Project Summary/Abstract
Anal cancer incidence has been increasing, by four times over the last three decades. The incidence rate is
unacceptably high among HIV-positive homosexual men, 131 per 100,000. The main challenge in anal cancer
diagnosis and prevention is the lack of a standardized screening program. In vivo optical microscopy
technologies such as confocal microscopy and optical coherence tomography have the potential to visualize
cellular morphologic changes associated with the anal malignancy, but their clinical adaptation has been
challenging. In this Trailblazer R21 project, we propose to develop a low-cost, scattering-based light sheet
microscopy (sLSM) device that can aid accurate diagnosis of anal cancer, with the goal of ultimately reducing
the anal cancer-associated morbidity and mortality. Our sLSM device will uniquely address the unmet needs in
existing in vivo microscopy technologies (e.g., CM, OCT), simultaneously achieving i) high lateral resolution (1-
2 µm) for examining cellular nuclear features in the epithelium, ii) large FOV (~2.5 mm), iii) visualization of the
entire epithelial thickness in a single image, and iv) low device cost (~$2,000). We expect that the sLSM device
will reveal the key diagnostic cellular features in vivo, which will facilitate detection of early-stage anal
malignancy and timely initiation of adequate treatment. The sLSM device will also guide the biopsy to
malignant lesions with high sensitivity and specificity to increase the biopsy yield and reduce the morbidity and
complication caused by the unnecessary biopsy of benign lesions. As the first step towards this goal, we will
develop the prototype handheld sLSM device and evaluate the accuracy of diagnosing anal malignancy in the
following aims: In Aim 1, we will develop a handheld sLSM probe for imaging anal mucosa. The sLSM device
will provide cellular resolution in the epithelium and reveal architectural details in deeper regions in a single
image. We will optimally design the illumination and detection optics to achieve the 1.4 µm lateral resolution
over a 2.5-mm FOV, 6.5 ± 0.9 µm axial resolution for the epithelium, and 18 ± 8 µm axial resolution for the
superficial lamina propria. In Aim 2, we will conduct a clinical study of imaging human anal tissues with the
handheld sLSM device. One hundred anal biopsies concerning for anal cancer will be first imaged with the
sLSM device. sLSM images will be compared with the corresponding histologic images to identify cellular and
architectural features visualized in sLSM images and to develop the sLSM diagnostic criteria. The sensitivity
and specificity of the sLSM for diagnosing anal malignancy will be evaluated. Automated image analysis
algorithms will be developed to quantitatively evaluate the cellular and architectural features. In addition to
providing a low-cost microscopy tool that aids accurate diagnosis of anal malignancy, the sLSM technology
can be used for in vivo diagnosis of other cancers (e.g., cervical, oral, skin cancers), intra-operative
assessment of the surgical margin, and quality assurance during the core needle biopsy.