Outcomes with volume-based dose specification in CT-planned high-dose-rate brachytherapy for stage I-II cervical carcinoma: A 10-year institutional experience.

OBJECTIVE: To determine prognostic factors for progression-free survival (PFS) and overall survival (OS) for stage I-II cervical-cancer patients treated using computed-tomography (CT)-planned high-dose-rate (HDR) intracavitary brachytherapy (BT). METHODS: A total of 150 patients were treated for Stage I-II cervical cancer using CT-planned BT between 4/2004 and 10/2014. Of these, 128 were eligible for inclusion. Kaplan-Meier local control (LC), pelvic control (PC), overall survival (OS), and PFS estimates were calculated. RESULTS: After a median follow-up of 30months, the 2-year LC rate was 96%, PFS was 88%, and OS was 88%. Overall, 18 patients (14%) experienced any recurrence (AR), 8 had distant recurrence only and 10 had a combination of local, pelvic, regional, and distant recurrence. No patients had LR only. A prognostic factor for AR was tumor size >4cm (p=0.01). Patients with tumors >4cm were 3.3 times more likely to have AR than those with tumors ≤4cm (hazard ratio [HR]=3.3; 95% confidence interval [CI] 1.28-9.47). Point A was 85% of prescription for tumors < 4 cm and decreased approximately 3% over 5 fractions compared to 90% of prescription for tumors > 4 cm that decreased approximately 4% over 5 fractions. Two patients (2%) experienced grade≥2 late toxicity. There were no acute or late grade≥3 toxicities. CONCLUSION: CT-planned BT resulted in excellent local control and survival. Large tumor size was associated with an increased risk of recurrence outside the radiation field and worse PFS and OS. A volume-optimized plan treated a smaller area than a point A standard plan for patients with Stage I-II cervical cancer that have received chemoradiation. Given the outstanding LC achieved with modern therapy including chemoradiation, HDR, and image-based BT, further efforts to combat spread outside the radiation field with novel therapies are warranted.

Feasibility and clinical implementation of MRI-guided surface brachytherapy.

Purpose: Best practices for high-dose-rate surface applicator brachytherapy treatment (SABT) have long relied on computed tomography (CT)-based imaging to visualize diseased sites for treatment planning. Compared with magnetic resonance (MR)-based imaging, CT provides insufficient soft tissue contrast. This work described the feasibility of clinical implementation of MR-based imaging in SABT planning to provide individualized treatment optimization. Material and methods: A 3D-printed phantom was used to fit Freiberg flap-style (Elekta, The Netherlands) applicator. Images were taken using an optimized pointwise encoding time reduction with radial acquisition (PETRA) MR sequence for catheter visualization, and a helical CT scan to generate parallel treatment plans. This clinical study included three patients undergoing SABT for Dupuytren's contracture/palmar fascial fibromatosis imaged with the same modalities.SABT planning was performed in Oncentra Brachy (Elekta Brachytherapy, The Netherlands) treatment planning software. A geometric analysis was conducted by comparing CT-based digitization with MR-based digitization. CT and MR dwell positions underwent a rigid registration, and average Euclidean distances between dwell positions were calculated. A dosimetric comparison was performed, including point-based dose difference calculations and volumetric segmentations with Dice similarity coefficient (DSC) calculations. Results: Euclidean distances between dwell positions from CT-based and MR-based plans were on average 0.68 ±0.05 mm and 1.35 ±0.17 mm for the phantom and patients, respectively. The point dose difference calculations were on average 0.92% for the phantom and 1.98% for the patients. The D95 and D90 DSC calculations were both 97.9% for the phantom, and on average 93.6% and 94.2%, respectively, for the patients. Conclusions: The sub-millimeter accuracy of dwell positions and high DSC's (> 0.95) of the phantom demonstrated that digitization was clinically acceptable, and accurate treatment plans were produced using MR-only imaging. This novel approach, MRI-guided SABT, will lead to individualized prescriptions for potentially improved patient outcomes.

Vaginal brachytherapy for early stage uterine papillary serous and clear cell endometrial cancer.

OBJECTIVE: To report clinical outcomes following adjuvant high-dose-rate (HDR) vaginal brachytherapy (VB) for early-stage uterine papillary serous (UPSC) and clear cell (CC) endometrial cancer. METHODS: A retrospective study of Stage I and II papillary serous and clear cell endometrial cancer treated with post-operative HDR VB between October 2005 and May 2012 was performed. A total of 37 patients were identified, 26 with UPSC, 9 with CC and 2 with mixed UPSC/CC. After total hysterectomy and bilateral salpingo-oophorectomy, VB was administered without external-beam radiation with a dose of 24 Gy in 6 fractions prescribed to the vaginal surface. Chemotherapy was given to 30 patients (75%). RESULTS: The median follow up time was 24.8 months (range, 2.0 to 71.5 months). Four patients relapsed, 2 with UPSC and 2 with CC. The initial site of relapse was concurrent vagina, pelvic/para-aortic nodes and abdominal wall (1), pelvic/para-aortic nodes (1) and para-aortic nodes alone (2). The 2-year vaginal-control rate was 96.8%. The pelvic-control rate including vaginal and nodal relapse was 93.5%. The 2-year disease-free and overall survival rates were 89.3% and 100%, respectively. CONCLUSION: HDR VB as the sole adjuvant treatment modality for early-stage UPSC/CC is associated with a low rate of vaginal relapse and excellent survival outcomes. This novel low-dose regimen for VB is safe and effective.

Catheter reconstruction and dosimetric verification of MRI-only treatment planning (MRTP) for interstitial HDR brachytherapy using PETRA sequence.

Objective. The feasibility of MRI-only treatment planning (MRTP) for interstitial high-dose rate (HDR) brachytherapy (BT) was investigated for patients diagnosed with gynecologic cancer.Approach. A clinical MRTP workflow utilizing a 'pointwise encoding time reduction with radial acquisition (PETRA)' sequence was proposed. This is a clinically available MRI sequence optimized to improve interstitial catheter-tissue contrast. Interstitial needles outside the obturator region were reconstructed using MR images only. For catheters penetrating through the obturator, a library-based reconstruction was proposed. In this work, dwell coordinates from the clinical CT-based reconstruction were used as the surrogate for the library-based approach. For MR-only plan, dwell times were activated and assigned as in the clinical plans. The catheter reconstruction was assessed by comparing dwell position coordinates. The dosimetric comparisons between a clinical plan and MR-only plan were assessed for physical and EQD2 dose and volume parameters forD90,D50andD98for clinical target volume (CTV) andD2cc,D0.1ccandD5ccfor OARs.Main results. Catheter reconstruction was possible using the optimized PETRA sequence on MR images. An overall reconstruction difference of 1.7 ± 0.5 mm, attributed to registration-based errors, was found compared to the CT-based reconstruction. The MRTP workflow has the potential to generate a treatment plan with an equivalent dosimetric quality compared to the conventional CT/MRI-based approach. For CTVD90, physical and EQD2 dose and volume parameter differences were 1.5 ± 1.9% and 0.7 ± 1.0 Gy, respectively. ForD2ccOARs, DVH (EQD2) differences were -0.4 ± 1.1% (-0.2 ± 0.5 Gy), 0.5 ± 2.8% (0.2 ± 1.3 Gy) and -0.5 ± 1.4% (-0.2 ± 0.5 Gy) for rectum, bladder, and sigmoid, respectively.Significance. With the proposed MRTP approach, CT imaging may no longer be needed in HDR BT for interstitial gynecologic treatment. A proof-of-concept study was conducted to demonstrated that MRTP using PETRA is feasible, with comparable dosimetric results to the conventional CT/MRI-based approach.

Finite element analysis and physiologic testing of a novel, inset glenoid fixation technique.

HYPOTHESIS: The success of shoulder arthroplasty surgery has been limited by a common complication: glenoid implant loosening. Eccentric loading of the glenoid due to migration of the humeral head is considered to be the major cause of glenoid loosening and is referred to as the rocking-horse phenomenon. Glenoid implant loosening may cause pain, limitation of function, and the need for complicated revision surgery. Our hypothesis was that an inset fixation technique could offer increased fixation strength and minimize the effects of the rocking-horse phenomenon on glenoid loosening. MATERIALS AND METHODS: Fixation strength and stress distribution were analyzed using two methods. First, mechanical simulation of physiologic in vivo cyclic loading was performed on 1 inset glenoid implant design and 2 standard onlay glenoid implant designs currently on the market. Second, 3-dimensional finite element analysis was performed to compare an inset glenoid implant and a standard onlay glenoid implant with a keel and a standard onlay pegged implant. RESULTS: After cyclic loading to 100,000 cycles, no glenoid implants demonstrated signs of loosening. Mechanical testing after cyclic loading demonstrated less distraction of the glenoid rim using an inset technique compared with an onlay technique. Finite element analysis results indicated that the inset technique achieved up to an 87% reduction in displacement. CONCLUSIONS: Mechanical tests and finite element analysis support the concept of inset glenoid fixation in minimizing the risk of glenoid loosening.

Interfraction dose deviation and catheter position in cervical interstitial and intracavitary image guided HDR brachytherapy.

Interstitial and intracavitary gynecological HDR brachytherapy involve precise, localized delivery to targets with high dose gradients, sparing adjacent organs at risk (OAR). Due to the proximity of the rectum, bowel and bladder to the target, deviations in the applicator or catheter with respect to patient anatomy can significantly increase dose to OAR. The magnitude and direction of applicator and catheter migration at each fraction was assessed for template interstitial and tandem and ring (T&R) cohorts. The cohort included twelve gynecological patients with intact cervical lesions treated with external beam and brachytherapy. Pre-treatment CT images were registered to the simulation CT with respect to the target. Treatment catheter positions transformed into the planning CT coordinate system to evaluate localized catheter displacement and dose distributions calculated at each fraction. Dose was evaluated on the planning CT with planning contours and dwell locations at treatment position. Absolute deviation, depth and deflection angle for all patients were 4.6 ± 4.2 mm, -1.4 ± 4.0 mm, and 3.1 ± 2.3° respectively (n = 516 catheter positions for all treatment fractions and patients, mean ± SD). Absolute catheter deviation and deflection magnitude for interstitial treatments increased overall with each subsequent fraction with an overall increase of catheter retraction at each fraction (p < 0.005, n = 492 catheters, Kruskal-Wallis). A target EQD2 D90 reduction of 10 ± 10% and 7.7 ± 8.7% of the planned dose for interstitial and T&R cohorts respectively. There was an overall increase in bladder and rectal doses at each fraction. Catheter tracking in interstitial and intracavitary gynecological treatments with CT imaging revealed significant changes in catheter positioning with respect to the target volume. Overall deviations increased in magnitude with each subsequent fraction in the interstitial treatments. This caused patient dosimetry deviations, including target dose reduction and adjacent OAR doses changes.

Selection criteria for high-dose-rate surface brachytherapy and electron beam therapy in cutaneous oncology.

PURPOSE: High-dose-rate (HDR) brachytherapy is an alternative treatment to electron external beam radiation therapy (EBRT) of superficial skin lesions. The purpose of this study was to establish the selection criteria for HDR brachytherapy technique (HDR-BT) and EBRT in cutaneous oncology for various clinical scenarios. MATERIAL AND METHODS: The study consists of two parts: a) EBRT and HDR-BT treatment plans comparison analyzing clinical target volumes (CTVs) with different geometries, field sizes, and topologies, and b) development of a prediction model capable of characterization of dose distributions in HDR surface brachytherapy for various geometries of treatment sites. RESULTS: A loss of CTV coverage for the electron plans (D90, D95) was recorded up to 45%, when curvature of the applicator increased over 30°. Values for D2 cm3 for both plans were comparable, and they were in range of ±8% of prescription dose. An increase in higher doses (D0.5 cm3 and D0.1 cm3) was observed in HDR-BT plans, and it was greater for larger lesions. The average increase was 3.8% for D0.5 cm3 and 12.3% for D0.1 cm3. When CTV was approximately flat, electron plans were comparable with HDR-BT plans, having lower average D2 cm3, D0.5 cm3, and D0.1 cm3 of 7.7%. Degradation of quality of electron plans was found to be more dependent on target curvature than on CTV size. CONCLUSIONS: Both EBRT and HDR-BT could be used in treatments of superficial lesions. HDR-BT revealed superior CTV coverage when the surface was very large, complex, curvy, or rounded, and when the topology was complicated. The prediction model can be used for an approximate calculation and quick assessment of radiation dose to organs-at-risk (OARs), at a depth or at a lateral distance from CTV.

Development and clinical implementation of semi-automated treatment planning including 3D printable applicator holders in complex skin brachytherapy.

PURPOSE: High-dose-rate brachytherapy (HDR-BT) is a treatment option for malignant skin diseases compared to external beam radiation therapy, HDR-BT provides improved target coverage, better organ sparing, and has comparable treatment times. This is especially true for large clinical targets with complex topologies. To standardize and improve the quality and efficacy of the treatments, a novel streamlined treatment approach in complex skin HDR-BT was developed and implemented. This approach consists of auto generated treatment plans and a 3D printable applicator holder (3D-AH). MATERIALS AND METHODS: The in-house developed planning system automatically segments computed tomography simulation images (a), optimizes a treatment plan (b), and generates a model of the 3D-AH (c). The 3D-AH is used as an immobilization device for the flexible Freiburg flap applicator used to deliver treatment. The developed, automated planning is compared against the standard clinical plan generation process for a flat 10 × 10 cm2 field, curved fields with radii of 4, 6, and 8 cm, and a representative clinical case. The quality of the 3D print is verified via an additional CT of the flap applicator latched into the holder, followed by an automated rigid registration with the original planning CT. Finally, the methodology is implemented and tested clinically under an IRB approval. RESULTS: All automatically generated plans were reviewed and accepted for clinical use. For the clinical workflow, the coverage achieved at a prescription depth for the flat 4, 6, and 8 cm applicator was (100.0 ± 4.9)%, (100.0 ± 4.9)%, (96.0 ± 0.3)%, and (98.4 ± 0.3)%, respectively. For auto planning, the coverage was (99.9 ± 0.3)%, (100.0 ± 0.2)%, (100.0 ± 0.3)%, and (100.1 ± 0.2)%. For the clinical test case, the D90 for the clinical workflow and auto planning was found to be 93.5% and 100.29% of the prescribed dose, respectively. Processing of the patient's CT to generate trajectories and positions as well as the 3D model of the applicator took <5 min. CONCLUSION: This workflow automates time intensive catheter digitizing and treatment planning. Compared to printing full applicators, the use of 3D-AH reduces the complexity of the 3D prints, the amount of the material to be used, the time of 3D printing, and amount of quality assurance required. The proposed methodology improves the overall treatment plan quality in complex HDR-BT and impact patient treatment outcomes potentially.

Combined interstitial and surface high-dose-rate brachytherapy treatment of squamous cell carcinoma of the hand.

PURPOSE: We present a case report of treatment using interstitial and surface high-dose-rate (HDR) brachytherapy for cutaneous squamous cell carcinoma (SCC) involving the interspace of the third and fourth digits. The patient refused two-ray amputation and the lesion was not amenable for external beam radiation therapy (EBRT). This is the first report detailing combined interstitial and surface HDR brachytherapy for a hand SCC. MATERIAL AND METHODS: The patient received 4050 cGy in 9 fractions, twice daily using 6 interstitial catheters and 8 Freiburg flap catheters. The clinical target was defined by MRI and ultrasound as a dorsal mass to the interspace between the heads of the third and fourth metacarpals measuring approximately 7 mm transverse × 5 mm volar-dorsal × 16 mm proximal-distal. RESULTS: The treatment resulted in radiographic and clinical tumor control. The patient retained functional use of her hand. However, there were both acute and late treatment-related side effects. Acutely, inpatient admission for pain control with a nerve block was needed. Long-term toxicity was notable for grade 2 skin necrosis treated with hyperbaric oxygen. CONCLUSIONS: The first interstitial and surface HDR brachytherapy for cutaneous squamous cell carcinoma of a finger interspace for hand function preservation is presented. The initial experience revealed that brachytherapy was tolerated but with notable acute and late side effects. Treatment did result in tumor shrinkage with organ preservation and function of two rays. A larger cohort of patients will be required for additional conclusions related to long-term clinical benefits in patients who refuse ray amputation.

A novel method for estimating SBRT delivered dose with beam's-eye-view images.

Stereotactic body radiation therapy is predicated on a high degree of targeting accuracy. However, inaccurate patient setup as well as intra-fractional motion can hinder the delivery of high doses preferentially to the target. To ensure that the coverage delivered to the patient is as planned, an image-guided verification system has been created to estimate the delivered dose retrospectively. This will not only aid the assessment of treatment techniques, but will also allow for more accurate dose response analysis. Patients with limited hepatic metastases from solid tumors were treated with SBRT. Implanted gold markers were used as target surrogates and a body frame and compression plate provided stereotactic localization and target immobilization, respectively. During treatment, an electronic portal imaging device (EPID), operating in cine mode, collected the exit dose. The sequences of images for each field were processed off-line using in-house software for registration and seed localization. The beam's-eye-view seed positions in the treatment images were compared to those in the DRR's to determine the target shifts in the imaging plane. These target shifts were then imported into the treatment planning software. Each original field was multiplied by the number of images taken during treatment. The calculated shift from each image was then applied to each of the new subfields. Summing all of these subfields together gives the dose distribution that was actually delivered to the patient. The dose-volume histograms for the planned and delivered distributions for four patients' complete treatments are shown. For two of the patients, underdosing due to a setup error or intra-fractional drift was not wholly resolved by subsequent fractions. For one of these patients two alternative corrective strategies have been applied, retrospectively, and the prescribed target coverage recovered for both. The delivered dose can be estimated using the information contained in cine EPID images acquired during irradiation. Calculating the dose actually delivered to the target will allow us to assess treatment procedures as well as more accurately report clinical results.

Permanent planar iodine-125 implants: the dosimetric effect of geometric parameters for idealized source configurations.

PURPOSE: To provide dosimetric information about permanent planar (125)I implants in a manner that is useful to the brachytherapist in the operative setting. METHODS AND MATERIALS: Reference planar permanent implants were simulated for a variety of areas with sources placed uniformly on a 1-cm grid. Implants having variable source spacing and curvature were simulated and compared with the reference implants. Dosimetric measures were calculated at 0.5 and 1.0 cm from the implant plane. RESULTS: A method for calculating dosimetric statistics for permanent implants ranging from 5 x 5 cm to 13 x 13 cm is presented. A formula to predict the reference source strength needed to achieve a desired dosimetric quantity is also presented. The effect of adjusting strand spacing to compensate for source activity is presented and is shown to be an effective means to adjust implants to use source strengths other than the reference strength. The effect of implant curvature compared with flat implants on dosimetric statistics is presented as a function of radius of curvature. CONCLUSIONS: The results presented in this work may be used to provide information about dose delivered from planar permanent implants.

Severe toxicity after permanent radioactive seed implantation for mediastinal carcinoid tumors.

PURPOSE: Permanent implantation of 125I seeds may be used when uninvolved surgical margins are unobtainable or close. Two cases of mediastinal carcinoid tumors with prior chemoradiation had tumors adherent to esophageal muscularis. Both underwent intraoperative permanent seed implantation and developed esophageal fistulas requiring surgical correction. METHODS AND MATERIALS: Custom permanent 125I seed mesh implants were fashioned intraoperatively in a geometrically coherent pattern. The implants were directly sutured to the partially resected esophageal wall. The postimplant CT scans were fused with the postfistula scans to provide dosimetric information at the fistula site. Doses were calculated from time of insertion to time of fistula formation. Neither patient showed evidence of disease recurrence at the time of fistula repair. RESULTS: Patient 1 developed an esophageal-pleural fistula 83 days after seed implantation. Patient 2 developed a broncho-pleural fistula 300 days after seed implantation. CONCLUSIONS: These cases demonstrated that implantation in the setting of extensive subcarinal space dissection and partial esophageal wall resection could cause fistula formation and the need for additional surgery. The high mucosal dose, despite the relatively low activity implant, was due to lack of geometric sparing of the mucosa. We recommend that extensive subcarinal space dissection be considered a contraindication to permanent seed implantation.

Custom-made micro applicators for high-dose-rate brachytherapy treatment of chronic psoriasis.

PURPOSE: In this study, we present the treatment of the psoriatic nail beds of patients refractory to standard therapies using high-dose-rate (HDR) brachytherapy. The custom-made micro applicators (CMMA) were designed and constructed for radiation dose delivery to small curvy targets with complicated topology. The role of the HDR brachytherapy treatment was to stimulate the T cells for an increased immune response. MATERIAL AND METHODS: The patient diagnosed with psoriatic nail beds refractory to standard therapies received monthly subunguinal injections that caused significant pain and discomfort in both hands. The clinical target was defined as the length from the fingertip to the distal interphalangeal joint. For the accurate and reproducible setup in the multi-fractional treatment delivery, the CMMAs were designed. Five needles were embedded into the dense plastic mesh and covered with 5 mm bolus material for each micro applicator. Five CMMAs were designed, resulting in the usage of 25 catheters in total. RESULTS: The prescription dose was planned to the depth of the anterior surface of the distal phalanx, allowing for the sparing of the surrounding tissue. The total number of the active dwell positions was 145 with step size of 5 mm. The total treatment time was 115 seconds with a 7.36 Ci activity of the 192Ir source. The treatment resulted in good pain control. The patient did not require further injections to the nail bed. After this initial treatment, additional two patients with similar symptoms received HDR brachytherapy. The treatment outcome was favorable in all cases. CONCLUSIONS: The first HDR brachytherapy treatment of psoriasis of the nail bed is presented. The initial experience revealed that brachytherapy treatment was well-tolerated and resulted in adequate control of the disease. A larger cohort of patients will be required for additional conclusions related to the long-term clinical benefits.

The value of systematic contouring of the bowel for treatment plan optimization in image-guided cervical cancer high-dose-rate brachytherapy.

PURPOSE: To investigate the dose-volume histogram metrics and optimization results of the contoured bowel in cervical cancer brachytherapy. METHODS AND MATERIALS: Treatment plans of cervical cancer patients treated with image-guided high dose rate were retrospectively analyzed with institutional review board approval. In addition to the clinical target volume, rectum, bladder, and sigmoid, the bowel was contoured at the time of planning (Group 1) or at the time of this analysis (Group 2). RESULTS: Thirty-two patients treated with 145 insertions were included. Before optimization, mean ± 1 standard deviation overall bowel minimum dose to the most irradiated 2 cm3 volume of an organ (D2cc) was 67.8 Gyα/ß3 ± 13.7 Gyα/ß3 (Group 1: 72.6 ± 13.2 Gyα/ß3; Group 2: 57.3 ± 8.0 Gyα/ß3). Before optimization, one patient in Group 1 presented a bowel D2cc metric exceeding 100 Gyα/ß3. After optimization, bowel D2cc mean ± 1 standard deviation was 59.4 ± 6.7 Gyα/ß3 (Group 1: 61.4 ± 6.0 Gyα/ß3, p < 0.001; Group 2: 55.2 ± 6.5 Gyα/ß3, p = 0.026). CONCLUSIONS: Given the potentially high doses and the benefit of optimization in reducing dose to the organs at risk, we recommend consideration of systematic contouring of the bowel when bowel is present in the pelvis.

Magnetic resonance-guided interstitial therapy for vaginal recurrence of endometrial cancer.

PURPOSE: To evaluate the feasibility and to describe the acute toxicity of a real-time intraoperative magnetic resonance (MR)-image guided interstitial approach to treating vaginal recurrence of endometrial cancer. METHODS AND MATERIALS: From February 2004 to April 2005, 10 patients with recurrent endometrial cancer underwent MR-guided interstitial brachytherapy. Parameters evaluated included needle placement, dose-volume histograms (DVH), and complications. RESULTS: Magnetic resonance-image guidance resulted in accurate needle placement. Tumor DVH values included median volume, 47 cc; V100, 89%; V150, 61%; V200, 38%; D90, 71 Gy; and D100, 60 Gy. DVH of organs at risk resulted in a median D2cc of external beam and brachytherapy dose (% of brachytherapy prescription): bladder, 75Gy(3) (88%); rectum, 70Gy(3) (87%); and sigmoid, 56Gy(3) (41%). All patients experienced either a Grade 1 or 2 acute toxicity related to the radiation; only 1 patient had Grade 3 toxicity. No toxicities were attributable to the use of MR guidance. CONCLUSIONS: Real-time MR guidance during the insertion of interstitial needles reduces the likelihood of an inadvertent insertion of the needles into the bladder and the rectum. Three-dimensional dosimetry allows estimation of the dose to organs at risk. Toxicities are limited.

Clinical implementation of a novel applicator in high-dose-rate brachytherapy treatment of esophageal cancer.

PURPOSE: In this study, we present the clinical implementation of a novel transoral balloon centering esophageal applicator (BCEA) and the initial clinical experience in high-dose-rate (HDR) brachytherapy treatment of esophageal cancer, using this applicator. MATERIAL AND METHODS: Acceptance testing and commissioning of the BCEA were performed prior to clinical use. Full performance testing was conducted including measurements of the dimensions and the catheter diameter, evaluation of the inflatable balloon consistency, visibility of the radio-opaque markers, congruence of the markers, absolute and relative accuracy of the HDR source in the applicator using the radiochromic film and source position simulator, visibility and digitization of the applicator on the computed tomography (CT) images under the clinical conditions, and reproducibility of the offset. Clinical placement of the applicator, treatment planning, treatment delivery, and patient's response to the treatment were elaborated as well. RESULTS: The experiments showed sub-millimeter accuracy in the source positioning with distal position at 1270 mm. The digitization (catheter reconstruction) was uncomplicated due to the good visibility of markers. The treatment planning resulted in a favorable dose distribution. This finding was pronounced for the treatment of the curvy anatomy of the lesion due to the improved repeatability and consistency of the delivered fractional dose to the patient, since the radioactive source was placed centrally within the lumen with respect to the clinical target due to the five inflatable balloons. CONCLUSIONS: The consistency of the BCEA positioning resulted in the possibility to deliver optimized non-uniform dose along the catheter, which resulted in an increase of the dose to the cancerous tissue and lower doses to healthy tissue. A larger number of patients and long-term follow-up will be required to investigate if the delivered optimized treatment can lead to improved clinical outcomes.

CT computer-optimized high-dose-rate brachytherapy with surface applicator technique for scar boost radiation after breast reconstruction surgery.

PURPOSE: Immediate breast reconstruction has become increasingly prevalent after mastectomy for breast cancer. Postoperative scar boost radiation for the reconstructed breast presents many planning challenges due to the shape, size, and curvature of the scar. High-dose-rate (HDR) surface applicator brachytherapy is a novel and effective method of delivering scar boost radiation. Two cases, one with a saline implant and one with a transverse rectus abdominis musculocutaneous flap reconstruction, illustrate the method and advantages of HDR optimization of surface applicators. METHODS AND MATERIALS: For 2 patients a mold of the breast was made with Aquaplast sheets. A reproducible system was used for arm positioning. Skin fiducials, including tattoos from external beam planning, were matched to fiducials on the mold. HDR catheters were sited on the mold at 1cm intervals, with the central catheter situated along the scar. Topographically, both scars demonstrated extreme curvature in both craniocaudal and mediolateral directions. A CT computer-optimized HDR plan was developed, with the reference dose prescribed at the skin surface. The dosimetry was compared to single-field and matched-field electron plans. RESULTS: This surface applicator technique provided a uniform skin dose of 100% to the entire clinical target volume (CTV) without hot spots in both patients. The patient position and surface applicator setup were consistently reproducible. The patients tolerated the treatment well with minimal skin erythema. In the single-field electron plan, skin dose was decreased to 50% at the periphery of the scar. Matching fields addressed this depth dose decrement, but resulted in large localized hot spots of more than 200% centrally in each field. CONCLUSION: CT computer-optimized HDR surface applicator brachytherapy provided a reproducible homogeneous method of treating highly curved scars on the reconstructed breast. Electron beam treatment would result in longer and more complex treatments yet still provide a less homogeneous dose than this surface applicator technique.

Palliative Therapy for Recalcitrant Cutaneous T-Cell Lymphoma of the Hands and Feet With Low-Dose, High Dose-Rate Brachytherapy.

IMPORTANCE: Cutaneous T-cell lymphoma (CTCL) of the hands and feet can be challenging to treat and cause significant disability for patients. Although CTCL is a highly radiosensitive tumor, the complex topography of acral surfaces presents challenges to achieving homogeneous superficial dosing of traditional electron beam therapy. In addition, traditional dosing may result in substantial acute cutaneous toxic effects. Recent reports demonstrate that low-dose palliative radiotherapy may be as effective as traditional regimens in CTCL. High dose-rate (HDR) brachytherapy allows for control of the depth of radiation penetration over complex curved surfaces. This study investigated the role of low-dose HDR brachytherapy for acral CTCL lesions. OBSERVATIONS: Six patients with a total of 8 acral CTCL lesions received low-dose HDR brachytherapy during a 3-year period. Rapid improvement and clinical clearance were observed in all treated lesions with minimal to no acute cutaneous toxic effects. During a mean follow-up period of 15.8 months, 1 lesion recurred locally; the remaining 7 lesions had sustained clinical remission. No long-term sequelae were observed. CONCLUSIONS AND RELEVANCE: This case series demonstrates that low-dose HDR brachytherapy provides excellent palliation for local control of acral CTCL lesions, offering homogeneous, controlled dosing for complex topographic sites with minimal to no cutaneous toxic effects.

Redesign of process map to increase efficiency: Reducing procedure time in cervical cancer brachytherapy.

PURPOSE: To increase intraprocedural efficiency in the use of clinical resources and to decrease planning time for cervical cancer brachytherapy treatments through redesign of the procedure's process map. METHODS AND MATERIALS: A multidisciplinary team identified all tasks and associated resources involved in cervical cancer brachytherapy in our institution and arranged them in a process map. A redesign of the treatment planning component of the process map was conducted with the goal of minimizing planning time. Planning time was measured on 20 consecutive insertions, of which 10 were performed with standard procedures and 10 with the redesigned process map, and results were compared. Statistical significance (p < 0.05) was measured with a two-tailed t test. RESULTS: Twelve tasks involved in cervical cancer brachytherapy treatments were identified. The process map showed that in standard procedures, the treatment planning tasks were performed sequentially. The process map was redesigned to specify that contouring and some planning tasks are performed concomitantly. Some quality assurance tasks were reorganized to minimize adverse effects of a possible error on procedure time. Test dry runs followed by live implementation confirmed the applicability of the new process map to clinical conditions. A 29% reduction in planning time (p < 0.01) was observed with the introduction of the redesigned process map. CONCLUSIONS: A process map for cervical cancer brachytherapy was generated. The treatment planning component of the process map was redesigned, resulting in a 29% decrease in planning time and a streamlining of the quality assurance process.