Intraoperative Brachytherapy Research Articles

Long-term Survival after Multimodality Therapy using Intraoperative High-dose-rate Brachytherapy for Locally Advanced and Recurrent Colorectal Cancer

Long-term Survival after Multimodality Therapy using Intraoperative High-dose-rate Brachytherapy for Locally Advanced and Recurrent Colorectal Cancer

Intraoperative 32P High Dose Rate Brachytherapy Plaque for Primary, Recurrent, and Metastatic Intracranial and Paraspinal Tumors

Treatment of paraspinal and intracranial tumors is complicated by the tolerance of sensitive structures to radiation, especially in the setting of prior treatment; the dural surface is often a critical site at risk for recurrence. Intraoperative brachytherapy using a short range source may allow delivery of therapeutic dose without damage to sensitive structures.

Clinical Application of Seed Nomogram for Real-time Intraoperative Prostate Brachytherapy

Clinical Application of Seed Nomogram for Real-time Intraoperative Prostate Brachytherapy

The impact of adjuvant brachytherapy with sublobar resection on pulmonary function and dyspnea in high-risk patients with operable disease: Preliminary results from the American College of Surgeons Oncology Group Z4032 Trial

Z4032 was a randomized study conducted by the American College of Surgeons Oncology Group comparing sublobar resection alone versus sublobar resection with brachytherapy for high-risk operable patients with non-small cell lung cancer (NSCLC). This evaluates early impact of adjuvant brachytherapy on pulmonary function tests, dyspnea, and perioperative (30-day) respiratory complications in this impaired patient population. Eligible patients with stage I NSCLC tumors 3 cm or smaller were randomly allocated to undergo sublobar resection with (SRB group) or without (SR group) brachytherapy. Outcomes measured included the percentage predicted forced expiratory volume in 1 second (FEV1%), percentage predicted carbon monoxide diffusion capacity (DLCO%), and dyspnea score per the University of California San Diego Shortness of Breath Questionnaire. Pulmonary morbidity was assessed per the Common Terminology Criteria for Adverse Events version 3.0. Outcomes were measured at baseline and 3 months. A 10% change in pulmonary function test or 10-point change in dyspnea score was deemed clinically meaningful. Z4032 permanently closed to patient accrual in January 2010 at 224 patients. At 3-month follow-up, pulmonary function data are currently available for 148 (74 SR and 74 SRB) patients described in this report. There were no differences in baseline characteristics between arms. In the SR arm, 9 patients (12%) reported grade 3 respiratory adverse events, compared with 12 (16%) in the SRB arm (P = .49). There was no significant change in percentage change in DLCO% or dyspnea score from baseline to 3 months within either arm. In the case of FEV1%, percentage change from baseline to 3 months was significant within the SR arm (P = .03), with patients reporting improvement in FEV1% at month 3. Multivariable regression analysis (adjusted for baseline values) showed no significant impact of treatment arm, tumor location (upper vs other lobe), or surgical approach (video-assisted thoracoscopic surgery vs thoracotomy) on 3-month FEV1%, DLCO%, and dyspnea score. There was no significant difference in incidence of clinically meaningful (10% pulmonary function or 10-point dyspnea score change) change between arms. Twenty-two percent of patients with lower-lobe tumors and 9% with upper-lobe tumors demonstrated 10% decline in FEV1% (odds ratio, 2.79; 95 confidence interval, 1.07-7.25; P = .04). Adjuvant intraoperative brachytherapy in conjunction with sublobar resection did not significantly worsen pulmonary function or dyspnea at 3 months in a high-risk population with NSCLC, nor was it associated with increased perioperative pulmonary adverse events. Lower-lobe resection was the only factor significantly associated with clinically meaningful decline in FEV1%.

SU-E-T-582: Monte-Carlo Study of Dosimetric Effects of Brachytherapy Seeds Presence in Lung External Beam SBRT

Purpose: In lungSBRT seeds left from a prior intraoperative brachytherapy may perturb the dose distribution near the target. We investigate the dosimetric effects of seeds present in the beam paths. Methods: BEAMnrc dosxyznrc code was used to generate 3D dose distributions for different seed arrangements using five 6 MV SBRT fields. A custom C++/Python code was developed to assign seeds of variable quantity and configuration to selected voxels with the Cs‐131 seed density. Two configurations of seed placement were considered: 1) an “odd” number of seeds per row, with the central column shadowing the isocenter, and 2) an “even” number of seeds per row without the isocenter shadowing. Results: For the “odd” configuration the isocenter dose decreased sharply with the number of seeds shadowing the isocenter (from 1.8% for 1 seed to 13.1% for 11 seeds). Adding more seeds in each row lowered the dose by additional 2.4% and this decrease was almost independent of the number of added seeds. A much smaller dose reduction (<1.8%) is observed for the “even” seed configuration, that does not shadow the isocenter directly. Conclusions: Dose reduction at the isocenter is proportional to the number of seeds that directly shadow the isocenter. Adding seeds in the beam path, without shadowing the isocenter, reduces the dose by a small amount. Since clinically the seeds are arranged in a mix of “odd” and/or “even” configurations with 1–2 rows and 1–2 columns, the isocenter dose is expected to be reduced by 0.6% to 5%.

671 poster SALVAGE HIGH-DOSE-RATE INTERSTITIAL BRACHYTHERAPY IN RECURRRENT AND PREVIOUSLY IRRADIATED HEAD AND NECK CANCER.

Results: A total dose of 50 Gy with PDR at a rate dose of 0.7 Gy/h was administered to the surgical bed. There was no important acute toxicity. The catheters were removed without problems and for the moment, the patient is alive and free of disease. The patient will need to be monitored for possible late toxicity. Conclusions: Conservative treatment of orbital tumors with surgery and intraoperative brachytherapy can be performed in certain circumstances if tumor removal is feasible. Col.laboration with surgeons is mandatory.

672 poster ENDOBRONCHIAL BRACHYTHERAPY: A TREATMENT OPTION WITH MINIMAL SIDE EFFECTS

Results: A total dose of 50 Gy with PDR at a rate dose of 0.7 Gy/h was administered to the surgical bed. There was no important acute toxicity. The catheters were removed without problems and for the moment, the patient is alive and free of disease. The patient will need to be monitored for possible late toxicity. Conclusions: Conservative treatment of orbital tumors with surgery and intraoperative brachytherapy can be performed in certain circumstances if tumor removal is feasible. Col.laboration with surgeons is mandatory.

Urethra-Sparing, Intraoperative, Real-Time Planned, Permanent-Seed Prostate Brachytherapy: Toxicity Analysis

To report the toxicity outcome in patients with localized prostate cancer undergoing (125)I permanent-seed brachytherapy (BT) according to a urethra-sparing, intraoperative (IO), real-time planned conformal technique. Data were analyzed on 250 patients treated consecutively for low- or intermediate-risk prostate cancer between 2005 and 2009. The planned goal was urethral V(150) = 0. Acute and late genitourinary (GU), gastrointestinal (GI), and erectile toxicities were scored with the International Prostate Symptom Score (IPSS) questionnaire and Common Terminology Criteria for Adverse Events (version 3.0). Median follow-up time for patients with at least 2 years of follow-up (n = 130) was 34.4 months (range, 24-56.9 months). Mean IO urethra V(150) was 0.018% ± 0.08%. Mean prostate D(90) and V(100) on day-30 computed tomography scan were 158.0 ± 27.0 Gy and 92.1% ± 7.2%, respectively. Mean IPSS peak was 9.5 ± 6.3 1 month after BT (mean difference from baseline IPSS, 5.3). No acute GI toxicity was observed in 86.8% of patients. The 3-year probability of Grade ≥2 late GU toxicity-free survival was 77.4% ± 4.0%, with Grade 3 late GU toxicity encountered in only 3 patients. Three-year Grade 1 late GI toxicity-free survival was 86.1% ± 3.2%. No patient presented Grade ≥2 late GI toxicity. Of patients with normal sexual status at baseline, 20.7% manifested Grade ≥2 erectile dysfunction after BT. On multivariate analysis, elevated baseline IPSS (p = 0.016) and high-activity sources (median 0.61 mCi) (p = 0.033) predicted increased Grade ≥2 late GU toxicity. Urethra-sparing IO BT results in low acute and late GU toxicity compared with the literature. High seed activity and elevated IPSS at baseline increased long-term GU toxicity.

Intraoperative 125I Brachytherapy Mesh After Sublobar Resection in Early Stage High Risk Non Small Cell Lung Cancer

Intraoperative 125I Brachytherapy Mesh After Sublobar Resection in Early Stage High Risk Non Small Cell Lung Cancer

Clinical Implementation of the RIC-100 32P Foil for Superficial and Intraoperative Brachytherapy Treatments

Clinical Implementation of the RIC-100 32P Foil for Superficial and Intraoperative Brachytherapy Treatments

Localizing intracavitary brachytherapy applicators from cone‐beam CT x‐ray projections via a novel iterative forward projection matching algorithm

To present a novel method for reconstructing the 3D pose (position and orientation) of radio-opaque applicators of known but arbitrary shape from a small set of 2D x-ray projections in support of intraoperative brachytherapy planning. The generalized iterative forward projection matching (gIFPM) algorithm finds the six degree-of-freedom pose of an arbitrary rigid object by minimizing the sum-of-squared-intensity differences (SSQD) between the computed and experimentally acquired autosegmented projection of the objects. Starting with an initial estimate of the object's pose, gIFPM iteratively refines the pose parameters (3D position and three Euler angles) until the SSQD converges. The object, here specialized to a Fletcher-Weeks intracavitary brachytherapy (ICB) applicator, is represented by a fine mesh of discrete points derived from complex combinatorial geometric models of the actual applicators. Three pairs of computed and measured projection images with known imaging geometry are used. Projection images of an intrauterine tandem and colpostats were acquired from an ACUITY cone-beam CT digital simulator. An image postprocessing step was performed to create blurred binary applicators only images. To quantify gIFPM accuracy, the reconstructed 3D pose of the applicator model was forward projected and overlaid with the measured images and empirically calculated the nearest-neighbor applicator positional difference for each image pair. In the numerical simulations, the tandem and colpostats positions (x,y,z) and orientations (alpha, beta, gamma) were estimated with accuracies of 0.6 mm and 2 degrees, respectively. For experimentally acquired images of actual applicators, the residual 2D registration error was less than 1.8 mm for each image pair, corresponding to about 1 mm positioning accuracy at isocenter, with a total computation time of less than 1.5 min on a 1 GHz processor. This work describes a novel, accurate, fast, and completely automatic method to localize radio-opaque applicators of arbitrary shape from measured 2D x-ray projections. The results demonstrate approximately 1 mm accuracy while compared against the measured applicator projections. No lateral film is needed. By localizing the applicator internal structure as well as radioactive sources, the effect of intra-applicator and interapplicator attenuation can be included in the resultant dose calculations. Further validation tests using clinically acquired tandem and colpostats images will be performed for the accurate and robust applicator/sources localization in ICB patients.

A novel ytterbium-169 brachytherapy source and delivery system for use in conjunction with minimally invasive wedge resection of early-stage lung cancer

Purpose To describe a novel source–delivery system for intraoperative brachytherapy in patients with early-stage lung cancer that is readily adaptable to a video-assisted thoracoscopic surgery approach and can be precisely delivered to achieve optimal dose distribution. Methods and Materials Radioactive ytterbium-169 ( 169Yb) was sealed within a titanium tube 0.28 mm in diameter and then capped and resealed by titanium wires laser welded to the tube to serve as the legs of a tissue-fastening system. Dose simulations were performed using Monte Carlo computer code (Los Alamos National Laboratory, Los Alamos, NM) to mimic the geometric and elemental compositions of the source, fastening apparatus, and surroundings. Results Five test source capsules were subjected to a tensile load to failure. Failure in each capsule occurred in the wire of the fastener leg; there were no weld failures. Monte Carlo simulations and subsequent dose measurement showed the perturbation by the source legs in the deployed (bent over) position to be small (4–5%) for 169Yb and much less than that for iodine-125 (32%). Conclusion We have developed a 169Yb brachytherapy source–delivery system that can be used in conjunction with commercially available surgical stapling instruments, facilitates the precise placement of brachytherapy sources relative to the surgical margin, assures the seeds remain fixed in their precise position for the duration of the treatment, overcomes the technical difficulties of manipulating the seeds through the narrow surgical incision associated with video-assisted thoracoscopic surgery, and reduces the radiation dose to the clinicians.

Limited resection followed by intraoperative seed implantation is comparable to stereotactic body radiotherapy for solitary lung cancer

The objective of this study was to compare the outcomes of patients who underwent wedge resection plus intraoperative brachytherapy versus patients who received stereotactic body radiotherapy (SBRT) for single malignant lung nodules. A retrospective chart review included 55 patients who were treated for single lung nodules, and 47 of those patients who had adequate information were chosen for the current analysis. Twenty-five patients with single malignant lung nodules received SBRT. Twenty-two patients underwent limited surgical resection plus radioactive seed implantation for solitary malignant lung nodules. Univariate statistical analysis demonstrated a significance difference only for age in the 2 groups: The mean age in the radioactive seed group (66.6 years) was statistically significantly different from the mean of the age in the SBRT group (75.9 years; 2-sided P=.04). No significant differences were observed between the 2 groups in terms of local control, distant metastasis, survival, or toxicity. The current results demonstrated comparable efficacy in outcome and toxicity between surgical resection with radioactive seed implantation and SBRT for the treatment of single malignant lung nodules in patients who were not candidates for lobectomy/pneumonectomy.

TU-D-BRB-06: Localizing Intracavitary Brachytherapy Applicators from Conebeam CT X-Ray Projections Via a Novel Iterative Forward Projection Matching (IFPM) Algorithm

Purpose: To present a novel method for reconstructing the 3D pose (positions & orientations) of radio‐opaque objects of known but arbitrary shape from a small set of 2D x‐ray projections, in support of intraoperative brachytherapy planning. Methods and materials: IFPM finds the object pose by minimizing the sum‐of‐squared‐intensity‐differences (SSD) between the computed and experimentally‐acquired auto‐segmented object projections. Starting with an initial estimate of the applicator pose, IFPM iteratively refines the pose parameters (positions and 3 Euler angles) until the SSD converges. The applicator model is a mesh of discrete points derived from a complex combinatorial geometric model of the actual applicator. Three pairs of computed and measured projection images, with known imaging geometry, are used. Projection images of an intrauterine tandem were acquired from Acuity digital‐simulator. Image pre‐processing step was performed to create blurred binary applicator‐only images. To quantify IFPM accuracy, the reconstructed 3D pose of the applicator model was forward projected and overlaid with the measured images and the dice similarity coefficient (DSC) was computed for each image‐pair.Results: In the numerical simulations, the tandem and colpostats positions (x, y, z) and orientations (α, β, γ) were estimated with (0.28, 0.3, 0.37) mm and (0.9, 0.8, 1.0)° accuracies, respectively. For the measured tandem images, the DSC was better than 0.88 for each image‐pair.Discussion: We have developed a new, accurate, and completely automatic method to localize radio‐opaque applicators of arbitrary shape from x‐ray projections. Also, no lateral film is required. By localizing the applicator internal structure and the sources, the effect of intra/inter‐applicator attenuation can be included in the resultant dose distribution. Further development and validation tests with tandem and colpostats will be performed for the accurate and robust applicator/sources localization in ICB patients. Supported by Varian Medical Systems

Intraoperative 125I Mesh Brachytherapy after Wedge Resection for Medically High Risk Stage I Non-Small Cell Lung Cancer: The University of Wisconsin Experience

Intraoperative 125I Mesh Brachytherapy after Wedge Resection for Medically High Risk Stage I Non-Small Cell Lung Cancer: The University of Wisconsin Experience

Sublobar Resection with Brachytherapy Mesh for Stage I Non-Small Cell Lung Cancer

Lobar resection is currently the standard approach for the treatment of stage I non-small cell lung cancer. Sublobar resection is generally considered a compromise, reserved for high-risk patients because of greater rates of local recurrence compared with lobar resection. Adjuvant radiation therapy may decrease these increased local recurrence rates, but because of respiratory motion and difficulties in identifying the staple line, radiation delivery can be challenging with an external beam approach. Adjuvant intraoperative brachytherapy with the use of low-dose rate iodine-125 seeds placed alongside the surgical staple has been used with success in several centers. A randomized multicenter North American study has also recently completed accrual, but the results of this are not yet available. In the following review, we outline the techniques used, safety considerations, and currently available outcomes of sublobar resection with adjuvant brachytherapy for non-small cell lung cancer.

Surgery combined with brachytherapy in patients with retroperitoneal sarcomas.

PurposeThe primary aim of this work was to analyze feasibility of combined treatment of retroperitoneal sarcomas (RS): surgery (S) and intraoperative brachytherapy (IOBRT). The secondary aim was to analyze results and complications after this treatment.Material and methods84 patients with retroperitoneal sarcomas were qualified for combined treatment (S and IOBRT) between June 1998 and September 2006. 65 of the patients (77.4%) had local recurrences. Sarcomas with intermediate and high grade of histological malignancy (G2, G3 – 76.2%) were the most frequent within the all surgically treated patients. Resection ability (R0/R1) in analyzed group of patients was estimated as 85% (74 cases). After intraoperative evaluation, 57 (67.8%) patients were qualified for IOBRT. Since 2000, in 34 patients (60%) an adjuvant postoperative external beam radiation therapy (EBRT) in dose of 50 Gy was applied. Median follow-up of the surviving patients was 40 months.ResultsOn the basis of the univariate analysis, relevant aspects negatively influencing overall survival rate within the RS group treated with IOBRT were as follows: surgery of sarcoma recurrence (p = 0.002), higher grade of histological malignancy (p = 0.05), histological type different than liposarcoma (p = 0.05) as well as no adjuvant EBRT (p = 0.05). On the basis of multivariate analysis one can ascertain that relevant factors negatively influencing LRFS in RS patients treated with IOBRT were: surgery due to recurrence of sarcoma (p = 0.008) and lack of EBRT (p = 0.01).ConclusionsCombined treatment (surgery and brachytherapy) was possible to be carried out on 68% of RS patients. The overall number of complications was quite high, however acceptable, taking into consideration the application of extensive, multi-organ treatments in case of sarcoma recurrences in this localization. The results suggest that the method of treatment will improve the final outcome when most of patients will be qualified for treatment of primary sarcomas in experienced centre.

Treatment advances for medically inoperable non-small-cell lung cancer: emphasis on prospective trials

Advances in technology have changed the treatment of patients with early stage non-small-cell lung cancer who are not healthy enough for standard surgical resection. Previously, patients with severe underlying cardiopulmonary dysfunction were often dissuaded from pursuing definitive therapy, even though most patients died from their lung cancer and not as a result of comorbid medical illness. Recent advances in the technology to treat early stage disease have led to new-found enthusiasm for treating and studying high-risk patients. This Review focuses on the management of these patients, including use of conformal radiotherapy, stereotactic body radiation therapy, sublobar resection, intraoperative brachytherapy, and radiofrequency ablation. Ongoing challenges are presented and prospective data are emphasised.

Research progress of brachytnerapy in soft tissue sarcoma

Brachytherapy has become an important treatment for soft tissue sarcoma by its unique radio-biology and radiation physics characteristics, the treatment time is divided in accordance with preoperative brachytherapy, intraoperative brachytherapy, postoperative brachytherapy, brachytherapy alone, which in im-proving the rate of limb preservation and local control rate sarcoma has played an important role. However, the timing of treatment, treatment modalities, the choice of implantation dose is still in dispute. Key words: Brachytherapy; Soft tissue neoplasms; Radiotherapy dosage

60 oral: Intraoperative Adaptive Brachytherapy is Necessary for High Quality I-125 Implants on Day 30

60 oral: Intraoperative Adaptive Brachytherapy is Necessary for High Quality I-125 Implants on Day 30