| Dosimetry of rotational photon fields with gravity-oriented eye blocks. | |
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MedLine Citation:
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PMID: 6706736 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Evolving radiotherapeutic technique is aimed at routine use of an eye protection accessory with uniformity of dose to facial tumors. Rotational 4 MV photon fields with gravity-oriented eye blocks are described in applications to patients and a phantom. A machine-oriented compensator with a slit and beveled edges at eye levels has been applied to increase uniformity of dose over the entire target, including partly blocked regions. Treatment planning parameters are derived from simple geometric relationships. Dose distributions and average tissue-air ratios (TAR) are calculated with a conventional radiotherapeutic treatment planning system, and measured during initial treatments via thermoluminescent dosemeters (TLD) in facial cavities. Machine monitor units of initial treatments (MU1) are calculated from prescribed dose D, TAR, percentage isodose lines, dose rates in air, and compensator transmission; for subsequent treatments, MU1 are modified using averages of unblocked target doses D measured during initial treatment: MU2 = (D/D)MU1. Doses measured on patients' eyelids have been 10 to 15% of prescribed dose. Three dimensional dose distributions were determined using TLD in an anthropomorphic phantom. With beam compensation, eye doses were 15% of unblocked target doses, doses to partly blocked target were 86 to 129% of unblocked target doses, and doses to unblocked target showed 5% mean standard deviations. In vivo and in phantom data were consistent with computer-calculated distributions. For uniformity of target dose, eye-sparing, and simplicity of irradiating tumors surrounding the eyes, the technique investigated compares favorably with conventional techniques. |
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Authors:
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M J Engler; A M Herskovic; B S Proimos |
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Publication Detail:
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Type: Journal Article |
Journal Detail:
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Title: International journal of radiation oncology, biology, physics Volume: 10 ISSN: 0360-3016 ISO Abbreviation: Int. J. Radiat. Oncol. Biol. Phys. Publication Date: 1984 Mar |
Date Detail:
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Created Date: 1984-05-11 Completed Date: 1984-05-11 Revised Date: 2004-11-17 |
Medline Journal Info:
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Nlm Unique ID: 7603616 Medline TA: Int J Radiat Oncol Biol Phys Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: 431-8 Citation Subset: IM |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Elementary Particles Eye / radiation effects* Eye Protective Devices* Facial Neoplasms / radiotherapy* Humans Models, Structural Protective Devices* Radiation Injuries / prevention & control Radiation Protection / methods* Radiotherapy Dosage Thermoluminescent Dosimetry* |
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