ABSTRACT
Owing to its favorable radioactive decay characteristics (T1/2 = 32.51 d, Eß [max] = 434.6 keV [70.5%] and 580.0 keV [29.5%], Eγ = 145.4 keV [48.5%]), 141 Ce could be envisaged as a theranostic radionuclide for use in nuclear medicine. The present article reports synthesis and evaluation of 141 Ce complex of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetramethylenephosphonic acid (DOTMP) as a potent theranostic agent targeting metastatic skeletal lesions. Ce-141 was produced with 314 ± 29 MBq/mg (n = 6) specific activity and >99.9% radionuclidic purity (n = 6). Around 185 MBq dose of [141 Ce]Ce-DOTMP was synthesized with 98.6 ± 0.5% (n = 4) radiochemical yield under optimized conditions of reaction, and the preparation showed adequately high in vitro stability. Biodistribution studies in normal Wistar rats demonstrated significant skeletal localization and retention of injected activity (2.73 ± 0.28% and 2.63 ± 0.22% of injected activity per gram in femur at 3 hours and 14 days post-injection, respectively) with rapid clearance from non-target organs. The results of biodistribution studies were corroborated by serial scintigraphic imaging studies. These results demonstrate the potential utility of 141 Ce-DOTMP as a theranostic molecule for personalized patient care of cancer patients suffering from painful metastatic skeletal lesions.
Subject(s)
Bone Neoplasms/complications , Bone Neoplasms/secondary , Cancer Pain/diagnostic imaging , Cancer Pain/radiotherapy , Cerium Radioisotopes/therapeutic use , Organophosphorus Compounds/therapeutic use , Adsorption , Animals , Cancer Pain/etiology , Durapatite/chemistry , Isotope Labeling , Organophosphorus Compounds/chemistry , Organophosphorus Compounds/pharmacokinetics , Radionuclide Imaging , Rats , Rats, Wistar , Tissue DistributionABSTRACT
Intravascular irradiation with beta emitters inhibits restenosis in arteries after balloon angioplasty or stent implantation. Yttrium-90 ((90)Y, T(1/2)=64 h) and cerium-144 ((144)Ce, T(1/2)=286 d) emit beta particles (E(max)=2.28--3.50 MeV) having an ideal energy range for brachytherapy delivery system. In this article, a previously reported method for depositing (32)P on poly(ethylene terephtalate) (PET) surfaces is generalized and modifications that allow deposition of other beta-emitting radioisotopes, such as (90)Y and (144)Ce, are demonstrated. PET films were first coated with chitosan hydrogel and then adsorbed different amounts of phosphoric acid (PA) in aqueous solutions. Yttrium was deposited onto the surface as YPO(4) after the films were immersed in YCl(3) solutions. 1 muCi (90)YCl(3) (2 x 10(-9) g) was used in each sample as a tracer for measuring the deposition efficiency, which is defined as the percentage of YCl(3) deposited on the surface compared to the amount of YCl(3) in solutions before the deposition. In order to improve the safety of brachytherapy treatments, polyurethanes were used to seal the deposited radioisotopes on the surface to minimize the leakage of the isotopes into the patients. The generality of this method presented here for a wide variety of particular radioisotopic components allows design of a broad range of versatile radioisotope sources.
Subject(s)
Brachytherapy/methods , Chitin/analogs & derivatives , Coated Materials, Biocompatible/chemistry , Cerium/chemistry , Cerium/therapeutic use , Cerium Radioisotopes/therapeutic use , Chitin/chemistry , Chitosan , Graft Occlusion, Vascular/radiotherapy , Humans , Hydrogels/chemistry , Phosphates/chemistry , Phosphates/therapeutic use , Phosphoric Acids/chemistry , Polyethylene Terephthalates/chemistry , Yttrium Radioisotopes/chemistry , Yttrium Radioisotopes/therapeutic useABSTRACT
A simple, disposable afterloading applicator for intracavitary irradiation of carcinoma of the nasopharynx has been found useful as a supplementary radiation boost to the primary site. Hopefully, local tumor control can be enhanced by employing this technique.
