As the trend to higher doses, smaller number of fractions, and tighter margins becomes an important part of radiotherapy, better verifiable localization is a necessity.
Image-guided localization provides this type of real-time high-precision localization. Based on implanted gold markers or anatomic landmarks, ACCULOC® - with ISOLOC™ software
and electronic portal imaging, computed radiography, or standard port films - provides precise couch moves to achieve target alignment.
In some situations, image-guided
localization is best achieved by utilizing implanted fiducials. NMPE has worked to develop the optimal size and shape for implanted gold markers. Implanted markers are broken
into two main categories - bone and soft tissue. (Fiducial Markers - patent pending)
ACCULOC bone markers are pure gold spheres. They are used in cranial and spinal
applications. They image clearly on electronic portal devices (EPID). The markers are typically placed in a small hole in the bone, and bone wax is used to ensure that they
stay in place. In thousands of cases there has never been a situation in which a gold marker moved from its seated position in the bone.
ACCULOC soft tissue markers are
cylindrical so that they can be easily inserted using a needle. The markers have been through a special knurling procedure so that the surface is cross-cut to inhibit migration
once the marker is placed.
Markers are imperative in all situations where the target moves with respect to external marks (e.g. tatoos). Certainly prostate, liver and
other such internal organs can be much more accurately targeted using implanted markers. In cases where the target moves in an identical fashion with respect to the adjacent
bony anatomy it is possible to utilize the bony anatomy as the registration points. |
