Cancer "live" in 3D
It is known that the spatial structure of the tissue within a single tumor can vary significantly. Researchers from the Technical University of Munich (TUM) and Helmholtz Zentrum München have succeeded in visualizing spatial changes in tumors using optoacoustics. This method may be useful for the future development of new drugs.
Malignant tumors consume nutrients and oxygen faster than healthy cells. Therefore, they are densely entwined with blood vessels. Depending on the type of tumor and the genetic profile, there are differences in how tumors look from the inside.
The role of spatial heterogeneity of the tumor has not been sufficiently studied. Optical microscopy, which is commonly used to understand biological functions, for example, provides limited information about the spatial heterogeneity of a tumor, since it allows only samples with a volume of less than a cubic millimeter to be examined.
High-resolution visualization
Munich researchers have developed a new technique – multispectral optoacoustic mesoscopy (MSOM), which has demonstrated the ability to distinguish the contrast in tumor samples at least 1000 times greater than is possible with optical microscopy, providing high-resolution visualization of tumor heterogeneity patterns.
With MSOM, a tumor submerged in water is first exposed to infrared laser radiation. Tumor components absorb these impulses and undergo a short-term increase in temperature, leading to a local increase in volume followed by contraction. This process of expansion and contraction generates a weak ultrasonic signal, which is detected by the detector.
The collected data are mathematically processed to form light absorption images that indicate various tumor structures reflecting the oxygenation and vascularization of the tumor. Images obtained using MSOM show the internal structure of tumors up to ten millimeters deep and with a resolution of less than 50 micrometers.
At the top is a diagram of the MSOM system, at the bottom are images obtained at different irradiation frequencies and their combination. The scale size is 1 mm.
Functional diversity of tumors
MSOM imaging of solid tumors allowed researchers to see them in a new light.
In the images of mammary carcinoma of mice, the researchers were able to evaluate patterns indicating the presence or absence of blood vessels, and thus study the features of the blood supply to cancer. MSOM can also determine the level of hemoglobin and indicate whether oxygen is associated with hemoglobin or not. In addition, MSOM images were used to determine the permeability of the vessel walls for nanoparticles. Using mouse models, the authors have already been able to track how the gold nanoparticles were transported.
3D images of the tumor without biopsy
Unlike traditional histology, in which a tissue sample must be excised and examined under a microscope by a specialist, MSOM allows for three-dimensional analysis of whole living tumors without biopsy. It will also help to obtain more accurate information about the growth or regression of the tumor under the influence of various drugs. This will facilitate and accelerate the development of medicines for people.
Article J.Li et al. Spatial heterogeneity of oxygenation and hemodynamics in breast cancer resolved in vivo by conical multispectral optoacoustic mesoscopy published in the journal Light: Science & Applications.
Aminat Adzhieva, portal "Eternal Youth" http://vechnayamolodost.ru based on the materials of TUM:High-resolution 3D view inside tumors.