Materials Up Ante Against Prostate Cancer

New materials and processing technologies hold promise to significantly improve medical outcomes for men suffering from prostate cancer.

Complete removal of the prostate has been considered the gold standard treatment for prostate cancer despite side effects including urinary incontinence and erectile dysfunction. New technology, however, makes it possible to destroy only the cancerous part of the prostate because of an improvement in prostate biopsy.

The TargetScan Touch System allows the physician to insert a biopsy needle in the targeted area and monitor the specific location of the tissue sample. Images can be captured and stored by the system to verify the location of the tissue samples. The system is more effective, precise, and systematic than traditional hand-held trans-rectal ultrasound biopsy systems, according to Michael Belgeri, director of operations for Envisioneering Medical Technologies of St. Louis.

The dual-channel prostate biopsy needle guide consists of two 13-gauge stainless steel tubes that are insert molded with resin. (Source: Plas-Tech Engineering.)

"The system converts what was once random into a systematic process," says Belgeri. In the past, biopsies were taken using a two-dimensional ultrasound device. The new technology provides a three-dimensional picture of the prostate.

One of the key components is a dual-channel needle guide, which is mounted to the biopsy system hardware. It consists of two 13-gauge stainless steel tubes that are insert-molded with acrylonitrile-butadiene-styrene (ABS) resin. The part is six inches long and has an inner diameter of 0.071-inches. The disposable needle guide serves as the pathway for the bendable biopsy needle to the target tissue.

"The guide tube is curved, essentially re-directing the needle towards the prostate at a fixed angle relative to the centerline of the probe," Belgeri told Design News. "The guide is able to revolve around the probe and also move along the length of the probe. This combined with the curved guide tube allows the needle to be directed at any desired tissue location in the prostate."

"The part has a complex geometry that requires tight sealing at four locations with a smooth flash-free finish for patient comfort," said Belgeri.

One of the first steps is quality control of the metal tubing, according to Scott Smith, vice president at Plas-Tech Engineering, the company that produces the guide tube. One goal is to eliminate the pairing of the tubes for precise placement in the mold. The tubes now can be randomly selected since they are all within required tolerances for insert molding. This step significantly reduced the cost of the finished product.

Another challenge was positioning the parts correctly in the cavity and filling completely without blowing the stainless steel tubes out of position and creating flash across the holes. Core pulls are sequenced appropriately and shutoffs and inserts are high tolerance. Stainless steel tube bends and inside dimension are held to 0.001 in. The ABS grade, which is FDA (Food and Drug Administration) approved, requires strong dimensional stability and compatibility with ethylene oxide sterilization.

"The big story with prostate tissue targeting is that it dovetails with focal treatment and that's what we see as the future of prostate cancer treatment," said Belgeri. He compared the new prostate treatment approach with the evolution of treatment of breast cancer to a more targeted, focused approach. There are an estimated 1.2 million prostate biopsies conducted annually in the United States.