The Experts below are selected from a list of 207 Experts worldwide ranked by ideXlab platform
Z Gao - One of the best experts on this subject based on the ideXlab platform.
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su ff t 416 the use of modumlc in combination with ig imrt for treating a very small Eye Tumor
Medical Physics, 2007Co-Authors: C Cheng, Z GaoAbstract:Introduction:IMRT employing a conventional MLC (1 cm leaf width at isocenter) for small Eye Tumors may be suboptimal because of its relatively large leaf width compared to the Tumor size. The combination of moduleaf (MMLC, 0.25 cm leaf width at isocenter), head immobilization and IG‐IMRT may offer a better alternative. In this study, two IMRT plans are generated for the treatment of a small Eye Tumor using a conventional MLC (MLC82, 1 cm leaf width), and MMLC with IGRT.Method and materials: A young patient with choroidal hemangioma was treated with a Primatom‐based IG‐IMRT technique. The size of the Tumor was delineated to be 4 cm3. A total of 12 Gy in 8 fractions was prescribed to the CTV, and the dose allowed to the right lens (0.12 cm3) was constraint to ⩽ 5 Gy. Treatment planning was carried out on the KonRad inverse planning software. Two plans were generated for a five‐field setup. One was optimized for dose delivery with the MLC82, while the other is optimized for the MMLC. The patient was setup in the treatment couch immobilized with the customized mask and a bite block. Image guidance was performed with a CT‐on‐rail system. Dosimetric measurements were carried out to verify the accuracy of dose delivery for the MMLC plan. Results: The plan for the MLC82 achieves a minimum dose of 7.53 Gy to the PTV and the maximum dose to the right lens is 8.2 Gy. With MMLC, the minimum dose is 12.3 Gy to the PTV while the maximum dose to the right lens is 5.15 Gy. Dosimetric measurement for the MMLC plan yielded good agreement with calculation. Conclusion: The use of IGRT, MMLC and customized mask improves the overall dose delivery accuracy and appears to be a superior choice for treatment of small Tumors.
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SU‐FF‐T‐416: The Use of ModuMLC® in Combination with IG‐IMRT for Treating a Very Small Eye Tumor
Medical Physics, 2007Co-Authors: C Cheng, Z GaoAbstract:Introduction:IMRT employing a conventional MLC (1 cm leaf width at isocenter) for small Eye Tumors may be suboptimal because of its relatively large leaf width compared to the Tumor size. The combination of moduleaf (MMLC, 0.25 cm leaf width at isocenter), head immobilization and IG‐IMRT may offer a better alternative. In this study, two IMRT plans are generated for the treatment of a small Eye Tumor using a conventional MLC (MLC82, 1 cm leaf width), and MMLC with IGRT.Method and materials: A young patient with choroidal hemangioma was treated with a Primatom‐based IG‐IMRT technique. The size of the Tumor was delineated to be 4 cm3. A total of 12 Gy in 8 fractions was prescribed to the CTV, and the dose allowed to the right lens (0.12 cm3) was constraint to ⩽ 5 Gy. Treatment planning was carried out on the KonRad inverse planning software. Two plans were generated for a five‐field setup. One was optimized for dose delivery with the MLC82, while the other is optimized for the MMLC. The patient was setup in the treatment couch immobilized with the customized mask and a bite block. Image guidance was performed with a CT‐on‐rail system. Dosimetric measurements were carried out to verify the accuracy of dose delivery for the MMLC plan. Results: The plan for the MLC82 achieves a minimum dose of 7.53 Gy to the PTV and the maximum dose to the right lens is 8.2 Gy. With MMLC, the minimum dose is 12.3 Gy to the PTV while the maximum dose to the right lens is 5.15 Gy. Dosimetric measurement for the MMLC plan yielded good agreement with calculation. Conclusion: The use of IGRT, MMLC and customized mask improves the overall dose delivery accuracy and appears to be a superior choice for treatment of small Tumors.
Arupa Ganguly - One of the best experts on this subject based on the ideXlab platform.
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genomic profile of 320 uveal melanoma cases chromosome 8p loss and metastatic outcome
Investigative Ophthalmology & Visual Science, 2013Co-Authors: Kathryn G Ewens, Carol L. Shields, Peter A Kanetsky, Jennifer Richardsyutz, Saad Aldahmash, Maria Carla De Luca, Carlos Bianciotto, Arupa GangulyAbstract:PURPOSE: Uveal melanoma (UM) was a fatal malignancy in 40% to 50% of cases. The aim of this study is to evaluate the independent contributions of chromosome 1, 3, 6, and 8 abnormalities for prognostication of metastasis, and to define multichromosome copy number aberration (CNA) signatures that can be used to evaluate risk. METHODS: A series of 320 UM were analyzed for chromosome 1, 3, 6, and 8 abnormalities using whole genome single-nucleotide polymorphism arrays. Results for changes in six chromosomal regions were analyzed using univariate and multivariate Cox proportional hazard modeling to identify significant predictors of metastasis and CNA signatures. RESULTS: Univariate Cox analysis indicated that losses of chromosome 3, 1p, 6q, and 8p and gain of 8q, as well as sex, source of Tumor tissue (fine-needle aspiration biopsy [FNAB] compared with Tumor from an enucleated Eye), Tumor basal diameter and height, and ciliary body involvement were all significant predictors of poor metastatic outcome. In the multivariate analysis, loss of chromosome 3 and 8p remained significant after adjusting for the effects of all other variables, as did sex, tissue source, and basal diameter. Multivariate analysis of the joint effects of changes in the six chromosomal regions showed that six signatures, including chromosome 3-loss, 1p-loss, 8p-loss, and/or 8q-gain had hazard ratios (HR) ranging from 7.90 to 37.25. CONCLUSIONS: In UM, Tumor size and location, tissue source, and sex were all significantly associated with increased metastasis. In addition, chromosome 3-loss and 8p-loss were found to be independent predictors of poor metastatic outcome and CNA signatures were identified that can add a specific HR value for classification of risk categories.
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Recent advances in retinoblastoma genetic research.
Current opinion in ophthalmology, 2009Co-Authors: Kim E. Nichols, Susan E. Walther, Elizabeth C. Chao, Carol L. Shields, Arupa GangulyAbstract:PURPOSE OF REVIEW Retinoblastoma is a pediatric Eye Tumor that serves as a paradigm for understanding the genetic basis of cancer. This review will highlight recent advances in retinoblastoma genetic research and discuss how these new findings influence our knowledge of retinoblastoma Tumorigenesis and management. RECENT FINDINGS Current data demonstrate that retinomas, benign retinal Tumors found in some retinoblastoma patients, exhibit bi-allelic mutations in RB1, the retinoblastoma gene, and lack of expression of the retinoblastoma protein. Interestingly, retinomas demonstrate a low level of genomic instability that becomes progressively more severe in retinoblastoma Tumors. Additionally, a subset of retinomas share genomic alterations with retinoblastoma. Collectively, these data suggest that retinomas represent true premalignant lesions and not regressed retinoblastoma Tumors, as previously thought. Translational advances in retinoblastoma genetic research include development of an allele-specific assay that now enables the identification of mutational mosaicism, thereby increasing the rate of RB1 mutation detection in bilaterally affected patients to as high as 95%. SUMMARY These and related research efforts reveal novel data that enhance our understanding of the biology of retinoblastoma. These observations may facilitate new therapeutic approaches to further decrease the morbidity and mortality associated with retinoblastoma and other more common forms of cancer.
C Cheng - One of the best experts on this subject based on the ideXlab platform.
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su ff t 416 the use of modumlc in combination with ig imrt for treating a very small Eye Tumor
Medical Physics, 2007Co-Authors: C Cheng, Z GaoAbstract:Introduction:IMRT employing a conventional MLC (1 cm leaf width at isocenter) for small Eye Tumors may be suboptimal because of its relatively large leaf width compared to the Tumor size. The combination of moduleaf (MMLC, 0.25 cm leaf width at isocenter), head immobilization and IG‐IMRT may offer a better alternative. In this study, two IMRT plans are generated for the treatment of a small Eye Tumor using a conventional MLC (MLC82, 1 cm leaf width), and MMLC with IGRT.Method and materials: A young patient with choroidal hemangioma was treated with a Primatom‐based IG‐IMRT technique. The size of the Tumor was delineated to be 4 cm3. A total of 12 Gy in 8 fractions was prescribed to the CTV, and the dose allowed to the right lens (0.12 cm3) was constraint to ⩽ 5 Gy. Treatment planning was carried out on the KonRad inverse planning software. Two plans were generated for a five‐field setup. One was optimized for dose delivery with the MLC82, while the other is optimized for the MMLC. The patient was setup in the treatment couch immobilized with the customized mask and a bite block. Image guidance was performed with a CT‐on‐rail system. Dosimetric measurements were carried out to verify the accuracy of dose delivery for the MMLC plan. Results: The plan for the MLC82 achieves a minimum dose of 7.53 Gy to the PTV and the maximum dose to the right lens is 8.2 Gy. With MMLC, the minimum dose is 12.3 Gy to the PTV while the maximum dose to the right lens is 5.15 Gy. Dosimetric measurement for the MMLC plan yielded good agreement with calculation. Conclusion: The use of IGRT, MMLC and customized mask improves the overall dose delivery accuracy and appears to be a superior choice for treatment of small Tumors.
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SU‐FF‐T‐416: The Use of ModuMLC® in Combination with IG‐IMRT for Treating a Very Small Eye Tumor
Medical Physics, 2007Co-Authors: C Cheng, Z GaoAbstract:Introduction:IMRT employing a conventional MLC (1 cm leaf width at isocenter) for small Eye Tumors may be suboptimal because of its relatively large leaf width compared to the Tumor size. The combination of moduleaf (MMLC, 0.25 cm leaf width at isocenter), head immobilization and IG‐IMRT may offer a better alternative. In this study, two IMRT plans are generated for the treatment of a small Eye Tumor using a conventional MLC (MLC82, 1 cm leaf width), and MMLC with IGRT.Method and materials: A young patient with choroidal hemangioma was treated with a Primatom‐based IG‐IMRT technique. The size of the Tumor was delineated to be 4 cm3. A total of 12 Gy in 8 fractions was prescribed to the CTV, and the dose allowed to the right lens (0.12 cm3) was constraint to ⩽ 5 Gy. Treatment planning was carried out on the KonRad inverse planning software. Two plans were generated for a five‐field setup. One was optimized for dose delivery with the MLC82, while the other is optimized for the MMLC. The patient was setup in the treatment couch immobilized with the customized mask and a bite block. Image guidance was performed with a CT‐on‐rail system. Dosimetric measurements were carried out to verify the accuracy of dose delivery for the MMLC plan. Results: The plan for the MLC82 achieves a minimum dose of 7.53 Gy to the PTV and the maximum dose to the right lens is 8.2 Gy. With MMLC, the minimum dose is 12.3 Gy to the PTV while the maximum dose to the right lens is 5.15 Gy. Dosimetric measurement for the MMLC plan yielded good agreement with calculation. Conclusion: The use of IGRT, MMLC and customized mask improves the overall dose delivery accuracy and appears to be a superior choice for treatment of small Tumors.
Joel Herault - One of the best experts on this subject based on the ideXlab platform.
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Phosphenes Under Proton therapy for Eye Tumors
International Journal of Radiation Oncology*Biology*Physics, 2015Co-Authors: Juliette Thariat, G. Loreti, Celia Maschi, Jean-pierre Caujolle, Joel HeraultAbstract:Purpose/Objective(s): Phosphenes, also called light flashes, are frequently reported by patients during radiation therapy of intraocular or encephalic Tumors, in the absence of ambient light. The pattern of expression of phosphenes (color often blue, shape, duration, location) varies widely. Astronauts also consistently reported visual sensations during space travels. The similarities and differences in phosphenes between patients and astronauts may provide clues to unravel the mechanisms involved in such phenomena. A Cerenkov effect due to charged particles moving at a speed greater than the phase velocity of light in that medium) has been suggested as a possible cause. Materials/Methods: We performed physical calculations to investigate the possible interactions under different conditions, analyzing different energies and particles involved. We also analyzed the phosphene patterns and correlations with clinical parameters in a series of Eye Tumor patients homogenously treated with ocular proton therapy. Results: Our analyses suggest that, apart from high energy photon/electron irradiation, the Cerenkov effect is unlikely involved in the occurrence of phosphenes in Eye proton therapy and that other phenomena must be involved. In our experience, phosphenes, most blue, were reported in 70% of 229 dark-adapted patients undergoing Eye proton therapy and a correlation between phosphenes and their characteristics was found with the distance to the macula and optic disk. Conclusion: Although phosphene characteristics were suggestive of Cerenkov radiation, our finding favors a direct contribution of ocular photoreceptors and possible interactions between cones and rods. Further neuroophthalmic electrophysiological investigations will be necessary to understand the mechanisms of phosphenes at the cellular level. Author Disclosure: J.O. Thariat: None. G. Loreti: None. C. Maschi: None. J. Caujolle: None. J. Herault: None.
Jorge Amador-zarco - One of the best experts on this subject based on the ideXlab platform.
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Survival in extra-orbital metastatic retinoblastoma:treatment results.
Clinical & translational oncology : official publication of the Federation of Spanish Oncology Societies and of the National Cancer Institute of Mexic, 2006Co-Authors: Carlos Leal-leal, Roberto Rivera-luna, Martha Flores-rojo, Juan C. Juárez-echenique, Juan C. Ordaz, Jorge Amador-zarcoAbstract:Introduction Retinoblastoma (RB) is the most frequent malignant Eye Tumor in childhood. In developing countries advanced stages are common. The purpose of this paper is to present our 21-year clinical experience with metastatic extra ocular RB patients treated with 5 different chemotherapy schemas at a single Mexican Pediatric referral center.
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Survival in extra-orbital metastatic retinoblastoma: treatment results
Clinical and Translational Oncology, 2006Co-Authors: Carlos Leal-leal, Roberto Rivera-luna, Martha Flores-rojo, Juan C. Juárez-echenique, Juan C. Ordaz, Jorge Amador-zarcoAbstract:Introduction Retinoblastoma (RB) is the most frequent malignant Eye Tumor in childhood. In developing countries advanced stages are common. The purpose of this paper is to present our 21-year clinical experience with metastatic extra ocular RB patients treated with 5 different chemotherapy schemas at a single Mexican Pediatric referral center. Materials and methods A retrospective analysis was carried out reviewing the clinical characteristics of patients with metastatic RB. The information analyzed included the delay in diagnosis after first symptoms, age, sex, ocular staging, and anatomic site of metastases, treatment scheme, initial response and status at the last contact or date of death. Results Eighty-one patients were included; age range was from 3 to 80 months. The most common site of metastasis was central nervous system (83.9%). From those patients treated with chemotherapy (n=74), 89.2% presented a complete initial response (n=66). Early mortality occurred in 7 cases before any treatment. Fifty-six received treatment and died with progressive disease. All patients without radiotherapy died with Tumor activity (n=15). The use of cisplatin was related with longer disease free intervals; no other variable was related with survival. Four patients were alive and disease free at 33 to 144.3 months of follow up from diagnosis. The prevalent cause of death was Tumor progression. Conclusions In our experience, metastatic RB has a very high mortality rate in spite of the use of different chemotherapy regimens.
