Recommendations on Standards for the Design of Medical Diagnostic Equipment for Adults with Disabilities, Advisory Committee Final Report

5.4.1.2 Transfer and Positioning Support Location Recommendations for Imaging Equipment with Transfer Surfaces

For imaging equipment with transfer surfaces, the Committee recommends adding transfer supports on tables with transfer depths of less than or equal to 24 inches and positioning supports for transfer depths greater than 24 inches. Both transfer and positioning supports are to be located opposite the transfer side.

Rationale for the recommendation

Imaging tables need some form of support on the opposite side of the table. Because of the size, diversity, and use of diagnostic imaging tables, this support will carry out different functions on different tables. The function dictates the design and load capability. This two-part recommendation recognizes the different use of the supports based on table width. The Committee used a 24-inch dividing point for table width to accommodate the dimensions for the maximum reach range.

For transfer surface depths on tables less than 24 inches wide, a transfer support must be available on the side opposite the entry to the transfer surface. Some imaging tables are narrow and may not have additional “table” surface beyond the transfer depth. For these narrow tables, a more substantial transfer support is necessary. This transfer support facilitates transfers and prevents patient falls over the opposite side of the table.

For transfer surface depths on tables greater than 24 inches wide, a positioning support must be available on the side opposite the entry to the transfer surface. For wider tables, a transfer support would not be functional because of its distance from the patient. If transfer is possible from either of the long sides of the table, then a positioning support must be available on the side opposite the transfer.

A positioning support requires a different load bearing capacity than a transfer support. Minimum load bearing requirements for supports are found in international standards (e.g. risk management ISO 14971; IEC60601-1; and use of IEC60601-2-52.) Generally, for positioning supports, the table is supporting the full weight of the patient rather than the support. In this situation, the load bearing requirements of the positioning support impose a different load rating. The location of this positioning support must accommodate the clinical use along with the patient’s positioning needs.

In some cases, current methods of imaging patients require table design that may not permit supports to attach to the table without compromising the diagnostic functionality of the table and/or requiring complete redesign of the table structural support. Some types of modalities capture images by using a table that moves. In those cases, attaching supports would likely impede the required movement. For example, some x-ray tables require bi-directional horizontal movement to perform the functions for the images. A new generation of equipment is necessary to address this.

Many/most imaging tables have a moving part and a stationary part dictated by diagnostic need. Many also move up and down. The tables must safely accommodate a wide range of patient sizes. These considerations factor into where the substantial support structure is located while still enabling the precise movement and imaging transparency of the table top/cradle. Therefore, in many cases, there currently is no feasible direct attachment point on the table for a support.

Any support design must take into consideration the risks associated with IV or other tubing, monitors and other such items entangling in the support as the table moves during the procedure. Support design must also assure sufficient clinician access to the patient during the exam for proper positioning, administration of imaging agents or drugs, patient monitoring, etc.