Nuclear Technology with Medical Applications

Chun-Kai Kao
March 18, 2012

Submitted as coursework for PH241, Stanford University, Winter 2012

Introduction

Nuclear Technology is widely used in medical applications. In these procedures, atoms with unstable nuclei are combined with other elements to form chvarious compounds. These compounds can then be used in two main ways: diagnostics and treatment.

Diagnostics

One of the techniques for nuclear medicine imaging is Scintigraphy, which is the use of internal radionuclides to create two-dimensional images. For example, a group of rsearchers performed "cinematic nuclear scintigraphy" to detect gastrointestinal bleeding in 2000, and resulted in an accuracy of 88%. [1] Before this research was performed, the inability to quickly identify and localize the source of gastrointestinal bleeding was a big problem for the patients. This delay often caused increase in bleeding, greater transfusion requirements, and worse prognosis. [2]

In this experiment, there were 26 patients (18 male) and 25 scans were identified as positive after the scintigraphy scan. Of the positive examinations, the correct site of bleeding was identified in 22 cases (88%). They then performed the corresponding surgical operation accordingly.

Treatment

The other major area nuclear technology has contributed to in medicine is the treatment of various illness, most notably cancer. One of the techniques is to use targed drug delivery to the tumor vasculature for the treatment. [3] The tumor vasculator is a very good target for cancer therapy because it is made up of nonmalignant endothelial cells that are genetically stable and therefore unlikely to mutate and become drug-resistant. Furthermore, these cells are more accessible to drugs and have an intrinsic amplification mechanism --it has been estimated that eliminating a single endothelial cell can inhibit the growth of 100 tumor cells. [4] This is just one of the examples of nuclear technology identifying a tumor and providing the treatment efficiently and accurately.

Conclusion

Currently radiology is already widely used in cancer treatment. However, even if the treatment was successful, the patient is often greatly weakened due to the treatment. While nuclear technology is very effective in "killing" tumor cells, it often destroys other cells in the body as well. One area of focus in the future is to develop technology that can identify tumor cells more accurately and to only "kill" the cells that are cancerous and leave the rest of the cells alone. In the most ideal case, the patient will not need to suffer any more than necessary. This is especially important for cancers such as lymphoma, which are disseminated through the entire body. If we can pinpoint those cells and only kill them without affecting the rest of the body, radiology therapy wil be more effective in targeting a wider range of patients.

© Chun-Kai Kao. The author grants permission to copy, distribute, and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.

Reference

[1] B. B. O'Neill et al., "Cinematic Nuclear Scintigraphy Reliably Directs Surgical Intervention for Patients With Gastrointestinal Bleeding," Arch. Surg. 135, 1076 (2000).

[2] A. F. Jacobson and M. D. Cerqueira, "Prognostic Significance of late Imaging Results In Technetium-99m-labeled Red Blood Cell Gastrintestinal Bleeding Studies With Early Negative Images," J Nucl. Med. 33, 202 (1992).

[3] W. Arap, R. Pasqualini and E. Rouslahti, "Cancer Treatment by Targeted Drug Delivery to Tumor Vasculature in a Mouse Model," Science 279 377 (1998).

[4] F. J. Burrows and P. E. Thorpe, "Vascular Targeting - a New Approach to the Therapy of Solid Tumors," Pharmacology and Therapeutics 64, 155 (1994).