Episcleral Plaque Brachytherapy Research Articles

Prescribing to tumor apex in episcleral plaque iodine-125 brachytherapy for medium-sized choroidal melanoma: A single-institutional retrospective review.

To report an institutional experience with episcleral plaque brachytherapy for medium-sized uveal melanoma. Variations in prescription dose point and dose rate were compared with Collaborative Ocular Melanoma Study (COMS) Group. A retrospective review was performed for 116 patients treated with iodine-125 plaque brachytherapy. About 85 Gy was prescribed to either the tumor apex (108 patients) or at 5mm (8 patients) with dose rate ranging from 50.6 to 98.2cGy/h. Patients were followed up for local tumor control, eye preservation, and vision retention. Dose and dose rate to tumor and sensitive structures were calculated. Multivariate and univariate analyses were performed to investigate correlation between clinical outcomes and dose/dose rate variables. Patients in this study were slightly older with worse visual acuity at baseline, but tumor size and position and ratio of ciliary body involvement were comparable to COMS population. Outcomes data were comparable to COMS: 95.3% local tumor control at 5years and 77.7% vision preservation at 3years. Only 4 patients needed enucleation because of tumor growth. Significant correlation was found between enucleation and tumor height and maximal scleral dose/dose rate as well as vision retention and tumor height and macula dose/dose rate. For tumors with <5mm height, prescribing to tumor apex enabled to decrease dose to all sensitive structures without any loss of local control. Although dose rate was lowered to 50.6cGy/h from the American Brachytherapy Society guidelines (60-105cGy/h) because of limited availability of operating room (i.e., weekly), there was no difference in either local tumor control or complications.

MO‐FG‐210‐02: Implementation of Image‐Guided Prostate HDR Brachytherapy Using MR‐Ultrasound Fusion

Ultrasound (US) is one of the most widely used imaging modalities in medical practice. Since US imaging offers real‐time imaging capability, it has becomes an excellent option to provide image guidance for brachytherapy (IGBT). (1) The physics and the fundamental principles of US imaging are presented, and the typical steps required to commission an US system for IGBT is provided for illustration. (2) Application of US for prostate HDR brachytherapy, including partial prostate treatments using MR‐ultrasound co‐registration to enable a focused treatment on the disease within the prostate is also presented. Prostate HDR with US image guidance planning can benefit from real time visualization of the needles, and fusion of the ultrasound images with T2 weighted MR allows the focusing of the treatment to the specific areas of disease within the prostate, so that the entire gland need not be treated. Finally, (3) ultrasound guidance for an eye plaque program is presented. US can be a key component of placement and QA for episcleral plaque brachytherapy for ocular cancer, and the UCLA eye plaque program with US for image guidance is presented to demonstrate the utility of US verification of plaque placement in improving the methods and QA in episcleral plaque brachytherapy.Learning Objectives: To understand the physics of an US system and the necessary aspects of commissioning US for image guided brachytherapy (IGBT). To understand real time planning of prostate HDR using ultrasound, and its application in partial prostate treatments using MR‐ultrasound fusion to focus treatment on disease within the prostate. To understand the methods and QA in applying US for localizing the target and the implant during a episcleral plaque brachytherapy procedures.

MO‐FG‐210‐03: Intraoperative Ultrasonography‐Guided Positioning of Plaque Brachytherapy in the Treatment of Choroidal Melanoma

Ultrasound (US) is one of the most widely used imaging modalities in medical practice. Since US imaging offers real‐time imaging capability, it has becomes an excellent option to provide image guidance for brachytherapy (IGBT). (1) The physics and the fundamental principles of US imaging are presented, and the typical steps required to commission an US system for IGBT is provided for illustration. (2) Application of US for prostate HDR brachytherapy, including partial prostate treatments using MR‐ultrasound co‐registration to enable a focused treatment on the disease within the prostate is also presented. Prostate HDR with US image guidance planning can benefit from real time visualization of the needles, and fusion of the ultrasound images with T2 weighted MR allows the focusing of the treatment to the specific areas of disease within the prostate, so that the entire gland need not be treated. Finally, (3) ultrasound guidance for an eye plaque program is presented. US can be a key component of placement and QA for episcleral plaque brachytherapy for ocular cancer, and the UCLA eye plaque program with US for image guidance is presented to demonstrate the utility of US verification of plaque placement in improving the methods and QA in episcleral plaque brachytherapy.Learning Objectives: To understand the physics of an US system and the necessary aspects of commissioning US for image guided brachytherapy (IGBT). To understand real time planning of prostate HDR using ultrasound, and its application in partial prostate treatments using MR‐ultrasound fusion to focus treatment on disease within the prostate. To understand the methods and QA in applying US for localizing the target and the implant during a episcleral plaque brachytherapy procedures.

MO‐FG‐210‐00: US Guided Systems for Brachytherapy

Ultrasound (US) is one of the most widely used imaging modalities in medical practice. Since US imaging offers real‐time imaging capability, it has becomes an excellent option to provide image guidance for brachytherapy (IGBT). (1) The physics and the fundamental principles of US imaging are presented, and the typical steps required to commission an US system for IGBT is provided for illustration. (2) Application of US for prostate HDR brachytherapy, including partial prostate treatments using MR‐ultrasound co‐registration to enable a focused treatment on the disease within the prostate is also presented. Prostate HDR with US image guidance planning can benefit from real time visualization of the needles, and fusion of the ultrasound images with T2 weighted MR allows the focusing of the treatment to the specific areas of disease within the prostate, so that the entire gland need not be treated. Finally, (3) ultrasound guidance for an eye plaque program is presented. US can be a key component of placement and QA for episcleral plaque brachytherapy for ocular cancer, and the UCLA eye plaque program with US for image guidance is presented to demonstrate the utility of US verification of plaque placement in improving the methods and QA in episcleral plaque brachytherapy.Learning Objectives: To understand the physics of an US system and the necessary aspects of commissioning US for image guided brachytherapy (IGBT). To understand real time planning of prostate HDR using ultrasound, and its application in partial prostate treatments using MR‐ultrasound fusion to focus treatment on disease within the prostate. To understand the methods and QA in applying US for localizing the target and the implant during a episcleral plaque brachytherapy procedures.

MO‐FG‐210‐01: Commissioning An US System for Brachytherapy: An Overview of Physics, Instrumentation, and Techniques

Ultrasound (US) is one of the most widely used imaging modalities in medical practice. Since US imaging offers real‐time imaging capability, it has becomes an excellent option to provide image guidance for brachytherapy (IGBT). (1) The physics and the fundamental principles of US imaging are presented, and the typical steps required to commission an US system for IGBT is provided for illustration. (2) Application of US for prostate HDR brachytherapy, including partial prostate treatments using MR‐ultrasound co‐registration to enable a focused treatment on the disease within the prostate is also presented. Prostate HDR with US image guidance planning can benefit from real time visualization of the needles, and fusion of the ultrasound images with T2 weighted MR allows the focusing of the treatment to the specific areas of disease within the prostate, so that the entire gland need not be treated. Finally, (3) ultrasound guidance for an eye plaque program is presented. US can be a key component of placement and QA for episcleral plaque brachytherapy for ocular cancer, and the UCLA eye plaque program with US for image guidance is presented to demonstrate the utility of US verification of plaque placement in improving the methods and QA in episcleral plaque brachytherapy.Learning Objectives: To understand the physics of an US system and the necessary aspects of commissioning US for image guided brachytherapy (IGBT). To understand real time planning of prostate HDR using ultrasound, and its application in partial prostate treatments using MR‐ultrasound fusion to focus treatment on disease within the prostate. To understand the methods and QA in applying US for localizing the target and the implant during a episcleral plaque brachytherapy procedures.

Clinical efficacy and prognostic factors of chemoreduction combined with topical treatment for advanced intraocular retinoblastoma.

To explore the clinical efficacy and prognostic factors of chemoreduction combined with topical treatment of advanced intraocular retinoblastoma (RB). A total of 22 eyes from 17 children with RB were selected for the study and treated with chemoreduction combined with topical cryotherapy, transpupillary thermotherapy (TTT) or episcleral plaque brachytherapy. Clinical and follow-up data were retrospectively analyzed. All children received 2~6 courses of chemoreduction treatment, (4.5±0.8 courses on average); 17 eyes from 13 children were treated by chemoreduction combined with cryotherapy or TTT and 5 eyes from 4 children with chemoreduction combined with 125I episcleral plaque brachytherapy. The eye retention rate was 81.8% (18/22), among which 38.9% (7/18) featured restored or maintained good vision. Postoperative follow-up period was 7 to 34 months, (18.6 ± 5.2 months on average). The recurrence rate was 41.2% (7/17), among which 57.1% (4/7) were controlled by supplementing or appending cryotherapy or TTT treatment during the follow-up period. The tumor basal diameter and thickness were significantly reduced (P<0.05 or P<0.01) after treatment. All children demonstrated different degrees of hair loss, 70.6% (12/17) with different degrees of gastrointestinal reactions, 5.88% (1/17) with neutropenia and 11.8% (2/17) being seriously infected during the chemotherapeutic treatment. Univariate and logistic regression analysis showed that tumor basal diameter before treatment had a significant effect on the prognosis (P<0.01). Chemoreduction combined with topical therapy can effectively control RB in the short term, and tumor basal diameter before treatment is an independent risk factor for prognosis.

Evaluate and Compare the Doses Differences between Line Source and Point Source Calculation Methods for Episcleral Plaque Brachytherapy

Evaluate and Compare the Doses Differences between Line Source and Point Source Calculation Methods for Episcleral Plaque Brachytherapy

Outcomes of Iodine-125 Plaque Brachytherapy for Uveal Melanoma With Intraoperative Ultrasonography and Supplemental Transpupillary Thermotherapy

To assess the impact on local tumor control of intraoperative ultrasonographic plaque visualization and selective application of transpupillary thermotherapy (TTT) in the treatment of posterior uveal melanoma with iodine-125 (I-125) episcleral plaque brachytherapy (EPB). Retrospective analysis of 526 patients treated with I-125 EPB for posterior uveal melanoma. Clinical features, dosimetric parameters, TTT treatments, and local tumor control outcomes were recorded. Statistical analysis was performed using Cox proportional hazards and Kaplan-Meier life table method. The study included 270 men (51%) and 256 women (49%), with a median age of 63 years (mean, 62 years; range, 16-91 years). Median dose to the tumor apex was 94.4 Gy (mean, 97.8; range, 43.9-183.9) and to the tumor base was 257.9 Gy (mean, 275.6; range, 124.2-729.8). Plaque tilt >1 mm away from the sclera at plaque removal was detected in 142 cases (27%). Supplemental TTT was performed in 72 patients (13.7%). One or 2 TTT sessions were required in 71 TTT cases (98.6%). After a median follow-up of 45.9 months (mean, 53.4 months; range, 6-175 months), local tumor recurrence was detected in 19 patients (3.6%). Local tumor recurrence was associated with lower dose to the tumor base (P=.02). Ultrasound-guided plaque localization of I-125 EPB is associated with excellent local tumor control. Detection of plaque tilt by ultrasonography at plaque removal allows supplemental TTT to be used in patients at potentially higher risk for local recurrence while sparing the majority of patients who are at low risk. Most patients require only 1 or 2 TTT sessions.

Postimplant Magnetic Resonance Imaging for Episcleral Plaque Brachytherapy

Postimplant Magnetic Resonance Imaging for Episcleral Plaque Brachytherapy

WE-G-WAB-06: Three-Dimensional Visualization Using Magnetic Resonance Imaging for Episcleral Brachytherapy

Purpose: Conventional treatment planning for episcleral plaque brachytherapy entails creating a two-dimensional (2D) isodose plan based on the tumor dimensions and distances to critical structures as defined by ultrasound and fundus photography. The purpose of this study was to compare 2D-based metrics of the tumor and normal eye anatomy with magnetic resonance (MR)-based metrics. Methods: Thirty-five patients with ocular melanoma were prescribed to receive 85 Gy over 96 hours using episcleral plaque brachytherapy with iodine-125. The plaque size and seed source strength were determined from the tumor characteristics as defined by ultrasound and fundus photography. The patients were imaged on a 1.5-Tesla MR unit using T1-and T2-weighted techniques. Images were exported to a brachytherapy planning system for contouring of tumor and normal eye anatomy, and identifying points of interest for critical structures, e.g., fovea and optic disk. The tumor apex height, basal dimensions, distances between tumor edge to fovea and to optic disk were averaged over all patients, and compared between 2D-and MR-based methods using statistical Signed test analysis. Results: There were no statistically significant differences between 2D-and MR-based methods for mean tumor apex height, basal dimensions, and distance to optic disk and to fovea. Four patients presented with tumors located anteriorly in the ciliary body. This tumor location proved to be challenging in estimating distances to optic disk and fovea based on 2D methods. These distances were measurable on MR regardless of tumor location. Conclusion: We have shown that tumor dimensions and distances measured using 2D-based methods can be reproducibly defined on MR. Future work will evaluate isodose plans on the MR images and compare them to 2D-based isodose plans. Additional work will include investigating different MR imaging techniques to enhance soft-tissue visualization.

Magnetic Resonance Imaging for Episcleral Plaque Brachytherapy

Use of ultrasound (US) and fundus photography is the current imaging standard for determining tumor involvement, location, and dimensions for uveal melanomas. From this information, episcleral brachytherapy isodose plans, based on the Collaborative Ocular Melanoma Study (COMS), are generated on two-dimensional (2D) models of a standard eye with anatomic structures, e.g., macula and optic disk, identified as points of interest in a single plane. We have developed a magnetic resonance (MR) imaging technique for patient-specific tumor and anatomic definition of the eye, and for three-dimensional (3D) COMS-based isodose planning.

Incidence and Treatment of Toxicity following 125I Episcleral Plaque Brachytherapy for Uveal Melanoma

Incidence and Treatment of Toxicity following 125I Episcleral Plaque Brachytherapy for Uveal Melanoma

Episcleral Plaque 125I Brachytherapy for Choroidal Melanoma: A Single Institution Retrospective Review

Episcleral plaque brachytherapy represents a standard treatment for appropriate choroidal melanoma patients. Variations in prescription dose and dose-rate exist for reasons of physician preference and logistics.

Indigenous 125I Brachytherapy Source for the Management of Intraocular Melanomas in India

Episcleral plaque brachytherapy using (125)I seed is a viable option for the management of intraocular cancer with minimal invasiveness and surgical complications. This article describes the fabrication of (125)I seeds and initial experience on their use for the management of intraocular choroidal melanomas. The process of (125)I seed fabrication includes immobilization of (125)I into palladium-coated silver wires, its encapsulation in titanium capsules using Nd: YAG laser and quality control to assure safety. Plaque preparation consists of the assignment of seeds to slots on the plaque to achieve a desired dose rate distribution. The clinical study reported here includes the retrospective review of 9 eyes of 9 patients who underwent ophthalmic brachytherapy between May 2008 and June 2011. The average apical diameter before brachytherapy was 7.6 mm and the average largest basal diameter was 12.1 mm, which reduced to 3.3 and 7.2 mm, respectively, after the procedure at an average follow-up of 24 months. Patients in our studies experienced good local tumor control. The results of this study represent a significant step forward in the management of intraocular tumors in India.

I-125 Episcleral Plaque Brachytherapy for Uveal Melanoma: A 15-year Single Institution Experience

To determine the long-term outcomes of I-125 episcleral plaque brachytherapy for uveal melanoma and identify dosimetric factors associated with ocular complications and tumor control. Medical records were reviewed for 494 patients treated with I-125 plaque brachytherapy for uveal melanoma from 1996 to 2011. Brachytherapy records for 436 patients were reviewed to analyze radiation doses at specific dose reference points. Ophthalmologic follow-up records were analyzed to assess the incidence of recurrence and ocular complications after therapy. Survival curves were estimated using the Kaplan-Meier method. Student's t test and Fisher's exact test were used to analyze the relationships of dose delivered and type of plaque to outcomes. Mean tumor thickness and long basal diameter were 4.9 mm and 12.1 mm, respectively. The median plaque size was 18 mm. One hundred ten plaques (22.6%) required a notch due to proximity to the optic nerve. The median follow-up was 42 months (range, 6-175 months). The estimated 5-year overall and cause-specific survivals were 73.2% and 88.6%, respectively. Local control was 95.3% with 26 local failures, and 56 patients (11.3%) developed metastatic disease. The mean doses to the tumor apex, tumor base, and prescription point were 98.8 Gy, 269.4 Gy and 85.6 Gy, respectively. The mean dose to the tumor base was similar in those with local control compared to those with local failures (269.1 Gy vs. 261.7 Gy; p = 0.74). The corresponding radiation dose to the tumor apex was 99.1 Gy versus 94.2 Gy (p = 0.15). Thirty-eight patients (6.8%) underwent enucleation. The reasons for enucleation included local recurrence (20 patients), second primary tumor (1 patient) and severe radiation toxicity (17 patients; 3% of treated patients). The mean dose to the tumor base in patients requiring enucleation was significantly greater than in those without enucleation (323.3 Gy vs. 263.5 Gy, p = 0.02). The corresponding mean radiation dose to the tumor apex was 95.1 Gy and 99.2 Gy (p = 0.11). Patients who required enucleation secondary to radiation toxicity had a significantly greater dose to the tumor base than those without enucleation (392.1 Gy vs. 263.7 Gy, p = 0.001). The corresponding mean radiation doses to the tumor apex were 92.3 Gy and 99.2 Gy (p = 0.07). There was no significant association between presence of a notch or size of the plaque and recurrence or enucleation (all p > 0.05). I-125 episcleral plaque brachytherapy leads to excellent local control and globe preservation. There is no association between need for a notched plaque or plaque size with tumor recurrence or need for enucleation. Patients requiring enucleation had higher a radiation dose to the base of the tumor.

SU-E-T-429: Image-Guided Eye Plaque Brachytherapy Optimization: Implications for Patients at 2-Year Follow-up.

Episcleral eye plaque brachytherapy has been utilized in the treatment of intra-ocular malignancies, delivering large prescription doses to the apex of the tumor. Advances in dose calculation and image guidance, via calibrated fundus images, enable localization of the tumor and determination of dose to the macula, optic disc, and lens. A two-year post-implant study aims to correlate dosimetry with local tumor control and changes in visual acuity, as well as assess the need for plaque optimization with respect to critical structures. A retrospective, two-year follow-up study of 21 patients who have received episcleral eye plaque brachytherapy at our institution was used to correlate dosimetry with clinical outcomes and evaluate the need for eye plaque optimization. BEBIG Plaque Simulator wasused in treatment planning; fundus photographs were registered for tumor localization and the TG43-U1 formulism enabled dose calculation of I-125- loaded COMS plaques. Doses to the apex, macula, and optic disc were correlated to changes in apex height and visual acuity. Selected patients were replanned using optimization strategies to reduce dose to critical structures. A total of seven patients (33%) noted improved eyesight at two years. 11 (52%) patients lost at least two lines of vision at two years. Two patients saw increases in apical height (9%) within two years. Optimized eye plaque plans were able to reduce optic disc and macular doses (average 68Gy and 80Gy, respectively) by 36% and 25% on the average, while maintaining the prescribed dose. Image guidance and optimization are important tools that can aid in treatment of intra-ocular malignancies, as these techniques provide physicists with the ability to spare critical structures while delivering the prescription dose, thus increasing the possibility of local control and vision sparing.

Quality control of 125I-brachytherapy seeds

An indigenous technology for the production of 125I brachytherapy sources has been developed for the management of intraocular cancer. This indigenous method of producing 125I seeds represents a new paradigm, and a thorough quality evaluation of the seeds in accordance with Atomic Energy Regulatory Board (AERB) of India was carried to ensure their safety during therapy. In this current work, we describe an overview of our experience, the efforts made in establishing enviable quality analysis of 125I seeds to ensure their safety in episcleral plaque brachytherapy.

Episcleral plaque brachytherapy using ′BARC I-125 Ocu-Prosta seeds′ in the treatment of intraocular tumors: A single-institution experience in India

Context:To analyze the results of episcleral plaque brachytherapy using indigenous Bhabha Atomic Research Centre (BARC) Iodine-125 Ocu-Prosta seeds for the management of intraocular tumors from a single institute.AIM:To report our initial experience and learning curve on the use of ‘BARC I-125 Ocu-Prosta seeds’ for the management of intraocular tumors such as choroidal melanomas, retinoblastomas and vasoproliferative tumors (VPT).Materials and Methods:We retrospectively reviewed 13 eyes of 13 patients who underwent ophthalmic brachytherapy between May 2008 to March 2012. Nine cases had choroidal melanomas; three had retinoblastomas while one case had VPT.Results:For choroidal melanomas the average apical diameter before brachytherapy was 7.6 mm and average largest basal diameter was 12.1 mm, respectively, which reduced to 4.2 mm and 7.7 mm after the procedure at an average follow-up of 24 months (range 10-43 months). Retinoblastoma and VPT also showed good regression after brachytherapy.Conclusion:Plaque radiotherapy using 125I seeds can be performed under peribulbar anesthesia and provides a viable option for the management of intraocular cancer with minimal invasiveness and surgical complications. Patients in our studies experienced excellent local tumor control. With the availability of indigenous ‘BARC I-125 Ocu-Prosta seeds’ locally, cost effective ophthalmic brachytherapy can be performed in India.

SU-E-T-589: IGRT-Assisted Episcleral Eye Plaque Brachytherapy

Purpose: The goal of episcleral eye plaque brachytherapy has been to deliver a prescribed dose to the apex of an intra‐ocular malignancy. Advances in dose calculation and image guidance allow for optimal plaque treatment planning. The BEBIG Plaque Simulator™ utilizes calibrated fundus collages to more precisely localize intra‐ocular tumors volumes, thus enabling physicists to plan plaque therapies that deliver the prescribed dose to the tumor while quantifying and limiting dose to critical optical structures, including the macula, optic disc, and lens. Methods and Materials: A retrospective study of 30 patients at our institution who previously received episcleral eye plaque brachytherapy based on conventional treatment planning techniques. For each patient, the originally defined Ultrasoundtumor dimensions, plaque specifications (COMS universal or notched), and treatment times were entered into Plaque Simulator. Fundus collages were calibrated and overlaid on a retinal diagram. The tumor was placed over the delineated tumor on the fundus collage. Doses to the tumor apex, macula, optic disc, and lens were calculated using TG‐43U1 formalism after assuming correct plaque placement. Results: Localization of intra‐ocular tumors allowed for accurate plaque placement and realistic dose calculation for critical structures. Recreated plans validated the original prescriptions while elucidating doses to critical structures. Doses to the macula and optic disc have been correlated to clinical outcomes, including radiation maculopathy and optic neuropathy, in an effort to evaluate dose thresholds that can be enforced in future plaque therapies. Conclusions: The use of image guidance gives radiationoncology‐ophthalmology teams the ability to deliver plaque therapy with the intent to control the tumor and spare critical structures. Dose determination may highlight the necessity of proper plaque placement, plaque size, source strength, and carrier angle optimization to deliver the prescribed dose while reducing dose to critical structures below suggested thresholds in order to preserve vision.

Local control and visual acuity following treatment of medium-sized ocular melanoma using a contact eye plaque: A single surgeon experience

Purpose To evaluate the outcomes of choroidal melanoma in (CM) patients treated with 125I episcleral plaque brachytherapy and to compare our single surgeon results with the multi-institutional Collaborative Ocular Melanoma Study (COMS). Methods and Materials A review was performed of all CM patients treated with 125I episcleral plaque brachytherapy by ophthalmologist in accordance with established COMS guidelines. Results The records of 35 patients were reviewed. The median longest basal tumor diameter and apical tumor height was 13.5 and 7.8 mm, respectively. Median dose to the apex was 8609 cGy at a median dose rate of 92 cGy/h. At a median followup of 45 months, 35 patients had local control and 33 had successful organ preservation. At 5 years, the local control rate was 100%, and the eye preservation rate was 94%. Five patients developed hepatic metastasis at a median of 58 months, and 2 succumbed from disease. The 5-year survival rate was 84%, and the 5-year rate of death with histopathologically confirmed metastasis was 15%. Of the 22 patients with at least 3 years of followup, 68% had a visual acuity in the treated eye of 20/200 or worse. Conclusion Excellent local control, eye preservation rates, and survival outcomes following 125I episcleral plaque application for CM can be optimized by having an experienced ophthalmologist place the plaques. Additionally, hepatic metastasis can occur more than 5 years postimplant regardless of local control; therefore, longer systemic staging should be considered.