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

4.4 Mammography Equipment

According to figures from the CDC, breast cancer is the most common malignancy among women, although lung cancer causes the most cancer deaths in women (www.cdc.gov/cancer/dcpc/data/women.htm). Women with mobility disabilities are significantly less likely to undergo mammography screening for breast cancer than are other women, and as disability severity increases the rates of screening decrease (Table 2.1). Many factors contribute to these lower rates of screening mammography, but as noted in the NPRM (p. 40), inaccessibility of radiology equipment is a major reason persons with disabilities do not undergo imaging studies. As discussed further in Section 2.1, the U.S. Preventive Services Task Force recommends screening mammography every two years for women ages 50 through 74 (Grade B level of evidence). Depending on her specific clinical circumstances (e.g., comorbid illnesses, level of health risks), this recommendation should apply equally to many if not most women with disabilities.

Mammography is a specialized diagnostic imaging study that raises particular considerations. As noted in Section 4.3.1, technologists participate actively in all imaging studies. In the case of mammography, technologists provide hands-on help to all women, assisting them in positioning their bodies and breasts on the equipment’s breast plates to obtain the necessary images. Technologists report that conducting mammography studies of adequate quality is difficult when women remain seated in wheelchairs or scooters during the test. Depending on the configuration of the mammography machine, women seated in wheelchairs may not be able to get close enough to the equipment to position their breast as needed on the breast platform. In other instances, the breast platform might not go low enough to image their breasts while in the seated position.

Although for convenience throughout this section we refer to women as the users of mammography, men do – albeit rarely – undergo mammography. Generally men undergo mammography to evaluate breast enlargement, tenderness, or a palpable lump. Breast cancers occur in men, although rarely.^DD Therefore, since women are the primary users of this equipment, the Committee focused on anthropometric measurements of women when possible.

Notes

^DD According to the National Cancer Institute, less than 1% of breast cancers occur in men (http://www.cancer.gov/cancertopics/pdq/treatment/malebreast/Patient).

4.4.1 Overview of Mammography Accessibility Considerations

Mammography equipment will likely require redesign to fully accommodate women seated in wheelchairs. Critical considerations in this redesign include the physical constraints needed for operation of the equipment, technical feasibility, patient safety, clinical standards, and the range of body sizes, physical functional abilities, and wheelchair sizes.

Mammography imaging involves complex interactions between moving parts. Ordinarily, the accessibility dimensions are static and are measured from a static element, such as the floor. To get the final dimensions for the equipment standard, the subcommittee needed to consider the elements “dynamically,” especially given how the equipment operates. Recognizing that the movable breast platform is the main action point, recommendations define each component in relationship to the breast platform. The unique aspects of mammography device design and operation require components to work when the breast platform is at breast height. Since breast platform design affects most of the other device components, defining each component in relationship to the breast platform creates proportions that, when incorporated into the design process, assure that women seated in wheelchairs can get effective imaging.

Because of the movable breast platform and C-arm, each recommendation defines the other device components in relation to the breast platform. This gives the opportunity to consider and maximize the dimensions that improve the accessibility during the equipment’s operation. To make final recommendations for mammography accessibility, the Committee balanced the knowledge of disability, a range of physical characteristics and diversity of body types and sizes with each device component. Committee members used the best data available recognizing that the data available did not always match precisely the operations of mammography equipment.

4.4.2 Mammography Equipment and Scooters

The Committee considered the interaction of women who use scooters with mammography equipment. As noted above, to obtain acceptable images, a woman’s chest wall must be flush with the breast platform. However, the steering column and other front components of many scooters prevent this necessary proximity without the woman swiveling their seat to a side position. Once the scooter user swivels to the side, she may be able to be positioned on the equipment without any interference between her scooter and the equipment.^EE The Committee’s mammography accessibility recommendations focus on interactions with wheelchair users. Mammography equipment recommendations also apply to use of a mammography chair for women who need to sit for the procedure but do not use a wheelchair and to women of short stature.

Notes

^EE The ability of a scooter user to remain seated in her swiveled scooter seat and receive a successful mammogram image depends on multiple factors, including the size of her scooter, the ability to raise and lower the scooter seat, whether there is sufficient room to maneuver the scooter, her physical abilities (e.g., to rotate her torso), and the skill of the technologist.

4.4.3 Implications of Mammography Equipment Components

To determine the accessibility standard recommendations, understanding mammography equipment components is essential. Figure 4.3.3(a) illustrates the terminology and the location on a mammography device that the Committee used to describe mammography components.

Figure 4.4.3(a)

Mammography Equipment Components

(SOURCE: Hologic, Inc.)

In order to get an image with sufficient detail, a woman’s breast must rest on top of the breast platform and her 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 woman seated in a wheelchair. In addition, knee and toe clearance must be adequate to allow the woman to get close enough to the breast platform without her knees or feet hitting parts of the equipment. Another important feature of mammography equipment is the base support (shown in Figure 4.4.3(a), which is critical for structural support, seismic stability, and installation safety. This base support must be low enough so that the woman’s wheelchair footrests can ride over it; furthermore, it must allow enough unobstructed floor space to ensure that her 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. Figure 4.4.3(b) shows an illustration of each accessibility feature.

Figure 4.4.3(b)
Features of Mammography Equipment Addressed by Committee

(SOURCE: Hologic, Inc.)