The new technique could identify cancerous breast lumps without surgery
At the moment, doctors can only check whether lumps are malignant or benign by doing a biopsy, where they surgically remove tissue, or through a needle test.
But scientists from Duke University in Durham, North Carolina have developed a method of using sound waves to see how much the lumps move deep inside the body.
Lead reserarcher Dr Katherine Nightingale said: "We are finding that different tissue types respond differently."
UK cancer experts have said the technique, detailed in the New Scientist journal would be "good news" if it can be developed.
Soundwaves
The fact that lumps differ in their elasticity led to the Duke University researchers developing a technique using ultrasound.
A handheld device using high density ultrasound "pushing" beams creates an acoustic force that moves the tissue.
Low density ultrasound - of the kind more conventionally used in medicine - is then used to track the movement of the tissue.
It can move between 10 and 15 micrometres.
The high strength ultrasound is used for less than a millisecond on the affected area.
This means the tissue does not get hot.
Checking
Dr Nightingale told BBC News Online women would normally palpate, or check, their breasts with their fingers and would only be able to feel lumps that are typically around one centimetre in diameter.
"This is like you're putting your finger inside the breast and palpating the tissue."
She said lumps that were smaller and deeper which could not be detected by surface checks would be more easily detected using the ultrasound technique.
In the next stage of the research, scientists will carry out clinical trials on 90 women over the next three years.
Stephen Duffy, of the Imperial Cancer Research Fund said although many breast cancers were confirmed by taking slices of tissue via a needle, so that few patient with benign lumps had to undergo surgery, the Duke's technique could be even better.
But he said it would have to be shown to be effective on all types and sizes of tissues.
"The sensitivity to all types of breast cancer is of great importance, as doctors will be very anxious to avoid misdiagnosing cancer as benign disease."