 Chemoprevention is currently one of the most powerful forms of cancer treatment. Chemoprevention describes the use of chemicals or natural compounds to lower a person's possibility of developing cancer or of cancer occurrence. Here, we'll examine some ways in which animal models and nuclear imaging are being used to assess chemopreventive substances and briefly discuss how similar imaging techniques are helping researchers map the states of other diseases. One promising natural agent being explored for use as a chemopreventive is Asiaticoside. Long known for its antioxidant and antibacterial effects, Asiaticoside could exhibit meaningful anti-cancer effects as well. An early study in this direction examined the effects of Asiaticoside in a popular rat model of human breast cancer. Specifically, rats were induced to develop mammary tumors with DMBA, a carcinogenic molecule whose effects tend to localize in mammary tissues. To determine how Asiaticoside modulates the trajectory of this cancer over the course of 12 weeks, researchers divided rats into five groups. Group one was made up of normal controls that were provided no-test treatment. Group two included rats treated with DMBA to induce tumor growth at week three. Group three included similar animals but who were also treated with Asiaticoside and after tumor induction. Group four animals were also similar but were only treated with Asiaticoside after tumor induction. And group five animals were treated with Asiaticoside alone. Researchers monitored the effects of Asiaticoside using what's known as a Meebiscan. Short for Technetium Cestimoebe, a Meebiscan uses a positively charged radioisotope of Technetium to probe for cancerous nodules in mammary tissues. This is based on the observation that malignant breast tissues concentrate the Meebiscan isotope well above the levels found in non-malignant tissues. Imaging revealed that Asiaticoside significantly reduced tumor volumes. All tumor-bearing rats treated with Asiaticoside showed signs of tumor regression and reduction. Separate experiments suggested that this anti-tumor effect was due to Asiaticoside's ability to induce apoptosis in cancer cells. Building on these findings, researchers later identified the cell-signaling molecules that make this action possible. The Technetium isotope used in this study is highly versatile and has proved amenable to imaging tissues elsewhere in the body. In one study, for example, researchers were interested in understanding the effects of retinoic acid on the brain. Retinoids are widely used to treat severe forms of acne but have also been linked to anxiety, mood disorders, and depression. To address this concern, researchers used the Technetium isotope to image the brains of rats treated with retinoic acid. The form of the isotope used is attached to a compound that undergoes a rapid lipophilic to hydrophilic transition. This feature enables the isotope complex to pass the blood-brain barrier and stabilize in the brain. In another study, researchers employed yet another form of Technetium isotope to study rats induced to develop diabetes. Here, the Technetium isotope was attached to a sulfur colloid that enables localization in the lymph nodes, liver, and spleen, among other tissues. This allowed the team to map the effects of early treatment with insulin throughout these regions of the body. Combining imaging techniques like these, with animal models of human disease, is a powerful approach in medical research. With the ability to monitor the effects of promising drugs like chemopreventives, this combination holds much potential for the development of new therapies that promote human health.