Page 70 - 2014 Printable Abstract Book
P. 70
dose and improve communication about radiation risk in pediatric x-ray imaging still exist. Dialogue,
collaboration and communication among all those involved in providing healthcare when integrated into
daily practice can help to identify and take advantage of these opportunities. One document, to be
published this year by the WHO entitled Communicating radiation risks in pediatric imaging to support
risk-benefit dialogue will hopefully further serve this effort.
(S1702) Computational Tools for Dose Assessment to Children in Diagnostic Imaging and Radiotherapy.
Wesley Bolch, University of Florida, Gainesville, FL
Computational phantoms of children and adolescents are an essential component for documenting
patient dose in both medical imaging and radiotherapy. For most nuclear medicine and interventional
fluoroscopy procedures, no 3D image of the body is present for dosimetric analysis, and thus organ doses
must be derived using these virtual anatomic models. In computed tomography and radiotherapy
treatment planning, 3D images are present, but organ contouring can be problematic. Furthermore,
phantoms are needed for documenting doses to organs that lie either partially or fully outside the imaging
or treatment field. Computational phantoms presently come in one of three format types, and in one of
four morphometric categories. Format types include stylized (mathematical equation-based), voxel
(segmented CT/MR images), and hybrid (NURBS and polygon mesh surfaces). Morphometric categories
th
include reference (small library of phantoms by age at 50 height/weight percentile), patient-dependent
(larger library of phantoms at various combinations of height/weight percentiles), patient-sculpted
(phantoms altered to match the patient's unique outer body contour), and finally, patient-specific (an
exact representation of the patient with respect to both body contour and internal anatomy). In this
presentation, we will review the history of pediatric anatomic models for dose assessment, and explore
the degree to which newer phantom technology can reduce errors in organ dose substantially through
explicitly considering patient body morphometry. Models for specific organs will be reviewed as well, with
particular emphasis on the pediatric skeleton and bone marrow.
(S1703) Curing Children with Cancer, But At What Cost? The Double-edged Sword of Cytotoxic Therapy.
Louis Constine, MD, FASTRO, University of Rochester, Rochester, NY
With advances in multimodality therapy and supportive care, the cure rate for childhood cancer continues
to improve and now approaches 80%. However, the therapy associated with this improved survival,
chemotherapy and radiotherapy (RT), can lead to adverse long-term health-related outcomes that
manifest months to years after completion of cancer treatment, commonly called late effects. Late effects
include organ dysfunction, subsequent malignant and benign neoplasms, and adverse psychosocial
sequelae, placing survivors at risk for chronic health conditions as they enter their adult years. In a report
from the Childhood Cancer Survivor Study (CCSS), the 30-year cumulative incidence for severe, disabling,
1
or life-threatening conditions or death due to a chronic condition was 42%; in another report from this
same cohort study, the 30-year cumulative mortality was 18% among survivors compared to the general
2
population, and radiotherapy increased this risk 2.2-fold. From the CCSS, where survivors all now have
over 20 years of follow-up since childhood cancer diagnosis, the risk of death remains highest for
recurrence of original disease, but 14% of deaths from this cohort are now from subsequent
3
malignancies. To prevent or ameliorate late effects related to RT exposure, an understanding of tissue
68 | P a g e
collaboration and communication among all those involved in providing healthcare when integrated into
daily practice can help to identify and take advantage of these opportunities. One document, to be
published this year by the WHO entitled Communicating radiation risks in pediatric imaging to support
risk-benefit dialogue will hopefully further serve this effort.
(S1702) Computational Tools for Dose Assessment to Children in Diagnostic Imaging and Radiotherapy.
Wesley Bolch, University of Florida, Gainesville, FL
Computational phantoms of children and adolescents are an essential component for documenting
patient dose in both medical imaging and radiotherapy. For most nuclear medicine and interventional
fluoroscopy procedures, no 3D image of the body is present for dosimetric analysis, and thus organ doses
must be derived using these virtual anatomic models. In computed tomography and radiotherapy
treatment planning, 3D images are present, but organ contouring can be problematic. Furthermore,
phantoms are needed for documenting doses to organs that lie either partially or fully outside the imaging
or treatment field. Computational phantoms presently come in one of three format types, and in one of
four morphometric categories. Format types include stylized (mathematical equation-based), voxel
(segmented CT/MR images), and hybrid (NURBS and polygon mesh surfaces). Morphometric categories
th
include reference (small library of phantoms by age at 50 height/weight percentile), patient-dependent
(larger library of phantoms at various combinations of height/weight percentiles), patient-sculpted
(phantoms altered to match the patient's unique outer body contour), and finally, patient-specific (an
exact representation of the patient with respect to both body contour and internal anatomy). In this
presentation, we will review the history of pediatric anatomic models for dose assessment, and explore
the degree to which newer phantom technology can reduce errors in organ dose substantially through
explicitly considering patient body morphometry. Models for specific organs will be reviewed as well, with
particular emphasis on the pediatric skeleton and bone marrow.
(S1703) Curing Children with Cancer, But At What Cost? The Double-edged Sword of Cytotoxic Therapy.
Louis Constine, MD, FASTRO, University of Rochester, Rochester, NY
With advances in multimodality therapy and supportive care, the cure rate for childhood cancer continues
to improve and now approaches 80%. However, the therapy associated with this improved survival,
chemotherapy and radiotherapy (RT), can lead to adverse long-term health-related outcomes that
manifest months to years after completion of cancer treatment, commonly called late effects. Late effects
include organ dysfunction, subsequent malignant and benign neoplasms, and adverse psychosocial
sequelae, placing survivors at risk for chronic health conditions as they enter their adult years. In a report
from the Childhood Cancer Survivor Study (CCSS), the 30-year cumulative incidence for severe, disabling,
1
or life-threatening conditions or death due to a chronic condition was 42%; in another report from this
same cohort study, the 30-year cumulative mortality was 18% among survivors compared to the general
2
population, and radiotherapy increased this risk 2.2-fold. From the CCSS, where survivors all now have
over 20 years of follow-up since childhood cancer diagnosis, the risk of death remains highest for
recurrence of original disease, but 14% of deaths from this cohort are now from subsequent
3
malignancies. To prevent or ameliorate late effects related to RT exposure, an understanding of tissue
68 | P a g e
