A Great Fiducial Marker
Particle therapy
The CT and MRI images show a line shaped 0.28×10 mm MR+ marker implanted in the prostate. Image courtesy of Gjøvik Hospital, Norway
A state-of-the-art image guidance tool
Gold Anchor is a state-of-the-art image guidance tool for Particle Treatments such as proton and carbon ion-beam therapies.
Proton and carbon ion-beams deliver most of their energy at a specific depth in tissue (the Bragg peak), beyond which there is minimal dose deposition. While this allows for highly targeted treatment, it also makes proton therapy extremely sensitive to even small positional errors. Fiducial markers help ensure the tumor is accurately aligned with the beam to maximize tumor dose while sparing healthy tissues.
Gold Anchor offers the following unique combination of benefits for particle therapy compared to alternatives:
- Low dose perturbation, due to the thin marker diameter. Gold Anchor markers are offered with ultrathin 0.28 mm or 0.4 mm diameter;
- Great kV-visibility (compared to low density markers such as polymer or carbon markers);
- Enhanced MR-visibility (due to the unique and patented marker material, an alloy of gold and 1.5% iron);
- Industry-leading thin needle (25G, 22G or 20G for Gold Anchor compared to 18G for most alternatives);
- Anchoring marker design, allowing imaging for dose planning on the same day as implantation.
Low dose perturbation
Dose perturbation downstream of the markers with the markers oriented perpendicular to the beam axis near the end of the SOBP (Spread-Out Bragg Peak). The doze is normalized to an unperturbed region.
Source: Extract from “Investigation of dosimetric effects of radiopaque fiducial markers for use in proton beam therapy with film measurements and Monte Carlo simulations”
The film measurements show dose perturbation for a Gold Anchor implanted with a line/zig-zag shape vs. regular gold markers.
Learn more
- “Comparison of translation algorithms in determining maximum allowable CTV shifts for Real-Time Gated Proton Therapy (RGPT) robustness evaluation in prostate cancers” Article (Singapore)
- “Real-time gated proton therapy with a reduced source to imager distance: Commissioning and quality assurance” Article (Singapore)
- “Carbon ion radiotherapy using fiducial markers for prostate cancer in Osaka HIMAK: Treatment planning” Article (Osaka, Japan)
- “Proton therapy planning and image-guidance strategies within a randomized controlled trial for high-risk prostate cancer” Article (Denmark)
Gating based on fiducial marker positions
Advances in technology now enable real-time tracking of fiducial markers during particle therapy. The Hitachi Real-Time Gated Proton Therapy (RGPT) system uses X-ray imaging and advanced software to perform gating based on fiducial marker positions.
Two Gold Anchor 0.28×10 mm markers implanted in breast prior to proton therapy treatment.
Fiducial markers usage in proton therapy
Fiducial markers can be used in proton therapy for breast cancer to improve target localization, account for breathing motion, and ensure precise alignment of the proton beam with the tumor, minimizing radiation exposure to surrounding healthy tissues, including the heart and lungs.