The following study shows the importance of real-time image guidance and robotic motion-compensation techniques used in CyberKnife.
Purpose
To report the characteristics of prostate motion as tracked by the stereoscopic X-ray images of the implanted fiducials during hypofractionated radiotherapy with CyberKnife.
Methods and Materials
Twenty one patients with prostate cancer who were treated with CyberKnife between January 2005 and September 2007 were selected for this retrospective study. The CyberKnife uses a stereoscopic X-ray system to obtain the position of the prostate target through the monitoring of implanted gold fiducial markers. If there is a significant deviation, the treatment is paused while the patient is repositioned by moving the couch. The deviations calculated from X-ray images acquired within the time interval between two consecutive couch motions constitute a data set.
Results
A total of 427 data sets and 4439 time stamps of X-ray images were analyzed. The mean duration for each data set is 697 s. At 30 s, a motion larger than 2 mm exists in about 5% of data sets. The percentage is increased to 8%, 11%, and 14% at 60 s, 90 s, and 120 s, respectively. A similar trend exists for other values of prostate motion.
Conclusions
With proper monitoring and intervention during treatment, the prostate shifts observed among the patients can be kept within the tracking range of the CyberKnife. On average a sampling rate of ~40 s between consecutive X-rays is acceptable to ensure sub-millimeter tracking. However, there is significant movement variation among patients and higher sampling rate may be necessary in some patients.
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Dear Dr. Mak, Dr. Grace, Thomas, Edwin, Aileen, Paula and Edith:
Thank you all for taking such good care of me during the planning and delivery of my CyberKnife treatment. I really appreciate the attentive and compassionate care that I have received the entire time I have been coming. Thanks again!
~ L.L. (diagnosed with adrenal metastasis)
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A great article on how a prostate cancer patient won battle against his insurance company for coverage on the CyberKnife treatment. As indicated in the article, the FDA approved the CyberKnife treatment more than a decade ago. Instead of undergoing 40 fractions of external radiation therapy or major surgery, CyberKnife only takes 4 treatment which offers a much more convenient and minimally invasive alternative for patients. Unfortunately, we still occasionally get denials from the insurance companies. Hopefully, they will soon recognize the benefits that CyberKnife offers and will make it available for all their patients.
I-Team: Insurance company makes exception for prostate cancer patient.
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“I did not know what to expect, but I had very caring people letting me know the process was nothing to be afraid of. What I liked was the assurance that all would be done in no time and the confidence they gave me.”
~ O.E diagnosed with Trigeminal Neuralgia
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Congratulations to our very own Dr. Albert Mak for being named “Top Doctor” by U.S. News and Report!
The U.S. News and Report identified the nation’s best doctors based on a peer nomination process. “At the Pasadena CyberKnife Center, we are committed to providing our patients with the highest level of patient care and support before, during and after their treatment. It is such an honor to be recognized by your peers and I am humbled by their support!” stated Dr. Mak.
Once again, CONGRATULATIONS Dr. Mak!
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