Mammography Industry: Review of Proposed Accessibility Standards

U.S. Access Board

May 8, 2012

Atlanta, Georgia

John LaViola, V.P. Engineering

Hologic, Inc. – Breast Health

Diagnostic Equipment – Mammography

Current State

Diagnostic Equipment – Mammography Current State

 Appropriate ergonomic design and patient accessibility features are goals for all 

mammography equipment manufacturers

 Per US FDA / EU MDD, manufacturers are required to address mammography human 

factors and usability

 No specific accessibility architectural standards exist for mammography equipment, but 

we have general requirements

o CFR Title 21, MQSA, and clinical organizations explicitly and implicitly define use 

cases and design requirements

o Consensus standards define safety and performance requirements (e.g., 

mechanical strength, “pinch points”)

Current Accessibility Features

[Photos: Three photographs showing typical mammography machines. The machines are 

similar looking, one has a patient standing at the machine for an examination.]

Wheelchair accommodations & hand/arm support features are provided

Diagnostic Equipment - Mammography

Question 8: To what extent does diagnostic equipment currently incorporate features that 

conform to the technical criteria proposed in Chapter M3?

Some features and clearances currently comply, but further assessment of certain proposed 

requirements in the context of mammography applications is required:

 Breast platform

 Knee/Toe clearance

 Standing support definitions

Breast platform

Breast Platform Height Standard: M303.4.1

Question 36. a) Is the proposed height range for the breast platform (30 inches high minimum 

and 42 inches high maximum above the floor) sufficient to accommodate patients seated in a 

wheelchair?
 Yes, but based on patient accessibility requests, several manufacturers lower the breast 

platform to 25” - 28”

 Recommend reassessing and clarifying height range to be an available range of travel 

instead of a specific minimum and maximum

Knee and toe clearance

Knee/Toe Clearance Standard: M303.2.4

“Knee and toe clearance under breast platforms shall be 25 inches (635 mm) deep.”

 Flat gantry base

 Clearance goes to the floor

 No provisions for base supports

[Illustration: Secondary drawing from Figure M5 of the Example Applications of the Proposed 

Medical Diagnostic Equipment Accessibility Standards. Drawing shows a woman using a 

manual wheelchair holding onto the supports of the mammography machine that has been 

adjusted to a lower height to accommodate a seated position.]

Toe Clearance Concerns

Example Base Lip Profile

[Photo: The legs and knee of person using a wheelchair is shown underneath the breast 

platform of a mammography machine. A lip projecting out from the equipment under the 

footrests of the wheelchair at the floor level is highlighted.]

 Lip often required for structural/seismic stability and installation

 Lip profiles can be designed for optimal wheelchair accessibility

Toe Clearance Amendment

 To guarantee wheelchair accessibility and structural stability, add an allowable base lip 

profile to the toe clearance requirements

o Standard for profile of base lip should be developed from anthropometric data 

on wheelchair footrest positioning

 To improve accessibility and minimize technical constraint, clearance should be 

specified as 25” minimum

Knee Clearance Standard: M303.2.4.2

Standard references knee clearance relative to the floor

“Knee clearance shall be provided at a depth of 11” minimum and 25” maximum at 9” above 

the floor and at a depth of 8” minimum at 27” above the floor...”

[Illustration: Figure M6 of the Example Applications of the Proposed Medical Diagnostic 

Equipment Accessibility Standards showing the minimum knee and toe clearances required by 

the proposed Standards. An outline of a person’s legs and associated portion of a wheelchair 

are shown in the clearance area.]
Knee Clearance for Mammography

Dependent on height of breast platform

 Clearance for legs necessary at a certain distance below breast platform

 Proper knee/torso clearance is dependent on breast platform contour

[Photo: Woman using a manual wheelchair pulled up underneath the breast platform and 

holding onto the supports of a mammography machine that has been adjusted to a lower 

height to accommodate a seated position. The distance between the breast platform surface 

and her lap is indicated.]

Knee Clearance Recommendations

 Ensure accessibility and clarify requirements (recommendation):

o Restructuring this section to define knee clearance in reference to breast 

platform height

o Clarifying interpretation of this knee clearance definition in relation to 25” 

knee/toe clearance depth requirement (M303.2.4)

Standing Supports

Standing Support Standard: M305.3.2

 “Where the support is vertical, it shall be 18” minimum in length and the bottom end of 

the support shall be 34” high minimum and 37” high maximum above the standing 

surface.”

 Derived from ICC A117.1-2009 “accessible bathing fixtures”

o May be inappropriate for mammography applications

[Illustration: Three-dimensional overview drawing of Figure M5 of the Example Applications of 

the Proposed Medical Diagnostic Equipment Accessibility Standards showing the features and 

minimum dimensions required by the proposed Standards. The two features addressed by the slide 

are highlighted.]

Standing Supports for Mammography

 Example: 6” gripping surface at 49” above the standing surface for patient 

positioning/immobilization

 For positioning, hand/arm supports are placed relative to breast platform

 Structural strength of current hand/arm supports comply with international safety standards.

[Photo: Woman standing at the breast platform and holding onto the supports of a 

mammography machine that has been adjusted to a higher height to accommodate an upright 

position. The distance between the floor, supports, and gripping surface are indicated.]

Standing Support Recommendations

 To ensure proper accessibility, recommend:
o Defining standing supports in relation to the breast platform

o Reassessing length/geometry requirements for standing supports

o Considering a specification on how far away from the chest wall the standing 

supports should be located

Removable Seat Compatibility

Removable Seat Considerations

Question 37 b) Should a folding or removable seat be required on other types of diagnostic 

equipment used by patients in a standing position?

 Mammography equipment accessibility should be achieved without the requirement for 

use of a folding or removable seat.

o Appropriate wheelchair and standing support accommodations should address 

all accessibility concerns.

Additional considerations

Diagnostic Equipment - Mammography

Question 2. What other barriers that affect the accessibility and usability of medical diagnostic 

equipment should be addressed in future updates to the standards?

Additional guidance may need to be considered for wheelchair accessibility (e.g., rotated views, 

diagnostic/interventional modes, arm-rest interference/pinch points).

[Photo: Woman using a manual wheelchair pulled up underneath a breast platform of a 

mammography machine that has been adjusted to an angled positioned and lower height to 

accommodate a seated position.]

[Photo: Close in view of a breast platform with woman using a manual wheelchair pulled up 

underneath it.]

General Questions and Reponses

Diagnostic Equipment - Mammography

Question 9. If diagnostic equipment does not currently incorporate features that conform to all 

the technical criteria proposed in Chapter M3, which technical criteria can be easily 

incorporated into the design or redesign and manufacture of equipment with little difficulty or 

expense? 

 As currently drafted, any non-conforming toe (gantry) clearances and standing support 

geometries equipment changes would likely involve significant structural modifications.

 Re-design expenses and resulting product costs are TBD and would vary from 

manufacturer to manufacturer. 

Diagnostic Equipment - Mammography

Question10. How often is diagnostic equipment redesigned?

Design changes to sub-assemblies are typically multi-year projects and may be longer for a 
complete system redesign.

Moving Forward

 Manufacturers are committed to providing optimal accessibility for all patients and 

welcome the opportunity to participate in standards development with the Access 

Board

 On April 20, 2012 at a meeting of the International Electro-technical Committee (IEC 

MT-31*) a spreadsheet was distributed to gather input from a broad representation of 

worldwide mammography equipment manufacturers regarding areas that may conflict 

with the proposed access requirements in Chapter M3

* IEC MT31 is responsible for development of design and test requirements for the basic safety 

and essential performance of mammographic X-ray equipment.