Breast Thermogram Image Acquisition Procedure*
and prepared for recording image snapshots.
(patient's name, etc.).
you use to store new images.
be selected (black). Prefix and Timestamp
are unchecked.
and their Countboxes set to '1' and '1.'
Maintaining camera calibration and focus for different patient views is an easily overlooked discipline. Specifically, the exact distance between the camera and the surface of the patient is a critical parameter for camera calibration, and small changes in camera-patient-distance are often ignored.
Small changes in distance may not be ignored. If the camera-patient-distance changes for each view, and the 'new' distance is not entered as an 'Object Parameter,' the camera is not calibrated, the ability to properly analyze the images is compromised. In short, the examination is tainted.
Camera-patient-distance uncertainty can be minimized by employing specific foot positions for each view. As before, alignment is made to a line marking the stored camera-patient distance:
Important: The end position of the heels for the oblique views is with the heel of the rotated foot against the inside heel of the stationary foot. The patient's weight is supported on the stationary foot. The patient is standing relaxed in natural posture.
Note that for each position, the patient's foot/feet are aligned with the camera-patient-distance line.
Impaired viewing and unreliable temperature measurements result when the areas of interest in the image are not in focus. This is a common issue owing to reliance on the camera's automatic focusing mechanism. Unfortunately, the auto-focus feature of infrared cameras is unsuitable for breast thermography examinations.
The camera should be focused slightly in front of the surface of the breast that is perpendicular to the camera. The camera's 'depth of field' maintains image focus for several inches behind the focal point, i.e., the entire breast is in focus.
Auto-focus concentrates on the hottest part of the image. Breasts are cooler than the torso and the axilla and located inches in front of these regions. Using auto-focus, the camera focuses on the torso during frontal views and on the axcilla during oblique and lateral views. The breasts are not in focus.
The focus issue is resolved by not using auto-focus, except to initially coarse focus the patient, and then manually touch up focus on the front surface of the breasts.
When the procedure outlined for positioning the patient is adhered to, the distance between the camera and the front of the surface of the breast remains constant. There is no need to refocus for each patient position.