Optics & Photonics News

traditional instrument, but “good enough,” Wachsmann-Hogiu said. ;is device could be used in the field to capture photos of blood samples and email them to a pathologist.

;e spectroscopy attachment follows the same principle of relative simplicity and low expense. ;e researchers attached a small transmission grating to the window of the cellphone, with two additional apertures to collimate the light. ;e results were not quite as sharp as the spectra from a high-end spectrometer, but the cellphone attachment’s components cost less than a dollar, while the dedicated instrument would cost thousands.

(Left) The spectrum of a ;uorescent bulb taken by an iPhone spectrometer. (Right) A comparison of spectra from an iPhone and a commercial spectrometer manufactured by Ocean Optics. While the iPhone is not as precise as the commercial unit, it accurately picks up the peaks in color intensity.

350 400 450 500 550 600 650

Wavelengh [nm]

Fluorescent bulb (iPhone)

Fluorescent bulb (oo)

Intensity [a.u.]

;e group began its experiments
with an Apple iPhone 2, but the
attachments could be used on later
models of the iPhone and non-Apple
phones. ;e cellphone imagers could
find a home in the classroom as well as
the medical field.

Multi-Mode Imaging Probe
Could Detect Ovarian Cancer

University of Connecticut/Biomed. Opt. Exp.

Ovarian cancer is di;cult to diag- nose in its early stages because symptoms often don’t manifest themselves until the disease has spread, and also because there is no e;ective screening method. Researchers at the University of Connecticut and the University of Southern California (U.S.A.) have developed a multi-mode imaging probe that could examine ovarian tissue via minimally invasive surgery (Biomed. Opt. Exp. 2, 2551; doi: 10.1364/ BOE. 2.002551).

;e device built by Quing Zhu and her colleagues integrates optical coherence tomography (OCT), photoacoustic imaging and ultrasound into a single-probe device.

OCT is gaining ground in biomedical
imaging because it can reveal morpho-
logical changes and precancerous lesions
in the first few millimeters of tissue; how-
ever, ovarian tissue is so dense that OCT
cannot penetrate it beyond 1 to 2 mm.
Photoacoustic probes excel at revealing
angiogenesis, or the growth of excessive
blood vessels—which can be a sign that a
growth is turning malignant. Ultrasound
probes can detect deep morphological
changes in tissue. By combining these
three modes with their di;erent ranges
and functionality, scientists would get a
better view of the ovaries.

Co-registered images of malignant ovarian tissue obtained with the hybrid imaging device. (Top to bottom) OCT image, ultrasound image, superimposed photoacoustic and ultrasound image and corresponding histology. Yellow arrow: malignant tissue.