the prescription dose were 95.6% for AAA and Acuros XB. The average minimum doses within the PTVs, expressed as a percentage of the prescription to the volume, were 82.3% and 83.6% for AAA and Acuros XB respectively. Neither comparison showed differences with statistical significance when subjected to a paired t‐test. Statistical significance was found in the average difference of the maximum dose for the mandible (242.5cGy, p=0.0005) and cord with a 5mm radial expansion (105.0cGy, p=0.0005) and in the median dose for the left parotid (25.0cGy, p=0.0423) and oral cavity (36.3cGy, p=0.002).Conclusion:The Acuros XB dose calculation algorithm did not exhibit significant differences in PTV coverage when compared to the AAA algorithm. Significant differences in critical structures are likely attributed to the structures proximity to high atomic number materials or air cavities, regions of known difficulty for the AAA algorithm.
SU‐E‐T‐319: Dosimetric Evaluation of IMRT with Mix‐Energy Beam for Deep Seated Targets
Authors: Sharma S , Manigandan D , Gandhi A , Sharma D , Subramani V , Chander S , Julkha P , Rath G 
Published: June 2015

Purpose:IMRT is preferred in the range of 6–10MV X‐rays. Partially adding high energy (>10MV) treatment fields, may provide advantage of both higher and lower energies. To study IMRT dose distribution obtained from treatment plans with single (6MV) and mixed‐energy (6MV and 15MV) for deep seated targets (separation more than 30cm).Methods:Five patients of carcinoma of cervix were studied using eclipse planning system. Two different dynamic IMRT plans were generated for Varian CL2300C/D linear accelerator; one is by using 6MV X‐ray with seven equally spaced coplanar beams. In second plan, 2 lateral oblique fields (gantry angle 102°, 255°) beam energy was modified to 15MV by keeping all other parameters and dose volume constraints constant. Dose prescription for the planning target volume (PTV) was (5040cGy/28f). For plan comparison, dose volume histogram (DVH) was used and PTV coverage index (CI=Target volume covered by prescription dose/Target volume), heterogeneity index (D5/D95), mean dose to organ at risk (OAR) and normal tissue integral dose (NTID, liter‐Gray) was also noted. Total monitor unit (MU) required to deliver a plan was also noted.Results:Mixed‐energy plan showed a better conformity and CI values were 0.942±0.032 and 0.960±0.040 for single‐energy and mixed‐energy plan, respectively. In addition, HI value of mixed energy beam is comparable to that of single energy and the values were within 1.084±0.034 and 1.082±0.032 for single energy and mixed‐energy plan, respectively. Variation in mean dose to bladder, rectum and bowel were within 1.05%, 0.87% and 0.90%. NTID was lesser for mixed‐energy beam due to use of two high‐energy fields. NTID were 1573.40±214.60 and 1510.20±249.80 litre‐Gray for single energy and mixed‐energy plan. MU needed to deliver a plan was similar in both plans and MUs were 238±45 and 237±47.Conclusion:Partial use of 15MV treatment fields in IMRT plan for deep seated targets showed dosimetric advantage over 6MV plan.
SU‐E‐T‐320: Dosimetric Evaluation of Intracranial Stereotactic Radiotherapy Plans Using Jaws‐Only Collimation On a LINAC
Authors: Mistry N , Kim A , Schaum J , Bermudez M , Driscoll K , Holowinski C , Yang C , Chen Y , Sheth N 
Published: June 2015

Purpose:To evaluate the dosimetry of cranial stereotactic radiotherapy (SRT) plans using jaws‐only collimation on linac that meets appropriate TG‐142 tolerances.Methods:Seventeen spherical targets were generated in the center of a head phantom with diameters ranging from 8 mm to 40 mm. Plans balanced treatment time with dose gradient and conformity using 13 static fields and 3 couch angles: 9 non‐opposed and coplanar fields and 4 non‐coplanar fields. The symmetrical jaws field size was target diameter plus 2 mm. The prescription (Rx) was 7 Gy per fraction to the 80% isodose line. Two plans were created for each target: one kept the collimator at 0° (C0), one adjusted the collimator angle 40° for each field to create a 360° sweep over the 9 coplanar fields (CR).Conformity of the Rx to the target was evaluated using a ratio of Rx to target volume (PITV). Heterogeneity was determined using a ratio of maximum dose to Rx dose. Falloff was scored using CGIg: the difference of effective radii of spheres equal to half and full Rx volumes.Results:All plans met RTOG SRS criteria for conformity and heterogeneity. The use of collimator rotation improved conformity by 3.2% on average, the mean PITV was 1.7±0.1 for C0 plans and 1.6±0.1 for CR. Mean heterogeneity was 1.25±0.0 for both C0 and CR. The mean CGIg was 75.9±16.4 for C0 plans and 74.4±17.0 for CR; with a mean dose falloff degradation of 2.5% by CR.Conclusion:Clinically acceptable SRT plans for spherical targets were created using jaws‐only collimation with static fields. The addition of sweeping collimator rotation improves conformity at the expense of gradient. This technique can expand the availability of SRT to patients especially to those who cannot travel to a facility with a dedicated stereotactic radiosurgery machine.
SU‐E‐T‐322: Dosimetric Evaluation of Rib Dose in Peripheral Lung Tumors Treated with X‐Ray Voxel Monte Carlo (XVMC) Based Lung Stereotactic Body Radiotherapy (SBRT) Following RTOG 0915 Guidelines
Authors: Pokhrel D , Sood S , Badkul R , Jiang H , Kumar P , Wang F 
Published: June 2015

Purpose:To evaluate XVMC computed rib doses for peripherally located non‐small‐cell‐lung tumors treated with SBRT following RTOG‐0915 guidelines.Methods:Twenty patients with solitary peripherally located non‐small‐cell‐lung tumors were treated using XVMC‐based SBRT to 50–54Gy in 5−3 fractions, respectively, for PTV(V100%)=95%. Based on 4D‐CT, ITV was delineated on MaximumIP images and organs‐at‐risk(OARs) including ribs were contoured on MeanIP images. Mean PTV(ITV+5mm uniform margin) was 46.1±38.7cc (range, 11.1–163.0cc). XVMC SBRT treatment plans were generated with a combination of non‐coplanar 3D‐conformal arcs/beams, and were delivered by Novalis‐TX consisting of HD‐MLCs and a 6MV‐SRS(1000MU/min) beam, following RTOG‐0915 criteria. XVMC rib maximum dose and dose to <1cc, <5cc, <10cc were evaluated as a function of PTV, prescription dose and 3D‐distance from tumor isocenter to the most proximal rib contour. Plans were re‐computed using heterogeneity‐corrected pencil‐beam (PB‐hete) algorithm utilizing identical beam geometry/MLC positions and MUs and subsequently compared to XVMC.Results:XVMC average maximum rib dose was 50.9±6.4Gy (range, 35.1–59.3Gy). XVMC mean rib dose to <1cc was 41.6±5.6Gy (range, 27.9–47.9Gy), <5cc was 31.2±7.3Gy (range, 10.6–43.1Gy), and <10cc was 21.2±8.7Gy (range, 1.1–36Gy), respectively. For the given prescription, correlation between PTV and rib doses to <5cc (p=0.005) and <10cc (p=0.018) was observed. 3D‐distance from the tumor isocenter to the proximal rib contour strongly correlated with maximum rib dose (p=0.0001). PB‐hete algorithm overestimated maximum rib dose and dose to <1cc, <5cc, and <10cc of ribs by 5%, 3%, 3%, and 3%, respectively.Conclusion:PB‐hete overestimates ribs dose relative to XVMC. Since all the clinical XVMC plans were generated without compromising the target coverage (per RTOG‐0915), almost all patient's ribs doses were higher than the protocol guidelines. As expected, larger tumor size and proximity to ribs received higher absolute dose to ribs. Prospective observation is needed to determine if XVMC delivered rib doses correlates with patient symptoms including chest wall pain and/or rib fractures.
SU‐E‐T‐325: Dosimetric Impact Due to FlexiShield in Electronic Brachytherapy (eBx) of Breast IORT: A Phantom Study
Authors: Kim Y , Huynh J , Ley M , Gonzalez V 
Published: June 2015

Purpose:To evaluate dosimetric change of eBx plan due to Flexishield.Methods:To simulate a clinically difficult case (skin spacing < 1 cm and touching chest wall), prostheses breast tissue phantom overlaid Xoft spherical balloon applicator. To minimize significant metal streak artifact, megavoltage CT (MVCT) scan was acquired using helical TomoTherapy HiART. Two sets of MVCT images were taken with/without FlexiShield for 15 cases: 4 for small (3–4 cm), 4 for medium (4–5 cm) and 7 for large (5–6 cm) balloon. Total 30 MVCT scans were obtained with 50 % contrast to improve image contrast of balloon relative to breast tissue phantom. Balloon deformation was measured in anterior‐posterior (AP) and lateral (LAT) dimensions in the middle of balloon. Skin spacing was also evaluated. Treatment plan was made based on each MVCT scan and two balloon surface doses (AP and LAT directions) and skin dose were compared between plans with/without FlexiShield.Results:The balloon was deformed due to pressure from both FlexiShield (skin side) and FlexiShield mini (chest wall side). Mean ± standard deviation (maximum) value was 1.5 ± 1.0 mm (3.3 mm) for AP compression and 0.4 ± 0.3 mm (1.1 mm) for LAT expansion. Balloon surface dose was increased by 1.8 ± 1.2 Gy (4.9 Gy) at AP point and decreased by 0.4 ± 0.4 Gy (1.3 Gy) at LAT point. Skin spacing was constantly reduced by 1.1 ± 0.8 mm (3 mm). Skin surface dose was increased by 1.5 ± 0.8 Gy (3.3 Gy) and its relative increase was 17.9 ± 9.3% (39.6%).Conclusion:FlexiShield deforms the balloon and reduces skin spacing, thereby resulting in higher dose in AP direction, lower dose in LAT direction, and elevated skin dose compared to the plan without FlexiShield. In the clinic, this balloon deformation and corresponding dose variation should be considered.