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1.
PLoS One ; 19(4): e0301435, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38635642

RESUMO

In radiotherapy, when photon energy exceeding 8 MV is utilized, photoneutrons can activate the components within the gantry of the linear accelerator (linac). At the end of the linac's lifecycle, radiation workers are tasked with its dismantling and disposal, potentially exposing them to unintentional radiation. This study aims to identify and measure the radioisotopes generated by this activation through spectroscopy, and to evaluate the effective dose rate. We selected nine medical linacs, considering various factors such as manufacturer (Siemens, Varian, and Elekta), model, energy, period of operation, and workload. We identified the radionuclides in the linac head by employing an in situ high-purity germanium (HPGe) detector. Spectroscopy and dose-rate measurements were conducted post-shutdown. We also measured the dose rates at the beam-exit window following irradiation with 10 MV and 15 MV photon beams. As a result of the spectroscopy, we identified approximately 20 nuclides including those with half-lives of 100 days or longer, such as 54Mn, 60Co, 65Zn, 122Sb, and 198Au. The dose rate measurements after 10 MV irradiation decreased to the background level in 10 min. By contrast, on 15 MV irradiation, the dose rate was 628 nSv/h after 10 min and decreased to 268 nSv/h after 1.5 hours. It was confirmed that the difference in the level of radiation and the type of nuclide depends on the period of use, energy, and workload. However, the type of nuclide does not differ significantly between the linacs. It is necessary to propose appropriate guidelines for the safety of workers, and disposal/move-install should be planned while taking into consideration the equipment's energy usage rate.


Assuntos
Manganês , Radioisótopos , Humanos , Dosagem Radioterapêutica , Aceleradores de Partículas , Fótons , Análise Espectral
2.
World J Microbiol Biotechnol ; 40(6): 171, 2024 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-38630327

RESUMO

A histidine acid phosphatase (HAP) (PhySc) with 99.50% protein sequence similarity with PHO5 from Saccharomyces cerevisiae was expressed functionally with the molecular mass of ∼110 kDa through co-expression along with the set of molecular chaperones dnaK, dnaJ, GroESL. The purified HAP illustrated the optimum activity of 28.75 ± 0.39 U/mg at pH 5.5 and 40 ˚C. The Km and Kcat values towards calcium phytate were 0.608 ± 0.09 mM and 650.89 ± 3.6 s- 1. The half-lives (T1/2) at 55 and 60 ˚C were 2.75 min and 55 s, respectively. The circular dichroism (CD) demonstrated that PhySc includes 30.5, 28.1, 21.3, and 20.1% of random coils, α-Helix, ß-Turns, and ß-Sheet, respectively. The Tm recorded by CD for PhySc was 56.5 ± 0.34˚C. The molecular docking illustrated that His59 and Asp322 act as catalytic residues in the PhySc. MD simulation showed that PhySc at 40 ˚C has higher structural stability over those of the temperatures 60 and 80 ˚C that support the thermodynamic in vitro investigations. Secondary structure content results obtained from MD simulation indicated that PhySc consists of 34.03, 33.09, 17.5, 12.31, and 3.05% of coil, helix, turn, sheet, and helix310, respectively, which is almost consistent with the experimental results.


Assuntos
Magnésio , Simulação de Dinâmica Molecular , Radioisótopos , Proteínas de Saccharomyces cerevisiae , Fosfatase Ácida/genética , Saccharomyces cerevisiae/genética , Histidina , Simulação de Acoplamento Molecular , Proteínas de Saccharomyces cerevisiae/genética
3.
Theranostics ; 14(6): 2560-2572, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38646643

RESUMO

Management of prostate cancer (PC) might be improved by combining external beam radiotherapy (EBRT) and prostate-specific membrane antigen (PSMA)-targeted radioligand therapy (RLT) with lutetium-177 (177Lu)-labeled PSMA inhibitors. We hypothesized a higher efficacy of the combination due to augmentation of the radiation dose to the tumor and interactions of EBRT with PSMA expression potentially increasing radiopharmaceutical uptake. Therefore, this study analyzed the influence of radiation on PSMA expression levels in vitro. The results were translated to evaluate the efficacy of the combination of photon EBRT and [177Lu]Lu-PSMA-617 in a murine PC xenograft model. Finally, a clinical case report on a combined elective field EBRT with RLT dose escalation illustrates a proof-of-concept. Methods: PSMA gene and protein expression were assessed in human PSMA-overexpressing LNCaP cells after irradiation using reverse transcription quantitative polymerase chain reaction (RT-qPCR), flow cytometry and On-Cell Western assays. In the in vivo therapy study, LNCaP tumor-bearing BALB/c nu/nu mice were irradiated once with 2 Gy X-ray EBRT and injected with 40 MBq [177Lu]Lu-PSMA-617 after 4 h or received single or no treatment (n = 10 each). Tumor-absorbed doses by [177Lu]Lu-PSMA-617 were calculated according to the Medical Internal Radiation Dosimetry (MIRD) formalism after deriving time-activity curves using a gamma probe. An exemplified patient case is demonstrated where fractionated EBRT (54 Gy to prostate; 45 Gy to pelvic lymphatics) and three cycles of [177Lu]Lu-PSMA-617 (3.4-6.0 GBq per cycle) were sequentially combined under concurrent androgen deprivation for treating locally advanced PC. Results: At 4 h following irradiation with 2-8 Gy, LNCaP cells displayed a PSMA protein upregulation by around 18% relative to non-irradiated cells, and a stronger upregulation on mRNA level (up to 2.6-fold). This effect was reversed by 24 h when PSMA protein levels were downregulated by up to 22%. Mice treated with the combination therapy showed significantly improved outcomes regarding tumor control and median survival (p < 0.0001) as compared to single or no treatment. Relative to monotherapy with PSMA-RLT or EBRT, the tumor doubling time was prolonged 1.7- or 2.7-fold and the median survival was extended by 24% or 60% with the combination, respectively. Additionally, tumors treated with EBRT exhibited a 14% higher uptake of the radiopharmaceutical as evident from the calculated tumor-absorbed dose, albeit with high variability in the data. Concerning the patient case, the tri-modality treatment was well tolerated and the patient responded with a long-lasting complete biochemical remission for five years following end of PSMA-RLT. The patient then developed a biochemical relapse with oligo-recurrent disease on follow-up imaging. Conclusion: The present preclinical and clinical data demonstrate that the combination of EBRT with dose escalation by PSMA-RLT improves tumor control and potentially prolongs survival. This may pave the way for further clinical investigations of this approach to explore the curative potential of the combination therapy.


Assuntos
Dipeptídeos , Compostos Heterocíclicos com 1 Anel , Lutécio , Antígeno Prostático Específico , Neoplasias da Próstata , Radioisótopos , Compostos Radiofarmacêuticos , Animais , Masculino , Neoplasias da Próstata/radioterapia , Neoplasias da Próstata/metabolismo , Humanos , Lutécio/uso terapêutico , Lutécio/farmacologia , Compostos Heterocíclicos com 1 Anel/uso terapêutico , Compostos Heterocíclicos com 1 Anel/farmacologia , Dipeptídeos/farmacologia , Dipeptídeos/uso terapêutico , Linhagem Celular Tumoral , Camundongos , Compostos Radiofarmacêuticos/uso terapêutico , Compostos Radiofarmacêuticos/farmacologia , Compostos Radiofarmacêuticos/farmacocinética , Radioisótopos/uso terapêutico , Radioisótopos/farmacologia , Camundongos Endogâmicos BALB C , Camundongos Nus , Glutamato Carboxipeptidase II/metabolismo , Glutamato Carboxipeptidase II/genética , Ensaios Antitumorais Modelo de Xenoenxerto , Antígenos de Superfície/metabolismo , Antígenos de Superfície/genética
5.
Q J Nucl Med Mol Imaging ; 68(1): 23-31, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38587360

RESUMO

Pediatric gastrointestinal imaging plays a crucial role in evaluating and managing digestive system disorders in children. This comprehensive review dives into the nuances of pediatric gastrointestinal imaging techniques, focusing on three specific modalities: gastric emptying scintigraphy (GES), intestinal transit scintigraphy (ITS), and gastrointestinal bleeding scintigraphy. GES involves real-time monitoring of stomach emptying using radiotracers and gamma camera technology. While challenges exist in standardizing protocols due to age-specific meal compositions, GES remains pivotal in diagnosing motility disorders, gastroesophageal reflux, and abdominal pain in children. ITS, utilizing [67Ga], provides insights into gastrointestinal motility disorders such as Hirschsprung disease. It aids in whole-gut transit evaluation, guiding surgical interventions and improving long-term clinical outcomes. Gastrointestinal bleeding scintigraphy, employing [99mTc], assists in diagnosing conditions like Meckel's diverticulum and occult bleeding, offering continuous monitoring to pinpoint the bleeding site along the entire gastrointestinal tract. SPECT-CT improves the accuracy and the standards of care. Each technique's protocol details, clinical indications, and diagnostic capabilities are thoroughly discussed, highlighting the importance of these non-invasive, functional imaging modalities in pediatric gastroenterology.


Assuntos
Esvaziamento Gástrico , Radioisótopos , Humanos , Criança , Cintilografia , Hemorragia Gastrointestinal
6.
Appl Radiat Isot ; 208: 111307, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38564840

RESUMO

Early works that used thermoluminescent dosimeters (TLDs) to measure absorbed dose from alpha particles reported relatively high variation (10%) between TLDs, which is undesirable for modern dosimetry applications. This work outlines a method to increase precision for absorbed dose measured using TLDs with alpha-emitting radionuclides by applying an alpha-specific chip factor (CF) that individually characterizes the TLD sensitivity to alpha particles. Variation between TLDs was reduced from 21.8% to 6.7% for the standard TLD chips and 7.9% to 3.3% for the thin TLD chips. It has been demonstrated by this work that TLD-100 can be calibrated to precisely measure the absorbed dose to water from alpha-emitting radionuclides.


Assuntos
Dosímetros de Radiação , Dosimetria Termoluminescente , Dosimetria Termoluminescente/métodos , Radioisótopos , Radiometria/métodos , Calibragem
7.
J Environ Manage ; 357: 120851, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38581894

RESUMO

Conventional liquid treatments for large-scale, low-level radioactive wastewater, such as ion exchange and waste solidification, face challenges due to the large amounts of secondary waste and high disposal costs. A new large-scale decontamination method is proposed that uses kapok fiber composites for rapid radionuclide adsorption and high volume reduction to minimize secondary waste. The composite consists of natural zeolite and kapok holocellulose, which has high water-soaking ability and low-temperature pyrolysis. The kapok composites, fabricated using a commercial wet-laid nonwoven manufacturing process, absorbs 99% of low-level radioactive cesium in 20 min, reducing the volume by 98% and the weight by 47% at 300 °C. The low-temperature pyrolysis process below 300 °C prevents cesium desorption and gasification by avoiding zeolite destruction. The mass-producible kapok composites can be used for adsorbing various radionuclides in large-scale wastewater by attaching specific adsorbents for target isotopes to the composites.


Assuntos
Resíduos Radioativos , Zeolitas , Águas Residuárias , Césio , Radioisótopos , Adsorção , Resíduos Radioativos/prevenção & controle
8.
Molecules ; 29(7)2024 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-38611763

RESUMO

Salvia miltiorrhiza seeds (SMS) are the main by-product of the production processing of Radix Salviae Miltiorrhizae. The main purposes of this work are to analyse the nutritional components in SMS, to explore the antioxidant activity of the chemical components in SMS and to evaluate the possibility of SMS as a raw material for functional foods. The contents of crude fibre, total protein, carbohydrates, total phenolics and flavonoids in SMS and the composition and relative content of fatty acids in SMS oil were determined. The results suggested that SMS has high contents of crude fibre (28.68 ± 4.66 g/100 g), total protein (26.65 ± 2.51 g/100 g), total phenolics (6.45 ± 0.55 mg of gallic acid equivalent/g) and total flavonoids (3.28 ± 0.34 mg of rutin equivalent/g), as well as a high level of α-linolenic acid (33.774 ± 4.68%) in their oil. Twenty-two secondary metabolites were identified in SMS residue, and nine compounds were isolated. The IC50 values of the total phenolic content in SMS on an ABTS radical, DPPH radical, superoxide radical and hydroxyl radical were 30.94 ± 3.68 µg/mL, 34.93 ± 4.12 µg/mL, 150.87 ± 17.64 µg/mL and 230.19 ± 24.47 µg/mL, respectively. The results indicate that SMS contain many nutrients and have high utilization value as a promising functional food.


Assuntos
Antioxidantes , Magnésio , Radioisótopos , Salvia miltiorrhiza , Antioxidantes/farmacologia , Flavonoides , Fenóis , Compostos Fitoquímicos/farmacologia , Sementes
9.
J Nucl Med Technol ; 52(1): 48-51, 2024 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-38443109

RESUMO

The radionuclide gastric emptying study is the gold standard for the diagnosis of gastroparesis. Methods: We performed a retrospective analysis of 510 patients to evaluate how often a diagnosis of slow gastric emptying determined by gastric emptying scintigraphy (GES) changes clinical management at our institution. Results: We found evidence of gastroparesis in 100 patients. A change in management was recommended for 62% within 1 mo of the GES. Conclusion: Our results illustrate the importance of performing GES on patients with clinically suspected gastroparesis.


Assuntos
Esvaziamento Gástrico , Gastroparesia , Humanos , Gastroparesia/diagnóstico por imagem , Estudos Retrospectivos , Cintilografia , Radioisótopos
10.
Environ Monit Assess ; 196(3): 330, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38427152

RESUMO

The Kanyakumari coast is known to be a high background natural radiation area due to the placer deposits of heavy minerals such as ilmenite, monazite, and rutile. The Kanyakumari river sediments that could be the source of the elevated amounts of natural radionuclides in the coastal sands have been studied in this paper. The activity concentrations of primordial radionuclides 226Ra, 232Th, and 40K were determined using high-purity germanium (HPGe) gamma-ray spectrometry. The mean activity concentrations of 226Ra, 232Th, and 40K were found to be 75 Bq kg-1, 565 Bq kg-1, and 360 Bq kg-1, respectively. The mean absorbed dose rate was 395 nGy h-1. Radiological hazard parameters were studied and compared with the world average values. The contribution of 232Th to the total dose rate was found to be higher than that of the two other radionuclides. The high mean ratio of 232Th/226Ra suggested an enrichment of 232Th and the occurrence of 226Ra leaching due to an oxidizing environment. Principal component analysis (PCA) was carried out for the radionuclides in order to discriminate the source of the sediments. This study provides new insights into the distribution of natural radionuclides in sediments of rivers and streams.


Assuntos
Monitoramento de Radiação , Poluentes Radioativos do Solo , Rios , Radiação de Fundo , Monitoramento Ambiental , Tório/análise , Radioisótopos/análise , Poluentes Radioativos do Solo/análise , Índia , Medição de Risco , Monitoramento de Radiação/métodos , Radioisótopos de Potássio/análise
11.
Yakugaku Zasshi ; 144(3): 291-297, 2024.
Artigo em Japonês | MEDLINE | ID: mdl-38432939

RESUMO

Recently, radiotheranostics, which systematically combines diagnosis by nuclear medicine imaging and treatment by internal radiotherapy, constitutes a new modality in cancer treatment, with some clinical reports showing marked effects on cancer. We have been developing multifunctional chelates containing a target recognition unit, a radiation release unit, and a radioactivity pharmacokinetics control unit in the same molecule to develop efficient agents for cancer radiotheranostics based on chemical control of radioactivity pharmacokinetics. Using these compounds, we have achieved improved cancer accumulation and reduced renal accumulation in tumor-bearing mice, and have developed novel hybrid radiotheranostic agents that can be applied to simultaneously perform target-specific molecular imaging using γ-ray emitting radionuclides and internal radiotherapy using α-particle-emitting radionuclides. For example, 111In/225Ac-labeled PSMA-DA1, which targets prostate-specific membrane antigen (PSMA) for radiotheranostics, achieved clear in vivo imaging of PSMA in tumor-bearing mice and showed marked tumor growth inhibition. In addition to PSMA, this platform for radiotheranostics has also shown efficacy against various cancer target molecules, including carbonic anhydrase IX (CA-IX), which is highly expressed in hypoxic regions of cancer, and glucagon-like peptide-1 receptor (GLP-1R), which is highly expressed in insulinomas. This review presents these recent results of our studies on radiotheranostics for cancer.


Assuntos
Neoplasias , Radioatividade , Masculino , Animais , Camundongos , Quelantes , Hipóxia , Neoplasias/diagnóstico por imagem , Neoplasias/tratamento farmacológico , Neoplasias/radioterapia , Radioisótopos
12.
Ann Med ; 56(1): 2320301, 2024 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38442298

RESUMO

Aim: This comprehensive review aims to explore the potential applications of Gastrin-releasing peptide receptor (GRPR) in the diagnosis and treatment of prostate cancer. Additionally, the study investigates the role of GRPR in prognostic assessment for individuals afflicted with prostate cancer.Methods: The review encompasses a thorough examination of existing literature and research studies related to the upregulation of GRPR in various tumor types, with a specific focus on prostate. The review also evaluates the utility of GRPR as a molecular target in prostate cancer research, comparing its significance to the well-established Prostate-specific membrane antigen (PSMA). The integration of radionuclide-targeted therapy with GRPR antagonists is explored as an innovative therapeutic approach for individuals with prostate cancer.Results: Research findings suggest that GRPR serves as a promising molecular target for visualizing low-grade prostate cancer. Furthermore, it is demonstrated to complement the detection of lesions that may be negative for PSMA. The integration of radionuclide-targeted therapy with GRPR antagonists presents a novel therapeutic paradigm, offering potential benefits for individuals undergoing treatment for prostate cancer.Conclusions: In conclusion, this review highlights the emerging role of GRPR in prostate cancer diagnosis and treatment. Moreover, the integration of radionuclide-targeted therapy with GRPR antagonists introduces an innovative therapeutic approach that holds promise for improving outcomes in individuals dealing with prostate cancer. The potential prognostic value of GRPR in assessing the disease's progression adds another dimension to its clinical significance in the realm of urology.


Assuntos
Neoplasias da Próstata , Receptores da Bombesina , Masculino , Humanos , Neoplasias da Próstata/diagnóstico , Neoplasias da Próstata/tratamento farmacológico , Biomarcadores , Regulação para Cima , Radioisótopos
13.
Probl Endokrinol (Mosk) ; 70(1): 13-17, 2024 Feb 27.
Artigo em Russo | MEDLINE | ID: mdl-38433537

RESUMO

Within the framework of the article, the authors analyzed the available information about the damage to the lacrimal apparatus during radionuclide therapy. In focus of article lesions of the lacrimal production system, the main and accessory lacrimal glands, as well as lacrimal drainage are considered. It was found that damage to the lacrimal apparatus is characteristic of 131I therapy for thyroid cancer, as well as for radioligand therapy using anti-PSMA antibodies labeled with 177Lu and 225Ac. 177Lu-PSMA and 225Ac-PSMA may damage the lacrimal gland with the formation of a clinically pronounced "dry eye syndrome". The pathogenesis of such lesions is associated with the accumulation of a radioisotope in the tissues of the lacrimal apparatus, while during therapy with 131I, accumulation is realized due to the expression of the sodium-iodine symporter in the nasolacrimal duct, and during therapy with 177Lu-PSMA and 225Ac-PSMA, the radiobiological effect is realized in connection with the expression PSMA by lacrimal tissue. An analysis of the available sources showed that to date there are no results of systematic studies on the problem, there is a lack of knowledge regarding the individual risks of developing these complications, methods for their prevention that have proven effectiveness have not been developed, and the treatment methods used, having relatively low efficiency, are not specialized. The authors concluded that the strengthening of interdisciplinary interaction, as well as the organization verification methodology and correct studies, can contribute to solving problems related to the study of the complications under consideration.


Assuntos
Aparelho Lacrimal , Lutécio , Radioisótopos , Actínio , Radioisótopos do Iodo
14.
Acta Biomater ; 179: 313-324, 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38490483

RESUMO

Nanoscale coordination polymer (NCP) is a class of hybrid materials formed by self-assembly of metal ions and organic ligands through coordination. The applications of NCP in biomedicine are quite extensive due to the diversity choice of metal ions and organic ligands. Here we designed Zr-P1 NCP based on Zr4+ selected as metal ion nodes and tetrakis(4-carboxyphenyl) ethylene as bridging ligands. Zr-P1 NCP was modified with functionalized pyrene derived polyethylene glycol (Py-PAA-PEG-Mal) on the surface and further conjugated with cRGD for active targeting of integrin αvß3 overexpressed in triple-negative breast cancer. Doxorubicin was loaded on Zr-P1 NCP with encapsulation efficiency up to 22 % for the treatment of triple negative breast cancer. 89Zr-P1 NCP can be used for in vivo tumor imaging due to the fluorescence properties resulting from the enhanced aggregation-induced Emission (AIE) behavior of P1 ligands and its positron emission tomography (PET) capability. Cellular evaluation indicated that the functionalized Zr-P1@PEG-RGD presented a good function for tumor cell targeting imaging and doxorubicin could be targeted to triple negative breast cancer when it was loaded onto Zr-P1@PEG-RGD, which corroborated with the in vivo results. In summary, 89Zr-P1@PEG-RGD can serve as a biocompatible nanoplatform for fluorescence and PET image-guided cargo delivery. STATEMENT OF SIGNIFICANCE: Nanoscale coordination polymer (NCP) is a class of hybrid materials formed by self-assembly of metal ions and organic ligands through coordination. The diversity of available metals and ligand structures upon NCP synthesis plays an advantage in establishing multimodal imaging platforms. Here we designed 89Zr-P1@PEG-RGD NCP based on Zr4+ selected as metal ion nodes and tetrakis(4-carboxyphenyl) ethylene as bridging ligands. 89Zr-P1@PEG-RGD nanomaterials have positron emission tomography (PET) capability due to the incorporation of zirconium-89, which can be used for in vivo tumor imaging with high sensitivity. The chemotherapeutic drug DOX was loaded on Zr-P1 NCP for the treatment of triple-negative breast cancer, and dual modality imaging can provide visual guidance for drug delivery.


Assuntos
Doxorrubicina , Tomografia por Emissão de Pósitrons , Radioisótopos , Neoplasias de Mama Triplo Negativas , Zircônio , Neoplasias de Mama Triplo Negativas/diagnóstico por imagem , Neoplasias de Mama Triplo Negativas/patologia , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Zircônio/química , Animais , Tomografia por Emissão de Pósitrons/métodos , Humanos , Linhagem Celular Tumoral , Feminino , Doxorrubicina/farmacologia , Doxorrubicina/química , Polímeros/química , Camundongos , Sistemas de Liberação de Medicamentos , Polietilenoglicóis/química , Camundongos Nus
15.
J Nucl Med ; 65(3): 409-415, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38428966

RESUMO

Posttreatment imaging of γ-emissions after peptide receptor radionuclide therapy (PRRT) can be used to perform quantitative dosimetry as well as assessment response using qualitative measures. We aimed to assess the impact of qualitative posttreatment imaging on the management of patients undergoing PRRT. Methods: In this retrospective study, we evaluated 100 patients with advanced well-differentiated neuroendocrine tumors undergoing PRRT, who had posttreatment SPECT/CT imaging at 24 h. First, we evaluated the qualitative assessment of response at each cycle. Then using a chart review, we determined the impact on management from the posttreatment imaging. The changes in management were categorized as major or minor, and the cycles at which these changes occurred were noted. Additionally, tumor grade was also evaluated. Results: Of the 100 sequential patients reviewed, most (80% after cycle 2, 79% after cycle 3, and 73% after cycle 4) showed qualitatively stable disease during PRRT. Management changes were observed in 27% (n = 27) of patients; 78% of those (n = 21) were major, and 30% (n = 9) were minor. Most treatment changes occurred after cycle 2 (33% major, 67% minor) and cycle 3 (62% major, 33% minor). Higher tumor grade correlated with increased rate of changes in management (P = 0.006). Conclusion: In this retrospective study, qualitative analysis of posttreatment SPECT/CT imaging informed changes in management in 27% of patients. Patients with higher-grade tumors had a higher rate of change in management, and most of the management changes occurred after cycles 2 and 3. Incorporating posttreatment imaging into standard PRRT workflows could potentially enhance patient management.


Assuntos
Tumores Neuroendócrinos , Octreotida , Humanos , Octreotida/uso terapêutico , Estudos Retrospectivos , Tumores Neuroendócrinos/diagnóstico por imagem , Tumores Neuroendócrinos/radioterapia , Tumores Neuroendócrinos/patologia , Radioisótopos , Receptores de Peptídeos
16.
Angew Chem Int Ed Engl ; 63(18): e202319578, 2024 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-38442302

RESUMO

The development of inert, biocompatible chelation methods is required to harness the emerging positron emitting radionuclide 45Ti for radiopharmaceutical applications. Herein, we evaluate the Ti(IV)-coordination chemistry of four catechol-based, hexacoordinate chelators using synthetic, structural, computational, and radiochemical approaches. The siderophore enterobactin (Ent) and its synthetic mimic TREN-CAM readily form mononuclear Ti(IV) species in aqueous solution at neutral pH. Radiolabeling studies reveal that Ent and TREN-CAM form mononuclear complexes with the short-lived, positron-emitting radionuclide 45Ti(IV), and do not transchelate to plasma proteins in vitro and exhibit rapid renal clearance in naïve mice. These features guide efforts to target the 45Ti isotope to prostate cancer tissue through the design, synthesis, and evaluation of Ent-DUPA, a small molecule conjugate composed of a prostate specific membrane antigen (PSMA) targeting peptide and a monofunctionalized Ent scaffold. The [45Ti][Ti(Ent-DUPA)]2- complex forms readily at room temperature. In a tumor xenograft model in mice, selective tumor tissue accumulation (8±5 %, n=5), and low off-target uptake in other organs is observed. Overall, this work demonstrates targeted imaging with 45Ti(IV), provides a foundation for advancing the application of 45Ti in nuclear medicine, and reveals that Ent can be repurposed as a 45Ti-complexing cargo for targeted nuclear imaging applications.


Assuntos
Neoplasias da Próstata , Sideróforos , Humanos , Masculino , Animais , Camundongos , Sideróforos/química , Enterobactina/metabolismo , Titânio/química , Uso Off-Label , Neoplasias da Próstata/metabolismo , Radioisótopos
17.
Phys Med Biol ; 69(9)2024 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-38537308

RESUMO

Objective.A Monte Carlo virtual source model named PHID (photon from Ion decay) that generates photons emitted in the complex decay chain process of alpha-emitter radionuclides is proposed, typically for use during the simulation of SPECT image acquisition.Approach.Given an alpha-emitter radionuclide, the PHID model extracts from Geant4 databases the photon emission lines from all decaying daughters for both isometric transition and atomic relaxation processes. According to a given time range, abundances and activities in the decay chain are considered thanks to the Bateman equations, taking into account the decay rates and the initial abundances.Main results.PHID is evaluated by comparison with analog Monte Carlo simulation. It generates photons with the correct energy and temporal distribution, avoiding the costly simulation of the complete decay chain thus decreasing the computation time. The exact time gain depends on the simulation setup. As an example, it is 30× faster for simulating 1 MBq of225Ac in water for 1 section Moreover, for225Ac, PHID was also compared to a simplified source model with the two main photon emission lines (218 and 440 keV). PHID shows that 2 times more particles are simulated and 60% more counts are detected in the images.Significance.PHID can simulate any alpha-emitter radionuclide available in the Geant4 database. As a limitation, photons emitted from Bremsstrahlung are ignored, but they represent only 0.7% of the photons above 30 keV and are not significant for SPECT imaging. PHID is open-source, available in GATE 10, and eases the investigation of imaging photon emission from alpha emitters.


Assuntos
Radioisótopos , Tomografia Computadorizada de Emissão de Fóton Único , Tomografia Computadorizada de Emissão de Fóton Único/métodos , Simulação por Computador , Fótons , Imagens de Fantasmas , Método de Monte Carlo
18.
Mar Pollut Bull ; 201: 116225, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38460435

RESUMO

The Huelva estuary is formed by the common mouths of the Odiel and Tinto Rivers, and inside this ecosystem is the biosphere reserve of the Odiel saltmarshes. This ecosystem has been historically affected by acid mine drainage (AMD) and by releases of pollutants from five phosphoric acid industrial plants and phosphogypsum (PG) waste stacks located in the area. This study carried out a comprehensive assessment of the environmental impact of the biosphere reserve of the Odiel saltmarshes. To this end, it was necessary to find a suitable sedimentary background (Piedras River in our case). To quantify this impact, several pollution indexes were used. According to the values reached by the indexes, this impact was classified as "serious" pollution for most trace elements, excepting the deepest layers, and "low-moderate" pollution for the 238U-series radionuclides, while no pollution for the 232Th-series and 40K radionuclides was found as expected.


Assuntos
Ecossistema , Poluentes Químicos da Água , Estuários , Resíduos Industriais/análise , Rios , Radioisótopos , Espanha , Monitoramento Ambiental , Poluentes Químicos da Água/análise
19.
Clin Nucl Med ; 49(5): 454-456, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38465961

RESUMO

ABSTRACT: Extravasation of the radiopharmaceutical during peptide receptor radionuclide therapy infusion is an unwanted infrequently reported event. We present the case of a 74-year old woman with a neuroendocrine tumor who was referred for peptide receptor radionuclide therapy. During intravenous infusion of 7.4 GBq [ 177 Lu]Lu-HA-DOTATATE in the upper right arm, extravasation of the radiopharmaceutical occurred through a displaced intravenous catheter. Planar scintigraphy showed pooling of radioactivity in the right upper arm. After 24 hours, the swelling in the arm was decreased; however, erythema was increased. One week later, symptoms had disappeared, and the patient did not experience any complications during follow-up of 11 months.


Assuntos
Lutécio , Tumores Neuroendócrinos , Compostos Organometálicos , Tomografia por Emissão de Pósitrons , Cintilografia , Feminino , Humanos , Idoso , Compostos Radiofarmacêuticos , Octreotida/efeitos adversos , Radioisótopos , Tumores Neuroendócrinos/diagnóstico por imagem , Tumores Neuroendócrinos/radioterapia , Receptores de Peptídeos , Compostos Organometálicos/efeitos adversos
20.
Clin Nucl Med ; 49(5): 472-474, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38465996

RESUMO

ABSTRACT: A 57-year-old woman with a metastatic bone malignant solitary fibrous tumor received 177 Lu-FAP-2286 therapy. After 1 treatment cycle, 68 Ga-FAP-2286 PET/CT revealed remission of the lesions. Moreover, the patient did not report any adverse effects.


Assuntos
Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Tumores Fibrosos Solitários , Feminino , Humanos , Pessoa de Meia-Idade , Radioisótopos , Radioisótopos de Gálio , Lutécio , Tumores Fibrosos Solitários/diagnóstico por imagem
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