X-ray scanning technology plays a crucial role in various sectors, most notably in security and healthcare. In security, these scanners are indispensable for detecting concealed threats in luggage, cargo, vehicles, and even on individuals. Medical professionals utilize x-rays as a vital diagnostic tool, allowing them to assess patient health, identify internal issues like tumors, and examine injuries such as fractures without invasive procedures. While both medical and security x-ray scanners operate on the same fundamental principles of physics, their applications, designs, and operational requirements differ significantly.
This article delves into the similarities and, more importantly, the differences between security x-ray scanners and medical x-ray scanners, providing a comprehensive understanding of x-ray technology as a versatile and essential tool in modern society. We will explore the nuances of each type, shedding light on why they are tailored for their specific purposes. While the sophisticated technology of airport security scanners and medical imaging is well-known, related but simpler technologies also exist, such as scanner strips for car alarms, which use different sensing principles but share the goal of enhancing security – in this case, vehicle security. Although distinct in technology and application from the high-powered scanners we will primarily discuss, even basic security measures like scanner strips for car alarms highlight the broad spectrum of security technologies designed to protect and safeguard.
THE SCIENCE BEHIND X-RAYS
X-rays are a form of electromagnetic (EM) radiation, a discovery attributed to Wilhelm Conrad Roentgen in 1895. Positioned on the EM spectrum between gamma rays and ultraviolet light (as illustrated in Figure 1), x-rays are characterized by their short wavelengths and high energy levels. This unique combination allows them to penetrate most materials, including human tissue, rendering them invisible to the naked eye yet potentially hazardous if not properly managed.
Figure 1: The electromagnetic spectrum, illustrating the relationship between wavelength, frequency, and energy. Understanding this spectrum is key to grasping the nature of x-rays and their applications. (Image Credit: NASA)
IONIZING RADIATION: A CLOSER LOOK
Radiation is broadly categorized into two types: non-ionizing and ionizing. Ionizing radiation is defined by its capacity to strip electrons from atoms. Non-ionizing radiation lacks the energy to do this, and consequently, is not associated with adverse health effects. X-rays, however, are classified as ionizing radiation. This ionization process can disrupt crucial cellular mechanisms, such as DNA strands and proteins, potentially leading to cellular damage and increasing the risk of cancerous mutations. Therefore, while ionizing radiation carries potential risks, when utilized correctly and with appropriate safety protocols, x-rays become incredibly valuable and safe for a wide range of applications. The following sections will detail how the benefits of x-rays in enhancing health and security significantly outweigh their inherent risks.
Figure 2: This diagram differentiates between ionizing and non-ionizing radiation within the electromagnetic spectrum, highlighting the position of x-rays and their potential impact on matter. (Image Credit: Wikipedia)
MEDICAL X-RAY APPLICATIONS
Medical x-ray systems are integral to modern healthcare, facilitating non-invasive and painless health assessments, disease diagnoses, and surgical planning. Beyond diagnostics, x-rays assist in various medical procedures, such as guiding the insertion of stents, catheters, and other internal medical devices with precision.
Several types of medical x-ray imaging techniques utilize ionizing radiation, each serving distinct diagnostic purposes:
- Radiography: This technique produces a single, static x-ray image, commonly used for dental x-rays and detecting bone fractures. The image is recorded for subsequent detailed evaluation.
- Fluoroscopy: In contrast to radiography, fluoroscopy generates a continuous x-ray image displayed on a monitor. This real-time imaging is invaluable for monitoring dynamic processes within the body, such as the movement of contrast agents (“dyes”) or guiding minimally invasive procedures.
- Computed Tomography (CT): CT scanning involves a detector that rotates around the patient, capturing multiple x-ray images from various angles. These individual scans are then computationally reconstructed to create detailed cross-sectional images, or “slices,” of internal organs and tissues. CT scans provide significantly more detailed anatomical information compared to radiography.
During a medical x-ray procedure, a controlled x-ray beam is directed through the patient’s body. Internal structures, such as bones and tissues, absorb or scatter a portion of the x-rays. Detectors positioned opposite the x-ray source capture the remaining x-ray pattern, which is then processed by computers to generate images for medical review. The level of detail and potential radiation exposure in medical x-rays vary depending on the specific type of scan being performed. Radiologists are rigorously trained to carefully manage and minimize patient radiation exposure, ensuring that it remains within safe limits and is always justified by the diagnostic benefits.
CT scans, while delivering more comprehensive diagnostic information, do expose patients to a higher dose of radiation compared to standard radiography. This is a necessary trade-off to achieve the highly detailed cross-sectional images that are crucial for detecting subtle pathologies, like early-stage cancers. During a CT scan, the patient lies on a motorized table that moves through a ring-shaped scanner. As the table moves, the scanner rotates rapidly, acquiring images from all directions. These images are then processed in a separate control room to generate the detailed “slices” that radiologists analyze. Despite the increased radiation, CT scans are often indispensable for identifying critical health threats, allowing for precise determination of a tumor’s presence, size, location, and its relationship to surrounding tissues.
Medical x-rays are an indispensable tool in modern healthcare, offering life-saving diagnostic capabilities. They visualize internal structures obscured by skin and bone, providing crucial information for diagnosis and treatment. While radiation exposure is a factor, the benefits of medical x-rays in terms of improved health outcomes significantly outweigh the minimal risks when procedures are performed by trained professionals.
SECURITY X-RAY SCANNING: PROTECTING PEOPLE AND PLACES
Security x-ray imaging is an essential technology for non-intrusive inspection of items, eliminating the need for physical searches and manual checks. These scanners rapidly produce detailed and reliable images, revealing the shape, material, and location of all contents within closed bags, packages, and containers. Security x-ray systems are available in a wide range of sizes, from compact units for small bags to large-scale systems capable of scanning cargo pallets, vehicles, and even entire trains. They are deployed across diverse sectors, including law enforcement, transportation, critical infrastructure protection, aviation security, and military operations. Selecting the appropriate x-ray security system depends primarily on the size and type of objects to be scanned and the specific threats being targeted.
Two primary types of x-ray security scanners are commonly used:
- Cabinet X-Ray Systems: These systems house the x-ray tube within a shielded enclosure, typically made of lead. This shielding effectively contains most of the x-ray radiation, preventing leakage outside the cabinet and ensuring safe operation in public environments.
- Personal Security Screening Systems: Used to screen individuals, particularly in high-security areas like airports. These systems include General Use X-Ray Screening Systems (backscatter systems) and Millimeter Wave Screening Systems, each employing different technologies for detecting concealed items on a person’s body.
CABINET X-RAY SYSTEMS: VERSATILE SECURITY SOLUTIONS
Cabinet x-ray systems are ubiquitous in security checkpoints worldwide, from critical infrastructure sites like government buildings and courthouses to airports, ports, and border crossings. These systems are designed for rapid and efficient inspection of baggage, air cargo, vehicles, and various other items without necessitating physical opening or disruption of contents. Cabinet x-ray systems are crucial for maintaining security while ensuring smooth and efficient throughput at checkpoints.
Astrophysics, a leading manufacturer in the field, offers a diverse portfolio of cabinet x-ray systems, each engineered for specific security missions and operational environments. The XIS-6545™, for example, is a compact baggage scanner ideally suited for airport security checkpoints where space is limited and operational speed is paramount.
For air cargo facilities handling large volumes of pallets and oversized baggage, more powerful systems are required. The XIS-1818DV 200kV™ strikes a balance between size, power, and throughput, capable of effectively scanning most cargo pallets. For facilities demanding even more detailed inspection capabilities, the Multi-View CT system provides a high-power x-ray source and advanced 3D image reconstruction software, enabling extremely thorough threat detection.
Ports and border crossings prioritize the rapid screening of vehicles, from passenger cars to large cargo trucks. Astrophysics provides solutions like the HXC-LaneScan™ and HXP series for these applications. The HXC-LaneScan™ is a drive-through system that can scan an entire car from roof to chassis in a single pass, while the HXP line offers truck scanners capable of detailed inspection of entire trailers and their contents. Both are highly effective in combating smuggling and trafficking of illicit goods across borders.
Figure 3: Passengers undergoing routine security screening using cabinet x-ray scanners before boarding a cruise ship at a port in Denmark. (Image Credit: Astrophysics Inc.)
PERSONAL SECURITY SCREENING SYSTEMS: ENSURING INDIVIDUAL SAFETY
Personal security screening systems are employed to screen individuals for concealed threats. “General Use Systems,” also known as “backscatter” systems, represent one category. These systems use a very low dose of x-rays and detect the radiation reflected back from the body, rather than the transmitted radiation. This reflected radiation provides a detailed image of the surface of the person being scanned, revealing concealed objects.
Figure 4: A Transportation Security Administration (TSA) officer conducting security screening using a millimeter wave scanner at an airport checkpoint. (Image Credit: Reuters)
The second type, “Millimeter Wave systems,” utilizes millimeter waves, which are non-ionizing and situated at the high-frequency end of the radio wave spectrum. Active millimeter wave systems emit radiation and analyze the reflected patterns to detect anomalies. Passive systems, conversely, detect naturally occurring millimeter wave radiation emitted by objects and the human body, identifying variations that may indicate concealed items.
In today’s security-conscious world, screening of both items and individuals is standard practice for accessing secure areas. Airports, courthouses, government buildings, critical infrastructure sites, cargo facilities, ports, and border checkpoints are all examples of locations where robust security measures, including scanning technologies, are essential. Scanning technology is a cornerstone of creating safer environments, enhancing the effectiveness of security personnel with advanced detection capabilities.
KEY DIFFERENCES BETWEEN SECURITY AND MEDICAL X-RAY SCANNERS
While medical and security x-ray scanners share fundamental technological principles – the detection and interpretation of attenuated or reflected electromagnetic radiation – their key differences stem from their specific applications, risk considerations, operator training, and system design.
Medical x-ray scanners, designed for direct irradiation of the human body, operate under stringent regulatory standards to minimize radiation exposure while maximizing diagnostic image quality. Operation of medical x-ray equipment and interpretation of the resulting images require extensive specialized training. Radiologists undergo years of medical education and specialized radiology training to accurately analyze medical scans and provide diagnoses.
Security scanning systems, in contrast, demand a different skillset from operators. While medical imaging emphasizes detailed analysis of subtle grayscale variations in images, security screening focuses on rapid threat detection across a wide range of object types and materials. Security inspectors must quickly analyze images of bags, vehicles, cargo, and containers, identifying potential threats concealed within diverse contents – often within seconds per scan. Security systems incorporate advanced image processing tools and automated features, such as Astrophysics Enhanced Imaging™ (EI™) and AI™-powered threat detection software, to aid inspectors in this fast-paced environment. Furthermore, the high volume of items scanned in security settings necessitates efficient and automated systems to maintain operational throughput.
Figure 5: A typical black and white medical x-ray image, showcasing the level of detail required for diagnostic purposes. (Image Credit: Nevit Dilmen/Wikipedia)
X-ray images, by nature, are grayscale as x-rays are outside the visible light spectrum. However, security x-ray systems commonly employ colorization programs to enhance image interpretation. These programs assign colors to different materials based on their atomic number, categorizing them into organic materials (plastics, food), inorganic materials (metals), and dense metals (steel, lead). This color-coding assists security personnel in quickly distinguishing material types, as shape and density alone may not be sufficient for object identification. Inspectors utilize both the original grayscale image and the colorized image to comprehensively analyze scans.
Medical x-ray systems generally do not use colorization programs. Since the human body is primarily composed of organic tissues, color-coding based on material type would be less informative and could potentially obscure subtle diagnostic details best visible in grayscale.
Figure 6: A colorized EI™ x-ray image of a duffel bag scanned by an Astrophysics x-ray scanner. The colorization program assigns colors based on the atomic numbers of the scanned materials, aiding in material discrimination. (Image Credit: Astrophysics Inc.)
ABOUT ASTROPHYSICS
Astrophysics is a leading manufacturer of x-ray security screening equipment with over two decades of industry experience. With over 40,000 systems deployed across more than 150 countries, Astrophysics is a trusted provider of security solutions for critical infrastructure, air cargo, ports, and borders worldwide. Headquartered in City of Industry, California, Astrophysics products are designed in the USA and assembled in North America, adhering to the highest quality standards. Astrophysics holds ISO 9001 and ISO 14001 certifications, demonstrating its commitment to quality and environmental management. Astrophysics x-ray scanners meet stringent industry specifications, and the company offers TSA and ECAC qualified systems for diverse security environments. Through superior imaging technology, continuous innovation, and exceptional customer service, Astrophysics has become a globally recognized brand in x-ray security. Stay connected with Astrophysics for the latest news and product updates on Twitter, LinkedIn, Facebook, and YouTube.
