Molecular Imaging for Cancer Research
Recent developments in molecular imaging have uncovered a world of possibilities for tumor imaging. Yet, imaging procedures still have a certain number of limitations, that optical imaging with the Photon Imager aims at answering. Below is a list of the requirements met by most researchers who image tumors in small animals, and how the Photon Imager can help ease procedures and increase performances.

Longitudinal studies with great repeatability

Studying cancer means being able to follow and study the growth of tumors, with minimal disturbance for the tumor biology. A great repeatability is essential for accurate comparison of tumors at different time points, in different animals, and in different conditions.
>> The Photon Imager is a totally non invasive solution for whole body fluorescence and bioluminescence imaging which offers excellent repeatability. Furthermore, the Photon Imager provides you not only with signal quantification, but also with the signal kinetics, which makes the control of repeatability over time and between individuals much more reliable and easier for bioluminescence.

Great numbers of animals

Since many parameters may impact the tumor growth or physiology, and with the always increasing versatility of therapies, experimental protocols usually require large numbers of animals; this is not possible when imaging procedures include time-consuming and tedious manipulations. This can be a limit to the maximum number of animals imaged per experiment, as well as a risk of degraded repeatability for the results.
>> Special focus on ergonomics: the Photon Imager was designed with a special care for ergonomics and user friendliness. In addition to its noninvasiveness, the following features makes it perfectly adapted for procedures with large numbers of animals, with a special care for physiology and ease of manipulation:
  • 5 mice capacity
  • Sliding stage
  • Heating table
  • Anesthesia bar
Furthermore, the real-time display of signal allows shorter acquisition times for certain protocols and gives the possibility to researchers to correct or optimize immediately the imaging procedure.

From early detection to tumor growth monitoring

The importance of early diagnosis for cancer treatment is regularly emphasized in clinics; treatments have often a much greater impact when started at an early stage. To be in line with today’s medicine requirements, imaging systems in research must allow them to study tumor biology from the earliest stage, or when detection relies on subtle differences in molecular affinity. The possibility to detect early tumors gives researchers a step ahead in their fight against cancer.
Photon Imager Dynamic Detection Range. Click to enlarge
>> Outstanding sensitivity and dynamic range: the technological design of the Photon Imager relies on an intensification of the signal by a factor 106; as a consequence, the Photon Imager is the most sensitive system on the market for detection of weak signals. Furthermore, users of the Photon Imager can rely on its outstandingly large dynamic range: Tumors and metastases luminescence expression can therefore be followed, quantified and compared, from early detection with weak signals, to large-size tumors with great signals.

Applications of the Photon Imager in Cancer Research

The following examples illustrate the interest of the Photon Imager for tumor imaging in the following applications:

Signal kinetics

The same mouse, bearing a fluc positive tumor, shows different bioluminescence time profiles after IV (right) and IP (left) injection of luciferin. The curves opposite illustrate this difference.
Such an experiment demonstrates the capacity of the system to provide relevant kinectics information, which is of great importance for biodistribution studies of anti cancer drugs.
From Keyaerts et al, Dynamic bioluminescence imaging for quantitative tumour burden assessment using IV or IP administration of D-luciferin, Eur J Nucl Med Mol Imaging, January (2008).


Early detection of tumor and metastases

Bioluminescence tumor imaging
2 weeks after the IV injection of the tumoral PC12 cells, tumors were imaged in the lungs of the animal.
Courtesy of R. Boisgard, CEA/SHFJ


Renal carcinoma
Renal carcinoma cells (RC-21) were inoculated into the right side of the kidney capsules. Metastases could be observed in both kidneys and ovaries after 6 weeks
Courtesy of I. Que, E. Kajizel and C. Löwik, LUMC, Leiden, Netherlands
Imaging of cells after inoculation in the heart
PC3 Pro4 cells were injected in the left ventricule of the heart (150 000 cells). Acquisition tool place 20 minutes after injection.
Courtesy of I. Que, G. Van Der Pluijm, C. Löwik, LUMC, Leiden, Netherlands
Ganglion metastases
30 sec. acquisition of ganglion metastases.
Courtesy of F. Ducongé, CEA/SHFJ, Orsay, France.





Tumor growth
Brain Imaging - Stem cell migration
Inoculation of C17.2 stem cells in the left hemisphere of the brain.
Courtesy of I. Que, E. Kajizel, C. Löwik, LUMC, Leiden, Netherlands





Tumor metabolism
Tumor protease activity
In vivo imaging of a tumor using VisEn Medical optical probe ProSense. Fluorescence intensity is linked with the tumor protease activity (especially cathepsin B's activity).
Courtesy of F. Ducongé, CEA/SHFJ, Orsay, France.



Tumor vascularization
Angiogenesis
In vivo imaging of a tumor vascularization using VisEn Medical optical probe Superhance. The dye is injected IV in the vascularization of the animal, and act as a blood pool agent. Since tumor vessels created by angiogenesis are particularly leaky due to windowed endotheliums and erractic architecure, and since Superhance is a small molecule, it accumulates in the tumor and provides a mean to evaluate the tumoral angiogenesis activity.In this example, three mice show increasing dye accumulation on the tumor site.
Courtesy of F. Ducongé, CEA/SHFJ, Orsay, France.