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1.
Clin Nucl Med ; 43(4): 282-283, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29432341

RESUMO

A 64-year-old woman underwent completion thyroidectomy with upper tracheal ring resection and right-sided neck dissection for papillary carcinoma of the thyroid infiltrating the trachea and was given I radioiodine treatment. Three years later, she presented with hemoptysis. On evaluation, she had increased serum thyroglobulin and negative iodine scan (TENIS). F-FDG PET/CT scan did not identify any site of disease. One year later, Ga-PSMA scan done revealed a moderate focal tracer-avid intratracheal soft tissue; biopsy revealed it to be metastatic papillary carcinoma of the thyroid. This case kindles the possibility of using Ga-PSMA PET/CT to reveal occult disease in cases of TENIS.


Assuntos
Ácido Edético/análogos & derivados , Radioisótopos do Iodo , Oligopeptídeos , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Tireoglobulina/sangue , Neoplasias da Glândula Tireoide/patologia , Neoplasias da Traqueia/diagnóstico por imagem , Neoplasias da Traqueia/secundário , Biópsia , Carcinoma Papilar/sangue , Carcinoma Papilar/diagnóstico por imagem , Carcinoma Papilar/patologia , Feminino , Fluordesoxiglucose F18 , Isótopos de Gálio , Radioisótopos de Gálio , Humanos , Pessoa de Meia-Idade , Neoplasias da Glândula Tireoide/sangue , Neoplasias da Glândula Tireoide/diagnóstico por imagem
2.
Clin Nucl Med ; 42(9): e412-e414, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28682848

RESUMO

A 66-year-old man on hormonal therapy with prostate cancer was referred for Ga-PSMA PET/CT scan for biochemical recurrence. Ga-PSMA PET/CT scan detected moderate heterogeneous tracer concentration in bilateral breast parenchyma, in addition to the abnormal tracer concentration in enlarged prostate gland, right external iliac lymph node, and sclerotic lesion in L4 vertebra. On clinical examination, he was found to have bilateral gynecomastia. Abnormal concentration of Ga-PSMA in breast cancer is now well known, and in this context, it is important to know that tracer localization can occur in gynecomastia as well, as evidenced in this case.


Assuntos
Ácido Edético/análogos & derivados , Ginecomastia/diagnóstico por imagem , Ginecomastia/metabolismo , Oligopeptídeos/metabolismo , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Idoso , Ácido Edético/metabolismo , Reações Falso-Positivas , Isótopos de Gálio , Radioisótopos de Gálio , Ginecomastia/patologia , Humanos , Masculino , Recidiva
3.
Indian J Nucl Med ; 32(1): 54-56, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28242988

RESUMO

A 48-year-old female presented with a pathological fracture of the right femur. 99mTc methylene diphosphonate bone scan revealed multiple areas of increased osteoblastic activity consistent with metastatic disease. Serum electrophoresis revealed monoclonal gammopathy. 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) scan revealed metabolically active lesions in bulky uterine cervix and osteolytic skeletal lesions. Unusual pattern of FDG uptake in uterine cervix and osteolytic skeletal lesions warranted a biopsy of the uterine cervix which revealed diffuse large B-cell lymphoma. 18F-FDG PET/CT scan helped in guiding the site of biopsy to reach a final diagnosis in this unusual case of lymphoma with a secondary involvement of uterine cervix presenting as a pathological fracture.

4.
Clin Nucl Med ; 42(6): 446-447, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28346248

RESUMO

Fibrous dysplasia (FD) is a benign bone lesion with a rare but potential for malignant transformation. Neither Tc-MDP nor F-FDG PET/CT can differentiate between FD and areas of malignant transformation in FD. We described a case of osteosarcoma developing in FD with selective uptake of tracer in malignant transformation areas demonstrated on a Ga-PSMA PET/CT scan. Our case highlights the ability of Ga-PSMA PET/CT to map tumor neoangiogenesis in osteosarcoma arising in FD, which can have potential implications in prognostication, possibility of antiangiogenesis-based therapeutic options, and in response assessment following chemotherapy.


Assuntos
Neoplasias Ósseas/complicações , Neoplasias Ósseas/diagnóstico por imagem , Ácido Edético/análogos & derivados , Displasia Fibrosa Óssea/complicações , Oligopeptídeos , Osteossarcoma/complicações , Osteossarcoma/diagnóstico por imagem , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Neoplasias Ósseas/patologia , Feminino , Isótopos de Gálio , Radioisótopos de Gálio , Humanos , Pessoa de Meia-Idade , Osteossarcoma/patologia
6.
Clin Nucl Med ; 42(3): e161-e162, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28045729

RESUMO

A 68-year-old man presented with right-side facial numbness. MRI showed an extra-axial mass infiltrating the right temporal bone. It was debulked surgically, and histopathology revealed metastatic adenocarcinoma. Ga PSMA PET/CT done in view of increased PSA levels and clinically suspicious hard lesion in prostate showed primary lesion in left side of prostate with metastases to the right temporal bone. Primary carcinoma of the prostate and metastases to the right temporal bone were proven histopathologically. Our case highlights the usefulness of Ga PSMA PET/CT in identifying the primary site in suspected prostate cancer and mapping the metastatic sites.


Assuntos
Adenocarcinoma/diagnóstico por imagem , Hipestesia/diagnóstico por imagem , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Neoplasias da Próstata/diagnóstico por imagem , Adenocarcinoma/patologia , Idoso , Queixo/diagnóstico por imagem , Queixo/patologia , Diagnóstico Diferencial , Ácido Edético/análogos & derivados , Isótopos de Gálio , Radioisótopos de Gálio , Humanos , Hipestesia/patologia , Masculino , Metástase Neoplásica , Oligopeptídeos , Compostos Organometálicos , Neoplasias da Próstata/patologia , Compostos Radiofarmacêuticos
7.
Clin Nucl Med ; 42(2): e126-e127, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27941377

RESUMO

The potential applications of Ga-labeled prostate-specific membrane antigen (PSMA) PET/CT in the imaging of prostate cancer are now well established. A few case reports regarding the potential use of Ga-PSMA PET/CT in nonprostate cancer malignancies are also published. Apparently, the tumor neoangiogenesis is the mechanism attributed to increased Ga-PSMA uptake in the tumor sites in nonprostatic malignancies. We describe the use of Ga-PSMA PET/CT in imaging multiple myeloma. The intense Ga-PSMA avidity of the lesions also opens up the possibility of theranostics with Lu-PSMA.


Assuntos
Mieloma Múltiplo/diagnóstico por imagem , Compostos Organometálicos , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Compostos Radiofarmacêuticos , Adulto , Ácido Edético/análogos & derivados , Isótopos de Gálio , Radioisótopos de Gálio , Humanos , Masculino , Oligopeptídeos
8.
Clin Nucl Med ; 42(2): e115-e116, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27997417

RESUMO

We describe the case of a 55-year-old man who presented with history of fever for 3 months that began 2 months after he had undergone open reduction and internal fixation of left humerus fracture. Implant infection was suspected, but conventional imaging remained unyielding. Ga-DOTA ubiquicidin PET/CT showed increased tracer uptake along the entire length of the implant in the left humerus. Implant removal and temporary external fixation were done. In 24 hours, the patient became afebrile, and blood culture on the fourth day was sterile.


Assuntos
Complexos de Coordenação/farmacologia , Peptídeos/farmacologia , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Infecções Relacionadas à Prótese/diagnóstico por imagem , Complexos de Coordenação/farmacocinética , Fraturas Ósseas/cirurgia , Radioisótopos de Gálio , Humanos , Masculino , Pessoa de Meia-Idade , Peptídeos/farmacocinética , Compostos Radiofarmacêuticos
9.
Clin Nucl Med ; 42(1): e41-e48, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27846000

RESUMO

OBJECTIVE: To evaluate the feasibility of using Ga PSMA-11 PET/CT for imaging brain lesions and its comparison with F-FDG. METHODS: Ten patients with brain lesions were included in the study. Five patients were treated cases of glioblastoma with suspected recurrence. F-FDG and Ga PSMA-11 brain scans were done for these patients. Five patients were sent for assessing the nature (primary lesion/metastasis) of space occupying lesion in brain. They underwent whole body F-FDG PET/CT scan and a primary site elsewhere in the body was ruled out. Subsequently they underwent Ga PSMA-11 brain PET/CT imaging. Target to background ratios (TBR) for the brain lesions were calculated using contralateral cerebellar uptake as background. RESULTS: In five treated cases of glioblastoma with suspected recurrence the findings of Ga PSMA-11 PET/CT showed good correlation with that of F-FDG PET/CT scan. Compared to the F-FDG, Ga PSMA-11 PET/CT showed better visualization of the recurrent lesion (presence/absence) owing to its significantly high TBR. Among the five cases evaluated for lesion characterization glioma and atypical meningioma patients showed higher SUVmax in the lesion with Ga PSMA-11 than with F-FDG and converse in cases of lymphoma. TBR was better with Ga PSMA PET/CT in all cases. CONCLUSION: Ga PSMA-11 PET/CT brain imaging is a potentially useful imaging tool in the evaluation of brain lesions. Absence of physiological uptake of Ga PSMA-11 in the normal brain parenchyma results in high TBR values and consequently better visualization of metabolically active disease in brain.


Assuntos
Neoplasias Encefálicas/diagnóstico por imagem , Glioblastoma/diagnóstico por imagem , Linfoma/diagnóstico por imagem , Neoplasias Meníngeas/diagnóstico por imagem , Meningioma/diagnóstico por imagem , Recidiva Local de Neoplasia/diagnóstico por imagem , Adulto , Idoso , Criança , Ácido Edético/análogos & derivados , Feminino , Fluordesoxiglucose F18 , Isótopos de Gálio , Radioisótopos de Gálio , Glioma/diagnóstico por imagem , Humanos , Masculino , Pessoa de Meia-Idade , Oligopeptídeos , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Compostos Radiofarmacêuticos , Imagem Corporal Total , Adulto Jovem
11.
Clin Nucl Med ; 41(10): e454-5, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27556797

RESUMO

65-year-old man with left-sided pelvic pain on evaluation was found to have features suggestive of either Paget disease or prostatic bone metastasis of the left hemipelvis based on Tc-MDP bone scan and MRI. Ga-PSMA PET/CT to assess the possibility of primary prostate cancer and if present to stage it helped to rule out prostate cancer because of absence of focal abnormal increased tracer uptake in the prostate gland. However, false-positive tracer uptake was noted in the left hemipelvis, which was subject to biopsy and histopathologically proven to be Paget disease involvement.


Assuntos
Antígenos de Superfície/química , Antígenos de Superfície/metabolismo , Glutamato Carboxipeptidase II/química , Glutamato Carboxipeptidase II/metabolismo , Osteíte Deformante/diagnóstico por imagem , Osteíte Deformante/metabolismo , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Idoso , Transporte Biológico , Neoplasias Ósseas/diagnóstico por imagem , Neoplasias Ósseas/secundário , Diagnóstico Diferencial , Reações Falso-Positivas , Humanos , Masculino , Neoplasias da Próstata/patologia
12.
Nucl Med Biol ; 43(8): 463-9, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-27231953

RESUMO

INTRODUCTION: [(68)Ga]PSMA-11 is a relatively recently introduced radiopharmaceutical for PET-CT imaging of prostate cancer patients. The availability of (68)Ge/(68)Ga generator and PSMA-11 ligand from commercial sources is facilitating the production of the radiopharmaceutical in-house. This paper describes our experience on the preparation of ~200 batches of [(68)Ga]PSMA-11 for conducting PET-CT imaging in patients suspected/suffering from prostate cancer. METHODS: The radiosynthesis of [(68)Ga]PSMA-11 was done in a hospital based nuclear medicine department using (68)Ge/(68)Ga generator and a manual synthesis module, both supplied by Isotope Technologies Garching (ITG), Germany. The production involved the reaction of 5µg (5.3nmol) of PSMA-11 ligand in 1 ml of 0.25M sodium acetate buffer with 4ml of (68)GaCl3 in 0.05M HCl for 5min at 105°C; followed by purification in a C18 cartridge and collection through a 0.22µm pore size filter. RESULTS: The radiochemical yields obtained were consistently high, 93.19%±3.76%, and there was hardly any batch failure. The radiochemical purity of the product was >99% and the product was stable for over 2h; however it was used in patients immediately after preparation. About 200 batches of [(68)Ga]PSMA-11 were prepared during the period and more than 300 patients received the tracer during the 14months of study. No adverse reaction was observed in any of the patients and the image qualities were consistent with literature reports. CONCLUSION: [(68)Ga]PSMA-11 with high radiochemical and radionuclidic purity is conveniently prepared by using a (68)Ge/(68)Ga generator and manual synthesis module. The radiochemical yields are very high; and activity sufficient for 3-4 patients can be prepared in a single batch; multiple batches can be done on the same day and when needed after a gap of 1.5-2h.


Assuntos
Radioisótopos de Gálio/química , Germânio/química , Compostos Organometálicos/síntese química , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Radioquímica/métodos , Técnicas de Química Sintética , Estabilidade de Medicamentos , Ácido Edético/análogos & derivados , Isótopos de Gálio , Oligopeptídeos , Compostos Organometálicos/química , Controle de Qualidade
13.
Clin Nucl Med ; 41(7): e353-4, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27055142

RESUMO

Ga-labeled prostate-specific membrane antigen (PSMA) is a potential tool in the imaging of recurrent prostate cancer. Ga-PSMA imaging is also useful for radiotherapy planning and in targeted therapy with Lu-PSMA. A few case reports regarding the use of Ga-PSMA in nonprostate cancer malignancies are also reported. We describe the use of Ga-PSMA imaging before Sm-EDTMP bone pain palliation therapy in a 58-year-old hormone refractory prostate cancer patient with extensive bone metastases.


Assuntos
Analgésicos não Narcóticos/uso terapêutico , Antígenos de Superfície , Neoplasias Ósseas/diagnóstico por imagem , Radioisótopos de Gálio , Glutamato Carboxipeptidase II , Compostos Organometálicos/uso terapêutico , Compostos Organofosforados/uso terapêutico , Dor/tratamento farmacológico , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/métodos , Neoplasias Ósseas/secundário , Radioisótopos de Gálio/farmacocinética , Glutamato Carboxipeptidase II/farmacocinética , Humanos , Masculino , Pessoa de Meia-Idade , Cuidados Paliativos/métodos
15.
Curr Radiopharm ; 9(1): 71-84, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-25771371

RESUMO

177Lu-EDTMP has been proposed as a potent bone pain palliation agent owing to theoretical advantage of reduced bone marrow suppression resulting from the low ß(-) energy and a suitably long half-life facilitating its wider distribution with less loss from radioactive decay. Herein, we report the pharmacokinetics, dosimetry and toxicity analysis of 177Lu-EDTMP in patients (phase-0/I study). In a phase-0 study, the biokinetics of skeletal and non-skeletal uptake of 177Lu-EDTMP was assessed in 6 patients with metastatic prostate cancer using tracer doses (172.7-206.9MBq). Data of whole skeletal uptake, blood and fractionated urine samples were obtained and dosimetric calculations were performed using the OLINDA/EXM 1.0 software. Prolonged bone retention was observed in all patients. Excretion was mainly via the renal route and blood clearance was rapid and biphasic. Mean estimated red marrow dose was 0.80±0.15mGy/MBq while mean total-body dose was 0.16±0.04mGy/MBq. A maximum tolerated dose (MTD) of 2000-3250MBqfor 177Lu-EDTMP was calculated. For the phase-I study, 21 patients with metastatic prostate cancer were given a therapeutic dose of 177Lu- EDTMP (692-5550MBq). Toxiciy (WHO), evaluated by assessment of hemoglobin levels, platelet and leukocyte counts over 12 weeks, was mainly limited to anemia or thrombocytopenia. Only transient toxicity was observed in 14/21 patients, of which 6 had baseline toxicity. Beyond the MTD, a significantly higher number of patients displayed grade 3-4 toxicity. Pain relief, assessed by VAS pain score, was observed in 86% patients with median relief duration of 7 weeks. The results demonstrate that 177Lu-EDTMP has excellent pharmacokinetic and dosimetric properties, besides being safe and effective. Along with estimating radiation dose values to certain critical organs, we have also proposed an MTD for 177Lu-EDTMP that correlated well with toxicity data. The encouraging dosimetry and toxicity data of 177Lu-EDTMP reported provide the basis for subsequent phases of the studies to establish complete effectiveness and safety of 177Lu-EDTMP as an attractive alternative to other radioactive bone pain palliation agents.


Assuntos
Neoplasias Ósseas/radioterapia , Compostos Organometálicos/administração & dosagem , Compostos Organofosforados/administração & dosagem , Neoplasias da Próstata/radioterapia , Compostos Radiofarmacêuticos/administração & dosagem , Idoso , Neoplasias Ósseas/secundário , Humanos , Masculino , Dose Máxima Tolerável , Pessoa de Meia-Idade , Compostos Organometálicos/efeitos adversos , Compostos Organometálicos/farmacocinética , Compostos Organofosforados/efeitos adversos , Compostos Organofosforados/farmacocinética , Cuidados Paliativos/métodos , Neoplasias da Próstata/patologia , Radioisótopos/administração & dosagem , Radioisótopos/efeitos adversos , Radioisótopos/farmacocinética , Radiometria , Compostos Radiofarmacêuticos/efeitos adversos , Compostos Radiofarmacêuticos/farmacocinética , Dosagem Radioterapêutica , Distribuição Tecidual
16.
Curr Radiopharm ; 9(1): 64-70, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-25771374

RESUMO

177Lu-EDTMP is currently being investigated as a potential agent for providing palliative care to the patients suffering from bone pain due to metastatic skeletal carcinoma. The present article describes the evaluation of 177Lu-EDTMP complex in four different canine patients with different types of primary and metastatic skeletal lesions with respect to its pharmacokinetic properties, dosimetry and therapeutic efficacy. The dogs were treated with a dose of ~44.4 MBq (1.2 mCi) per kg body weight of 177Lu-EDTMP, synthesized in-house with high radiochemical purity (98.8 ± 0.4 %) and excellent in vitro stability. The radiopharmaceutical showed favourable pharmacokinetic properties, such as, preferential accumulation at skeletal lesion sites and fast clearance from blood and other non-target organs through urinary route. The administered dose of the radiopharmacutical showed excellent therapeutic efficacy in case of a dog suffering from skeletal metastasis originating from primary tumor elsewhere. On the other hand, two of the remaining three patients with primary bone cancer showed stable disease intially with palliative effect. The fourth patient having metal implant induced osteosarcoma with severe limb oedema did not show any response to the treatment.


Assuntos
Neoplasias Ósseas/radioterapia , Compostos Organometálicos/administração & dosagem , Compostos Organofosforados/administração & dosagem , Radioisótopos/administração & dosagem , Compostos Radiofarmacêuticos/administração & dosagem , Animais , Neoplasias Ósseas/patologia , Neoplasias Ósseas/secundário , Cães , Feminino , Masculino , Compostos Organometálicos/farmacocinética , Compostos Organofosforados/farmacocinética , Osteossarcoma/patologia , Osteossarcoma/radioterapia , Radioisótopos/farmacocinética , Radiometria , Compostos Radiofarmacêuticos/farmacocinética , Distribuição Tecidual
18.
Curr Radiopharm ; 6(3): 152-80, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24059327

RESUMO

Radionuclide therapy (RNT) based on the concept of delivering cytotoxic levels of radiation to disease sites is one of the rapidly growing fields of nuclear medicine. Unlike conventional external beam therapy, RNT targets diseases at the cellular level rather than on a gross anatomical level. This concept is a blend of a tracer moiety that mediates a site specific accumulation followed by induction of cytotoxicity with the short-range biological effectiveness of particulate radiations. Knowledge of the biochemical reactions taking place at cellular levels has stimulated the development of sophisticated molecular carriers, catalyzing a shift towards using more specific targeting radiolabelled agents. There is also improved understanding of factors of importance for choice of appropriate radionuclides based on availability, the types of emissions, linear energy transfer (LET), and physical half-life. This article discusses the applications of radionuclide therapy for treatment of cancer as well as other diseases. The primary objective of this review is to provide an overview on the role of radionuclide therapy in the treatment of different diseases such as polycythaemia, thyroid malignancies, metastatic bone pain, radiation synovectomy, hepatocellular carcinoma (HCC), neuroendocrine tumors (NETs), non-Hodgkin's lymphoma (NHL) and others. In addition, recent developments on the systematic approach in designing treatment regimens as well as recent progress, challenges and future perspectives are discussed. An examination of the progress of radionuclide therapy indicates that although a rapid stride has been made for treating hematological tumors, the development for treating solid tumors has, so far, been limited. However, the emergence of novel tumor-specific targeting agents coupled with successful characterization of new target structures would be expected to pave the way for future treatment for such tumors.


Assuntos
Neoplasias/radioterapia , Medicina Nuclear/métodos , Radioisótopos/uso terapêutico , Compostos Radiofarmacêuticos/química , Compostos Radiofarmacêuticos/uso terapêutico , Radioterapia/métodos , Doenças Ósseas/radioterapia , Elétrons , Humanos , Transferência Linear de Energia , Nanopartículas/química , Tumores Neuroendócrinos/radioterapia , Manejo da Dor , Policitemia/radioterapia , Radioimunoterapia/métodos
19.
Cancer Biother Radiopharm ; 28(10): 737-45, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23931111

RESUMO

OBJECTIVE: Thulium-170 [T1/2=128.4 days, Eß(max)=968 keV, and Eγ=84 keV (3.26%)] could be considered an easily producible and cost-effective alternative to (89)Sr for the preparation of radiopharmaceuticals for palliation of bone pain arising due to skeletal metastases. Multidentate aminomethylene polyphosphonic acids have already been proven to be effective as carrier moieties for developing radiolabeled bone pain palliation agents using lanthanide radionuclides. Therefore, an attempt was made to evaluate the potential of a series of (170)Tm-labeled acyclic (diethylenetriaminepentamethylene phosphonic acid and triethylenetetraminehexamethylene phosphonic acid) and cyclic polyaminopolyphosphonic acids (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetramethylene phosphonic acid [DOTMP] and 1,4,8,11-tetraazacyclotetradecane-1,4,8,11-tetramethylene phosphonic acid [CTMP]) toward their use as alternative bone pain palliation agents. EXPERIMENTAL: Thulium-170 was produced by irradiating the natural Tm2O3 target at a thermal neutron flux of 7×10(13) n·cm(-2)·s(-1) for a period of 60 days. All the phosphonic acid ligands were synthesized and characterized in-house. The protocols for radiolabeling the phosphonic acids with (170)Tm were standardized. Biological evaluation of the (170)Tm-labeled phosphonic acids were carried out in normal Wistar rats by biodistribution as well as by scintigraphic studies. RESULTS: Thulium-170 was produced with adequate specific activity (173 Ci/g, 6.41 TBq/g) and high radionuclidic purity (99.62%). All the (170)Tm-labeled phosphonic acids, except (170)Tm-CTMP, were prepared with very high radiochemical purity (>98%) under optimized reaction conditions and exhibited high stability. All the agents showed selective skeletal accumulation with insignificant uptake in other vital organs/tissues and major clearance through renal pathway. These findings were also substantiated by scintigraphic studies. CONCLUSIONS: Although all the (170)Tm-labeled phosphonic acids showed significant and selective skeletal accumulation, radiochemical studies indicate that (170)Tm-DOTMP is the best choice for carrying out further evaluation toward its use for clinical applications.


Assuntos
Osso e Ossos/diagnóstico por imagem , Ácidos Fosforosos/farmacocinética , Radioisótopos/farmacocinética , Compostos Radiofarmacêuticos/farmacocinética , Túlio/química , Túlio/farmacocinética , Animais , Osso e Ossos/metabolismo , Osso e Ossos/patologia , Marcação por Isótopo , Cuidados Paliativos , Ácidos Fosforosos/química , Poliaminas/química , Poliaminas/farmacocinética , Radioisótopos/química , Cintilografia , Compostos Radiofarmacêuticos/química , Ratos , Ratos Wistar , Distribuição Tecidual
20.
Nucl Med Biol ; 40(7): 946-54, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23850487

RESUMO

AIM: Integrin αvß3 plays a significant role in angiogenesis during tumor growth and metastasis, and is a receptor for the extracellular matrix proteins with the exposed arginine(R)-glycine(G)-aspartic acid(D) tripeptide sequence. The over-expression of integrin αvß3 during tumor growth and metastasis presents an interesting molecular target for both early detection and treatment of rapidly growing solid tumors. Considering the advantages of (177)Lu for targeted radiotherapy and enhanced tumor targeting capability of cyclic RGD peptide dimer, an attempt has been made to optimize the protocol for the preparation of clinical dose of (177)Lu labeled DOTA-E[c(RGDfK)]2 (E=Glutamic acid, f=phenyl alanine, K=lysine) as a potential agent for targeted tumor therapy. METHODS: (177)Lu was produced by thermal neutron bombardment on enriched Lu2O3 (82% in (176)Lu) target at a flux of 1 × 10(14) n/cm(2).s for 21 d. Therapeutic dose of (177)Lu-DOTA-E[c(RGDfK)]2 (7.4GBq) was prepared by adding the aqueous solution of the ligand and (177)LuCl3 to 0.1M NH4OAC buffer containing gentisic acid and incubating the reaction mixture at 90°C for 30 min. The yield and radiochemical purity of the complex was determined by HPLC technique. Parameters, such as, ligand-to-metal ratio, pH of the reaction mixture, incubation time and temperature were varied using tracer quantity of (177)Lu (37 MBq) in order to arrive at the optimized protocol for the preparation of clinical dose. Biological behavior of the radiotracer prepared was studied in C57/BL6 mice bearing melanoma tumors. RESULTS: (177)Lu was produced with a specific activity of 950 ± 50 GBq/mg (25.7 ± 1.4 Ci/mg) and radionuclidic purity of 99.98%. A careful optimization of several parameters showed that (177)Lu-DOTA-E[c(RGDfK)]2 could be prepared with adequately high radiochemical purity using a ligand-to-metal ratio ~2. Based on these studies therapeutic dose of the agent with 7.4 GBq of (177)Lu was formulated in ~63 GBq/µM specific activity with high yield (98.2 ± 0.7%), radiochemical purity and in vitro stability. Biodistribution studies carried out in C57/BL6 mice bearing melanoma tumors revealed specific accumulation of the radiolabeled conjugate in tumor (3.80 ± 0.55% ID/g at 30 min p.i.) with high tumor to blood and tumor to muscle ratios. However, the uptake of the radiotracer in the tumor was found to be reduced to 1.51 ± 0.32 %ID/g at 72 h p.i. CONCLUSIONS: The present work successfully demonstrates the formulation of an optimized protocol for the preparation of (177)Lu labeled DOTA-E[c(RGDfK)]2 for PRRT applications using (177)Lu produced by direct neutron activation in a medium flux research reactor.


Assuntos
Dimerização , Lutécio/uso terapêutico , Peptídeos Cíclicos/química , Peptídeos Cíclicos/uso terapêutico , Doses de Radiação , Radioquímica/métodos , Radioisótopos/uso terapêutico , Animais , Estabilidade de Medicamentos , Compostos Heterocíclicos com 1 Anel/química , Humanos , Marcação por Isótopo , Melanoma/radioterapia , Camundongos , Octanóis/química , Peptídeos Cíclicos/farmacocinética , Traçadores Radioativos , Água/química
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