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A Closer Examination of X-Ray Technology…Answers to Your Most Asked Questions

Fri, 03/06/2009 - 7:00am

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Most are familiar with X-Ray technology and its use in airports to inspect baggage or in medical and dental offices for examinations. However, the general public is less aware of the important role X-Ray technology plays in the Pharmaceutical, Food, Chemical and Packaging industries.

The pharmaceutical industry maintains strict controls on reducing and eliminating contaminants before they reach consumers. To help users better understand how X-Rays are used for Pharmaceutical product inspection, this article examines some of the most frequently asked questions.

What role does X-Ray technology play in the Pharmaceutical industry?

X-ray systems are effective in scanning products for foreign objects after they are packaged and sealed. For example, foil blister packs and tablet/capsule containers with foil safety seals. X-ray machines also allow you to see the product in the package to ensure that the products are not damaged in any way.

What is a cabinet X-Ray system?

A "cabinet" X-Ray system is a US Food and Drug Administration (FDA) classification given to this type of equipment. The cabinet minimizes X-Ray emissions and access to the X-Ray beam.

What capabilities should you look for in an X-Ray system?

X-ray inspection systems should reliably identify contaminants, scan for missing or broken products, detect packing voids, confirm fill levels and control product and package mass. Additionally, the system's software should monitor, document and record all aspects of the inspection process and equipment operating parameters.

Can X-Ray machines keep a record of each of the rejected products to provide for further information?

An x-ray machine logs the date, time and type of reject. It also saves an inspection image of the product so you can view the contaminant.

Will X-Ray equipment scan for clumps or inconsistencies in my product?

Clumps of product often create a darker gray scale image in a homogenous product. Accordingly, there is an opportunity for detection of clumps and inconsistencies despite the fact they have the same atomic number or chemical composition
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What capabilities does X-Ray equipment have in detecting the presence of leaflets or premiums in my packages?

X-ray systems are effective in detecting premiums (including leaflets) in most packages. Eriez reviews performance by testing customers' product with the premium for every customer request.

Can X-Ray technology distinguish between contaminants?

As a rule, this type of technology will only allow for the detection of foreign objects and will not differentiate among types.

What is the most common contaminant found in pharmaceutical applications?

The most common form of foreign object is broken stainless steel dies from the tablet press machines.

Does the orientation of the contaminant in the packaging have any effect on the detection capability of the system?

Yes. An x-ray beam is 2-3 mm thick and is directed toward a silicon array of diodes (which is a device that effectively is looking for photons or light). If a foreign object is perpendicular to the beam, it is less detectable because it is less dense. Conversely, if it is vertical (or on plane with the beam), it is more dense and therefore more detectable.

What size contaminant is expected to be detected?

The size of foreign object detected depends on the selected model, beam energy, product characteristics, the contaminant type (i.e. bone, glass, metal, etc.) and the package material.

Is it safe to stand or walk near a cabinet X-Ray system while it is producing X-Rays?

Yes. Manufacturers are required to certify that their products meet the US Federal radiation safety performance standard for cabinet x-ray systems. Specifically, the standard requires that the radiation emitted from a cabinet x-ray system not exceed 0.5 milliroentgens in one hour at any point five centimeters from the external surface. Most cabinet X-Ray systems emit less than this limit. In addition, the standard also requires safety features that include warning lights, key lock, warning labels and interlocks.

To put this into perspective, the average person in the United States receives about 360 millirem of radiation per year from background radiation. (Note: one milliroentgen of exposure to x-rays will result in approximately one millirem of dose. These terms are defined below.) Sources of background radiation include the sun, radon and tobacco, to name a few. Accordingly, 80 percent of exposure most people receive comes from natural sources. The remaining 20 percent comes from manmade radiation sources, primarily medical X-Rays.*

Is it okay for pregnant women to stand or walk near a cabinet X-Ray system while it is producing x-rays?

Yes. The limit on radiation emission established by the performance standard is sufficiently restrictive that there is no additional hazard for specific populations such as children or pregnant women.*

Are the operators of cabinet X-Ray systems required to wear a "radiation badge" or dosimeter?

Personnel monitoring equipment is not required by Federal regulation for operators of cabinet X-Ray systems. The Federal limit on cabinet X-Ray system emissions ensures the maximum possible exposure from cabinet x-ray systems in the workplace will always fall below the minimum threshold where personnel monitoring might be required*. However, each state's Department of Health (DOH) or Department of Environmental Protection (DEP) governs and regulates its own state and may require badge monitoring.

Are the operators of cabinet X-Ray systems required to wear physical protection when operating the system?

No, the system uses very low levels of X-Ray energy; emissions are virtually undetectable.

What do the terms exposure and dose mean? What do their measurement units mean?

Exposure is a term defining the amount of ionizing radiation that strikes living or inanimate material. Dose is the quantity of radiation or energy absorbed. Dose may refer to the following: -Absorbed dose: the amount of energy deposited per unit mass.

-Equivalent dose: the absorbed dose adjusted for the relative biological effect of the type of radiation being measured.

Roentgen (R) is a unit of exposure of ionizing radiation and indicates the strength of the ionizing radiation. One Roentgen is the amount of x-ray needed to produce ions carrying one electrostatic unit of electrical charge in one cubic centimeter of dry air under standard conditions.

Roentgen absorbed dose (rad) is the basic unit of absorbed radiation dose. A dose of one rad to an object means each gram of the object received 100 ergs of energy or one rad = 100 ergs/gram.

Roentgen Equivalent Man (rem) is the basic unit of equivalent dose, and relates the absorbed dose in human tissue to the biological effect of the radiation. Not all radiation has the same biological effect, even for the same amount of absorbed dose.*

Do X-Ray systems require special registration paperwork?

For each X-Ray system sold, the manufacturer will submit a report to the FDA; this is called a product report. The purchaser will need to contact the appropriate state agency and then register the equipment. (The form varies from state to state.)

Who is qualified to operate the X-Ray system?

After basic training, virtually anyone can successfully operate an X-Ray system. Today's X-Ray systems are easier than ever to operate. Eriez systems utilize a Windows-based program that is typical to common household computers. This feature lowers operators' apprehension and minimizes errors.

Will food products become irradiated when passed through a cabinet X-Ray system?

No! In order to induce changes in a product (or sterilize it) very powerful beams of radiation are required. The radiation dose typically received by objects scanned by a cabinet x-ray system is one millirad or less. The minimum dose used in food irradiation for food preservation or destruction of parasites or pathogens is 30,000 rad. *

Why have X-Ray machines become such a popular method of detection in the pharmaceutical industry?

X-ray machines are more versatile than traditional metal detectors and offer greater inspection capabilities. A cabinet X-Ray system is able to detect more than just metal. It enables users to scan for count, missing products, mass and deformities, as well as many other processing errors. It is a total quality control device.

How difficult is it for operators to make a transition to X-Ray technology?

The quick answer is most operators are familiar with computers and Windows software, therefore they find it easier to operate than a menu-driven program that is typically found in today's inspection devices. However, with X-Ray, operators need to familiarize themselves with regulatory and safety requirements.

How effective is X-Ray equipment in the detection of nonmetallic contaminants?

X-ray technology is excellent at detecting non-metallic contaminates--- as long as the foreign object has a detectable element such as silicon, chlorine or calcium. Accordingly, foreign objects such as stone, glass and certain plastics can be efficiently detected.

*Portions of this information were adapted from and more information may be obtained from the Food and Drug Administration website
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