A review of US anthropometric reference data (1971–2000) with comparisons to both stylized and tomographic anatomic models

Anatomical gender differences in cervical vertebrae of size-matched volunteers

STUDY DESIGN

Clinical literature consistently identifies women as more susceptible to trauma-related neck pain, commonly resulting from soft tissue cervical spine injury. Structural gender differences may explain altered response to dynamic loading in women leading to increased soft tissue distortion and greater injury susceptibility.

OBJECTIVE

Identify anatomic gender differences in cervical spinal geometry that contribute to decreased column stability in women.

SUMMARY OF BACKGROUND DATA

Previous studies investigating male and female vertebral and vertebral body geometry demonstrated female vertebral dimensions were smaller. However, populations were not size matched and parameters related to biomechanical stability were not reported.

METHODS

Computed tomography scans of the cervical spine were obtained from size-matched young healthy volunteers. Geometrical dimensions were obtained at the C4 level and analysis of variance determined significant gender differences.

RESULTS

Two volunteer subsets were size matched based on sitting height and head circumference. All geometrical measures were greater in men for both subsets. Vertebral width and disc-facet depth were significantly greater in men. Additionally, segmental support area, combining interfacet width and disc-facet depth, was greater in men, indicating more stable intervertebral coupling.

CONCLUSION

Present results of decreased linear and areal cervical dimensions leading to decreased column stability may partially explain increased traumatic injury rates in women.

Computational Anthropomorphic Models of the Human Anatomy: The Path to Realistic Monte Carlo Modeling in Radiological Sciences

The widespread availability of high-performance computing and popularity of simulations stimulated the development of computational anthropomorphic models of the human anatomy for medical imaging modalities and dosimetry calculations. The widespread interest in molecular imaging spurred the development of more realistic three- to five-dimensional computational models based on the actual anatomy and physiology of individual humans and small animals. These can be defined by either mathematical (analytical) functions or digital (voxel-based) volume arrays (or a combination of both), thus allowing the simulation of medical imaging data that are ever closer to actual patient data. The paradigm shift away from the stylized human models is imminent with the development of more than 30 voxel-based tomographic models in recent years based on anatomical medical images. We review the fundamental and technical challenges of designing computational models of the human anatomy, and focus particularly on the latest developments and future directions of their application in the simulation of radiological imaging systems and dosimetry calculations.

Revisions to the ORNL series of adult and pediatric computational phantoms for use with the MIRD schema

The age-dependent series of stylized computational phantoms developed at the Oak Ridge National Laboratory in the late 1970's to early 1980's has found wide applicability in dosimetry studies ranging from dose coefficient compilations for external and internal photon emitters, simulations of patient radiological exams, and dose reconstruction activities. In the present study, we report on a series of revisions to the Oak Ridge National Laboratory series for their intended use within the MIRD schema of medical internal dosimetry. These revisions were made to (1) incorporate recent developments in stylized models of the head, brain, kidneys, rectosigmoid colon, and extra-pulmonary airways; (2) incorporate new models of the salivary glands and the mucosa layer of the urinary bladder, alimentary tract organs, and respiratory airways; (3) adopt reference values of elemental tissue compositions and mass densities from ICRP Publication 89 and ICRU Report 46; (4) provide for explicit treatment of left and right organs within organ pairs; (5) provide for a systematic tabulation of electron absorbed fractions as a function of energy and subject age for all internal organs; and (6) provide for methods of deriving patient-specific values of the specific absorbed fraction for both electrons and photons through interpolation/extrapolation of their phantom-derived values. While tomographic computational phantoms provide improved anatomic realism given the CT or MR image sets used in their construction, there does not yet exist a comprehensive series of reference pediatric tomographic phantoms, nor the ability to simulate very fine anatomic structures as can be modeled via mathematical approximation. Consequently, stylized pediatric phantoms will continue to fill this data need in medical dosimetry.

Design and control optimization of microclimate liquid cooling systems underneath protective clothing

The use of protective clothing, whether in space suits, hazardous waste disposal, or sporting equipment, generally increases the risk of heat stress and hyperthermia by impairing the capacity for evaporative heat exchange from the body to the environment. To date the most efficient method of microclimate cooling underneath protective clothing has been via conductive heat exchange from circulating cooling fluid next to the skin. In order to make the use of liquid microclimate cooling systems ((LQ)MCSs) as portable and practical as possible, the physiological and biomedical engineering design goals should be towards maximizing the efficiency of cooling to maintain thermal comfort/neutrality with the least cooling possible to minimize coolant and power requirements. Meeting these conditions is an extremely complex task that requires designing for a plethora of different factors. The optimal fitting of the (LQ)MCSs, along with placement and design of tubing and control of cooling, appear to be key avenues towards maximizing efficiency of heat exchange. We review the history and major design constraints of (LQ)MCSs, the basic principles of human thermoregulation underneath protective clothing, and explore potential areas of research into tubing/fabric technology, coolant distribution, and control optimization that may enhance the efficiency of (LQ)MCSs.