Every year, countless women undergo mammograms as part of their breast cancer screening routine. But behind each of those images is a carefully calibrated system, regulated by law and monitored by specialized medical physicists who work to balance two critical needs: detecting cancer early while minimizing radiation exposure to one of the body’s most radiosensitive tissues.
For Breast Cancer Awareness Month, we spoke with Mike Heard, a diagnostic medical physicist at CAMP who has spent decades ensuring mammography programs meet the highest safety and quality standards. His insights reveal a field that’s far more complex, more carefully regulated than most people realize.
The Catch-22 of Breast Cancer Screening
“It’s a little bit of a catch-22,” Mike explains. “Breast tissue is radiosensitive, which means it’s really not great to radiate it anyway, but we need to radiate it in order to test for signs of cancer.”
This fundamental tension drives everything about modern mammography. With one in eight women facing a breast cancer diagnosis in their lifetime, effective screening is essential. Yet the very tool used to detect cancer, X-ray radiation, poses its own risk to breast tissue if not carefully controlled.
That’s where medical physicists come in.
Why Mammography Has Its Own Special Rules
Unlike other diagnostic imaging modalities, mammography operates under its own federal law: the Mammography Quality Standards Act. This legislation requires that every mammography system in the United States be evaluated annually by a qualified medical physicist.
“Because breast tissue is radiosensitive, they decided they needed physicists to evaluate the radiation amount that breasts were getting and they put a limit on it,” Mike says. The law established strict quality control metrics that go far beyond standard medical imaging requirements.
The extensive regulation around mammography exists to ensure high quality mammograms for women. Radiologists who read mammograms must maintain special certification and continuing education. They participate in peer review programs. Equipment undergoes annual physics evaluations. Quality control procedures are documented and reviewed.
“Mammography is a really well-regulated, specific imaging modality that is specifically designed to help,” Mike emphasizes. With breast cancer affecting such a significant percentage of women, this rigorous oversight ensures that screening programs maintain the highest standards of safety and accuracy.
As a diagnostic medical physicist certified by the American Board of Radiology, Mike evaluates mammography equipment across Colorado, Montana, and Wyoming. His annual inspections assess radiation dose, image quality, and program compliance with federal regulations. He also serves as a resource when facilities have questions about best practices or when inspectors need expert guidance.
How Mammography Differs From Other X-Rays
When you get a chest X-ray or a CT scan, the radiation exposure is considered acceptable because most tissues in your body, like muscle, bone, and organs, have relatively low radiosensitivity. Breast glandular tissue is different.
“Every tissue type in your body has a different sensitivity to radiation,” Mike explains. “And breast, glandular tissue specifically, is just highly radiosensitive.”
Mammography systems compensate by using much lower energy X-rays than standard radiography. The specialized equipment includes high-quality detectors and ultra-high-resolution monitors that allow radiologists to spot calcifications measuring just microns in size, which are tiny calcium deposits that can indicate certain types of breast cancer.
The balance is delicate: higher radiation doses generally produce better images, but mammography must achieve diagnostic quality while staying well below regulatory dose limits.
The Evolution: From Film to Digital to 3D Mammography
The biggest revolution in mammography came about 15 to 20 years ago with the shift from film to digital detectors.
“Film had a very narrow window,” Mike recalls, comparing it to photography. “If you overexpose it, like a camera, if you leave film in the sun, it’s all black. And if you underexpose it, you can’t see anything.”
Film required a specific amount of radiation to produce a diagnostic image. Digital detectors changed everything. These solid-state systems could capture diagnostic-quality images using less radiation than film—an immediate win for patient safety.
But the real game-changer came next: 3D mammography, also called tomosynthesis.
How 3D Mammography Works
Traditional 2D mammography takes images from just a couple of angles—typically a top-down view and one at an angle. Radiologists would mentally reconstruct the breast’s three-dimensional structure from these flat images, but depth information was limited.
“Just like photography, if you just take one image from one perspective, you lose depth,” Mike explains. “Everything that’s stacked on top of itself, you can’t really tell what it is.”
3D mammography solves this by taking a series of low-dose images as the X-ray arm moves in an arc over the breast. These images are then combined digitally to create a three-dimensional dataset that radiologists can examine layer by layer, similar to a CT scan.
The clinical impact has been profound. “Let’s say you had calcifications distributed throughout the breast, but you’re looking at it from only one angle. It might look like those are clustered together,” Mike explains. “If you can rotate it and look at it another way, you can see that those are dispersed.”
This means fewer false positives, fewer unnecessary biopsies, and more accurate diagnoses. Today, virtually every mammography system Mike tests is a 3D system. “The last 2D systems disappeared a few years ago,” he notes. “It’s so much better.”
AI in Mammography: Ahead of Its Time
When asked about emerging technologies, Mike revealed something surprising: “They’ve been using AI for a long time in mammography. Way longer than we’ve been using it for Google.”
Before a radiologist ever sees a mammogram, automated AI screening programs analyze the images, flagging areas that need closer attention. These computer-aided detection (CAD) systems serve as a preliminary screening layer, though a certified radiologist always reviews every image.
The use of AI in breast cancer detection predates its widespread adoption in consumer technology, demonstrating how critical this field is to women’s health.
The Future of Breast Cancer Detection
While 3D mammography represents the current standard, researchers continue pushing boundaries:
Low-Dose Breast CT: Scientists are developing CT scanners specifically for breast imaging. Unlike current 3D mammography, which captures images in an arc, a true CT would circle completely around the breast, gathering more comprehensive data. The challenge? Doing so without exceeding safe radiation limits.
Breast MRI: Magnetic resonance imaging uses magnetic fields instead of radiation, eliminating concerns about dose. MRI excels at differentiating tissue types and is increasingly used for breast-specific imaging. However, MRI scans are expensive, time-consuming (30 minutes versus seconds for mammography), and not yet practical as a universal screening tool. MRI is more beneficial for women who are at higher risk typically from several factors, including certain genetic markers, family history, high breast density, and others.
Nuclear Medicine: This approach involves injecting a small amount of radioactive material that cancerous tissue absorbs more readily than normal tissue. The resulting images highlight areas of concern based on metabolic activity rather than anatomy.
Ultrasound Advances: While ultrasound doesn’t use radiation, its resolution doesn’t yet match mammography for detecting tiny calcifications. Researchers continue working to improve this technology.
“There are pluses and minuses to both,” Mike says. “Right now, mammograms are kind of the standard, but they’re working on making everything better.”
What This Means for Patients
For women undergoing mammography, this behind-the-scenes work translates to:
- Radiation doses kept to safe minimums while maintaining diagnostic quality
- Equipment that’s regularly tested and calibrated by certified physicists
- Advanced 3D imaging that reduces false positives and improves accuracy
- AI-assisted screening that provides an additional layer of analysis
- Specialized radiologists who maintain specific certification in breast imaging
“We try to help with that,” Mike says simply of his role in breast cancer detection. It’s understated, but the impact is profound. Every carefully calibrated machine, every dose measurement, every quality control check contributes to the goal of catching cancer early while keeping women safe.
As mammography technology continues advancing and new imaging modalities emerge, medical physicists will remain essential guardians of that delicate balance, ensuring that the tools we use to enhance patient care are as safe as they are effective.
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