Voice of developer : User-friendly Positioning Tool Utilizing AI technology

The content on this page is intended to healthcare professionals and equivalents.

* This artice is base on interview with Ms. Risako Nobuyama, who is a develper of Positining MAP
* Positining MAP is an optionfor Fujifilm Digital Mammography,AMULET SOPHINITY

Overview of the functionality

Interview with Ms. Risako Nobuyama

The AMULET SOPHINITY’s projection function (Positioning MAP) supports positioning based on past image data.

Skin lines and nipple positions extracted from past images are projected onto the exposure table surface, making it possible to capture images that can be easily compared with past ones.
Also, the image of the opposite side can be inverted and projected onto the table to compare the right and left breasts.

Impetus for the development of the projection function

Our main focus when developing a device is to ensure that it is patient-friendly.
To this end, we have been striving to provide a device that is easy to handle and operate, taking into account opinions and feedback from users, including doctors and technologists.

It is often pointed out at home and abroad that positioning in mammography imaging is both more important and more difficult than in other X-ray imaging.

As we explored the reasons behind such opinion, we found that difficulties lie in taking symmetrical images of the breast and in achieving reproducible imaging so that newer images can be compared with past ones.
Such difficulties have been overcome by superior positioning technology of technologists. These facts have led us to develop this device to support positioning.

To support positioning - Visualizing what technologists have in their mind

We focused on what technologists do to take symmetrical images and to achieve reproducible imaging that allows comparison of newer images taken with past ones.
What we learned is that technologists perform positioning based on various information obtained from past images, including the amount of stretching of the breast and imaging conditions (e.g., compression pressure and angle).

We thought we would be able to support optimal positioning if we could visualize the information they have in their mind, thereby reducing their effort in obtaining information from past images prior to imaging.
The first idea was to have a monitor next to the mammography device that displays previously taken images and markers for nipple positions.

However, we thought turning the attention from the breast to the monitor for confirmation could interfere with the positioning workflow. Hence, in order to enable reference to past images in a more efficient manner, we came up with a concept to visualize what technologists have in their mind onto the exposure table, which led to the idea of direct projection of data onto the exposure table and the compression plate.
We thought such function could provide reference point information extracted from past images using AI^* technology to less experienced technologists as well as busy technologists who have scarce time to review past images to achieve their desired positioning. Finally, the development of the projection function began.

Path to product launch

In order to incorporate the projection function into a mammography device, it was necessary to place a projector inside the device and project images in a manner that would not interfere with the imaging. Various challenges emerged during this process, and we had a hard time overcoming three issues in particular.

The first challenge was to install the projector in a limited space with a source-to-image distance (SID) of 650 mm. This focal distance is much shorter than that of a typical projector. In addition, when projecting an image onto a screen, the size and focus of the image must be adjusted by adjusting the position and angle of the projector. We had to achieve these within a limited space inside the mammography device. Heat emissions from the projector also had to be taken into account, and we faced many challenges in this respect during the design phase.

The second challenge was the visibility of the projected information.
Because mammography involves imaging of delicate areas, many facilities pay careful attention to lighting. Diverse types of lighting are used, ranging from warm lighting to clean and clear lighting.
Under these different conditions, the font size, line thickness, color, etc. were adjusted through trial and error to ensure that the projected lines, text, and other information are clearly visible.
We also paid close attention to the information projection area, as not to obstruct the view during positioning, and the materials used.

The third challenge was the processing speed of the internal software that enables timely projection of information.
The skin line and nipple position information acquired by the positioning analysis function is projected together with the current compression plate pressure and breast thickness information, with the font size expanding and contracting in conjunction with the movement of the height-adjustable compression plate.
We also focused on processing speed to keep up with the technologists’ imaging speed even when projecting various information.
The technologists may move quickly from the time they finish positioning to the time they press the imaging button. In order not to hinder this sense of speed, we proceeded with development while incorporating the opinions of technologists and many others within the company.

Utilization of function

- Not only for positioning support, but also as a communication tool -

The projection function projects skin lines and imaging information of past images onto the imaging space. Although I mentioned that this function is designed to effectively support less experienced technologists, I hope skilled technologists will also take advantage of this function.
With the provision of historical information by the device, we expect that imaging-related work of technologists will be reduced, enabling more care to be offered patients.

In addition, we have received feedback from facilities that have installed the device, saying that this function is very useful as a communication tool with patients.
After seeing the projected skin line, one patient may think, “As my breast has to be stretched to this extent, I’ll try to cooperate,” and another patient who sees the nipple position may easily understand where to stand.
For example, a patient who is asked by a technologist to move a little to the right will be able to see how much the “little” is by seeing the projected information.
We hope this function will also be utilized as a tool to facilitate communication with patients.

In closing

This positioning tool, developed using AI^* technology, is expected to bring new possibilities to the field of mammography.
We sincerely hope quicker and more accurate positioning will be realized by reducing the burden on technologists and improving convenience for both the patients and the technologists.

* The extraction of the reference point of the nipple position for positioning was designed using an AI technology called “deep learning.” There is no automatic change in performance or accuracy of the system after installation.