Wireless Oscillating Device For Power Doppler-Based Interstitial Needle Tip Identification

Brachytherapy (BT) is a form of radiation therapy which typically relies on the insertion of needles to deliver radiation and is commonly used to treat a variety of cancer sites including prostate cancer. Accurate needle tip identification is key for safe and effective BT, as errors can result in radiation delivery that deviates from the planned dose. Typically, standard brightness (B)-mode ultrasound (US) imaging is used, however, artifacts can limit the visibility of needles. We propose a novel wireless mechanical oscillator for needle perturbation in a power Doppler (PD)-based needle tip identification method to overcome these limitations and improve needle tip identification accuracy in BT.We evaluated our method using a tissue equivalent phantom with the clinical US system and needles. In this proof-of-concept study, we assessed the performance of our PD US method using tip error computed based on a reference needle. Signed mean +/- SD tip error was -0.03 +/- 0.49 mm, while absolute mean error was 0.33 +/- 0.33 mm, demonstrating our PD US method provided accurate needle tip identification for ideal visualization in phantom. We also demonstrated that our PD US method is capable of visualizing needles that cannot be seen using B-mode US due to shadowing, providing promise for the clinical utility of our method. Our wireless mechanical oscillator for PD-based needle tip identification is simple to use and easy to implement, requiring no modifications to clinical equipment. A prospective clinical trial has been approved to assess our method in the clinic.