December 11, 2013 — C4 Imaging LLC announced U.S. Food and Drug Administration (FDA) 510(k) clearance of its first product, the Sirius MRI Marker. The positive-signal magnetic resonance imaging (MRI) marker will be used following treatment of prostate cancer with brachytherapy to facilitate seed localization within the prostate, utilizing a single post-implant MRI procedure.
Brachytherapy, or radioactive seed implantation, is a standard option for the curative treatment of prostate cancer. Brachytherapy involves implanting around 100 radioactive seeds into the prostate. Its popularity has increased due to its effectiveness, convenience, relatively low incidence of erectile dysfunction and minimal invasiveness [1]. Radiation released from the seeds penetrates the surrounding prostate tissue at a limited distance, with most of the radiation concentrated within the prostate. Outcomes after brachytherapy depend greatly on the quality of the implant: eight-year prostate-specific antigen (PSA) relapse-free survival rates of 93 percent for high-quality implants versus 76 percent for low-quality implants have been reported [2].
"A Positive-Signal MRI marker can enhance seed detection. This represents a significant advancement for prostate brachytherapy," said Steven Frank M.D., founder and chairman, C4 Imaging. "If seeds can be readily localized with MRI, it would lead to more effective treatment and better patient outcomes."
"The encapsulation of a contrast agent within a permanently implantable device allows positive MRI seed localization after brachytherapy to be offered to more than 200,000 men diagnosed with prostate cancer in the U.S. each year [3]," said Andrew Bright, president and CEO, C4 Imaging.
"With our 510(k) now cleared, we're actively pursuing options for supplying Sirius to physicians treating prostate cancer in the U.S., as well as seeking regulatory clearance in Canada and Europe,” Bright added.
For more information: www.c4imaging.com
References
[1] Frank SJ, et al. American College of Radiology Appropriateness Criteria Permanent Source Brachytherapy for Prostate Cancer. Brachytherapy. 2011; 10(5): 357-362.
[2] Zelefsky MJ, et al. Multi-institutional analysis of long-term outcome for stages T1-T2 prostate cancer treated with permanent seed implantation. Int. J. Radiat. Oncol. Biol. Phys. 2007; 67(2): 327-333.
[3] American Cancer Society. Cancer Facts & Figures 2013. Atlanta: American Cancer Society; 2013.
November 04, 2026 
