ABSTRACT
PURPOSE: To measure the scattered dose to ovary from radiotherapy for neuroblastoma in female children and to evaluate the relevant risks for radiation-induced ovarian damage. MATERIAL AND METHODS: Radiotherapy for child neuroblastoma was simulated on the water phantom. The scattered dose to ovary is measured by ionization chamber on the linear accelerator with 3-dimensional conformal radiation therapy and intensity-modulated radiation therapy treatment producing 6MV and 10MV X-rays. The treatment planning procedure was carried out on a computer system (TPS, Oncentra). Optimization of the number and orientation of beams were performed in order to minimize the ovarian dose. RESULTS: For the target dose of 21.6 Gy, the scattered dose to ovary was ranged from 1.3 to 46.8 cGy depending on the treatment method and the energy of the beams. The ovarian dose of intensity-modulated radiation therapy is 1.32 to 1.64 times higher than that of 3-dimensional conformal radiation therapy. The ovarian dose of 6MV beam's energy is 1.52 to 1.64 times higher than that of 10MV beam's energy. For the radiotherapy, the scattered dose of ovaries on phantom by ionization chamber was 1.40 to 2.32 times higher than that on TPS calculated. CONCLUSION: The dosimetric data suggest that pediatric radiotherapy is not associated with a risk for permanent damage to the ovaries in female children. Through choosing the beams' energy and treatment plan's method, the scattered dose of ovaries can be reduced. The risk for development of hereditary disorders in offspring conceived after exposure is low.
Subject(s)
Neuroblastoma/radiotherapy , Ovary/radiation effects , Radiotherapy Dosage , Scattering, Radiation , Age Factors , Child , Child, Preschool , Female , Humans , Neoplasm Staging , Neuroblastoma/diagnosis , Organs at Risk , Phantoms, Imaging , Radiotherapy, Intensity-Modulated/adverse effects , Radiotherapy, Intensity-Modulated/methodsSubject(s)
Hydrogels , Polyvinyl Alcohol/chemical synthesis , Radiation Dosage , Radiation Monitoring/instrumentation , Cross-Linking Reagents/chemistry , Dose-Response Relationship, Radiation , Equipment Design , Feasibility Studies , Ferrous Compounds/chemistry , Fluorescent Dyes/chemistry , Gamma Rays , Glutaral/chemistry , Particle Accelerators , Phantoms, Imaging , Phenols , Polyvinyl Alcohol/radiation effects , Solutions/chemistry , Spectrophotometry, Ultraviolet , Sulfoxides , Time Factors , Xylenes/chemistryABSTRACT
Lead has recently been recognised as a source of environmental pollution, including the lead used for radiation shielding in radiotherapy. The bremsstrahlung radiation caused by the interaction between the electron beam and lead may reduce the accuracy of radiotherapy. To avoid the use of lead, a new material composed of tungsten and hydrogenated styrene-butadiene-styrene copolymer is studied with the Monte Carlo (MC) method and experiment in this paper. The component of the material is chosen after simulation with the MC method and the practical measurement is taken to validate the shielding ability of the material. The result shows that the shielding ability of the new material is good enough to fulfill the requirement for application in radiotherapy. Compared with lead alloy, the present new material is so flexible that can be easily customized into arbitrary shapes. Moreover, the material is environmentally friendly and can be recycled conveniently. Therefore, the material can be used as an effective lead substitute for shielding against electron beams in radiotherapy.
