Bone Densitometer Hardware Validation (Bone Densitometer Validation) - 07.12.17

Overview | Description | Applications | Operations | Results | Publications | Imagery

ISS Science for Everyone

Science Objectives for Everyone
One of the most common side effects of space travel is a loss of bone density, which happens because of microgravity. Researchers can study these effects by evaluating mice flown in space, and use the results to develop treatments for bone density loss in space as well as in patients on Earth. Bone Densitometer Hardware Validation (Bone Densitometer Validation) tests an X-ray device the size of a kitchen microwave oven, which measures bone density, muscle and fat in mice living on the International Space Station.
Science Results for Everyone
Information Pending

The following content was provided by John C. Vellinger, and is maintained in a database by the ISS Program Science Office.
Experiment Details

OpNom:

Principal Investigator(s)
Eugene D. Boland, Ph.D., Techshot, Greenville, IN, United States

Co-Investigator(s)/Collaborator(s)
Information Pending

Developer(s)
Techshot, Incorporated, Greenville, IN, United States

Sponsoring Space Agency
National Aeronautics and Space Administration (NASA)

Sponsoring Organization
National Laboratory (NL)

Research Benefits
Earth Benefits, Scientific Discovery

ISS Expedition Duration
September 2014 - September 2015

Expeditions Assigned
41/42,43/44

Previous Missions
Information Pending

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Experiment Description

Research Overview

  • The bodies of crew members living in space for months experience some of the same adverse health effects usually only experienced on Earth by senior citizens.
  • A good diet and vigorous exercise helps crew members strengthen their bones and muscles while in space.
  • More research is needed to find even better ways of keeping crew members healthy on long-duration space missions, and improve the lives of individuals on Earth suffering from bones weakened from osteoporosis.
  • Mice living in space experience bone loss even faster than crew members.
  • The Bone Densitometer (BD), developed by Techshot, will be used indefinitely aboard the International Space Station to scan the bones of mice to study the problem and to research possible new treatments.
  • The first use of BD in space, during increment 40/41, will serve as a test to validate the performance of the system.
  • Mice are scanned on Earth at the Kennedy Space Center just prior to their launch on the SpaceX-4 mission. The same mice are scanned again aboard the station. The results of the two scans are expected to be identical.
  • After the device's successful validation, crew members will periodically scan mice and send the results back to scientists on Earth for analysis.

Description
Quantitative measures of bone and muscle loss in mice during orbital space flight are needed for space biology studies as well as for the development of countermeasures for crew members by NASA and for bone-loss syndromes on Earth by commercial entities.

The "gold standard" of bone density measurement is Dual Energy X-ray Absorptiometry (DEXA) in which the absorption of X-rays is quantified at two key X-ray energies. This method is used to calculate absolute bone density, in g/cm2, in humans, mice and other laboratory animals.

The Bone Densitometer (BD) measures X-ray absorption by bone and soft tissue and reports bone density in mice. It can also determine soft-tissue density, lean/fat ratio and total animal mass (i.e., weighing mice in space).

The system is a spaceflight qualified version of GE Medical's Lunar PIXImus. A small x-ray source exposes the entire animal to a cone shaped beam of both high (80kV) and low (35kV) energy x-rays. A high-resolution digital picture (0.18 x 0.18mm) is taken of an image of the xrays hitting a luminescent panel. The ratio of attenuation of the high and low energies allows the BD to separate bone from tissue and, from within the tissue samples, the lean and fat. It provides bone mineral and body composition results from total body imaging in approximately three minutes. Fast imaging allows faster access to important data and is safer on animals.

The system allows automated, accurate and precise measurement of bone and tissue for small animals weighing 10-40 g. Bone, fat and lean measurements exhibit excellent correlation to total ashed or chemical extraction weights. The BD uses a lower x-ray energy than that used for peripheral densitometry in humans in order to achieve contrast in the extremely low density bone. Excellent precision of BMD and %Fat makes it ideal for longitudinal studies.

With an image area of 80 mm x 65 mm, the BD can image the entire body of most mice,and the subcranial region of large ob\ob mice. Regions of interest (ROIs), such as spine and femur, are manually selectable. The system is compact and provides high-resolution images in addition to quantitative measurements in real time. The user can trace a ROI interactively on the screen.

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Applications

Space Applications
Crew members on long-duration space missions suffer bone density loss, which they try to prevent by exercising often and eating healthy meals, but current and future missions lasting a year or more may require additional countermeasures to keep crew members healthy. This investigation validates the space readiness of a tool that measures bone density in mice, which can be used as a model for studying bone density loss in humans.

Earth Applications
Crew members living in orbit experience some of the same health problems as elderly people on Earth, including bone density loss. New drugs and therapies to treat bone loss in space could also be used to help people on Earth. The PixiMus technology used in this investigation is commonly used on Earth, but verifying its capabilities in space will help researchers and biotech firms test new therapies on space-borne rodents, measuring how well they work. Results could benefit millions of elderly people who suffer from osteoporosis and other bone density-related ailments.

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Operations

Operational Requirements and Protocols
The launch orientation is critical to the payload. This payload is dependent upon the MSG as well as the AEM Rodent Habitat.
This experiment is set to launch on SpaceX (unpowered). Once on station, it is transferred to the EXPRESS Rack. The crew then performs a hardware checkout procedure. An Exam Box is inserted into the MSG. Once the specimen is in the Exam Box, it then needs to be transferred to the bone densitometer hardware. An image needs to be taken of the specimen and downlinked. Once complete, the Exam Box is transferred back to the MSG and the animal is removed.

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Decadal Survey Recommendations

Information Pending

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Results/More Information

Information Pending

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Related Websites
Techshot, Inc.

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Imagery

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NASA Image: ISS052E004180 - Astronaut Peggy Whitson performing change out of Imaging Unit on the Bone Desitometer (BD) located in Node 2.

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Bone Densitometer Flight Unit with monitor. Image courtesy of Techshot.

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NASA Image: ISS052E004182 - Astronaut Peggy Whitson performing change out of Imaging Unit on the Bone Desitometer (BD) located in Node 2.

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Bone Densitometer Flight Unit. Image courtesy of Techshot.

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