10 CFR Part 35.3045 (a)(1)(i): The target (prostate, in this case) receives a dose that was less than 80 percent of the prescribed dose.

10 CFR Part 35.3045 (a)(3): Other organs or tissue other than the target (prostate) receive doses above 0.5 Sv and 50 percent more than the expected dose to the organ or tissue.

As a result of the recent prostate brachytherapy misadministrations and the subsequent NRC inspection, the Philadelphia Veteran Affairs Medical Center (PVAMC) adopted the following criteria to determine whether or not a prostate brachytherapy implant results in a medical event. Every prostate seed implant program should include a similar criteria in their quality management program.

10 CFR Part 35.3045 (a)(1)(i)
The first condition fails if the calculated D90 from the post-treatment plan is less than 80 percent of the prescribed dose.

10 CFR Part 35.3045 (a)(3)
The PVAMC established the following guidelines to determine if the rectum or bladder receives a dose above 0.5 Sv and 50 percent more than the expected dose.

Rectum: Dose to 1.33 cubic centimeter volume exceeded 150 percent of the pre-treatment plan dose.

The D1.33 was selected because it is the volume of the VariSeed treatment planning program used to identify high dose volume during the pre-treatment planning. D1.33 is also found in the literature: “Defining the Risk of Developing Grade 2 Proctitis following I-125 Prostate Brachytherapy Using a Rectal Dose-Volume Histogram Analysis”

Bladder: 3 or more seeds located in the bladder wall.

This criteria was selected based on the review of a patient’s post-treatment plan which identified that two seeds in the bladder contributed to less than 60 Gy (equivalent to 60 Sv) to the bladder wall. The dose to the bladder wall with the seeds in the wall was compared to the dose to the bladder wall with the seeds removed. This criteria was well below the bladder tolerance dose.

References:
http://adamswebsearch.nrc.gov/idmws/ViewDocByAccession.asp?AccessionNumber=ML090900382
10 CFR Part 35.3045 defines reporting and notification of a medical event using by product material
NRC Inspection Report No 030-34325/08-029 (DNMS) on the medical event which occurred at Philadelphia Veteran Affairs Medical Center

When the inspection report is completed and issued, it will be interesting to learn the licensee’s root cause and not only what steps were taken by the licensee to prevent such an incident from recurring, but also whether such steps are deemed adequate by the NRC. 

While news of misadministration is always scary and unfortunate, there is always a lesson to be learned by everyone to prevent a similar event from happening at any treatment center.

You can read the official NRC press release here:
http://www.nrc.gov/reading-rm/doc-collections/news/2009/09-027.iv.html

A link to the final inspection report as well as a follow-up post will be on this site when the NRC releases the report.

Also, it’s worth mentioning the NYT had a neat graphical “tutorial” on prostate seed implants for the layperson who wanted to know how the procedure is performed. Check it out here.