For as long as modern medicine has been able to capture images of the insides of our bodies, light has been an essential tool of the medical profession. From X-Rays to MRIs to CT scans, revealing what happens inside our bodies—without opening them—require light.

Lasers are being used in innovative ways all the time in the medical industry. From measuring brain waves to determining pain response. They’re regularly being used for cervical examinations, reducing discomfort and examination length and have begun to replace the x-rays traditionally used in mammography.

Cancer cells are far easier to detect and measure using laser technology. Melanomas used to be measured with traditional methods (visually, which leaves room for error), but now they’re now measured much more accurately using lasers. This helps specialists monitor melanoma growth rates and respond more appropriately with particular treatments.

Lasers are also used in optical coherence tomography and can give high-resolution (on the order of microns), cross-sectional, and three-dimensional images of biological tissue in real time. Ophthalmologists use this technology to see a cross section of the cornea in order to diagnose retinal disease and glaucoma.

X-rays, which have previously been enormous and prohibitively expensive, are shrinking, getting small enough to fit on the back of a small truck. This adaptation alone promises to improve response time, help medical professionals find tumors earlier in underserved populations, study extremely fast reactions that occur too rapidly for observation with conventional x-rays, or detect nuclear materials concealed within a shielded container.