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Transmission of Imaging and Data (TRIAD) is a standard-based system built by the American College of Radiology to provide the seamless exchange of images and data for accreditation of clinical trials and registries. Scripts of structures' names validation profiles created in TRIAD are used in the automated submission process. It is essential for users to understand the logistics of these scripts for successful submission of radiation therapy cases with less iteration.

Purpose: To study the effect of different filters on the dose response curves of the Gafchromic XRQA2 film. To measure the kV XVI cone-beam CT (CBCT) surface dose received during 3D and 4D imaging protocols in three body regions (head and neck, chest and pelvis). Methods: GafChromic XR- QA2 film (International Specialty Products, Wayne, NJ) dose response curves were generated for three irradiation settings: 100 kVp S20/F0; 120 kVp S20/F0 and 120 kVp S20/F1(F1 is a Bowtie filter). Film pieces were irradiated in air by the X-ray Volume Imager (XVI) mounted on the Elekta Synergy linear accelerator (Elekta, Crawley, UK) and their responses were correlated to air kerma measurements. To measure the CBCT surface dose, film pieces were taped on the surface of a male Alderson Rando Phantom (Alderson Research Laboratories, Inc., Long Island City, New York) at four different places (Anterior, Posterior, Right Lateral, Left Lateral). Results: The dose response curves of XRQA2 film generated with F1 and F0 filters were found to differ by 5 to 7% when the air kerma changed between 2 and 5 cGy. This was less than the observed difference (more than 15%, especially at low air kerma) in the dose response curves when different energies (100 and 120 kVp) and same filter were used. Surface dose ranged between 0.02 cGy and 4.99 cGy. The lowest average surface dose (0.05 cGy) was observed when the fast head and neck protocol was used, whilst the highest average surface dose (3.06 cGy) was noticed when the chest m20 protocol was used. Conclusions: Filters seem to have less effect on the dose response of the film compared with energy. Gafchromic XRQA2 film was used successfully to measure the XVI CBCT surface dose. The dose was found to vary from one imaging protocol to another, with 4D protocols not necessarily delivering more doses. © 2012, American Association of Physicists in Medicine. All rights reserved.

The efficacy of stereotactic body radiotherapy (SBRT) has been well demonstrated. However, it presents unique challenges for accurate planning and delivery especially in the lungs and upper abdomen where respiratory motion can be significantly confounding accurate targeting and avoidance of normal tissues. In this paper, we review the current literature on SBRT for lung and upper abdominal tumors with particular emphasis on addressing respiratory motion and its affects. We provide recommendations on strategies to manage motion for different, patient-specific situations. Some of the recommendations will potentially be adopted to guide clinical trial protocols.

Background To establish the feasibility of the dosimetric compliance criteria of the RTOG 1308 trial through testing against Intensity Modulation Radiation Therapy (IMRT) and Passive Scattering Proton Therapy (PSPT) plans. Methods Twenty-six lung IMRT and 26 proton PSPT plans were included in the study. Dose Volume Histograms (DVHs) for targets and normal structures were analyzed. The quality of IMRT plans was assessed using a knowledge-based engineering tool. Results Most of the RTOG 1308 dosimetric criteria were achieved. The deviation unacceptable rates were less than 10 % for most criteria; however, a deviation unacceptable rate of more than 20 % was computed for the planning target volume minimum dose compliance criterion. Dose parameters for the target volume were very close for the IMRT and PSPT plans. However, the PSPT plans led to lower dose values for normal structures. The dose parameters in which PSPT plans resulted in lower values than IMRT plans were: lung V5Gy (%) (34.4 in PSPT and 47.2 in IMRT); maximum spinal cord dose (31.7 Gy in PSPT and 43.5 Gy in IMRT); heart V5Gy (%) (19 in PSPT and 47 in IMRT); heart V30Gy (%) (11 in PSPT and 19 in IMRT); heart V45Gy (%) (7.8 in PSPT and 12.1 in IMRT); heart V50% (Gy) (7.1 in PSPT and 9.8 in IMRT) and mean heart dose (7.7 Gy in PSPT and 14.9 Gy in IMRT). Conclusions The revised RTOG 1308 dosimetric compliance criteria are feasible and achievable.

Purpose: In this study, the relevant characteristics of the new Gafchromic XRQA2 film for its application in measuring kV cone beam computed tomography(CBCT)imagedoses were thoroughly investigated. Methods: The film was calibrated free in air to air kerma levels between 0 and 9 cGy using 120 kVp photon beams produced by the x-ray volume imager.Films were scanned using transmission and reflection scanning modes with the Epson Expression 10000 XL flat-bed document scanner. The impact of film size, region of interest for the analysis, scan uniformity, scan resolution, scan orientation and alternate scanning sides on the analysis process were investigated. Energy dependence, postirradiation growth of reflectance with time and irradiation angular dependence of the film were tested at different air kerma levels. Results: The net reflectance changed by ∼3% when the size of the film piece changed from 1 cm × 2 cm to 10 cm × 11 cm and changed by ∼1% when ROI changed from 0. 7 cm × 0. 7 cm to 8 cm × 8 cm, suggesting a good uniformity of the film. The film was successfully analyzed using the transmission scanning mode, calibration curves from both transmission and reflection scanning modes showed similar behavior. The calibration uncertainty was somewhat lower when the film was scanned using reflection mode (6% and 8% for reflection and transmission modes, respectively.) Higher scanning resolution came with increasing calibration uncertainty. The calibration uncertainty for reflection and transmission modes increased from ∼3.5% to 7% and from ∼3.5% to 9%, respectively when scanning resolution was changed from 50 to 400 dpi. Scanning the film on alternate sides using transmission mode led to variation of 16%–19% in the net optical density at doses commonly used for CBCT procedures. The film response changed by almost 10% when it was exposed to beams of two different energies (100 and 120 kVp.) Other features of the film such as film orientation, postexposure growth, and irradiation angular dependence were also investigated. Conclusions: The size of film piece and analysis ROI used for calibration slightly affected the film response. Both transmission and reflection scanning modes can be used to analyze the Gafchromic XRQA2, with the reflection mode having a somewhat lower calibration uncertainty. Scanning films on alternate sides using transmission mode significantly affects the optical density. The film response was shown to be energy dependent. The films reached stability in about 6 h after exposure. The film response was proven to be independent of irradiation angle except when the beam is parallel to the film surface.

A comparative study was made between a combination of α-RBS and NRA and proton backscattering (BS) for the analysis of as-prepared and metallised porous silicon samples of different thicknesses and porosities. In general, α-RBS and NRA was found to give better information on the composition of surface metal layers and the content within porous silicon of oxygen and carbon, especially when the amounts of oxygen and carbon are small (∼2–4 at.%) and when their amounts are high enough to cause peak overlap in BS spectra. However, BS was shown to have advantages for the analysis of metal penetration at depths of more than 1 μm or when the samples were covered with a layer of metal several tenths of a micron in thickness.

Accelerator-based nuclear techniques were used to study the ageing of as-prepared and aluminium-capped porous silicon samples with a porosity of 55% and with two different morphologies (microporous and mesoporous). Aluminium surface capping layers with thicknesses in the range 0.1-0.5 m were applied by rf sputtering. The uncapped microporous samples aged more rapidly in air than did mesoporous samples. The sputtered capping layers were found to be effective for stabilizing porous silicon against atmospheric oxidation, irrespective of the thickness of the capping layer.

Cobalt has been deposited on and in porous silicon by chemical vapour infiltration and deposition using deuterated cobalt carbonyl hydride, DCo(CO) 4 . This precursor is unstable, and below about 22°C decomposes with an initial half-life of 10 min, probably forming DCo 3 (CO) 9 . After a time which depends on the precursor concentration, the precursor decomposes more rapidly. This reaction increases the concentration of cobalt and the ratio of cobalt to hydrogen within the pores. At temperatures above about 22°C, a similar but smaller increase occurs in the concentration of cobalt, and Co 2 (CO) 8 is thought then to be the main decomposition product. Thermolysis preserves the increased levels of metal within the pores; it is inferred that each cobalt atom becomes linked to one silicon atom at the pore wall.

Ion beam analysis data are presented on both freshly prepared and `aged' porous silicon layers of widely varying (10 - 85%) porosity. Both evaporated Al and PECVD surface capping layers are shown to suppress some of the rapid ion beam induced changes in chemical composition that have been reported during analysis of uncapped layers. Specifically, these capping layers were successful in eliminating carbon and oxygen accumulation within the material but they only slightly reduced hydrogen loss under ion bombardment. Evaporated aluminium surface capping layers were partially successful in suppressing long term ambient oxygen pick-up.

Rhenium was deposited in porous silicon by Chemical Vapour Infiltration and Deposition (CVID) using a deuterium rhenium carbonyl DRe(CO)5 precursor. The results indicate that the precursor penetrates into the pores and reaches a saturation level very quickly (in less than 2 min) to give a uniform rhenium concentration of 8–10 at% of the silicon content to a measurable depth of at least 1.5 μm. High levels of oxygen were also observed at ∼ SiO1.5. In addition to having a high level of carbon at about one third of the oxygen level, the carbon content of the samples dropped during analysis, suggesting that it was present in a volatile form.

Thin cobalt layers have been grown on and in porous silicon by chemical vapour infiltration and deposition using HCo(CO)4. The process can be controlled to give a capping layer with or without metal in the pores. Thin coats on the pore walls have been measured to depths of several μm and thick coats to depths of 0.1 μm. Results from mass spectroscopy indicate that when a cobalt hydride precursor molecule decomposes on a pore wall it releases its hydrogen atom accompanied by three from the pore wall, so forming direct metal-silicon bonds.

Surface doses received during seven different imaging protocols (using the kV XVI imager) were measured on a Rando phantom surface using nanoDot optical stimulated luminescence dosimeters (OSLD) for three different body regions (head and neck, chest and pelvis). For each protocol, the surface dose was measured at four different locations on the surface of the phantom (ANT., POST., LLAT. and RLAT.). The surface dose at any location in the irradiated area can range between 0.008 cGy (fast head and neck protocol) and 4.38 cGy (symmetry 4D). The average surface dose in the irradiated area ranged between 0.038 cGy and 2.34 cGy. The measured doses were compared with nominal scan dose, provided by the vendor and calculated doses.

Purpose: Permanent seed implants have traditionally been used to treat prostate, lung and head or neck cancers using I-125 and Pd-103. Cs-131, which has higher dose rate is being used to treat brain, head and/or neck cancers in our clinic, therefore, we chose to monitor the dose received by surgeons during the extensive procedure. The aims of this work are to assess the level of radiation exposure to surgeons and the instantaneous exposure at bedside and 1 m from patients. Methods: Ten patients received Cs-131 implants for recurrent brain,head and/or neck cancer; the median implanted activity, number of implanted seeds and prescription dose at 0.5 cm from the perpendicular plane of the implant were: 54.3 mCi (14.52 – 77); 19 (4 – 24) and 60 Gy (range 42 – 60) respectively. Radiation exposure was recorded at bedside and 1 m from the patient using Victoreen ion chamber (Fluke Biomedical, Cleveland, OH). Exposure to surgeons was measured using TLD (Mirion Technologies (GDS), Inc., USA). Results: The median equivalent dose rate at 1 m and bedside immediately following implantation were 1.49×10-2 mSv/h (8.77×10-3–2.63×10-2) and 7.76×10-2 mSv/h (3.1×10-2– 1.53×10-1) respectively. Median equivalent dose to surgeons’ hands was 0.60 mSv (0.33 – 1.48) and no doses were detected for whole-body. Surgical reconstruction for one patient was performed 71 days post-implant and resulted in zero exposure to surgeons. Conclusion: The recorded exposure rates were low when compared with the literature. Post procedure surveys at bed site and 1 m indicated that all patients were within safe limits for discharge (< 0.05 mSv/h at 1 m). However, as a precautionary measure, patients were advised to avoid direct contact with children and pregnant women within four weeks of the implant and stay at least at 3 ft from other people. Surgeons doses were well within occupational dose limits.

Purpose: To investigate the significance of using pinpoint ionization chambers (IC) and RadCalc (RC) in determining the quality of lung SBRT VMAT plans with low dose deviation pass percentage (DDPP) as reported by ScandiDos Delta4 (D4). To quantify the relationship between DDPP and point dose deviations determined by IC (ICDD), RadCalc (RCDD), and median dose deviation reported by D4 (D4DD). Methods: Point dose deviations and D4 DDPP were compiled for 45 SBRT VMAT plans. Eighteen patients were treated on Varian Truebeam linear accelerators (linacs); the remaining 27 were treated on Elekta Synergy linacs with Agility collimators. A one-way analysis of variance (ANOVA) was performed to determine if there were any statistically significant differences between D4DD, ICDD, and RCDD. Tukey's test was used to determine which pair of means was statistically different from each other. Multiple regression analysis was performed to determine if D4DD, ICDD, or RCDD are statistically significant predictors of DDPP. Results: Median DDPP, D4DD, ICDD, and RCDD were 80.5% (47.6%–99.2%), −0.3% (−2.0%–1.6%), 0.2% (−7.5%–6.3%), and 2.9% (−4.0%–19.7%), respectively. The ANOVA showed a statistically significant difference between D4DD, ICDD, and RCDD for a 95% confidence interval (p < 0.001). Tukey's test revealed a statistically significant difference between two pairs of groups, RCDD-D4DD and RCDD-ICDD (p < 0.001), but no difference between ICDD-D4DD (p = 0.485). Multiple regression analysis revealed that ICDD (p = 0.04) and D4DD (p = 0.03) are statistically significant predictors of DDPP with an adjusted r2 of 0.115. Conclusion: This study shows ICDD predicts trends in D4 DDPP; however this trend is highly variable as shown by our low r2. This work suggests that ICDD can be used as a method to verify DDPP in delivery of lung SBRT VMAT plans. RCDD may not validate low DDPP discovered in D4 QA for small field SBRT treatments.

Purpose: To establish a workflow for NRG-GY006 IMRT pre-treatment reviews, incorporating advanced radiotherapy technologies being evaluated as part of the clinical trial. Methods: Pre-Treatment reviews are required for every IMRT case as part of NRG-GY006 (a randomized phase II trial of radiation therapy and cisplatin alone or in combination with intravenous triapine in women with newly diagnosed bulky stage I B2, stage II, IIIB, or IVA cancer of the uterine cervix or stage II-IVA vaginal cancer. The pretreatment review process includes structures review and generating an active bone marrow(ABM)- to be used as an avoidance structure during IMRT optimization- and evaluating initial IMRT plan quality using knowledgeengineering based planning (KBP). Institutions will initially submit their simulation CT scan, structures file and PET/CT to IROC QA center for generating ABM. The ABM will be returned to the institution for use in planning. Institutions will then submit an initial IMRT plan for review and will receive information back following implementation of a KBP algorithm, for use in re-optimization, before submitting the final IMRT used for treatment. Results: ABM structure is generated using MIM vista software (Version 6.5, MIM corporation, Inc.). Here, the planning CT and the diagnostic PET/CT are fused and a sub threshold structure is auto segmented above the mean value of the SUV of the bone marrow. The generated ABM were compared with those generated with other software system (e.g. Velocity, Varian) and Dice coefficient (reflects the overlap of structures) ranged between 80 – 90% was achieved. A KBP model was built in Varian Eclipse TPS using the RapidPlan KBP software to perform plan quality assurance. Conclusion: The workflow for IMRT pretreatment reviews has been established. It represents a major improvement of NRG Oncology clinical trial quality assurance and incorporates the latest radiotherapy technologies as part of NCI clinical trials. This project was supported by grants U24CA180803 (IROC), UG1CA189867 (NCORP), U10CA180868 (NRG Oncology Operations), U10CA180822 (NRG Oncology SDMC) from the National Cancer Institute (NCI) and PA CURE grant

A study was made of the effect of soil moisture content and porosity on the diffusion of radon through soil. It was found that the diffused radon concentration decreases exponentially with the increase of soil thickness. The diffusion coefficient of radon through soil was found to decrease with the increase of the moisture content and to increase with the increase of porosity. A field study was also conducted to investigate the effect the above parameters on radon concentration values as measured at a depth of ∼50 cm below the earth's surface.

Purpose: The value of Half Value Layer (HVL) is essential in quantifying the ability of an x-ray beam to penetrate the material being studied. This paper examines the use of three different types of detectors for measuring HVL of the 120keV photon beam of the X-ray Volume Imager (XVI) cone beam CT system mounted on the Elekta Synergy (Crawley, UK) Linac: ionization chamber, Gafchromic film and diode. The effects of collimator diameters are presented and the chamber tip and chamber horizontalmethods are compared to investigate the source of variations in the measurement of HVL. Methods: The measurements are done in free airboth using an ionization chamber calibrated for absolute dosimetry [University of Wisconsin Accredited Dosimetry Laboratory] and the Gafchromic film dosimeters [XR-QA2 (International Specialty Products, Wayne, NJ)]. The beam is collimated to the size of the detector to measure the exposed dose. The different thicknesses of the aluminum attenuators are added to beam to measure individual doses every time and repeated until the dose fell to below 50% of the initial unattenuated value. Dose measurements with a semiconductor diode detector [Barracuda MPD (RTI Electronics AB, NJ)] is also carried out. We plotted all results on a semi-log graph to find HVL value. Results: When the measurements are made using ionization chamber with different collimator diameters we obtained 1.6% difference in HVL values. Measurements with chamber tip and horizontal methods agree with each other to within approximately 1.6% percentage difference. The percentage difference of the HVL values measured using the diode and ionization chamber is about 6.4% and that of using Gafchromic film and ionization chamber is about 8% percent. Conclusions: Gafchromic films and diodes can be used to measure HVL value of 120 keV photon beams. Recommendations for consistency in HVL measurements are provided. © 2012, American Association of Physicists in Medicine. All rights reserved.

As part of the consolidation of the cooperative group clinical trial program of the National Clinical Trials Network (NCTN) of the National Cancer Institute (NCI), an Imaging and Radiation Oncology Core services organization (IROC) has been formed from current leading quality assurance (QA) centers to provide QA, along with clinical and scientific expertise, for the entire NCTN (1). An integrated information technology (IT) infrastructure, the IROC cloud, has been implemented to foster collaborative and effective interactions among participating institutions, QA centers, NCTN cooperative groups and statistics data management centers, and the IT infrastructure of the NCI (Fig. 1). An integral component of the IROC cloud is the Transfer of Images and Data (TRIAD) system designed for imaging and radiation therapy digital data transmission. The TRIAD system is now being used for digital radiation therapy and imaging data transmission for NCTN (and other) clinical trials. Fig. 1 IROC cloud: An IROC Information Technology (IT) infrastructure vision. Consistency of submitted data contributes to better consistency in the treatment and review of trial data, and it facilitates scientific collaborations and also promotes safe clinical practice. The details of this data submission process are presented here.

Purpose: To evaluate patient specific quality assurance (PSQA) for the delivery of volumetric modulated arc therapy (VMAT) by disease site. To compare planning-delivery system (PDS) PSQA pass rates in a dual vendor institution. Methods: PSQA is performed for VMAT plans using a ScandiDos Delta4 phantom. Verification plans are calculated using Varian Eclipse and Elekta Monaco treatment planning systems (TPS) for patients treated using Varian Truebeam and Elekta linear accelerators respectively. Individual arcs are delivered to the Delta4 phantoms and assessed using the gamma index pass criterion(3% Dose Deviation(DD%), 3mm Distance to Agreement(DTA),10% dose threshold and 90% gamma index). Results: A total of 287 VMAT plans and 680 arcs were analyzed. The passing rates for VMAT QA plans were 95% and 98% for head/neck and pelvis/prostate plans respectively, and 100% for chest/abdomen, spine, lung Stereotactic Body Radiotherapy (SBRT) and Stereotactic Radiosurgery(SRS) plans. Average gamma indices were: (99 ± 2) % for pelvis/prostate, chest/abdomen and lung SBRT plans, (97 ± 4) % for head and neck plans and (98 ± 3) % for spine plans. The average DD% and DTA pass rates ranged from 82% to 90% and 98% to 99% respectively for plans in different disease sites. Paired t-test analysis (two tails) indicated no significant differences in the gamma indices between plans delivered using different PDS; the P values were: 0.08, 0.45, and 0.94 for lung SBRT, head/neck and pelvis/prostate plans respectively. The statistical power for comparing PDS in different disease sites with an alpha of 0.05 is 1. Conclusion: The Gamma indices based on 3% DD%, 3 mm DTA and 10% dose threshold for the VMAT QA plans in all disease sites were well above 90%, suggesting the possibility of using a more stringent PSQA criterion. No significant differences were observed in the QA of VMAT plans delivered using different PDS.

Purpose: This study compares gamma passing rates for a cohort of similar intensity modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT) quality assurance (QA) plans to determine the equivalence of the patient specific QA plan delivery. The passing criterion is 90% gamma index with 3% dose difference (DD), 3mm distance-to-agreement (DTA) and a dose threshold of 10%. Methods: Gamma passing results of previously treated IMRT QA plans, delivered to Sun Nuclear MapCheck phantom, and VMAT QA plans, delivered to ScandiDos Delta4 phantom, are organized by anatomical site and treatment machine. Both Varian and Elekta machines are included. Pairs of IMRT and VMAT plans are matched based on site, machine, and PTV volume to ensure similar plan cohorts. A two-tailed t-test analysis of the data with an alpha of 0.05 determines if there exists a statistically significant difference. Power was calculated to detect a difference of 4%; all data sets were strong with above a 0.8 power. Results: The first data set consisting of 20 matched pairs of prostate plans was statistically insignificant (p-value=0.90, Power=0.99). The 14 matched pairs set of head and neck plans has a statistically significant Result (p-value=0.028, Power=0.88). The head and neck IMRT gamma indexes have a mean of 93.1% and range of 82%-100% while the VMAT gamma indexes have a mean of 96.7% and range of 92%-100%. The two combined data sets of matched plans had a statistically insignificant Result (p-value=0.073, Power=0.99). Conclusion: Overall, IMRT and VMAT have equivalent passing rates when comparing the gamma analysis using a passing criterion of 3% DD and 3mm DTA. When separated by site, prostate IMRT and VMAT plans have equivalent passing rates while head and neck plans have a statistically significant variation of passing rates. The passing rates for the two modalities are independent of delivery machine for matched PTV target volumes.

Purpose: To test whether unified vendor specified beam conformance for matched machines implies volumetric modulated arc radiotherapy(VMAT) delivery consistency. Methods: Twenty-two identical patient QA plans, eleven 6MV and eleven 15MV, were delivered to the Delta⁴(Scandidos, Uppsala, Sweden) on two Varian TrueBEAM matched machines. Sixteen patient QA plans, nine 6 MV and seven 10 MV, were delivered to Delta⁴ on two Elekta Agility matched machines. The percent dose deviation(%DDev), distance-to-agreement(DTA), and the gamma analysis(γ) were collected for all plans and the differences in measurements were tabulated between matched machines. A paired t-test analysis of the data with an alpha of 0.05 determines statistical significance. Power(P) was calculated to detect a difference of 5%; all data except Elekta %DDev sets were strong with above a 0.85 power. Results: The average differences for Varian machines (%DDev, DTA, and γ) are 6.4%, 1.6% and 2.7% for 6MV, respectively, and 8.0%, 0.6%, and 2.5% for 15MV. The average differences for matched Elekta machines (%DDev, DTA, and γ) are 10.2%, 0.6% and 0.9% for 6 MV, respectively, and 7.0%, 1.9%, and 2.8% for 10MV.A paired t-test shows for Varian the %DDev difference is significant for 6MV and 15MV(p-value6MV=0.019, P6MV=0.96; p-value15MV=0.0003, P15MV=0.86). Differences in DTA are insignificant for both 6MV and 15MV(p-value6MV=0.063, P6MV=1; p-value15MV=0.907, P15MV=1). Varian differences in gamma are significant for both energies(p-value6MV=0.025, P6MV=0.99; p-value15MV=0.013, P15MV=1). A paired t-test shows for Elekta the difference in %DDev is significant for 6MV but not 10MV(p-value6MV=0.00065, P6MV=0.68; p-value10MV=0.262, P10MV=0.39). Differences in DTA are statistically insignificant(p-value6MV=0.803, P6MV = 1; p-value10MV=0.269, P10MV=1). Elekta differences in gamma are significant for 10MV only(p-value6MV=0.094, P6MV=1; p-value10MV=0.011, P10MV=1). Conclusion: These results show vendor specified beam conformance across machines does not ensure equivalent patient specific QA pass rates. Gamma differences are statistically significant in three of the four comparisons for two pairs of vendor matched machines.

Purpose: Accurate contour delineation is crucial for radiotherapy. Atlas based automatic segmentation tools can be used to increase the efficiency of contour accuracy evaluation. This study aims to optimize technical parameters utilized in the tool by exploring the impact of library size and atlas number on the accuracy of cardiac contour evaluation. Methods: Patient CT DICOMs from RTOG 0617 were used for this study. Five experienced physicians delineated the cardiac structures including pericardium, atria and ventricles following an atlas guideline. The consistency of cardiac structured delineation using the atlas guideline was verified by a study with four observers and seventeen patients. The CT and cardiac structure DICOM files were then used for the ABAS technique.To study the impact of library size (LS) and atlas number (AN) on automatic contour accuracy, automatic contours were generated with varied technique parameters for five randomly selected patients. Three LS (20, 60, and 100) were studied using commercially available software. The AN was four, recommended by the manufacturer. Using the manual contour as the gold standard, Dice Similarity Coefficient (DSC) was calculated between the manual and automatic contours. Five-patient averaged DSCs were calculated for comparison for each cardiac structure.In order to study the impact of AN, the LS was set 100, and AN was tested from one to five. The five-patient averaged DSCs were also calculated for each cardiac structure. Results: DSC values are highest when LS is 100 and AN is four. The DSC is 0.90±0.02 for pericardium, 0.75±0.06 for atria, and 0.86±0.02 for ventricles. Conclusion: By comparing DSC values, the combination AN=4 and LS=100 gives the best performance. This project was supported by NCI grants U24CA12014, U24CA180803, U10CA180868, U10CA180822, PA CURE grant and Bristol-Myers Squibb and Eli Lilly.

Purpose: 2D-2D kV image guided radiation therapy (IGRT) credentialing evaluation for clinical trial qualification was historically qualitative through submitting screen captures of the fusion process. However, as quantitative DICOM 2D-2D and 2D-3D image registration tools are implemented in clinical practice for better precision, especially in centers that treat patients with protons, better IGRT credentialing techniques are needed. The aim of this work is to establish methodologies for quantitatively reviewing IGRT submissions based on DICOM 2D-2D and 2D-3D image registration and to test the methodologies in reviewing 2D-2D and 2D-3D IGRT submissions for RTOG/NRG Oncology clinical trials qualifications. Methods: DICOM 2D-2D and 2D-3D automated and manual image registration have been tested using the Harmony tool in MIM software. 2D kV orthogonal portal images are fused with the reference digital reconstructed radiographs (DRR) in the 2D-2D registration while the 2D portal images are fused with DICOM planning CT image in the 2D-3D registration. The Harmony tool allows alignment of the two images used in the registration process and also calculates the required shifts. Shifts calculated using MIM are compared with those submitted by institutions for IGRT credentialing. Reported shifts are considered to be acceptable if differences are less than 3mm. Results: Several tests have been performed on the 2D-2D and 2D-3D registration. The results indicated good agreement between submitted and calculated shifts. A workflow for reviewing these IGRT submissions has been developed and will eventually be used to review IGRT submissions. Conclusion: The IROC Philadelphia RTQA center has developed and tested a new workflow for reviewing DICOM 2D-2D and 2D-3D IGRT credentialing submissions made by different cancer clinical centers, especially proton centers. NRG Center for Innovation in Radiation Oncology (CIRO) and IROC RTQA center continue their collaborative efforts to enhance quality assurance services and to be consistently adaptive to the new advances in radiation therapy. This project was supported by NCI grants U10CA180868, U10CA180822, U24CA180803, U24CA12014 and PA CURE Grant.

Purpose: To measure CBCT dose profiles inside phantom using Gafchromic XRQA2 film. Methods: Gafchromic XRQA2 film (International Specialty Products, Wayne, NJ) whole sheets were placed between slabs of the IMRT head and torso free point phantom, model 002H9K (Computerized Imaging Reference Systems, Inc, Norfolk, Virginia). Doses were acquired during chest and head imaging protocols of the Volume Imager (XVI) mounted on the Elekta linar accelerator (Elekta, Crawley, UK). Scanned films were analyzed using ImageJ (National Institute of Health, Bethesda, MD). Results: For the Chest protocol (full trajectory), dose ranged between 1.25 and 2.11 cGy, with average dose of 1.78 cGy. Here, the dose increased over the first 3 cm from the right surface of the phantom, it then leveled off, with average fluctuation of around 5% (within uncertainty level, with the exception of few points where a fluctuation of 24% was observed). Dose eventually started to drop in the left side of the phantom till it reached its lowest value. For the head and neck protocol (trajectory is 200°), dose ranged between 0.02 and 0.13 cGy, with average value of 0.09 cGy. The dose was more or less uniform from the right surface of the phantom till its center (it fluctuated within uncertainty level of 20 to 40% and even higher at some low dose points) and then started to increase from almost the center of the phantom until it reached its highest value near the left surface. Conclusion: Full trajectory protocol led to uniform dose distribution in the middle part of the phantom and doses were less near surfaces. However, for a protocol with a trajectory of 200° degree, the dose was uniform in one part of the phantom and showed increase in the other part, consistent with the start/stop angle of the gantry. Measured dose fluctuated mostly within uncertainty levels. This project is funded, in part, under a grant with the Pennsylvania Department of Health. The Department specifically declaims responsibility for any analyses, interpretations or conclusions

Purpose: To evaluate surface doses for beams with and without flattening filter (FF and FFF) in breast cancer treatment plans. Measurements were performed for validation. Delivery:TrueBeam, used in this study, is a linear accelerator newly designed to deliver both flattened and flattening filter free beams. Planning: Eclipse treatment planning system (TPS) is commissioned and utilized. We used 6 MV half beams from FFF mode to plan standard tangential breast treatments due to its similar shape to wedged FF beams. We compare these plans with those from 6MV flattened beams with 30° wedges. Measurement Validation: We used a Rando phantom and InLightTM nanoDotsOptically stimulated luminescence dosimetry(OSLD) system to measuresurface doses from FFF beams. Medial, apex and lateral locations from central plane, as well as positions from caudal and cranial regions, were included. Results:Planning comparison: surface doses from plans with FFF beams were2.2%–4.7% lower than those with flattened beams with wedges, when doses at deeper depth from central axis stay close in value. Measurement validation: In the apex region of central plane,the OSLD readouts are 4.5% – 6.3% higher than calculated. In the caudal, cranial and medial regions, TPS underestimated the surface dose from 7.2–8.7%. Conclusions: For standard tangential breast plans, surface doses are lower with FFF beam than with flattened beams with wedges. The surface doses from FFF beams were validated with OSLD measurements, taking into account the uncertainty of the dosimeter and its angular dependence..

Purpose: To study the process of generating dose calibration curve for a new radiochromic film model (GafChromic XR‐QA2) using ion chamber and flat‐bed document scanner. To investigate the effectiveness of both scanning modes (reflection and transmission) for film dosimetry. To investigate the impact of scanning spatial resolution on the uncertainty of dose calibration. Methods: The reference dosimetry system included GafChromic XR‐QA2 (ISP, Wayne, NJ) films designed for low dose measurement of low energy photonbeam, a Farmer‐type ion chamber calibrated for absolute dosimetry for photon energies of 100kVp and 120kVp, and an Epson Expression 10000 flat‐bed document scanner (Epson, Nagano, Japan). A kilovoltage cone‐beam CT system mounted on Elekta linac (Elekta, Crawley, UK) was used to irradiate the films. Film response (pixel value change in reflection scanning mode or optical density change in transmission mode) was correlated to air kerma using ion chamber measurements. Fifteen dose points ranging from 0 to 9cGy were used to generate calibration curves with optimal fitting function selection. Calculation of uncertainty included experimental and curve fitting uncertainties. Several different scanning spatial resolutions were tested to study its impact on the experimental uncertainty of dose calibration curve. Results: Both scanning modes generated repeatable and smooth calibration curves with small curve fitting uncertainty (

Purpose: To review IGRT credentialing experience and unexpected technical issues encountered in connection with advanced radiotherapy technologies as implemented in RTOG clinical trials. To update IGRT credentialing procedures with the aim of improving the quality of the process, and to increase the proportion of IGRT credentialing compliance. To develop a living disease site-specific IGRT encyclopedia. Methods: Numerous technical issues were encountered during the IGRT credentialing process. The criteria used for credentialing review were based on: image quality; anatomy included in fused data sets and shift results. Credentialing requirements have been updated according to the AAPM task group reports for IGRT to ensure that all required technical items are included in the quality review process. Implementation instructions have been updated and expanded for recent protocols. Results: Technical issues observed during the credentialing review process include, but are not limited to: poor quality images; inadequate image acquisition region; poor data quality; shifts larger than acceptable; no soft tissue surrogate. The updated IGRT credentialing process will address these issues and will also include the technical items required from AAPM: TG 104; TG 142 and TG 179 reports. An instruction manual has been developed describing a remote credentialing method for reviewers. Submission requirements are updated, including images/documents as well as facility questionnaire. The review report now includes summary of the review process and the parameters that reviewers check. We have reached consensus on the minimum IGRT technical requirement for a number of disease sites. RTOG 1311(NRG-BR002A Phase 1 Study of Stereotactic Body Radiotherapy (SBRT) for the Treatment of Multiple Metastases) is an example, here; the protocol specified the minimum requirement for each anatomical sites (with/without fiducials). Conclusion: Technical issues are identified and reported. IGRT guidelines are updated, with the corresponding credentialing requirements. An IGRT encyclopedia describing site-specific implementation issues is currently in development.

Purpose: To investigate the adherence of treatment plans of prostate cancer patients with the dosimetric compliance criteria of the new in house phase I trial of high dose rate (HDR) brachytherapy combined with stereotactic body radiotherapy (SBRT) for intermediate risk prostate cancer patients. Methods: Ten prostate cancer patients were treated using this trial. They received one fraction of HDR to 15Gy, followed by external beam(EB) boost of 3.2Gy(Level 1, five patients) or 3.94Gy(level 2, five patients) per fraction for 10 or 7 fractions, respectively, both equivalent to EB treatments of 113.5Gy in 2Gy fractions. The EB plans were either IMRT or VMAT plans. DVH analysis was performed to verify the adherence of treatment plans to the dosimetric criteria of the trial. Results: For Level 1 patients, target coverage were adequate, with CTV V32Gy(%) of 99.0±1.0 (mean ± 1 standard deviation), and PTV V31Gy(%) of 99.6±0.3. PTV V32.9Gy(%) is 1.4±3.1 and PTVmax is 32.9±0.2Gy. Rectum, bladder and femoral heads sparing were well within protocol criteria. For Level 2 patients, CTV V27.6Gy(%) is 98.7±1.8; PTV V26.7Gy(%) is 99.0±1.4. PTV V28.4Gy(%) is 1.3±1.4, with three patients having minor deviation from protocol. Again critical structures were spared compliant to the protocol. The analysis of HDR plans show similar results, with adequate dose coverage to the prostate and sparing of critical structures including urethra and rectum. V100(%) and V90(%) of prostate are 96.0±1.1 and 98.9±0.5. Urethra D10(%) is 113.1±2.9. Rectum V80(cc) is 1.4±0.5. Hotspot in prostate is substantially higher than what the protocol specifies. But the criteria for hotspot are only guidelines, serving to lower the dose to urethra . Conclusion: This new high biological equivalent dose prostate trial has been carried out successfully for ten patients. Based on dosimetric analysis, all HDR and external plans were compliant to the protocol criteria, with only minor deviations.

Purpose: To evaluate the image quality and imaging dose of the Varian TrueBeam OBIv.1.5 CBCT system in a clinical adaptive radiation therapy environment, simulated by changing phantom thickness. Methods: Various OBI CBCT protocols(Head, Pelvis, Thorax, Spotlight) were used to acquire images of Catphan504 phantom(nominal phantom thickness and 10 cm additional phantom thickness). The images were analyzed for low contrast detectability(CNR), uniformity(UI), and HU sensitivity. These results were compared to the same image sets for planning CT(pCT)(GE LightSpeed 16- slice). Imaging dose measurements were performed with Gafchromic XRQA2 film for various OBI protocols (Pelvis, Thorax, Spotlight) in a pelvic-sized phantom(nominal thickness and 4cm additional thickness). Dose measurements were acquired in the interior and at the surface of the phantom. Results: The nominal CNR[additional thickness CNR] for OBI was—Pelvis:1.45[0.81],Thorax:0.86[0.48], Spotlight:0.67[0.39],Head:0.28 [0.10]. The nominal CNR[additional thickness CNR] for pCT was— Pelvis:0.87[0.41],Head:0.60[0.22]. The nominal UI[additional thickness UI] for OBI was—Pelvis:11.5[24.1],Thorax:17.0[20.6], Spotlight:23.2[23.2], Head:15.6[59.9]. The nominal UI[additional thickness UI] for pCT was— Pelvis:9.2[8.6],Head:2.1[2.9]. The HU difference(averaged over all material inserts) between nominal and additional thickness scans for OBI: 8.26HU(Pelvis), 33.39HU(Thorax), 178.98HU(Head), 108.20HU (Spotlight); for pCT: 16.00HU(Pelvis), 19.85HU(Head). Uncertainties in electron density were calculated based on HU values with varying phantom thickness. Average electron-density deviations (ρ(water)=1)for GE-Pelvis,more » GE-Head, OBI-Pelvis, OBI-Thorax, OBI-Spotlight, and OBI-Head were: 0.0182, 0.0180, 0.0058, 0.0478, 0.2750, and 0.3115, respectively.The average phantom interior dose was(OBI-nominal):2.35cGy(Pelvis), 0.60cGy(Thorax), 1.87cGy(Spotlight); OBI-increased thickness: 1.77cGy(Pelvis), 0.43cGy(Thorax), 1.53cGy (Spotlight). Average surface dose(OBI-nominal): 2.29cGy(Pelvis), 0.56cGy(Thorax), 1.79cGy (Spotlight); OBI-increased thickness: 1.94cGy(Pelvis), 0.48cGy(Thorax), 1.47cGy (Spotlight). Conclusion: The OBI-Pelvis protocol offered comparable CNR and HU constancy to pCT for each geometry; other protocols, particularly Spotlight and Head, exhibited lower HU constancy and CNR. The uniformity of pCT was superior to OBI for all protocols. CNR and UI were degraded for both systems/scan types with increased thickness. The OBI interior dose decreased by approximately 30% with additional thickness. This work was funded, in part, under a grant with the Pennsylvania Department of Health. The Department of Health specifically declaims responsibility for any analyses, interpretations, or conclusions.« less

Purpose: To provide quantitative and qualitative image quality metrics and imaging dose for modern Varian On-board Imager (OBI) (ver. 1.5) and Elekta X-ray Volume Imager (XVI) (ver. 4.5R) cone-beam computed tomography (CBCT) systems in a clinical adaptive radiation therapy environment by accounting for varying patient thickness. Methods: Image quality measurements were acquired with Catphan 504 phantom (nominal diameter and with additional 10 cm thickness) for OBI and XVI systems and compared to planning CT (pCT) (GE LightSpeed). Various clinical protocols were analyzed for the OBI and XVI systems and analyzed using image quality metrics, including spatial resolution, low contrast detectability, uniformity, and HU sensitivity. Imaging dose measurements were acquired in Wellhofer Scanditronix i'mRT phantom at nominal phantom diameter and with additional 4 cm phantom diameter using GafChromic XRQA2 film. Calibration curves were generated using previously published in-air Air Kerma calibration method. Results: The OBI system full trajectory scans exhibited very little dependence on phantom thickness for accurate HU calculation, while half-trajectory scans with full-fan filter exhibited dependence of HU calculation on phantom thickness. The contrast-to-noise ratio (CNR) for the OBI scans decreased with additional phantom thickness. The uniformity of Head protocol scan was most significantly affected with additional phantom thickness. The spatial resolution and CNR compared favorably with pCT, while the uniformity of the OBI system was slightly inferior to pCT. The OBI scan protocol dose levels for nominal phantom thickness at the central portion of the phantom were 2.61, 0.72, and 1.88 cGy, and for additional phantom thickness were 1.95, 0.48, and 1.52 cGy, for the Pelvis, Thorax, and Spotlight protocols, respectively. The XVI system scans exhibited dependence on phantom thickness for accurate HU calculation regardless of trajectory. The CNR for the XVI scans decreased with additional phantom thickness. The uniformity of the XVI scans was significantly dependent on the selection of the proper FOV setting for all phantom geometries. The spatial resolution, CNR, and uniformity for XVI were lower than values measured for pCT. The XVI scan protocol dose levels at the central portion of the phantom for nominal phantom thickness were 2.14, 2.15, and 0.33 cGy, and for additional phantom thickness were 1.56, 1.68, and 0.21 cGy, for the Pelvis M20, Chest M20, and Prostate Seed S10 scan protocols, respectively. Conclusions: The OBI system offered comparable spatial resolution and CNR results to the results for pCT. Full trajectory scans with the OBI system need little-to-no correction for HU calculation based on HU stability with changing phantom thickness. The XVI system offered lower spatial resolution and CNR results than pCT. In addition, the HU calculation for all scan protocols was dependent on the phantom thickness. The uniformity for each CBCT system was inferior to that of pCT for each phantom geometry. The dose for each system and scan protocol in the interior of the phantom tended to decrease by approximately 25% with 4 cm additional phantom thickness.

Purpose: To evaluate the effect of different beam filters on the dose response curves of nanoDot OSL dosimeters at kV CBCT energy. Methods: The InLight™ OSL dosimetry system (Landauer,Inc., Glenwood, IL, USA) consisting of nanoDot dosimeters and MicroStar reader was calibrated using the X‐ray Volume Imager (XVI) mounted on the Elekta Synergy (Elekta, Crawley, UK) linac and the On Board Imager(OBI) mounted on the Varian True Beam (Varian Medical systems, Palo Alto, CA) linac. Doses ranged between 0 and 12 cGy were delivered to nanoDot OSLDs on 5 cm thick PMMA slab using 120kVp F0(no filter) and F1(Bowtie filter)XVI CBCT beams, 125 kVp half fan (HF) and full fan (FF) OBI beams. Dose points were correlated to absolute air kerma levels measured in air using the 0.6 cc Farmer ionization chamber and converted to dose in water at the phantom surface according to AAPM TG61. Results: Dose response curves for all imaging settings were linear. The dose response curves for the 120 kVp F0 and F1 VXI CBCT beams differed by 8 to 9 %. The dose response curves for the 125 kVp FF and HF OBI CBCT beams also differed by 7 to 8 %. These results suggest that nanoDot dosimeters are sensitive not only to differences in kVp of the beam but also to differences in spectra resulted from the use of different filters. Conclusion: Dose response curves of nanoDot OSLDs for photon beams of same kVp but filtered with different filters are different. Hence,the use of correction factors (based solely on differences in the response of the OSLDs at different kVps) to allow the reading of the MicroStar reader to be converted from one set of reference condition to another is not sufficient to ensure accurate estimation of measured doses.It is important to create dose response curve at every irradiation setting. This project is funded, in part, under a grant with the Pennsylvania Department of Health. The Department specifically declaims responsibility for any analyses, interpretations or conclusions

Purpose: To investigate the effect of energy (kVp) and filters (no filter, half Bowtie, and full Bowtie) on the dose response curves of the Gafchromic XRQA2 film and nanoDot optical stimulated luminescence dosimeters (OSLDs) in CBCT dose fields. To measure surface and internal doses received during x-ray volume imager (XVI) (Version R4.5) and on board imager (OBI) (Version 1.5) CBCT imaging protocols using these two types of dosimeters. Methods: Gafchromic XRQA2 film and nanoDot OSLD dose response curves were generated at different kV imaging settings used by XVI (software version R4.5) and OBI (software version 1.5) CBCT systems. The settings for the XVI system were: 100 kVp/F0 (no filter), 120 kVp/F0, and 120 kVp/F1 (Bowtie filter), and for the OBI system were: 100 kVp/full fan, 125 kVp/full fan, and 125 kVp/half fan. XRQA2 film was calibrated in air to air kerma levels between 0 and 11 cGy and scanned using reflection scanning mode with the Epson Expression 10000 XL flat-bed document scanner. NanoDot OSLDs were calibrated on phantom to surface dose levels between 0 and 14 cGy and read using the inLight{sup TM} MicroStar reader. Both dosimeters were used to measure in field surface and internal doses in a malemore » Alderson Rando Phantom. Results: Dose response curves of XRQA2 film and nanoDot OSLDs at different XVI and OBI CBCT settings were reported. For XVI system, the surface dose ranged between 0.02 cGy in head region during fast head and neck scan and 4.99 cGy in the chest region during symmetry scan. On the other hand, the internal dose ranged between 0.02 cGy in the head region during fast head and neck scan and 3.17 cGy in the chest region during chest M20 scan. The average (internal and external) dose ranged between 0.05 cGy in the head region during fast head and neck scan and 2.41 cGy in the chest region during chest M20 scan. For OBI system, the surface dose ranged between 0.19 cGy in head region during head scan and 4.55 cGy in the pelvis region during spot light scan. However, the internal dose ranged between 0.47 cGy in the head region during head scan and 5.55 cGy in the pelvis region during spot light scan. The average (internal and external) dose ranged between 0.45 cGy in the head region during head scan and 3.59 cGy in the pelvis region during spot light scan. Both Gafchromic XRQA2 film and nanoDot OSLDs gave close estimation of dose (within uncertainties) in many cases. Though, discrepancies of up to 20%-30% were observed in some cases. Conclusions: Dose response curves of Gafchromic XRQA2 film and nanoDot OSLDs indicated that the dose responses of these two dosimeters were different even at the same photon energy when different filters were used. Uncertainty levels of both dosimetry systems were below 6% at doses above 1 cGy. Both dosimetry systems gave almost similar estimation of doses (within uncertainties) in many cases, with exceptions of some cases when the discrepancy was around 20%-30%. New versions of the CBCT systems (investigated in this study) resulted in lower imaging doses compared with doses reported on earlier versions in previous studies.« less

Purpose: To investigate the impacts of scanning parameters on the characterization of the GafChromic XRQA2 films and eventually on the accuracy of the measured kV doses when both reflection and transmission scanning modes are used. To study some characteristics of this film model. Methods: GafChromic XR‐QA2 (International Specialty Products, Wayne, NJ) films were irradiated in air by the X‐ray Volume Imager (XVI) mounted on the Elekta linear accelerator (Elekta, Crawley, UK). They were then scanned using the Epson Expression 10000 XL flat‐bed document scanner (Seiko Epson Corporation, Nagano, Japan) and analyzed using ImageJ software (National Institute of Health, Bethesda, MD). The effect of the scanning parameters: scanning reproducibility; scanner non uniformity; scanner resolution (dpi); scanner configuration; region of interest of the analysis; and scanning orientation on the characterization process was investigated. Film characteristics such as post irradiation growth of pixel value were also studied. Results: The characterization process is sensitive to the scanning parameters. Each parameter could lead to a variation in the mean pixel value (PV), which would eventually affect the uncertainty of the measured doses. The magnitudes of these variations were found to differ from one parameter to another and ranged from 1 % to 5% and even more. The scanner nonuniformity in particular led to a variation from 5% to 15% in the mean PV. Scanner resolution and configuration were also identified as important parameters. Post irradiation growth of PV was observed over the first 24 h (increased by 5%) and leveled off thereafter (< 0.5% change). Conclusions: The magnitudes of the effect of the different scanning parameters on the PV have been quantified, some of them found to be significantly affecting the PV. Hence, the scanning procedure must be carried out with a great care in order to minimize the uncertainty of the measured doses.