phosphorus-radioisotopes and Intracranial-Aneurysm

Endovascular treatment of intracranial aneurysms is safe and effective but is associated with angiographic recurrences. Beta radiation prevents recanalization after coil embolization in experimental models. We wanted to assess the feasibility of using radioactive coil embolization to improve long-term results of endovascular treatment.. Platinum coils were ion-implanted with 0.13 to 0.26 microCi/cm of 32P. Forty-one patients aged 34 to 84 years with 44 aneurysms with a high propensity for recurrences were included. Radioactive coils were introduced into aneurysms to reach a target volumetric activity of 0.018 microCi/mm3. Nonradioactive coils were also used to ensure the same safety and the same angiographic results as the standard procedure. Angiographic results, procedure-related complications, and neurological events during follow-up were recorded. Angiographic follow-up data are available in 36 lesions 6 months after treatment.. Forty of 44 aneurysms (91%) could be treated with radioactive coils. Target activities could be reached in 88% of lesions that could actually be coiled (35/40). Total activities ranged from 1.72 to 80.9 microCi, for a mean of 20.13+/-20.80 microCi. Procedure-related complications occurred in 7% of patients. Initial angiographic results were satisfactory (complete occlusions or residual necks) in 75% of lesions. Angiographic recurrences occurred in 11 (31%) of patients followed, within the expected range for standard coils. There was no complication from beta radiation during a mean follow-up period of 10 months.. Radioactive coil embolization is feasible; target volumetric activities can be reached in most aneurysms considered for endovascular treatment.

Topics: Adult; Aged; Aged, 80 and over; Beta Particles; Cerebral Angiography; Embolization, Therapeutic; Feasibility Studies; Female; Follow-Up Studies; Humans; Implants, Experimental; Intracranial Aneurysm; Male; Middle Aged; Phosphorus Radioisotopes; Platinum; Radiotherapy Dosage; Recurrence; Treatment Outcome

Recanalization after coil embolization can be prevented by radiation emitted from 32P coils. We wanted to determine the upper limits of 32P activities that could be implanted onto coils with respect to the potential injury to nearby nerves, delay in organization of the clot, and effects on neointima formation and recanalization.. We studied the effects of various 32P activities on recanalization and organization of thrombus after coil occlusion of canine arteries and on neointima formation at the neck of canine carotid bifurcation aneurysms. We also tested potential injury to nerves in the vicinity of radioactive or nonradioactive coils in 3 models: the brachial plexus (near proximal vertebral arteries) and the lingual nerve in a lingual artery bifurcation aneurysm model, both models being treated by radioactive or standard coil occlusion. Finally, we wrapped lingual nerves with nonradioactive or high-activity coils and studied their effects on lingual nerves and tongues. Results were assessed with a pathological scoring system and compared with Mann-Whitney and Kruskal-Wallis tests.. No deleterious effect of radiation on nerves could be detected. Neointima formation was not hampered, scores of aneurysms treated with 32P-coils being significantly better when compared with treatments with standard coils (P=0.002). Arteries treated with high-activity coils (>3.39 microCi) showed absent recanalization but delayed organization of the clot at 3 months compared with low-activity or nonradioactive coils (P<0.05).. beta-Radiation can prevent recanalization after coil occlusion. We could not demonstrate any deleterious effects of radioactivity on nervous structure or on neointima formation. Delayed organization of thrombus provides a rational basis to establish an upper limit for 32P activities to be implanted onto coils.

Topics: Animals; Blood Coagulation; Brachial Plexus; Carotid Artery Diseases; Dogs; Embolization, Therapeutic; Intracranial Aneurysm; Lingual Nerve; Phosphorus Radioisotopes; Tunica Intima

Recanalization after selective endovascular treatment of intracranial aneurysms with platinum coils has been widely reported in the literature. Beta radiation emitted from (32)P ion-implanted coils can prevent recanalization in animal models. A complete inventory of radioactive coils may not be realistic; our hypothesis was that it might not be necessary to reach target activities in most aneurysms. A limited supply of three or four types of coils may decrease the inventory difficulties related to the use of an isotope with a half-life of 2 weeks.. We reviewed 154 aneurysms selectively treated with standard coils. We calculated the volumetric activity obtained if all coils (simulation 1) were radioactive with linear activities of 0.13 (scenario I) or 0.26 microCi/cm (scenario II). Then, we simulated a treatment with standard coils plus a selection of radioactive coils limited to three (simulation 2) or four types of commonly used coils (simulation 3). Resulting activities were calculated and reported to the lesion volume. For each scenario and simulation, the percentage of lesions, in which the target volumetric activity (0.018 microCi/mm3) was reached, was reported.. Success in reaching target volumetric activities varied from 55-99% according to different simulations. A supply of four types of coils was sufficient to reach target activities in 86-95% of patients commonly treated in our institution. Target activities were difficult to reach in giant aneurysms.. It is feasible to reach target activities in most lesions by using a limited coil supply.

Topics: Computer Simulation; Embolization, Therapeutic; Equipment Design; Feasibility Studies; Humans; Intracranial Aneurysm; Models, Theoretical; Phosphorus Radioisotopes; Retrospective Studies

Beta radiation can prevent recanalization after embolization. Our goal was to assess the feasibility of endovascular treatment of intracranial aneurysms using coils of a predetermined activity of 32P per centimeter.. We studied the total length of coils deployed into 357 intracranial aneurysms. Aneurysmal volumes were estimated using 3 mathematical models. We simulated that coils were implanted with 0.26 microCi/cm of 32P, calculated resulting volumetric activities, and compared them with "effective" levels derived from experimental data and "safe" levels prescribed for the clinical use of 32P in cystic craniopharyngiomas.. Effective activities would have been reached in 92% to 98% of lesions had the coils been radioactive at the time of treatment.. Radioactive coil embolization of aneurysms is feasible in most patients.

Topics: Adult; Aged; Beta Particles; Combined Modality Therapy; Embolization, Therapeutic; Feasibility Studies; Female; Humans; Intracranial Aneurysm; Male; Middle Aged; Models, Theoretical; Phosphorus Radioisotopes; Prostheses and Implants; Retrospective Studies