Bone-Rad Therapeutics has developed a proprietary method of utilizing radionuclides in combination with conventional polymethylmethacrylate (PMMA) bone cement to deliver a therapeutic radiation dose while simultaneously strengthening the bone, effectively creating a brachytherapy bone cement.
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The dose distributions from P-32 radioactive cement provide a unique capability to deliver a highly localized dose to tumor-involved bone with minimal exposure to nearby radiosensitive tissues such as the spinal cord and nerves. The steepness of the dose drop-off from P-32 radioactive cement would be difficult or impossible to achieve with a gamma-emitting radionuclide, which would produce emissions that would penetrate through the vertebra and irradiate the spinal cord and nerves. Furthermore, emissions from an alpha-emitting or low-energy beta-emitting radionuclide would likely be completely absorbed within the cement itself or by bone immediately adjacent to the cement.



Additionally, P-32 is an ideal radionuclide for brachytherapy bone cement due to its clinically relevant half-life (14.3 days), which is long enough to sustain its use from the time of manufacture to clinical implantation, yet short enough to deliver 94% of the total dose within 2 months.



Finally, the uniformity of the P-32 distribution within brachytherapy bone cement was evaluated by calculating the standard deviation (as a percentage of the mean) of the dose rate along three straight lines along the axis of a long tube filled with radioactive cement. The standard deviation of the dose rate along the axis of the cement-filled tube was 0.21% of the mean for the top and bottom lines, and 0.33% of the mean for the middle line, indicating that the P-32 was sufficiently mixed within the radioactive cement.