1.1 This practice establishes the minimum requirements for computed tomography (CT) examination of test objects using fan beam systems (systems that generate one or a few CT cross sectional slices at a time). The examination may be used to nondestructively disclose physical features or anomalies within a test object by providing radiological density and geometric measurements. This practice implicitly assumes the use of penetrating radiation, specifically X-ray and γ-ray.

1.2 CT is broadly applicable to any material or test object through which a beam of penetrating radiation passes. The principal advantage of CT is that it provides densitometric (that is, radiological density and geometry) images of thin cross sections through an object without the structural superposition in projection radiography.

1.3 There are areas in this practice that may require agreement between the purchaser and the supplier, or specific direction from the cognizant engineering organization. These items should be addressed in the purchase order or the contract. Generally, the items are application specific or performance related, or both.

1.4 Techniques and applications employed with CT are diverse. This practice is not intended to be limiting or restrictive. Refer to Guides E1441 and E1672 that provide additional information and guidance on CT fundamentals and tradeoffs in designing or purchasing a CT system, or both.

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