A novel breast specific stereotactic radiosurgery device (BSRD) was invented at our institution. Over the last several years the device has been systematically evaluated demonstrating the stereotactic accuracy of its patented breast immobilization system and dosimetric benefits in comparison to external beam radiotherapy, proton beam radiotherapy and brachytherapy. Based on these evaluations, an Investigator Device Exemption (IDE) was obtained through the FDA and a study was developed and approved to test its feasibility. This report is the 1st clinical experience of this device on this pre-FDA approved feasibility study. This protocol was approved through the Institutional Review Board. Eligible patients were > 60 years, recommended to undergo whole breast radiation(WBRT) without nodal radiation, had a tumor bed(TB) well visualized on CT simulation and the TB volume was < 25% of the WB. Once deemed eligible, patients received a single fraction of 8 Gy using the BSRD to the TB + 1cm prior to WBRT (40 Gy in 15 fx or 50 Gy in 25 fx). The primary objective of this trial was to ensure the adequacy of the radiation dose distribution(DD) with a secondary endpoint of acute toxcity. Dosimetric parameters evaluated in the protocol included planning tumor volume(PTV) coverage, PTV max dose, PTV min dose, and maximum dose to the skin, chest wall, rib, lung and heart. In order to meet the primary endpoint of feasibility, the two stage design by Simon was utilized. This tests the null hypothesis that the true proportion of patients for whom BSRD treatment planning is able to generate an acceptable DD is < 60%. Seventeen patients will be accrued, with a planned interim analysis in the 1st stage after 8 patients, where the DD needs to be acceptable in 6 or more in order to move forward to stage 2. Between 3/18/16 and 12/21/16, 9 patients signed consent for treatment and 8 patients underwent successful treatment. One patient, who was found not to eligible after simulation, was treated with conventional WBRT off study. The TB volume ranged from 2.86 to 20.38cc, while the PTV ranged from 21.69 to 89.56cc. The median(range) skinmax, lungmax, heartmax, and PTVmax dose were 2.04Gy(1.13-2.87), 1.40(0.1-1.98), 1.01(0.1-2.2) and 8.71 Gy(8.35-9.26), respectively. One patient with a deep seeded TB had a minor deviation and received a dose over the prescription dose to the chest wall, while a second patient had inadequate coverage of the PTV(major deviation). Acute toxicity related to the device has been minimal with one patient developing small blisters related to the immobilization device that was seen immediately following removal of the device. Based on an adequate dose distribution seen in 7 of the 1st 8 patients, stage 2 was initiated. The plan is to complete accrual this spring and submit the results for FDA approval.

Purpose: A dedicated stereotactic breast radiotherapy device, GammaPod, was developed to treat early stage breast cancer. The first clinical unit was installed and commissioned at University of Maryland. We report our methodology of absolute dosimetry in multiple calibration conditions and dosimetric verifications of treatment plans produced by the system. Methods: GammaPod unit is comprised of a rotating hemi-spherical source carrier containing 36 Co-60 sources and a concentric tungsten collimator providing beams of 15 and 25 mm. Absolute dose calibration formalism was developed with modifications to AAPM protocols for unique geometry and different calibration medium (acrylic, polyethylene or liquid water). Breast cup-size specific and collimator output factors were measured and verified with respect to Monte-Carlo simulations for single isocenter plans. Multiple isocenter plans were generated for various target size, location and cup-sizes in phantoms and 20 breast cancer patients images. Stereotactic mini-farmer chamber, OSL and TLD detectors as well as radio-chromic films were used for dosimetric measurements. Results: At the time of calibration (1/14/2016), absolute dose rate of the GammaPod was established to be 2.10 Gy/min in acrylic for 25 mm for sources installed in March 2011. Output factor for 15 mm collimator was measured to be 0.950. Absolute dose calibration was independently verified by IROC-Houston with a TLD/Institution ratio of 0.99. Cup size specific output measurements in liquid water for single isocenter were found to be within 3.0% of MC simulations. Point-dose measurements of multiple isocenter treatment plans were found to be within −1.0 ± 1.2 % of treatment planning system while 2-dimensional gamma analysis yielded a pass rate of 97.9 ± 2.2 % using gamma criteria of 3% and 2mm. Conclusion: The first GammaPod treatment unit for breast stereotactic radiotherapy was successfully installed, calibrated and commissioned for patient treatments. An absolute dosimetry and dosimetric verification protocols were successfully created.

Purpose:To test a novel total body irradiation (TBI) system using conformal partial arc with patient lying on the stationary couch which is biologically equivalent to a moving couch TBI. This improves the scanning field TBI, which is previously presented.Methods:The Uniform MU Modulated arc Segments TBI or UMMS‐TBI scans the treatment plane with a constant machine dose rate and a constant gantry rotation speed. A dynamic MLC pattern which moves while gantry rotates has been designed so that the treatment field moves same distance at the treatment plane per each gantry angle, while maintaining same treatment field size (34cm) at the plane. Dose across the plane varies due to the geometric differences including the distance from the source to a point of interest and the different attenuation from the slanted depth which changes the effective depth. Beam intensity is modulated to correct the dose variation across the plane by assigning the number of gantry angles inversely proportional to the uncorrected dose.Results:Measured dose and calculated dose matched within 1 % for central axis and 3% for off axis for various patient scenarios. Dose from different distance does not follow the inverse square relation as it is predicted from calculation. Dose uniformity better than 5% across 180 cm at 10cm depth is achieved by moving the gantry from −55 to +55 deg. Total treatment time for 2 Gy AP/PA fields is 40–50 minutes excluding patient set up time, at the machine dose rate of 200 MU/min.Conclusion:This novel technique, yet accurate but easy to implement enables TBI treatment in a small treatment room with less program development preparation than other techniques. The VMAT function of treatment delivery is not required to modulate beams. One delivery pattern can be used for different patients by changing the monitor units.

Purpose:GammaPod™, the first stereotactic radiotherapy device for early stage breast cancer treatment, has been recently installed and commissioned at our institution. A multidisciplinary working group applied the failure mode and effects analysis (FMEA) approach to perform a risk analysis.Methods:FMEA was applied to the GammaPod™ treatment process by: 1) generating process maps for each stage of treatment; 2) identifying potential failure modes and outlining their causes and effects; 3) scoring the potential failure modes using the risk priority number (RPN) system based on the product of severity, frequency of occurrence, and detectability (ranging 1–10). An RPN of higher than 150 was set as the threshold for minimal concern of risk. For these high‐risk failure modes, potential quality assurance procedures and risk control techniques have been proposed. A new set of severity, occurrence, and detectability values were re‐assessed in presence of the suggested mitigation strategies.Results:In the single‐day image‐and‐treat workflow, 19, 22, and 27 sub‐processes were identified for the stages of simulation, treatment planning, and delivery processes, respectively. During the simulation stage, 38 potential failure modes were found and scored, in terms of RPN, in the range of 9ߝ392. 34 potential failure modes were analyzed in treatment planning with a score range of 16ߝ200. For the treatment delivery stage, 47 potential failure modes were found with an RPN score range of 16ߝ392. The most critical failure modes consisted of breast‐cup pressure loss and incorrect target localization due to patient upper‐body alignment inaccuracies. The final RPN score of these failure modes based on recommended actions were assessed to be below 150.Conclusion:FMEA risk analysis technique was applied to the treatment process of GammaPod™, a new stereotactic radiotherapy technology. Application of systematic risk analysis methods is projected to lead to improved quality of GammaPod™ treatments.Ying Niu and Cedric Yu are affiliated with Xcision Medical Systems.

Purpose:The first GammaPod™ unit, a dedicated prone stereotactic treatment device for early stage breast cancer, has been installed and commissioned at University of Maryland School of Medicine. The objective of this study was to investigate potential dosimetric impact of inaccurate breast contour.Methods:In GammaPod treatments, patient's beast is immobilized by a breast cup device (BCID) throughout the entire same‐day imaging and treatment procedure. 28 different BICD sizes are available to accommodate patients with varying breast sizes. A mild suction helps breast tissue to conform to the shape of the cup with selected size. In treatment planning, dose calculation utilizes previously calculated dose distributions for available cup geometry rather than the breast shape from CT image. Patient CT images with breast cups indicate minor geometric discrepancy between the matched shape of the cup and the breast contour, i.e., the contour size is larger or smaller. In order to investigate the dosimetric impact of these discrepancies, we simulated such discrepancies and reassessed the dose to target as well as skin.Results:In vicinity of skin, hot/cold spots were found when matched cup size was smaller/larger than patient's breast after comparing the corrected dose profiles from Monte Carlo simulation with the planned dose from TPS. The overdosing/underdosing of target could yield point dose differences as large as 5% due to these setup errors (D95 changes within 2.5%). Maximal skin dose was overestimated/underestimated up to 25%/45% when matched cup size was larger/smaller than real breast contour.Conclusion:The dosimetric evaluation suggests substantial underdosing/overdosing with inaccurate cup geometry during planning, which is acceptable for current clinical trial. Further studies are needed to evaluate such impact to treating small volume close to skin.

Purpose:The first GammaPod™ unit for prone stereotactic treatment of early stage breast cancer has recently been installed and calibrated. Thirty‐six rotating circular Co‐60 beams focus dose at an isocenter that traverses throughout a breast target via continuous motion of the treatment table. The breast is immobilized and localized using a vacuum‐assisted stereotactic cup system that is fixed to the table during treatment. Here we report on system calibration and on verification of geometric and dosimetric accuracy.Methods:Spatial calibration involves setting the origin of each table translational axis within the treatment control system such that the relationship between beam isocenter and table geometry is consistent with that assumed by the treatment planning system. A polyethylene QA breast phantom inserted into an aperture in the patient couch is used for calibration and verification. The comparison is performed via fiducial‐based registration of measured single‐isocenter dose profiles (radiochromic film) with kernel dose profiles. With the table calibrations applied, measured relative dose distributions were compared with TPS calculations for single‐isocenter and dynamic (many‐isocenter) treatment plans. Further, table motion accuracy and linearity was tested via comparison of planned control points with independent encoder readouts.Results:After table calibration, comparison of measured and calculated single‐isocenter dose profiles show agreement to within 0.5 mm for each axis. Gamma analysis of measured vs calculated profiles with 3%/2mm criteria yields a passing rate of >99% and >98% for single‐isocenter and dynamic plans respectively. This also validates the relative dose distributions produced by the TPS. Measured table motion accuracy was within 0.05 mm for all translational axes.Conclusion:GammaPod table coordinate calibration is a straightforward process that yields very good agreement between planned and measured relative dose distributions. The dynamic table motions used for dose painting are consistent with planned control points.CY, YN, PM, PH are employees of Xcision Medical Systems

Purpose:To: (1) describe an independent, automated, systematic software‐based protocol for verifying clinical data accuracy/integrity for mitigation of data corruption/loss risks following radiation oncology information system (ROIS) upgrades; and (2) report on application of this approach in an academic/community practice environment.Methods:We propose a robust approach to perform quality assurance on the ROIS after an upgrade, targeting four data sources: (1) ROIS relational database; (2) ROIS DICOM interface; (3) ROIS treatment machine data configuration; and (4) ROIS‐generated clinical reports. We investigated the database schema for differences between pre‐/post‐upgrade states. Paired DICOM data streams for the same object (such as RT‐Plan/Treatment Record) were compared between pre‐/post‐upgrade states for data corruption. We examined machine configuration and related commissioning data files for changes and corruption. ROIS‐generated treatment appointment and treatment parameter reports were compared to ensure patient encounter and treatment plan accuracy. This protocol was supplemented by an end‐to‐end clinical workflow test to verify essential ROI functionality and integrity of components interfaced during patient care chain of activities. We describe the implementation of this protocol during a Varian ARIA system upgrade at our clinic.Results:We verified 1,638 data tables with 2.4 billion data records. For 222 under‐treatment patients, 605 DICOM RT plans and 13,480 DICOM treatment records retrieved from the ROIS DICOM interface were compared, with no differences in fractions, doses delivered, or treatment parameters. We identified 82 new data tables and 78 amended/deleted tables consistent with the upgrade. Reports for 5,073 patient encounters over a 2‐week horizon were compared and were identical to those before the upgrade. Content in 12,237 xml machine files was compared, with no differences identified.Conclusion:An independent QA/validation approach for ROIS upgrades was developed and implemented at our clinic. The success of this approach ensures a robust QA of ROIS upgrades without manual paper/electronic checks and associated intensive labor.

We have developed a dedicated stereotactic radiation therapy device, the GammaPod™, for delivering a focal dose of radiation in the breast with patients in the prone position. The GammaPod uses 36 rotating Co-60 sources to focus the radiation at the machine's isocenter. The dose is delivered to the stereotactically localized target within the breast by continuously moving the patient in a planned trajectory relative to the fixed isocenter. The system comprises the irradiation unit, the breast immobilization/target immobilization system, the patient loading system, and a dedicated inverse planning system. The irradiation unit consists of a hemi-spherical source carrier containing the 36 sources, a tungsten collimator assembly that fits inside and concentric with the source carrier and a dynamically controlled patient support table. Two sets of 36 collimator holes are used to create beams of either 25mm or 15mm diameter and 36 tungsten rods block the sources when the system is in the beam-off state. The combination of 25mm and 15mm beams used in a treatment delivery is determined automatically by the inverse planning system. Once the sources are aligned with the collimator holes of a selected size, the source carrier and collimator assembly rotate together to form 36 non-coplanar, concentric, conical arcs focused at the isocenter. The breast is immobilized using a dual-layered breast cup applying a comfortable negative pressure between the two layers. The cup is embedded with fiducial markers that define a stereotactic coordinate system. An integrated patient loader transfers the patient from standing to prone position for treatment. In APBI plan comparison examples, against four tangential linear accelerator beams, GammaPod reduces V50 by more than 40%. For a centrally located 6.4cm diameter target, the maximum dose to the heart and lung is 10% and V5 for the heart and lung is 6.5%, and 4.3%, respectively. In another comparison to various brachytherapy approaches, the skin dose was shown to be substantially reduced from 76-144% to 21-23%, with substantially reduced dose heterogeneity. Using geometric beam focusing, dynamic treatment delivery and stereotactic localization, the GammaPod has shown its ability to deliver highly focused uniform dose distributions to breast targets with rapid dose fall-off.

At our institution, a novel, non-invasive breast-specific stereotactic radiation therapy (BSRT) device was developed which produces highly conformal dose distributions within the breast. This device employs a stereotactic immobilization breast cup which applies comfortable negative pressure to pull the breast tissue away from the chest wall. In this study, we investigate, in the postoperative setting, the dosimetric advantages that the BSRT-device immobilization affords with the consequent reductions in planning target volume (PTV) expansion. Nine patients, previously treated with whole breast external beam radiation therapy, underwent CT simulation in the prone position using a vacuum-assisted breast immobilization device on an IRB-approved protocol. The breast immobilization device has been validated to reduce set up errors to less than 2 mm (Mutaf 2013). Using target volumes adherent to the National Surgical Breast and Bowel Project (NSABP) B-39 protocol, 2 plans were generated using the BSRT planning software. The first plan utilized a 10 mm PTV expansion as per NSABP B-39, while the second employed a 3mm expansion, safely above the reproducibility of the immobilization device. Each plan was evaluated for dose delivered to the skin (defined as 5 mm envelope overlying the ipsilateral breast), ipsilateral breast tissue, ipsilateral chest wall, ipsilateral lung, and heart. Based on the work by Hepel et. al., the volume of ipsilateral breast receiving each of several percentages of total dose (Vx%) is predictive of the development of fibrosis and inferior cosmetic outcomes. The above structures were examined for various Vx%. A Wilcoxon rank sum test was utilized for statistical assessment of results. The median PTV_EVAL decreased from 181.5 (94.6-286.7) to 109.3 cc (56.9-166.1). The BSRT technique with immobilization resulted in a statistically significant reduction in dose to surrounding normal structures as expected. The most dramatic reductions were seen in the V5%, V20%, V50%, V80%, and V100% of the ipsilateral breast, which were reduced relative, on average, by 16.5%, 24.5%, 42.0%, 63.3%, and 86.4% (p<0.02). Additionally, the V15% and V40%of the breast skin were reduced by 31.1% and 60.4% (p<0.02), respectively. The chest wall also received reduced dose at multiple dose levels (p<0.04). Sparing of the lung and heart were not statistically significant due to the substantial sparing with the BSRT delivery technique alone. This novel BSRT device yields considerable dosimetric improvements in clinically relevant parameters in part due to its unique immobilization techniques. The reduction in PTV margin from 10 to 3 mm substantially reduces dose to the ipsilateral breast, skin, and chest wall which could have a substantial impact on toxicity and quality of life. Clinical trials utilizing this BSRT device will begin in 2015.

Purpose: To assess dose calculation accuracy of cone-beam CT (CBCT) based treatment plans using a patient-specific stepwise CT-density conversion table in comparison to conventional CT-based treatment plans. Methods: Unlike CT-based treatment planning which use fixed CT-density table, this study used patient-specific CT-density table to minimize the errors in reconstructed mass densities due to the effects of CBCT Hounsfield unit (HU) uncertainties. The patient-specific CT-density table was a stepwise function which maps HUs to only 6 classes of materials with different mass densities: air (0.00121g/cm3), lung (0.26g/cm3), adipose (0.95g/cm3), tissue (1.05 g/cm3), cartilage/bone (1.6g/cm3), and other (3g/cm3). HU thresholds to define different materials were adjusted for each CBCT via best match with the known tissue types in these images. Dose distributions were compared between CT-based plans and CBCT-based plans (IMRT/VMAT) for four types of treatment sites: head and neck (HN), lung, pancreas, and pelvis. For dosimetric comparison, PTV mean dose in both plans were compared. A gamma analysis was also performed to directly compare dosimetry in the two plans. Results: Compared to CT-based plans, the differences for PTV mean dose were 0.1% for pelvis, 1.1% for pancreas, 1.8% for lung, and −2.5% for HN in CBCT-based plans. The gamma passing rate was 99.8% for pelvis, 99.6% for pancreas, and 99.3% for lung with 3%/3mm criteria, and 80.5% for head and neck with 5%/3mm criteria. Different dosimetry accuracy level was observed: 1% for pelvis, 3% for lung and pancreas, and 5% for head and neck. Conclusion: By converting CBCT data to 6 classes of materials for dose calculation, 3% of dose calculation accuracy can be achieved for anatomical sites studied here, except HN which had a 5% accuracy. CBCT-based treatment planning using a patient-specific stepwise CT-density table can facilitate the evaluation of dosimetry changes resulting from variation in patient anatomy.

Three dimensional conformal radiation therapy (3D-CRT) is the most widely used form of PBI. Unfortunately, this approach has been demonstrated to compromise cosmetic results in comparison to whole breast radiation therapy. Investigators have demonstrated that the smaller, symmetric volumes involved in pre-operative PBI substantially increase eligibility for PBI as well as the potential for improved cosmetic outcomes. We aimed to improve upon these results using a novel BSRT device developed at our institution which has previously demonstrated significant dosimetric advantages over intensity modulated techniques (IMRT PBI). On an IRB approved protocol, 16 previously treated breast cancer patients underwent CT simulation in the prone position with use of the BSRT-device vacuum-assisted breast immobilization cup. The setup accuracy of this immobilization device has previously been validated to be less than 2 mm allowing for a reduction in PTV margins to 3 mm. A spherical contour of diameter equal to each patient’s pathologic tumor size was placed in the center of the lumpectomy cavity to simulate a gross tumor volume. Clinical target volume (15mm) and 2 separate planning target volume (PTV_10mm and PTV_3mm) expansions were performed. IMRT (PTV_10mm) and BSRT plans (PTV_10mm and PTV_3mm) were then generated by separate and blinded planners. The dose to the ipsilateral breast, breast skin, chest wall, lung, and heart was recorded for several percentages of the prescribed dose (Vx%). A paired sample t-test was utilized for statistical analysis. The BSRT device produced substantial reductions in comparison to IMRT PBI for both PTV expansions and for all surrounding critical structures. Two patients ineligible for planning due to BSRT device physical limitations with the PTV_10mm were eligible with PTV_3mm. The benefits were most dramatic in dose to the ipsilateral breast tissue with relative reductions of the V20%, V50%, V80%, and V100% by 32.5%, 42.1%, 38.6%, and 28.2% (p<0.003), respectively, for PTV_10mm, and of V5%, V20%, V50%, V80%, and V100% by 28.0%, 58.5%, 66.8%, 66.9%, and 64.0% (p<0.001), respectively, for PTV_3mm. The V15% and V40%of the breast skin were decreased by 35.3% and 46.1% with PTV_10mm (p<0.001) and by 63.9% and 71.2% with PTV_3mm, (p<0.001). Dosimetric improvements were also made in sparing of the heart, ipsilateral lung, and chest wall (p<0.05). BSRT is particularly advantageous for delivering highly conformal therapy to small, regular pre-operative volumes. With the potential to deliver ablative PBI doses in the neoadjuvant setting, pre-operative BSRT deserves further investigation in the form of a multi-institutional clinical trial which will soon be underway.

Purpose: A dedicated stereotactic breast radiotherapy device, GammaPod, was developed to treat early stage breast cancer. The first clinical GammaPod unit is currently being commissioned to treat its first patient in summer 2015. We provide an absorbed dose calibration formalism following AAPM protocols with modifications for the calibration medium and unique geometry of GammaPod. We also provide cross-comparison of the dosimetric calibration using different types of dosimeters. Methods: GammaPod is comprised of a rotating hemi-spherical source carrier containing 36 Co-60 sources and a concentric rotating tungsten collimator providing beam diameters of 1.5 and 2.5 cm. A solid breast phantom made of ultra-high-molecular-weight polyethylene (density 0.935 g/cm3) with an effective depth of 7cm is used for absolute dose calibration. Due to the non-water equivalent medium, we utilized the former AAPM TG-21 protocol, but cross-compared the calibration with TG-51 calibrated OSLD and radiochromic film dosimeters. Polyethylene medium and chamber-specific calibration parameters are derived and provided for Exradin A-18 and Capintec PR-05P ionization chambers. Results: The first clinical unit was installed with a total Co-60 activity of 2672 Ci in November 2014. Maximum dose rate was determined to be 2.76 Gy/min and 2.63 Gy/min for 2.5 and 1.5 cm collimators respectively at 7 cm depth. The determination of Ngas and appropriate polyethylene dosimetric quantities (stopping power and absorption coefficient ratios) is performed using NIST data tables and supplied as reference for calibration of subsequent units. Calibration crosscheck was accomplished with OSLD and radiochromic films, both with secondary TG-51 based calibrations, yielding relative dose differences less than 1%. Conclusion: The first GammaPod treatment unit for breast stereotactic radiotherapy was successfully installed and calibrated for commencement of patient treatments in 2015. An absolute dose calibration formalism was established for the unique geometry of GammaPod and the method is validated with different detectors. P Hoban, Y Niu and C Yu are employees of Xcision Medical Systems.

Purpose:Enable a scanning field total body irradiation (TBI) technique, using dynamic arcs, which is biologically equivalent to a moving couch TBI.Methods:Patient is treated slightly above the floor and the treatment field scans across the patient by a moving gantry. MLC positions change during gantry motion to keep same field opening at the level of the treatment plane (170 cm). This is done to mimic the same geometry as the moving couch TBI technique which has been used in our institution for over 10 years. The dose rate and the gantry speed are determined considering a constant speed of the moving field, variations in SSD and slanted depths resulting from oblique gantry angles. An Eclipse (Varian) planning system is commissioned to accommodate the extended SSD. The dosimetric foundations of the technique have been thoroughly investigated using phantom measurements.Results:Dose uniformity better than 2% across 180 cm length at 10cm depth is achieved by moving the gantry from −55 to +55 deg. Treatment range can be extended by increasing gantry range. No device such as a gravity‐oriented compensator is needed to achieve a uniform dose. It is feasible to modify the dose distribution by adjusting the dose rate at each gantry angle to compensate for body thickness differences. Total treatment time for 2 Gy AP/PA fields is 40–50 minutes excluding patient set up time, at the machine dose rate of 100 MU/min.Conclusion:This novel yet transportable moving field technique enables TBI treatment in a small treatment room with less program development preparation than other techniques. Treatment length can be extended per need, and. MLC‐based thickness compensation and partial lung blocking are also possible.

We have previously reported the dosimetric benefits of preoperative 3DCRT-APBI as well as the preliminary findings of our first 10 patients receiving preoperative 3DCRT-APBI (ASTRO 2011). Here we present results with additional patient accrual. This is an IRB-approved prospective trial testing the feasibility of preoperative APBI followed by planned partial mastectomy for patients with early-stage breast cancer. Eligible patients had unifocal invasive breast cancers ≤3 cm and negative clinical axillary lymph nodes by ultrasound or MR imaging. If imaging suggested suspicious findings, a targeted biopsy was required to confirm a negative axilla. Invasive lobular or pure in situ cancers were excluded. The gross tumor volume was the preoperative tumor as seen on CT. Clinical and planning target volumes were expansions similar to those used in RTOG 0319. Patients received 38.5 Gy in 3.85 Gy fractions delivered twice daily at least 6 hours apart. Partial mastectomy and sentinel lymph node biopsy were performed at least 21 days following completion of radiation therapy. Adjuvant therapy was given as per standard of care. Twenty-five of a planned 40 patients have completed protocol treatment thus far. Median patient age was 64 years (range, 51-85 years), and median preoperative tumor size was 1.1 cm (range, 0.45-3 cm). Tumor grade was as follows: nine patients with grade 1; 14 with grade 2, and two with grade 3. Receptor status showed 19 patients to be ER/PR+, HER 2-; one patient triple positive; one patient triple negative; and two patients ER+, PR/HER 2-. With a median follow-up of 27.6 months (range, 5.8-43.3 months), no local, regional, or distant failures have been noted. Surgery was performed at a median of 31 days after completion of radiation therapy (range, 21-63 days). A complete pathologic response based on H&E staining was seen in 4 patients (17%). Three patients underwent re-excision for close or positive margins. Three patients were found to have positive nodes at the time of surgery, and six underwent chemotherapy. There were four grade 3 toxicities of seroma formation. Patient-reported cosmetic outcome was rated as good to excellent in the majority (79%) of cases. Preoperative 3DCRT-APBI is feasible and well tolerated in select patients with early-stage breast cancer, with no reported local recurrences. The pathologic response rates associated with this nonablative APBI dose regimen are particularly encouraging and support further exploration of the use of preoperative RT in the setting of breast conservation therapy. The final results from this study will provide valuable supporting data for our upcoming trials utilizing a preoperative radioablative approach for treatment of early-stage breast cancers.

Purpose:Our Radiation Oncology Department uses clinical practice guidelines for patient treatment, including normal tissue sparing and other dosimetric constraints. These practice guidelines were adapted from national guidelines, clinical trials, literature reviews, and practitioner's own experience. Modern treatment planning systems (TPS) have the capability of incorporating these practice guidelines to automatically create radiation therapy treatment plans with little human intervention. We are developing a software infrastructure to integrate clinical practice guidelines and radiation oncology electronic medical record (EMR) system into radiation therapy treatment planning system (TPS) for auto planning.Methods:Our Smart Auto‐Planning Framework in an EMR environment (SAFEE) uses a software pipeline framework to integrate practice guidelines,EMR, and TPS together. The SAFEE system starts with retrieving diagnosis information and physician's prescription from the EMR system. After approval of contouring, SAFEE will automatically create plans according to our guidelines. Based on clinical objectives, SAFEE will automatically select treatment delivery techniques (such as, 3DRT/IMRT/VMAT) and optimize plans. When necessary, SAFEE will create multiple treatment plans with different combinations of parameters. SAFEE's pipeline structure makes it very flexible to integrate various techniques, such as, Model‐Base Segmentation (MBS) and plan optimization algorithms, e.g., Multi‐Criteria Optimization (MCO). In addition, SAFEE uses machine learning, data mining techniques, and an integrated database to create clinical knowledgebase and then answer clinical questions, such as, how to score plan quality or how volume overlap affects physicians' decision in beam and treatment technique selection.Results:In our institution, we use Varian Aria EMR system and RayStation TPS from RaySearch, whose ScriptService API allows control by external programs. These applications are the building blocks of our SAFEE system.Conclusion:SAFEE is a feasible method of integrating clinical information to develop an auto‐planning paradigm to improve clinical workflow in cancer patient care.