SAVI Device Research Articles

TU-FG-201-10: Quality Management of Accelerated Partial Breast Irradiation (APBI) Plans

Purpose: Since 2008, over 700 patients received high dose rate (HDR) APBI treatment at Virginia Hospital Center. The complexity involved in the planning process demonstrated a broad variation between patient geometry across all applicators, in relation to anatomical regions of interest. A quality management program instituting various metrics was implemented in March 2013 with the goal of ensuring an optimal plan is achieved for each patient. Methods: For each plan, an in-house complexity index, geometric conformity index, and plan quality index were defined. These indices were obtained for all patients treated. For patients treated after the implementation, the conformity index and quality index were maximized while other dosimetric limits, such as maximum skin and rib doses, were strictly kept. Subsequently, all evaluation parameters and applicator information were placed in a database for cross-evaluation with similar complexity. Results: Both the conformity and quality indices show good correlation with the complexity index. They decrease as complexity increases for all applicators. Multi lumen type balloon applicators demonstrate a minimal advantage over single lumen applicators in increasingly complex patient geometries, as compared to SAVI applicators which showed considerably greater advantage in these circumstances. After the implementation of the in-house planning protocol, there is a direct improvement of quality for SAVI plans. Conclusion: Due to their interstitial nature, SAVI devices show a better conformity in comparison to balloon-based devices regardless of the number of lumens, especially in complex cases. The quality management program focuses on optimizing indices by utilizing prior planning knowledge based on complexity levels. The database of indices assists in decision making and has subsequently aided in balancing the experience level among planners. This approach has made APBI planning more robust for patient care, with a measurable improvement in the plan quality.

SU‐E‐T‐401: Evaluation of TG‐43 Dose Calculation Accuracy for SAVI‐Based Accelerated Partial Breast Irradiation (APBI) Via Monte Carlo Simulations

Purpose:The current standard TG‐43 dose calculation method for SAVI‐based Accelerated Partial Breast Irradiation (APBI) assumes an ideal geometry of infinite homogeneous water. However, in SAVI treatments, the air cavity inside the device and the short source‐to‐skin distance raise concerns about the dose accuracy of the TG‐43 method. This study is to evaluate TG‐43 dose calculation accuracy in SAVI treatments using Monte Carlo (MC) simulations.Methods:We recalculated the dose distributions of 15 APBI patients treated with SAVI devices, including five cases with a size of 6–1, five with 8−1 and five with 10−1, using our in‐house developed fast MC dose package for HDR brachytherapy (gBMC). A phase‐space file was used to model the Ir‐192 HDR source. For each case, the patient CT was converted into a voxelized phantom and the dwell positions and times were extracted from treatment plans for MC dose calculations. Clinically relevant dosimetric parameters of the recalculated dose were compared to those computed via the TG‐43 approach.Results:A systematic overestimation of doses was found for the 15 cases in TG‐43 results, with D90, V150, and V200 for PTV_eval 2.8±1.8%, 2.0±2.2%, and 1.8±3.5% higher than MC results. TG‐43 also overestimated the dose to skin with the maximum dose 4.4±8.4% higher on average. The relatively large standard deviation seen in the difference of maximum skin dose is partially ascribed to the statistical uncertainty of MC simulations when computing the maximum dose. It took gBMC ∼1 minute to compute dose for a SAVI plan.Conclusion:The high efficiency of our gBMC package facilitated the studies with a relatively large number of cases. An overestimation of TG‐43 doses was found when using this MC package to recompute doses in SAVI cases. Clinical utilization of TG‐43 dose calculation method in this scenario should be aware of this fact.

GPU-Based Monte Carlo Dose Calculations for High-Dose-Rate Brachytherapy and Evaluations of TG-43 Accuracy in APBI Treatments With SAVI Devices

GPU-Based Monte Carlo Dose Calculations for High-Dose-Rate Brachytherapy and Evaluations of TG-43 Accuracy in APBI Treatments With SAVI Devices

Dose Modification Factor Analysis of Multilumen Brachytherapy Applicator With Monte Carlo Simulation

The Contura brachytherapy applicator is a silicone balloon with five lumens in which a high-dose-rate brachytherapy source can traverse. Multilumen applicators, like the Contura, are used in accelerated partial breast irradiation (APBI) brachytherapy in instances where asymmetric dose distributions are desired; for example, when the applicator surface-to-skin thickness is small (< 7 mm). In these instances, the air outside the patient and the lung act as a poor scattering medium, scattering less dose back into the breast and affecting the dose distribution. The recent report by Task Group 186 of the American Association of Physicists in Medicine (AAPM) has outlined the importance of moving towards brachytherapy dose calculations using heterogeneity corrections. However, at this time, many commercial treatment planning systems do not correct for tissue heterogeneity, which can result in inaccuracies in the planned dose distribution. To quantify the deviation in the skin dose we utilize the dose modification factor (DMF), defined as the ratio of the dose rate at 1 cm beyond the applicator surface with homogenous medium, to the dose rate at 1 cm with heterogeneous medium. This investigation models the Contura applicator with the Monte Carlo N-Particle code version 5, and determines a DMF through simulation. Taking all geometrical considerations into account, an accurate model of the Contura balloon applicator was created in MCNP and used to run simulations. The dose modification factor was found to be only slightly dependent on whether the dose distribution was symmetric or asymmetric. These results indicate that the dose delivered to part of the PTV may be lower than the planned dose by up to 12%, and that these brachytherapy plans should be viewed with caution. In addition to studying the effects of backscatter, an evaluation was made regarding the capabilities of the Contura device to shape an asymmetric dose distribution. We compared these results to a previous study of a MammoSite ML and a SAVI device and found that the dose shaping capabilities of the Contura were quite similar to that of the MammoSite ML, but markedly inferior to the SAVI.

Dose modification factor analysis of multilumen balloon brachytherapy applicator with Monte Carlo simulation.

The Contura brachytherapy applicator is a silicone balloon with five lumens in which a high‐dose‐rate brachytherapy source can traverse. Multilumen applicators, like the Contura, are used in accelerated partial breast irradiation (APBI) brachytherapy in instances where asymmetric dose distributions are desired; for example, when the applicator surface‐to‐skin thickness is small (< 7 mm). In these instances, the air outside the patient and the lung act as a poor scattering medium, scattering less dose back into the breast and affecting the dose distribution. The recent report by Task Group 186 of the American Association of Physicists in Medicine (AAPM) has outlined the importance of moving towards brachytherapy dose calculations using heterogeneity corrections. However, at this time, many commercial treatment planning systems do not correct for tissue heterogeneity, which can result in inaccuracies in the planned dose distribution. To quantify the deviation in the skin dose we utilize the dose modification factor (DMF), defined as the ratio of the dose rate at 1 cm beyond the applicator surface with homogenous medium, to the dose rate at 1 cm with heterogeneous medium. This investigation models the Contura applicator with the Monte Carlo N‐Particle code version 5, and determines a DMF through simulation. Taking all geometrical considerations into account, an accurate model of the Contura balloon applicator was created in MCNP and used to run simulations. The dose modification factor was found to be only slightly dependent on whether the dose distribution was symmetric or asymmetric. These results indicate that the dose delivered to part of the PTV may be lower than the planned dose by up to 12%, and that these brachytherapy plans should be viewed with caution. In addition to studying the effects of backscatter, an evaluation was made regarding the capabilities of the Contura device to shape an asymmetric dose distribution. We compared these results to a previous study of a MammoSite ML and a SAVI device and found that the dose shaping capabilities of the Contura were quite similar to that of the MammoSite ML, but markedly inferior to the SAVI.PACS number: 87.53.Jw

Accelerated partial breast irradiation using a strut-based brachytherapy device: A multi-institutional initial report on acute and late toxicity with greater than 24-month follow-up.

149 Background: Accelerated partial breast irradiation (APBI) is commonly used in early-stage breast cancer. The SAVI Collaborative Research Group is a multi-institutional group created to study outcomes in patients who received APBI utilizing strut-based brachytherapy. This analysis reports the acute and late toxicities for patients with greater than 2-year follow-up (F/U) from this study. Methods: 904 APBI patients (ductal carcinoma in situ [n=267] or invasive breast cancer [n=637]), received HDR brachytherapy (34 Gy in 10 fractions) using the SAVI device (Cianna Medical). Patients with dosimetry and documented follow-up were evaluated within 6 weeks of treatment for early adverse events (AEs), and at 1 year, 2 years, and beyond for late AEs. Dosimetric parameters were evaluated with respect to toxicity and will be presented. Results: In 212 patients (median age 62.9 years, range 40-88) all with follow-up greater than 24 months, the median tumor size was 12mm. As of last follow-up (&gt;24 months) cumulative rates of erythema and hyperpigmentation of grade 2 or higher were 1.4% and 0.5%. The incidence of grade 2 or higher telangiectasia, seroma and fat necrosis were 2.8%, 2.8%, and 0.5% respectively. Conclusions: Adverse events for APBI with SAVI are low in incidence, low in grade and compare favorably to other HDR APBI methods.

SU-E-T-229: Monte Carlo Dosimetric Study of SAVI HDR Applicator for Partial Breast Irradiation.

To investigate the dosimetric variation by Monte Carlo and experimentally simulating the situation with and without tissue invagination and the potential translation and rotation of the SAVI applicator for partial breast irradiation. The SAVI applicator with the cavity filled with air and water was merged into a water phantom and the delivered dose was simulated by MCNP monte carlo program. The results verified using an ion chamber and film were compared with a homogenous dose calculation by the treatment planning system. A dose variation from the SAVI translational shift was simulated and measured by moving an ion chamber along with the central axis direction. A dose change from the SAVI rotation was simulated and measured by placing an ion chamber at a fixed point while rotating the SAVI device about the central axis. The dosimetric variations for the SAVI device were found to be related to the cavity dimension, source arrangement, and dwell times. For the single dwell source placed in the center of the applicator, the maximum difference of the dose with the air cavity at 1cm away from the air-water boundary is about 7% higher than that with water filling in the cavity. But the simulation and measurements with nearly fully loaded multi-sources for the same situation show a difference of less than 3%. The 3% dose variation in average was found from either the 3 mm translation or 3 degree rotation of the SAVI applicator. The maximum dosimetric effect of an air cavity is 7% off compared with a water filled cavity when a single dwell source position is used in the center of the central catheter. Multiple catheters of the SAVI applicator with a nearly fully loaded dwell source position produce the discrepancy of less than 3% and allow for optimal and conformal dose distribution to a lumpectomy cavity while minimizing the dose to adjacent normal structures.

SU-E-T-365: Dosimetric Study of An HDR Applicator of SAVI for Partial Breast Irradiation

Purpose: To investigate the dosimetric effect by experimentally simulating the situation with and without tissue invagination and the potential translation and rotation of the SAVI applicator for partial breast irradiation. Methods: The SAVI applicator with the cavity filled with air and water was merged into a water phantom and the delivered dose was measured using an ion chamber and film. The measurements were compared with a homogenous dose calculation by the treatment planning system. A dose variation from the SAVI translational shift was measured by moving an ion chamber along with the central axis direction. A dose change from the SAVI rotation was measured by placing an ion chamber at a fixed point while rotating the SAVI device about the central axis. Results: The dosimetric effects for the SAVI device were found to be related to the cavity dimension, source arrangement, and dwell times. For the single dwell source placed in the center of the applicator, the maximum difference of the dose with the air cavity at 1cm away from the air‐water boundary is about 7% higher than that with water filling in the cavity. But the measurements with nearly fully loaded multi‐sources for the same situation show a difference of less than 3%. The 3% dose variation in average was found from either the 3 mm translation or 3 degree rotation of the SAVI applicator. Conclusions: The maximum dosimetric effect of an air cavity is 7% off compared with a water filled cavity when a single dwell source position is used in the center of the central catheter. Multiple catheters of the SAVI applicator with a nearly fully loaded dwell source position produce the discrepancy of less than 3% and allow for optimal and conformal dose distribution to a lumpectomy cavity while minimizing the dose to adjacent normal structures.

SU-E-T-596: High Dose Brachytherapy Planning of a Left Breast Cancer Patient with in Situ Pacemaker:

Purpose: To investigate the benefits of multilumen partial breast Brachytherapy device, SAVI, in reducing dose to in situ pacemakers in patients with cancer of the left breast. Methods: A left breast cancer patient with an in situ pacemaker underwent breast conservative surgery and was referred for Partial Breast Irradiation (PBI) using Ir‐192 High Dose Rate Brachytherapy. The preliminary estimation of the pacemaker dose from a pre‐insertion CT study was about 8 % of the prescribed dose which exceeded the generally accepted dose of 2Gy. The challenge was to use a suitable applicator to treat the tumor bed and 1 cm margin without exceeding the 2Gy limit to the pacemaker and the leads. A seven catheter SAVI device was selected and implanted in the left breast in an optimal direction and a 3D treatment plan was generated following a post insertion CT scan, using the Oncentra Brachy treatment planning system. Several optimization tools available in the planning system namely inverse, graphical, and dose point optimization were utilized to selectively load the catheters and reduce the dose to pacemaker and leads. A set of calibrated TLD chips were used to determine the surface dose on the pacemaker, which was then compared to the calculated surface dose. The pacemaker parameters were monitored before and after the 10 fraction (bid 5days) HDR brachytherapy, by a vendor representative and were found to functioning properly. Results: Using the seven catheter SAVI device it was possible to limit the pacemaker/ leads dose to less than 2 Gy, with an overall satisfactory dose to the target volume. Conclusions: By combining the optimization tools of today's Brachytherapy planning system and a multilumen SAVI applicator, HDR partial breast irradiation can be successfully delivered for left breast cancer patients with in situ pacemaker, with out the concern of interrupting pacemaker functionality

Evaluation of two intracavitary high-dose-rate brachytherapy devices for irradiating additional and irregularly shaped volumes of breast tissue

The SAVI and Contura breast brachytherapy applicators represent 2 recent advancements in brachytherapy technology that have expanded the number of women eligible for accelerated partial breast irradiation in the treatment of early-stage breast cancer. Early clinical experience with these 2 single-entry, multichannel high-dose-rate brachytherapy devices confirms their ease of use and dosimetric versatility. However, current clinical guidelines for SAVI and Contura brachytherapy may result in a smaller or less optimal volume of treated tissue compared with traditional interstitial brachytherapy. This study evaluates the feasibility of using the SAVI and Contura to irradiate larger and irregularly shaped target volumes, approaching what is treatable with the interstitial technique. To investigate whether additional tissue can be treated, 17 patients treated with the SAVI and 3 with the Contura were selected. For each patient, the planning target volume (PTV) was modified to extend 1.1 cm, 1.3 cm, and 1.5 cm beyond the tumor bed cavity. To evaluate dose conformance to an irregularly shaped target volume, 9 patients treated with the SAVI and 3 with the Contura were selected from the original 20 patients. The following asymmetric PTV margin combinations were assessed for each patient: 1.5/0.3, 1.3/0.3, and 1.1/0.3 cm. For all patients, treatment planning was performed, adopting the National Surgical Adjuvant Breast and Bowel Project guidelines, and dosimetric comparisons were made. The 6–1 and 8–1 SAVI devices can theoretically treat a maximal tissue margin of 1.5 cm and an asymmetric PTV with margins ranging from 0.3 to 1.5 cm. The 10–1 SAVI and Contura can treat a maximal margin of 1.3 cm and 1.1 cm, respectively, and asymmetric PTV with margins ranging from 0.3–1.3 cm. Compared with the Contura, the SAVI demonstrated greater dosimetric flexibility. Risk of developing excessive hot spots increased with the size of the SAVI device. Both the SAVI and Contura appear capable of treating >1.0-cm margins and irregularly shaped PTVs. The 6–1 SAVI device demonstrated the greatest versatility in targeting PTVs approaching what is treatable using the interstitial technique.

Accelerated Partial Breast Irradiation at Virginia Hospital Center: Post Hoc Analysis of Dosimetry Comparing Mammosite, Contura, and SAVI Devices

Dosimetric factors in 123 consecutive patients treated with accelerated partial breast brachytherapy using three different applicators were analyzed to evaluate mean differences across key planning variables.

SU-GG-T-37: Monte Carlo Dose Comparison Assessing Material Inhomogeneity Effects in Breast Brachytherapy

Purpose: To quantify the effect of material heterogeneity on dosimetry in single‐entry breast brachytherapy devices such as the MammoSite, Contura, and SAVI in comparison to the assumed homogeneity of the TG‐43 formalism, with an emphasis on devices with a close proximity to the skin. Method and Materials: A simple phantom was constructed in the Penelope Monte Carlo code consisting of a sphere of varying size and position situated within a larger cube surrounded by air. The cube was always composed of water while the sphere could be water or air in order to compare a more realistic heterogeneous model with the homogenous model used in the TG‐43 formalism. Spacing between the sphere and the cube surface was brought as close as 7mm to test the clinical limits of the SAVI device as pertains to skin spacing. Seeds were represented as point sources with a single band or energy at 365 keV (approximating an iridium 192 source) and simulated to be either at the air‐water interface or in the center of the sphere. Results: Simulations indicated that dose to the water — in the heterogeneous case for >2mm from the air‐water interface — was different by <10% maximum and ∼3% on average, from dose calculated for the homogenous case. At <2mm from the air‐water interface, however, the difference in dose for the heterogeneous case was ∼30% of the homogenous case on average and could be as high as 230% for close (7mm) spacing. Conclusions: Although the dose differs between the air‐water and water‐water interfaces, the discrepancy was limited to 1–2mm from the interface and could be reduces in some situation. Further exploration needs to be done to assess the actual dose being given as opposed to what has been calculated for all brachytherapy devices with air‐tissue interfaces.

Evaluation of three APBI techniques under NSABP B‐39 guidelines

This work compares two accelerated partial breast irradiation modalities, MammoSite brachytherapy and three‐dimensional conformal radiotherapy (3D‐CRT), to a new method, strut‐adjusted volume implant (SAVI) brachytherapy, following NSABP B‐39 guidelines. A total of 21 patients treated at UC San Diego with the SAVI device were evaluated in this comparison. Nine of the 21 patients were eligible for all three modalities and were dosimetrically compared evaluating V90, V150, V200, total target volume, maximum skin, lung, and chestwall/rib dose. The target volumes (PTV_EVAL) differed with SAVI, having the least total volume at 59.9 cc vs. 71.5 cc and 351.6 cc for MammoSite and 3D‐CRT, respectively. The median V90, V150 and V200 for the three modalities were 97.7%, 25.0 cc, 10.4 cc (SAVI) vs. 97.6%, 23.9 cc, 5.0 cc (MammoSite) vs. 100% (V90 3D‐CRT). The maximum dose for SAVI, MammoSite, and 3D‐CRT, respectively, relative to the prescribed dose, for the lung: 80.0%, 150.0%, and 104.9%; for rib: 108.8%, 225.0%, and 114.7%; for skin: 75.0%, 135.0%, and 108.6%. Comparing modalities, PTV coverage varied between 97.6%–100.0% with more breast tissue covered by 3D‐CRT, as expected, given the differences between external beam and brachytherapy. The maximum lung, skin and rib doses were lowest for the SAVI, highlighting its ability to conform to exclude normal tissues. In offering partial breast radiation, the availability of a variety of techniques allows for maximal patient eligibility, and comparison of individual method pros and cons may guide the most appropriate choice for each patient.PACS number: 87.53.Jw; 87.53.Kn; 87.55.D

APBI Brachytherapy Device Stability and the Importance of Pre-fraction Device QA

Purpose: Recently, several new single-entry, intracavitary breast brachytherapy applicators have emerged with multiple catheters that allow dose modulation to spare normal tissue, such as skin, chestwall, and lung. However, since these catheters are differentially loaded with the HDR source, care must be taken to ensure there is no rotation, change in the device, or change in cavity conformance that could potentially alter the dose modulation from beneficial to detrimental. In this study, we retrospectively assess the rotational stability, strut symmetry, and cavity conformance of the SAVI device. Methods and Materials: Fifty patients treated at UC San Diego with the SAVI device were retrospectively reviewed for the number of patients that needed re-planning as a function of rotation, strut asymmetry (splay), cavity conformance, or a combination of these factors. At our institution, the radiation oncologist surgically places the SAVI device followed immediately by a planning CT scan. A treatment plan is generated immediately after the surgical insertion. Results: Of the 50 patients treated, 4 were re-planned for device rotation, 8 were re-planned due a change in strut symmetry, and 2 for cavity conformance; all within a 24 hour window following surgical insertion of the device. An additional 7 of the 50 (14.0%) were re-planned outside of the 24 hour window, making them unexpected re-plans, primarily due to rotation. Conclusion: The interfraction stability of multicatheter, intracavitary breast devices is crucial for efficacy and patient safety. All cases were planned immediately after insertion since they were inserted by the treating radiation oncologist in the HDR suite. However, our recommendation is to allow 24 hours after device insertion for settling of the device, especially in the case of strut splay. Heeding this advice, 14 of 50 cases presented would not have needed replanning. Obvious strut splay or air pockets necessitate planning to be delayed for 24 hours to allow stable conformance. In practice, with a 24 hour time window between insertion and planning only 14.0% of cases reviewed needed re-planning due to changes in the position or symmetry of the device. All of these cases were re-planned regardless of the amount of change; however, further analysis will evaluate the dosimetric relevance of the re-plan. This study also demonstrates that daily evaluation of the device before each fraction is essential to evaluate rotation, strut symmetry, and cavity conformance.

SU‐FF‐T‐48: Dosimetric Feasibility of Using Low Energy Sources in Multi‐Lumen Device for Partial Breast Brachytherapy

Purpose: To evaluate the dosimetric feasibility of using low energy sources (Cs‐131, I‐125, Pd‐103) in the multi‐lumen device for partial breast brachytherapy. The sources are placed into the device for multiple days until the desired dose is achieved, then withdrawn with the device. This outpatient procedure only requires two visits, one for source placement and another for device withdrawal. Method: A 10‐1 SAVI device was fully expanded, CT‐scanned and imported into VariSeed. Cavity, PTV (cavity + 1cm margin) and PTV_eval (PTV − cavity) were created. The same type and activity of seeds were added into the multi‐lumen device to cover the PTV_eval and seed activity was adjusted to achieve a nominal dose (50Gy in one half‐life of source). Different seed types and distributions were tested. Oncentra Brachy and IPSA optimization was used to generate a HDR plan for comparison. Dosimetric parameters (D90, V100, V150, and V200 of PTV_eval) and skin dose were compared. Results: D90, V100, V150, and V200 of PTV_eval of HDR plan are 107%, 97%, 52cc, and 24cc. The most comparable LDR plan is from a non‐uniform distributed 90 3.2U Cs‐131 source, which gives 102%, 92%, 52cc, and 26cc. Skin dose is lower than the HDR plan by ∼10% of the prescription dose from 0.5 ∼ 5 cm away from the PTV edge. With the comparable coverage, I‐125 gives slightly higher V150 and V200 (56cc and 30cc, respectively), while Pd‐103 gives much higher V150 and V200 (66cc and 46cc respectively). Conclusion: Cs‐131 is the best choice among the 3 commercially available low energy sources. It can provide adequate target coverage and similar dose homogeneity compared to HDR dosimetry in reasonable days (10 days). The faster dose fall‐off of the low energy sources give it advantage of less dose to the surrounding healthy tissues including skin, heart, and lung.

Partial Breast Brachytherapy Utilizing the Single-entry, Multicatheter SAVI Device in Patients with less than 7 mm Skin-to-Cavity Distance: Favorable Acute Skin Toxicity Outcomes from a Phase II Trial

Partial breast irradiation (PBI) offers an abbreviated, 5-day adjuvant treatment course for selected patients with early-stage breast cancer as an alternative to the standard, protracted course of whole-breast irradiation. Single-catheter balloon brachytherapy devices provide a simple means for delivering PBI and have gained wide acceptance. However, such devices may be contraindicated for treatment of tumor cavities within 7 mm of skin surface due to high radiation doses that may be delivered superficially. The multicatheter SAVI device provides a possible solution to this limitation in that its multiple-catheter design permits greater dose conformality and, potentially, greater skin sparing. This phase II study of SAVI PBI reports acute toxicity outcomes for a subset of implanted patients with less than 7 mm skin-to-cavity distance. Twenty-three patients have been accrued to a phase II trial of SAVI PBI. A subset of 12 patients was found to have less than 7 mm skin-to-cavity spacing and was selected for this analysis. All patients were diagnosed with TIS - 2N0 ductal carcinoma and negative margins. Placement of the SAVI device was performed either intraoperatively or in-office under ultrasound guidance. A total dose of 34.0 Gy in 10 twice-daily fractions was prescribed to a planning target volume (PTV) created by a 3-dimensional 1.0 cm expansion of the lumpectomy cavity. This PTV was then truncated by 5 mm from skin to limit skin dose, and a point dose constraint of 100% of the prescribed dose was assigned to the skin. Studied acute toxicities included erythema, desquamation, edema, seroma, and infection and were assessed during treatment and at 2 weeks, 1 month, and 3 months post-treatment. Toxicities were graded according to a simplified scale: 0 (none), 1 (seen on close observation), or 2 (obvious on casual observation). Follow-up for all patients ranged from 1 - 6 months. Mean dosimetric parameters were as follows: minimum dose to 90% PTV was 99.3% (range, 89.6 - 108.5%) of prescribed dose, maximum skin dose was 85.1% (range, 78.8 - 98.5%) of prescribed dose, V150 was 26.7 cc (range, 8.7 - 58.2 cc), and V200 was 12.3 cc (range, 3.6 - 30.5 cc). At 1 month post-treatment, 9 of 12 patients were noted to have Grades 1 - 2 radiation erythema which resolved in all patients followed to 3 months. No patient was noted to have dry or moist desquamation at any follow-up point. At 1 month, 8 of 12 patients were noted to have Grades 1 - 2 edema; at 3 months, 2 of 8 patients were noted to have Grade 1 edema. A SAVI permits well-tolerated PBI in patients with superficial tumor cavities and for whom single-catheter balloon brachytherapy may be technically contraindicated.