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

Overview: The subcommittee recognized that to get the best accessibility, equipment would need redesign to accommodate persons seated in wheeled mobility devices for the exam. In developing its proposals, the subcommittee considered the physical constraints needed for operation of the equipment, technical feasibility, patient safety, and clinical standards. The subcommittee weighed all the provisions for technical criteria in light of the equipment functionality and the need to image a range of body sizes, functionality, and types.

The subcommittee considered the interaction of mammography devices with individuals using scooter. Due to the need for the woman’s chest wall to be flush with the breast platform, the front scooter components make this position impossible without the person swiveling to the side. Thus, the final recommendations focused on the mammography device’s interaction with wheelchairs. Mammography equipment recommendations are also operable with use of a mammography chair for patients who need to sit for the procedure but do not use a wheelchair.

Mammography imaging involves complex interactions between moving parts. To get the final dimensions, the subcommittee needed to consider the elements “dynamically.” The dynamic angle is necessary because of the way the equipment operates. Recognizing that all operations center on the movable breast platform, recommendations define each component in relationship to the breast platform. The unique aspects of mammography device design and operation requires components to work when the breast platform is at breast height. Since breast platform design affects most of the other device components, defining each in relationship to the breast platform creates proportions that when incorporated into the design process assure that women in mobility devices can get effective imaging.

Ordinarily, the accessibility dimensions are static and measured from a static element such as the floor. Because of the movable breast platform and C-arm, each recommendation defines the other device components in relation to the breast platform. The static point is with the breast platform at the height of 34 inches. This allowed the subcommittee with industry input to consider and maximize the dimensions that improved the accessibility during the equipment’s operation. The result is that this report defines traditional accessibility elements from a different vantage point.

To determine the final criteria for the mammography devices, the subcommittee balanced the knowledge of disability, range of physical characteristics and diversity of body types and sizes with each device component. The members considered industry input on how the dimensions and operation of one element would interact with the other elements. Such input helped interpret how these interactions would affect each other. The subcommittee used the best data available recognizing that the data available did not always match precisely the operations of mammography equipment.

To determine the recommendation, it was critical for all to have an understanding of the equipment components. The diagram below illustrates the set of terminology and the location on a mammography device used to describing the mammography components below. (Figure 1 below)

Figure 1. Overview of the subcomponents of a mammography machine.

In order to get a quality image, the patient’s breast needs to rest on top of the breast platform and the chest wall needs to be flush with the front edge of the breast platform. For this to be possible, the breast platform needs to go low enough to accommodate a patient seated in a wheelchair. There also needs to be enough knee and toe clearance to ensure that the patient can get close enough to the breast platform without knees or feet hitting parts of the equipment. One important feature of mammography equipment is the base support, also shown in Figure 1, which is critical for structural support, seismic stability, and installation safety. This base support must be low enough so that a patient’s footrests can ride over it and it must allow enough unobstructed floor space to ensure that a wheelchair’s front caster wheels do not hit it. Lastly, the configuration of the positioning supports must provide enough flexibility for all patients to be able to reach and hold them. An illustration of each is in Figure 2 below.

Figure 2. Overview of the critical dimensions that impact the accessibility of mammography equipment.