Why did you apply this technology to prostate cancer in particular?
Dr. Dogra: As an adjunct professor of urology, I am interested in prostate cancer. It is the second leading cause of cancer death in American men, behind only lung cancer. Transrectal ultrasound (TRUS)-guided prostate biopsy is the gold standard for diagnosis, but it’s an invasive procedure and its overall success rate is about 70% due to false-negative results. This shows that there is a need for a new imaging technique for the diagnosis of prostate cancer.
What are the main differences between PA imaging and TRUS-guided prostate biopsy?
Dr. Dogra: TRUS-guided prostate gland biopsy is invasive, requiring a minimum of 12 core biopsy samples to be taken from the prostate. It is also associated with many complications, mainly bleeding and discomfort. Most men do not like it.
PA imaging is noninvasive, requires no biopsy or blood test, and has shown better sensitivity and specificity even in our initial results.
Those were the results you presented at the annual meeting of the American Roentgen Ray Society (ARRS) in April 2013 in Washington, DC?
Dr. Dogra: Yes. Our PA imaging of prostate cancer predicted 25 out of 26 nonmalignant tissues correctly and it predicted 13 out of 16 malignant tissues correctly. This translates to a sensitivity of 81.3% and specificity of 96.2%.
What about cost?
Dr. Dogra: PA imaging is far cheaper technology than biopsy. A biopsy costs about $3,000, whereas this whole [PA imaging] machine is going to cost about $40,000. Therefore, the [PA imaging] tests will be very cheap—hundreds of dollars, not thousands.
What role do you see PA imaging playing in the diagnosis of prostate cancer?
Dr. Dogra: PA imaging will help patients with prostate cancer tremendously. We plan to have a screening model and a diagnostic model. This will help eliminate prostate biopsy in a significant number of patients.
Which professionals are most likely to administer PA imaging for prostate cancer?
Dr. Dogra: In our opinion it depends on who embraces the technology early. It will have a very short learning curve. Therefore, urologists, urologic surgeons, and radiologists will be able to use it. Pathologists can use this technology ex vivo in grossing their prostate specimens better.
How much special training will be required to use this technology?
Dr. Dogra: Not much. It will be very intuitive.
When will this technology to be widely available?
Dr. Dogra: In about five years.
Can PA imaging be applied to other cancers as well?
Dr. Dogra: Yes. We have used it in thyroid cancer, with wonderful results. However, the current laser we are using limits us. We don’t have the money at the moment to research a laser that penetrates deeper. That’s why we have chosen organs that are easily accessible or are superficial. We can apply this type of imaging to the liver and to the pancreas, but this modality is in its infancy and needs more technical developments in laser technology for deeper penetration.
For more information on multispectral photoacoustic imaging, please contact Dr. Dogra.