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Purpose: Primary or recurrent urethral stenoses are common clinical problems. The aim of this feasibility study was development and application test of a novel radioactive catheter for potential use in low-dose-rate (LDR) brachytherapy to prevent urethral stenosis. Material and methods: A beta radiation emitting phosphorous-32 (32P)-foil was developed and integrated in indwelling catheter, which is usually inserted after surgical intervention in the urethra. Activity and dose distribution were measured after neutron activation of the phosphorus-31 (31P)-foil component with scintillation techniques as well as radiochromic films, and compared to MC simulations. Practicability and radiation safety of this new applicator were tested on male rabbits, which, before catheter application, had undergone a new method of stricture induction by radial laser light irradiation. Results: Measured dose distributions of catheters with 32P-foils were found to be in good agreement with MC simulations. Wash-out tests confirmed the radioactive catheter setup to be inside permitted limits of a sealed source. Strictures could be induced by laser light in all animals, surgically treated by slitting and irradiation with a 7-day dose of 15 Gy or 30 Gy, without adverse effects of radiation during a 4-week observation time. Conclusions: This proof-of-concept study presents a safe and technically simple approach to LDR brachytherapy intending to prevent urethral stenosis. The prescribed irradiation dose can be administered in a reproducible and precise manner using a urethral catheter as a carrier of beta radiating foil. The study duration of 63 days was too short to make statistically significant stricture-related conclusions. This approach may be considered for similar problems in other hollow organs and in cases regarding superficial hyper-proliferation. [ABSTRACT FROM AUTHOR]

Purpose Ostial restenosis is a common cause of failures in paranasal sinus surgery. The aim of the current study was to investigate the use of low-dose-rate brachytherapy to prevent neo-ostial restenosis in an animal model. Methods and Materials In 14 rabbits, maxillary neo-ostia were created and measured. One side each was stented with a regular silicone stent, the other side was either not stented ( n = 7) or stented with a phosphorous-32 implanted stent depositing a low-dose radiation of 15 Gy ( n = 7) within 1 week, after which all stents were removed. After a period of additional 12 weeks of recovery, the animals were sacrificed, the neo-ostia were again measured, and the areas and histopathologic changes compared in between the groups. Results After 15-Gy stenting, the mean ostial areas were even slightly enlarged by 5.1% compared to the area at stent removal, whereas a significant reduction in area, indicating a process of restenosis, by 56.1% or 54.0% was seen in the control groups with no stent and normal stent, respectively. Furthermore, no indication for adverse histopathologic radiation effects was seen in the 15-Gy group. Conclusions Low-dose-rate brachytherapy with phosphorous-32 doped silicone stents showed promising results in the prevention of neo-ostium restenosis in this proof-of-concept study, indicating that further preclinical and clinical testing may be warranted. [ABSTRACT FROM AUTHOR]

Patients with hemophilia suffer from repeated episodes of hemarthrosis leading to chronic inflammation and synovitis. Radiosynovectomy is an effective nonsurgical modality that can reduce inflammation, pain, and hemarthrosis in such cases. We describe an adolescent male with severe Hemophilia A, who developed arterial vasculitis and perivasculitis targeting the brachiocephalic, right common carotid, and right subclabvian arteries occurring within few days after difficult Phosphorus-32 radiosynovectomy, possibly as a complication of the procedure. Despite prophylaxis with recombinant FVIII therapy, he developed chronic synovitis and underwent radionuclide synovectomy with P-32 injection to the left ankle and right knee. Five days later, he developed pain in the lower right neck and right upper chest. Computed tomography and magnetic resonance imaging and angiography demonstrated inflammation involving the arteries of the right thoracic inlet. Geiger-Mueller meter indicated increased radioactivity not only in the left ankle and right knee but also in the right upper chest. Detection of radioisotope at the right thoracic inlet corresponding to the area of vasculitis was indicative of likely deposition of the P-32 isotope in an area exposed to maximum cardiac output and increased blood flow, leading to subclavian, carotid, and innominate arteritis with surrounding edema.