Suggested Citation:"Appendix B: Glossary, Acronyms, and Abbreviations." National Academies of Sciences, Engineering, and Medicine. 2015. Airport Passenger Screening Using Backscatter X-Ray Machines: Compliance with Standards. Washington, DC: The National Academies Press. doi: 10.17226/21710.
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Glossary, Acronyms,
and Abbreviations
| AAPM | American Association of Physicists in Medicine |
| absorbed dose | The amount of energy from ionizing radiation deposited at a given point. Absorbed dose is measured in Gray. |
| advanced imaging technology (AIT) | Technology is intended to screen passengers at airports or other secure facilities (such as prisons) that allow for visual detection of both metallic and non-metallic threat items, including weapons, explosives, and other concealed objects on passengers. These items would not be detected by walk-through metal detectors. |
| air kerma | Radiation quantity often used to express the radiation concentration delivered to a point, such as the entrance surface of the body. It is measured in joules/kilogram (J/kg). |
| ALARA | as low as (is) reasonably achievable |
| ANSI | American National Standards Institute |
| AS&E | American Science and Engineering, Inc. |
| ATR | automatic target recognition |
Suggested Citation:"Appendix B: Glossary, Acronyms, and Abbreviations." National Academies of Sciences, Engineering, and Medicine. 2015. Airport Passenger Screening Using Backscatter X-Ray Machines: Compliance with Standards. Washington, DC: The National Academies Press. doi: 10.17226/21710.
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| backscatter | The reflection of waves or signals back to the direction from which they came. |
| BMI | body mass index |
| bystanders | Persons—for example, operators or persons waiting in line to be scanned—not being scanned but who may receive dose from the operation of the backscatter X-ray machine because of their proximity to the inspection area. |
| CDC | Centers for Disease Control and Prevention |
| CPE | charged particle equilibrium |
| DDE | deep dose equivalent |
| DHS | Department of Homeland Security |
| effective dose | Effective dose is a dose parameter that takes into consideration the type of radiation and the sensitivity of the body parts exposed. Effective dose is expressed in sieverts (Sv). |
| EMO | emergency-off (button) |
| FAT | factory acceptance test |
| FDA | Food and Drug Administration |
| HPS | Health Physics Society |
| HVL | half-value layer |
| ICRP | International Commission on Radiological Protection |
| ICRU | International Commission on Radiation Units and Measurements |
| interlocks | Systems (devices or processes) used to prevent failure of a machine. Interlocks can be electrical, mechanical, or software. |
Suggested Citation:"Appendix B: Glossary, Acronyms, and Abbreviations." National Academies of Sciences, Engineering, and Medicine. 2015. Airport Passenger Screening Using Backscatter X-Ray Machines: Compliance with Standards. Washington, DC: The National Academies Press. doi: 10.17226/21710.
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| JHU/APL | Johns Hopkins University/Applied Physics Laboratory |
| KERMA | kinetic energy released in matter (known as kerma) |
| Linear-nonthreshold (LNT) dose reponse model of radiation effects | Model used for radiation protection purposes to estimate risks at low radiation doses where there is not sufficient epidemiological or biological evidence to draw direct conclusions about risks. The linear nonthreshold model assumes that there is a linear relationship between dose and effect and therefore allows for extrapolation from the outcomes observed at higher radiation doses to lower doses. |
| NCRP | National Council on Radiation Protection and Measurements |
| NIST | National Institute of Standards and Technology |
| NRC | National Research Council |
| NURBS | Non-Uniform Rational Basis Spline |
| organ dose | The absorbed dose averaged over an organ. Organ dose is measured in Gray. |
| OSHA | Occupational Safety and Health Administration |
| OSL | optically stimulated luminescence |
| PDD | percent depth dose |
| primary and secondary screening | Primary screening is screening that all passengers are subject to. Secondary screening is additional screening that may be used based on the response to the primary screening, randomization, or other metrics that suggest that further information is needed about a passenger (e.g., to possibly resolve an alarm during primary screening). |
Suggested Citation:"Appendix B: Glossary, Acronyms, and Abbreviations." National Academies of Sciences, Engineering, and Medicine. 2015. Airport Passenger Screening Using Backscatter X-Ray Machines: Compliance with Standards. Washington, DC: The National Academies Press. doi: 10.17226/21710.
×
| radiation | The energy that comes from a source and travels through some matter or through space. There are two types of radiation: ionizing and nonionizing. Ionizing radiation, which includes X-rays, is considerably more energetic compared to nonionizing radiation such as that found in microwaves. Ionizing radiation is more harmful to living organisms per unit of energy deposited than is nonionizing radiation as it has the potential to cause DNA damage and, consequently, cancer. Currently, there is no convincing evidence that nonionizing radiation can cause cancer, with few exceptions; for example, ultraviolet and skin cancer. |
| RFP | request for proposals |
| SAT | site acceptance test |
| scan | The operation necessary to produce one image (e.g., front view) from one radiation source. One radiation source simultaneously producing multiple images also constitutes one scan. Two sources simultaneously producing two images constitute two scans. In some cases several scans may be required for a single screening of the subject. |
| screening | The sum of radiation exposures or scans necessary to image objects concealed on all sides of the body as intended by the system design under normal conditions. Examples: (1) for backscatter systems a screening typically consists of four scans, one from each side; (2) for transmission systems a screening typically consists of one scan. |
| SDE | shallow dose equivalent |
| Sievert (Sv) | The international (SI) name for the unit of dose equivalent radiation measured in J/kg, calculated by multiplying the absorbed dose (in Gy) with a weighting factor. |
| SP | single pose |
| SSD | source-skin distance |
Suggested Citation:"Appendix B: Glossary, Acronyms, and Abbreviations." National Academies of Sciences, Engineering, and Medicine. 2015. Airport Passenger Screening Using Backscatter X-Ray Machines: Compliance with Standards. Washington, DC: The National Academies Press. doi: 10.17226/21710.
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| TMR | tissue-maximum ratio |
| TSA | Transportation Security Administration |
| TSIF | Transportation Systems Integration Facility |
| uncertainty | Lack of sureness or confidence in predictions of models or results of measurements (NCRP Report No. 158). |
| USAPHC | U.S. Army Public Health Command |
Suggested Citation:"Appendix B: Glossary, Acronyms, and Abbreviations." National Academies of Sciences, Engineering, and Medicine. 2015. Airport Passenger Screening Using Backscatter X-Ray Machines: Compliance with Standards. Washington, DC: The National Academies Press. doi: 10.17226/21710.
×
Suggested Citation:"Appendix B: Glossary, Acronyms, and Abbreviations." National Academies of Sciences, Engineering, and Medicine. 2015. Airport Passenger Screening Using Backscatter X-Ray Machines: Compliance with Standards. Washington, DC: The National Academies Press. doi: 10.17226/21710.
×
Suggested Citation:"Appendix B: Glossary, Acronyms, and Abbreviations." National Academies of Sciences, Engineering, and Medicine. 2015. Airport Passenger Screening Using Backscatter X-Ray Machines: Compliance with Standards. Washington, DC: The National Academies Press. doi: 10.17226/21710.
×
Suggested Citation:"Appendix B: Glossary, Acronyms, and Abbreviations." National Academies of Sciences, Engineering, and Medicine. 2015. Airport Passenger Screening Using Backscatter X-Ray Machines: Compliance with Standards. Washington, DC: The National Academies Press. doi: 10.17226/21710.
×
Suggested Citation:"Appendix B: Glossary, Acronyms, and Abbreviations." National Academies of Sciences, Engineering, and Medicine. 2015. Airport Passenger Screening Using Backscatter X-Ray Machines: Compliance with Standards. Washington, DC: The National Academies Press. doi: 10.17226/21710.
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