Novel low-kVp beamlet system for choroidal melanoma
<p>Abstract</p> <p>Background</p> <p>Treatment of choroidal melanoma with radiation often involves placement of customized brachytherapy eye-plaques. However, the dosimetric properties inherent in source-based radiotherapy preclude facile dose optimization to critical o...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
BMC
2006-09-01
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| Series: | Radiation Oncology |
| Online Access: | http://www.ro-journal.com/content/1/1/36 |
| _version_ | 1818083187830554624 |
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| author | Wong Adrian Waggener Robert G Fuller Clifton D Esquivel Carlos Meltz Martin Blough Melissa Eng Tony Y Thomas Charles R |
| author_facet | Wong Adrian Waggener Robert G Fuller Clifton D Esquivel Carlos Meltz Martin Blough Melissa Eng Tony Y Thomas Charles R |
| author_sort | Wong Adrian |
| collection | DOAJ |
| description | <p>Abstract</p> <p>Background</p> <p>Treatment of choroidal melanoma with radiation often involves placement of customized brachytherapy eye-plaques. However, the dosimetric properties inherent in source-based radiotherapy preclude facile dose optimization to critical ocular structures. Consequently, we have constructed a novel system for utilizing small beam low-energy radiation delivery, the Beamlet Low-kVp X-ray, or "BLOKX" system. This technique relies on an isocentric rotational approach to deliver dose to target volumes within the eye, while potentially sparing normal structures.</p> <p>Methods</p> <p>Monte Carlo N-Particle (MCNP) transport code version 5.0(14) was used to simulate photon interaction with normal and tumor tissues within modeled right eye phantoms. Five modeled dome-shaped tumors with a diameter and apical height of 8 mm and 6 mm, respectively, were simulated distinct positions with respect to the macula iteratively. A single fixed 9 × 9 mm<sup>2 </sup>beamlet, and a comparison COMS protocol plaque containing eight I-125 seeds (apparent activity of 8 mCi) placed on the scleral surface of the eye adjacent to the tumor, were utilized to determine dosimetric parameters at tumor and adjacent tissues. After MCNP simulation, comparison of dose distribution at each of the 5 tumor positions for each modality (BLOKX vs. eye-plaque) was performed.</p> <p>Results</p> <p>Tumor-base doses ranged from 87.1–102.8 Gy for the BLOKX procedure, and from 335.3–338.6 Gy for the eye-plaque procedure. A reduction of dose of at least 69% to tumor base was noted when using the BLOKX. The BLOKX technique showed a significant reduction of dose, 89.8%, to the macula compared to the episcleral plaque. A minimum 71.0 % decrease in dose to the optic nerve occurred when the BLOKX was used.</p> <p>Conclusion</p> <p>The BLOKX technique allows more favorable dose distribution in comparison to standard COMS brachytherapy, as simulated using a Monte Carlo iterative mathematical modeling. Future series to determine clinical utility of such an approach are warranted.</p> |
| first_indexed | 2024-12-10T19:34:01Z |
| format | Article |
| id | doaj.art-9d4ab74c33a84a1594b22f9c2bc04348 |
| institution | Directory Open Access Journal |
| issn | 1748-717X |
| language | English |
| last_indexed | 2024-12-10T19:34:01Z |
| publishDate | 2006-09-01 |
| publisher | BMC |
| record_format | Article |
| series | Radiation Oncology |
| spelling | doaj.art-9d4ab74c33a84a1594b22f9c2bc043482022-12-22T01:36:10ZengBMCRadiation Oncology1748-717X2006-09-01113610.1186/1748-717X-1-36Novel low-kVp beamlet system for choroidal melanomaWong AdrianWaggener Robert GFuller Clifton DEsquivel CarlosMeltz MartinBlough MelissaEng Tony YThomas Charles R<p>Abstract</p> <p>Background</p> <p>Treatment of choroidal melanoma with radiation often involves placement of customized brachytherapy eye-plaques. However, the dosimetric properties inherent in source-based radiotherapy preclude facile dose optimization to critical ocular structures. Consequently, we have constructed a novel system for utilizing small beam low-energy radiation delivery, the Beamlet Low-kVp X-ray, or "BLOKX" system. This technique relies on an isocentric rotational approach to deliver dose to target volumes within the eye, while potentially sparing normal structures.</p> <p>Methods</p> <p>Monte Carlo N-Particle (MCNP) transport code version 5.0(14) was used to simulate photon interaction with normal and tumor tissues within modeled right eye phantoms. Five modeled dome-shaped tumors with a diameter and apical height of 8 mm and 6 mm, respectively, were simulated distinct positions with respect to the macula iteratively. A single fixed 9 × 9 mm<sup>2 </sup>beamlet, and a comparison COMS protocol plaque containing eight I-125 seeds (apparent activity of 8 mCi) placed on the scleral surface of the eye adjacent to the tumor, were utilized to determine dosimetric parameters at tumor and adjacent tissues. After MCNP simulation, comparison of dose distribution at each of the 5 tumor positions for each modality (BLOKX vs. eye-plaque) was performed.</p> <p>Results</p> <p>Tumor-base doses ranged from 87.1–102.8 Gy for the BLOKX procedure, and from 335.3–338.6 Gy for the eye-plaque procedure. A reduction of dose of at least 69% to tumor base was noted when using the BLOKX. The BLOKX technique showed a significant reduction of dose, 89.8%, to the macula compared to the episcleral plaque. A minimum 71.0 % decrease in dose to the optic nerve occurred when the BLOKX was used.</p> <p>Conclusion</p> <p>The BLOKX technique allows more favorable dose distribution in comparison to standard COMS brachytherapy, as simulated using a Monte Carlo iterative mathematical modeling. Future series to determine clinical utility of such an approach are warranted.</p>http://www.ro-journal.com/content/1/1/36 |
| spellingShingle | Wong Adrian Waggener Robert G Fuller Clifton D Esquivel Carlos Meltz Martin Blough Melissa Eng Tony Y Thomas Charles R Novel low-kVp beamlet system for choroidal melanoma Radiation Oncology |
| title | Novel low-kVp beamlet system for choroidal melanoma |
| title_full | Novel low-kVp beamlet system for choroidal melanoma |
| title_fullStr | Novel low-kVp beamlet system for choroidal melanoma |
| title_full_unstemmed | Novel low-kVp beamlet system for choroidal melanoma |
| title_short | Novel low-kVp beamlet system for choroidal melanoma |
| title_sort | novel low kvp beamlet system for choroidal melanoma |
| url | http://www.ro-journal.com/content/1/1/36 |
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