Bal Gill made the life-changing discovery when she visited Camera Obscura & World of Illusions in the Royal Mile in May.
The Thermal Camera, which was installed in 2009, is a popular part of the attraction and lets visitors see a visual of all their body hot spots.
But when Bal took a photo, she noticed something strange - a red heat patch coming from her left breast.
And on returning home she investigated further and discovered that thermal imaging cameras are often used as a tool by oncologists. Bal made an appointment with her doctor and was sadly diagnosed with breast cancer.
The 41-year-old, from Slough in Berkshire, contacted the Camera Obscura staff to let them know of her experience.
She said: "I visited with my family in May 2019 during the school holidays. We had been to Edinburgh Castle and on the way down we saw the museum.
"While making our way through the floors we got to the thermal imaging camera room. As all families do, we entered and started to wave our arms and look at the images created. While doing this I noticed a heat patch (red in colour) coming from my left breast. We thought it was odd and having looked at everyone else they didn’t have the same. I took a picture and we carried on and enjoyed the rest of the museum.
"A few days later when we returned home I was flicking through my pictures and I saw the image. At this point I searched on Google to see what this could mean and I saw a lot of articles about breast cancer and thermal imaging cameras. I made an appointment with the doctor and as it turns out I do have breast cancer, thankfully really early stages. I have now had two surgeries and have one to go to prevent it from spreading.
"I just wanted to say thank you: without that camera I would never have known. I know it’s not the intention of the camera but for me it really was a life-changing visit. I can not tell you enough about how my visit to the Camera Obscura changed my life."
Andrew Johnson, general manager of Camera Obscura & World of Illusions, said: "We did not realise that our Thermal Camera had the potential to detect life-changing symptoms in this way.
"We were really moved when Bal contacted us to share her story as breast cancer is very close to home for me and a number of our team. It’s amazing that Bal noticed the difference in the image and crucially acted on it promptly. We wish her all the best with her recovery and hope to meet her and her family in the future."
Thermography, also called thermal imaging, is a tool used by breast cancer specialists and uses a special camera to measure the temperature of the skin on the breast’s surface. It is a non-invasive test that involves no radiation.
Thermography is based on two ideas; because cancer cells are growing and multiplying very fast, blood flow and metabolism are higher in a cancer tumor; as blood flow and metabolism increase, skin temperature goes up.
Breast cancer is the most common form of cancer in the UK. October is Breast Cancer Awareness Month, a worldwide annual campaign involving thousands of organisations, highlighting the importance of breast awareness, education and research.
One in seven women in the UK will be affected in her lifetime and around 55,000 women are diagnosed every year. Breast Cancer Awareness Month starts on October 1 and ends on October 31 every year.