Exploring Photoacoustic Tomography for Ovarian Cancer Screening
Introduction to Ovarian Cancer
Ovarian cancer poses a significant health risk due to its low survival rates, primarily because it is often diagnosed in the later stages, specifically the third or fourth stage. At these advanced stages, the survival rate is typically between 25-30%. Ovarian cancer encompasses a variety of tumors, which can be classified as either malignant or benign. One of the challenges in early detection is the unreliability of current ovarian cancer screening methods.
Photoacoustic Tomography: An Innovative Imaging Technique
Photoacoustic tomography (PAT) is an advanced imaging technique that enables detailed scanning of tissues. This method employs a specific laser that prompts tissue to emit an excitatory signal, which is subsequently captured for visualization. A recent study led by Nandy and colleagues aimed to explore the potential of PAT in visualizing malignant ovarian tissue, and their findings were published in the journal *Radiology*.
Research Objectives and Methodology
The study investigated the use of PAT as a means to identify potential biomarkers for ovarian tumors. Researchers focused on two key indicators: relative total hemoglobin concentration (rHBT) and oxygen saturation (sO2). This pilot study included participants scheduled for salpingo-oophorectomy (removal of the ovary and fallopian tube) and those diagnosed with ovarian tumors or at high risk for such malignancies. Between February and December 2017, researchers successfully enrolled 16 participants and analyzed a total of 26 ovaries.
Findings on Distinguishing Cancerous from Normal Ovaries
The research revealed distinct differences in vascular structures between invasive cancers and normal or benign ovaries. Notably, invasive epithelial ovarian cancers exhibited approximately 1.9 times higher levels of rHBT compared to normal or benign ovaries. Conversely, sO2 levels in patients with invasive cancers were found to be about 9.1% lower than those in benign or normal ovaries. The “other” group demonstrated sO2 levels more aligned with the invasive group.
Limitations and the Need for Further Research
While the study demonstrated promising results, the authors acknowledged certain limitations. The PAT technique is capable of analyzing tissue depths of approximately 5 centimeters. Cases involving cystic masses that are devoid of blood or exhibit low blood levels could hinder the accuracy of PAT signals, thereby affecting the determination of sO2 and rHBT levels.
In conclusion, the distinguishing characteristics observed in the sO2 results from this pilot study may offer valuable insights into ovarian cancer detection. However, the authors emphasized the necessity for larger-scale studies to validate the efficacy of PAT for ovarian cancer screening.
Reference
Nandy S, et al. Evaluation of Ovarian Cancer: Initial Application of Coregistered Photoacoustic Tomography and US. Radiology. 2018; 00:1–8. doi: 10.1148/radiol.2018180666.
Author
Written by Olajumoke Marissa Ologundudu B.Sc. (Hons)