Radioactive bone cement for the treatment of spinal metastases: a dosimetric analysis of simulated clinical scenarios

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.

Watertight Robust Osteoconductive Barrier for Complex Skull Base Reconstruction: An Expanded-endoscopic Endonasal Experimental Study

“…The OP can act as a drug-carrier 35) for radioactive particles, 33) and can be loaded with controlled release system of antibiotics (gentamicin, vancomycin), 35) therefore, WRO-barrier can survive in avascular environment induced by postoperative adjunctive radio/chemotherapy. 33,34) Besides, the WRO-barrier can resist infection by its high antimicrobial potency. 35) In real clinical application, we can replace the protective inlay Goretex sheet by fascia lata graft (natural layer) as an additional defensive measure against infection.…”

“…3); third, large defect (from anterior-to-posterior fossae) with irregular bony framework (challenging sloping angles) (Figs. 1 and 3); fourth, tailorable reconstructive material with clinical evidence (bone paste); fifth, dynamic settings (simulating the postoperative patient handovers/daily activity); sixth, suddenly elevated H 2 O pressure (simulating sudden/unexpected increase in the intracranial pressure (ICP): cough, sneezing); seventh; relatively little biological reaction in the early postoperative period; eighth, avascular reconstructive-bed (postoperative adjunctive chemo-radiotherapy) 33,34) ; ninth, redo-EEA for recurrent-or-staged tumor surgery; and tenth, ARTCEREB (Otsuka Pharmaceutical Factory, Inc., Tokyo, Japan) as a CSF-substitute, 37) instead of water, to simulate the real intraoperative wet condition that might have specific (biochemical/physical) contributing effect, and we added red-color to accurately diagnose the leakage point.…”

“…We selected a well-known malleable osteoconductive-and-osteoinductive material, 32–36) which became a robust barrier within a few minutes, that have good biocompatibility, superior bone regeneration and can survive in avascular environment. 33,34) Herein, we present the watertight robust osteoconductive (WRO)-barrier for ESBR as an alternative durable option and we will discuss its distinct qualities and limitations.…”

Monte Carlo Dosimetric Study of Percutaneous Vertebroplasty and Brachytherapy for the Treatment of Spinal Metastases

“…Kaneko et al evaluated a radiation transport modeling method for dose calculation in a vertebra containing radioactive bone cement, using MCNP extended code (MCNPX v. 2.5) and EBT radiochromic film [ 12 ]. The same group also simulated some clinical scenarios such as bone cement leakage with MCNP v.5 [ 23 ]. However, there are insufficient data for the dose distributions of brachytherapy seeds and beta-emitting bone cement in the spinal canal.…”