In the second presentation, specific focus will be on pediatric proton therapy. Late effects based on the current understanding of dose-volume response in normal tissues will be discussed. Practical issues that have to be faced when treating children will also be discussed such as daily sedation and immobilization. Case studies will be presented showing the treatment technique and resulting dosimetry, highlighting the objectives for tumor coverage and organ-at-risk sparing. These cancers include leukemia treated with total body irradiation, medulloblastoma, treated with craniospinal irradiation plus a conformal boost to the posterior fossa, neuroblastoma, requiring focal abdominal irradiation to avoid kidney, liver, and vertebral body damage, retinoblastoma, requiring treatment to an eye while minimizing dose to surrounding tissues, and a variety of other tumors which occur anywhere in the body. These can be some of the most complex treatments that are delivered in the radiation therapy department. In the first presentation, an overview of childhood cancers and their corresponding treatment techniques will be given. The dosimetric tradeoffs made during the planning process are complex and require careful consideration for children treated with radiotherapy. For bilateral retinoblastoma for example, an irradiated child has a 40% chance of developing a second cancer by age 50. Additionally, children are more prone than adults to developing secondary cancers after radiation. Because most therapy departments treat mostly adults, when the rare 8 year-old patient comes to the department for treatment, the physicist may not understand the clinical issues of his disease which drive the planning and delivery decisions. This is because bones, brain, breast tissue, and other organs are more sensitive to radiation in children than in adults. The treatment of children with cancer using radiation therapy is one of the most challenging planning and delivery problems facing the physicist. Breast or prostate cancers, typical in adults, are rarely seen in children but instead a variety of tumors occur in children that are rarely seen in adults examples are germinomas, ependymomas and primitive neuroectodermal tumors, which require treatment of the child’s more » brain or neuroblastoma, requiring treatment in the abdomen. Children get very different cancers than adults. Children have not smoked, abused alcohol, or been exposed to environmental carcinogens for decades, and of course, have not fallen victim to the aging process. This is because, fortunately, children get cancer at a rate nearly 100 times lower than adults. Most Medical Physicists working in radiotherapy departments see few pediatric patients. Results corroborate the Malone model with an independent dataset and support the efficacy of using less complex models to estimate fracture age in children. All three more » models produced similar estimates with substantial imprecision. Two machine learning models were used to test predictions of the new scale. By dividing these assessments into learning and test (validation) sets, the accuracy of a newly proposed fracture healing scale was compared to a previous study. We subjectively assessed visible characteristics of healing in radiograms of fractures occurring in 942 living children and adolescents. In contrast to the orthopedic definition, a fracture in forensic casework is only considered to be healed when the area around the fracture has been remodeled to the point that the fracture is difficult to detect on a radiograph or on the surface of the bone itself, a process that can take several years. Multiple studies in both the clinical and forensic literature have attempted to develop a usable scale to assess pediatric bone healing on radiographs using various healing characteristics. However, the dating of fractures from radiographs is difficult, imprecise, and lacks consensus, as only a few aspects of the healing process are visible on radiographs. A timeline of pediatric bone healing using fracture healing characteristics that can be assessed solely using radiographs would be practical for forensic casework, where the fracture event may precede death by days, months, or years.
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