Research and Publications
Treatment with Spine-Rad™ Cement requires accurate knowledge of the radiation transport once the radioactive cement is implanted in the bone. An accurate model will allow the treating physicians to determine optimal implant placement and resulting radiation dose that will be delivered to the surrounding structures. Members of the Bone-Rad team are leaders in this development, resulting in the following peer-reviewed research studies (click the publication titles below for a more in-depth look at each study):
Kaneko TS, Sehgal V, Skinner HB, Al-Ghazi MSAL, Ramsinghani NS, Keyak JH. Phys Med Biol. 2010 May 7;55(9):2451-63.
ABSTRACT: Spinal metastases are a common and serious manifestation of cancer, and are often treated with vertebroplasty/kyphoplasty followed by external beam radiation therapy (EBRT). As an alternative, we have introduced radioactive bone cement, i.e. bone cement incorporated with a radionuclide. In this study, we present a Monte Carlo radiation transport modeling method to calculate dose distributions within vertebrae containing radioactive cement. Model accuracy was evaluated by comparing model-predicted depth-dose curves to those measured experimentally in eight cadaveric vertebrae using radiochromic film. The high-gradient regions of the depth-dose curves differed by radial distances of 0.3-0.9 mm, an improvement over EBRT dosimetry accuracy. The low-gradient regions differed by 0.033-0.055 Gy/h/mCi, which may be important in situations involving prior spinal cord irradiation. Using a more rigorous evaluation of model accuracy, four models predicted the measured dose distribution within the experimental uncertainty, as represented by the 95% confidence interval of the measured log-linear depth-dose curve. The remaining four models required modification to account for marrow lost from the vertebrae during specimen preparation. However, the accuracy of the modified model results indicated that, when this source of uncertainty is accounted for, this modeling method can be used to predict dose distributions in vertebrae containing radioactive cement.
Kaneko TS, Sehgal V, Skinner HB, Al-Ghazi MSAL, Ramsinghani NS, Keyak JH. Phys Med Biol. 2012 Jul 7;57(13):4387-401.
ABSTRACT: Vertebral metastases are a common manifestation of many cancers, potentially leading to vertebral collapse and neurological complications. Conventional treatment often involves percutaneous vertebroplasty/kyphoplasty followed by external beam radiation therapy. As a more convenient alternative, we have introduced radioactive bone cement, i.e. bone cement incorporating a radionuclide. In this study, we used a previously developed Monte Carlo radiation transport modeling method to evaluate dose distributions from phosphorus-32 radioactive cement in simulated clinical scenarios. Isodose curves were generally concentric about the surface of bone cement injected into cadaveric vertebrae, indicating that dose distributions are relatively predictable, thus facilitating treatment planning (cement formulation and dosimetry method are patent pending). Model results indicated that a therapeutic dose could be delivered to tumor/bone within ∼4 mm of the cement surface while maintaining a safe dose to radiosensitive tissue beyond this distance. This therapeutic range should be sufficient to treat target volumes within the vertebral body when tumor ablation or other techniques are used to create a cavity into which the radioactive cement can be injected. With further development, treating spinal metastases with radioactive bone cement may become a clinically useful and convenient alternative to the conventional two-step approach of percutaneous strength restoration followed by radiotherapy.