Current radiopharmaceuticals最新文献

Objective: Previously, low-dose radiation therapy was used for pneumonia treatment. We aimed to investigate the safety and effectiveness of carbon nanoparticles labeled with Technetium isotope (^99mTc) in a form of ultradispersed aerosol in combination with standard COVID-19 therapy. The study was a randomized phase 1 and phase 2 clinical trial of low-dose radionuclide inhalation therapy for patients with COVID-19 related pneumonia.

Methods: We enrolled 47 patients with confirmed COVID-19 infection and early laboratory signs of cytokine storm and randomized them into the Treatment and Control groups. We analyzed blood parameters reflecting the COVID-19 severity and inflammatory response.

Results: Low-dose ^99mTc-labeled inhalation showed a minimal accumulation of radionuclide in lungs in healthy volunteers. We observed no significant differences between the groups before treatment in WBC-count, D-dimer, CRP, Ferritin or LDH levels. We found that Ferritin and LDH levels significantly raised after the 7th day follow-up only in the Control group (p < 0.0001 and p = 0.0005, respectively), while mean values of the same indicators did not change in patients in the Treatment group after the radionuclide treatment. D-dimer values also lowered in the radionuclide treated group, however, this effect was not statistically significant. Furthermore, we observed a significant decrease in CD19+ cell counts in patients of the radionuclide-treated group.

Conclusion: Inhalation low-dose radionuclide therapy of ^99mTc aerosol affects the major prognostic indicators of COVID-19- related pneumonia restraining inflammatory response. Overall, we identified no evidence of major adverse events in the group receiving radionuclide.

Background: New generation PET/CT devices provide quality images using low radiopharmaceutical activities. Dose monitoring is carried out for nuclear medicine personnel, other health personnel, and companions by determining the radiation dose emitted from low-activity patients to the environment. In particular, it is necessary to revise the working conditions of the personnel according to the radiation dose exposed.

Aim: It was aimed to reevaluate the radiation dose rate transmitted to the environment from patients injected with ¹⁸F-FDG.

Materials and methods: A total of 31 patients (14F, 17M) who underwent ¹⁸F-FDG PET/CT imaging were included. The mean ¹⁸F-FDG activity of 7.26 ± 1.29 mCi was used for injection. After injection, radiation dose rates (mR/h) were measured at distances of 25, 50, 100, 150, and 200cm for 3 different periods from the level of the head, thorax, abdomen, and pelvis by using a GM counter. Additionally, biological samples such as urine and sweat were taken during 3 different periods. The activity amounts (μCi) in the samples were measured with a well-type counter.

Results: Strong correlations were calculated between normalized dose rates obtained by all regions and time. Considering the nuclear medicine staff handling time with a PET/CT patient, the average dose received by staff was calculated between a range of 0.002-0.004 mSv/pt. The radiation dose exposed to the porter and nurse was calculated as 0.049 mSv/pt for the 2^nd hour and 0.001-0.007 mSv/pt for the 4^th hour, respectively. The companion was exposed to a dose between 0.073-0.147 mSv and 0.024-0.048 mSv for public transport and private car transportation after 4-6 hours of injection (for 30-60 min of travel duration), respectively. For inpatients, the received dose for porters, serving 20min from a distance of 30cm for the 2^nd and 4^th hours after the PET/CT scan, was 0.049 mSv/pt and 0.048 mSv/pt, respectively. And for nurses serving from a 50cm distance between 1-5 minutes, these values were found to be 0.001-0.007mSv/pt, 0.001-0.007mSv/pt, and 0.001-0.006mSv/pt, respectively.

Conclusion: The radiation dose of nuclear medicine staff, porters, nurses, and companions are found to be below the recommended dose limit by the ICRP. According to our results, there is no need for any restrictions for patients, companions, or healthcare personnel in PET/CT units.

Angiogenesis phenomenon, as a highly affecting factor on the growth and spread of cancer cells, depends on specific molecular interactions between components of the extracellular matrix and vascular cells. αv integrin acts as a cell adhesive molecule involved in tumor invasion and angiogenesis. Among the various combinations of integrin subunits expressed on the surface of cells, α_vβ₃ integrin has a particularly interesting expression pattern during angiogenesis. The α_vβ₃ integrin is a vital receptor affecting tumor growth, tumor invasiveness, metastasis, and angiogenesis overexpressed on various human tumors, leading to the development of different theranostics probes and radiopharmaceuticals. The α_vβ₃ integrin can recognize several extracellular matrix molecules in the base of the RGD adhesive sequence. This review provides an overview of the status, trends and future of the most studied α_vβ₃ integrin-binding ligand, RGD tripeptides, labeled with various radioisotopes. An overview of the pre-clinical models for radiolabeled RGD peptides and clinical aspects of the RGD- based radiopharmaceuticals is provided with some new considerations and ways forward.

Background: Despite substantial research, the mechanisms behind stress Tako-tsubo cardiomyopathy (TTC) remain rather elusive.

Objective: The purpose of this paper was to provide a detailed review of the mainstream factors underlying the pathophysiology of TTC, highlighting the novel contributions of molecular pathology and in-vivo molecular imaging.

Methods: A careful literature review selected all papers discussing TTC, specifically those providing novel insights from myocardial pathology and cardiac molecular imaging.

Results: Results concerning myocardial pathology, defect extension, sites and relationships between functional parameters underline the existence of a causal relationship between a determinant (e.g., the release of catecholamines induced by stress) and an outcome for TTC, which is not limited to a reversible contractile cardiomyopathy, but it includes reversible changes in myocardial perfusion and a long-lasting residual deficit in sympathetic function. Besides, they reinforce the hypothesis that sympathetic nerves may exert a complex control on cardiac contractile function, which is likely to be direct or indirect through metabolism and microvascular perfusion changes during anaerobic and aerobic conditions.

Conclusion: TTC is characterized by acute transient left ventricular systolic dysfunction, which can be challenging to distinguish from myocardial infarction at presentation. Catecholamineinduced myocardial injury is the most established theory, but other factors, including myocardial metabolism and perfusion, should be considered of utmost importance. Each effort to clarify the numerous pathways and emerging abnormalities may provide novel approaches to treat the acute episode, avoid recurrences, and prevent major adverse cardiovascular events.

Introduction: This study aimed to determine the critical organ doses in ²²³Ra, ⁸⁹Sr, ¹⁵³Sm, and ³²P treatments via dosimetry using the phantoms.

Material and methods: The OpenDose was used to calculate S values (mGy MBq^-1s^-1) for bone surface, red bone marrow, urinary bladder wall, testes, ovaries, uterus, and kidneys using male (ICRP110AM) and female (ICRP110AF) phantoms. The cortical thoracic spine was modeled as metastasis. Moreover, the absorbed doses were computed via MIRD formalism according to the activities of 3.3, 148, 2220, and 370 MBq for ICRP110AM and 4.015, 148, 2701, and 370 MBq for ICRP110AF in ²²³Ra, ⁸⁹Sr, ¹⁵³Sm, and ³²P treatments, respectively.

Results: Whilst the maximum bone surface doses were found as 1.22E+02 and 8.51E+01 mGy at ³²P treatment, the minimum bone surface doses were calculated as 8.42E-02 and 8.26E-02 mGy at ²²³Ra. In terms of the comparison of red bone marrow, urinary bladder wall, and kidney doses, ¹⁵³Sm and ⁸⁹Sr treatments showed maximum doses of 2.45E-03, 1.50E-03, 3.23E-07, 5.45E-06, 1.20E-01, 1.49E-01 mGy and the minimum doses with 3.46E-05, 1.99E-05, 6.33E-09, 8.77E-09, 1.19E-04, 1.15E-04 mGy, respectively. The maximum testes and ovaries-uterus doses were found as 6.17E-08, 7.40E-06, 3.46E-07 mGy in ¹⁵³Sm treatment, and minimum testes and ovaries doses as 1.70E-09, 1.34E-07 mGy in ²²³Ra. The minimum uterus dose with 7.03E-09 mGy was determined in ⁸⁹Sr treatment.

Conclusion: It is observed that ²²³Ra produces low critical organ doses in the treatment of painful bone metastasis. Among the beta-emitting radionuclides, ⁸⁹Sr stands out by showing optimal dosimetric results.

Nuclear medicine specialty involves the administration of unsealed radioactive substances to patients to allow specific diagnostics and treatments using radiopharmaceuticals, radiotracers, and materials. Developing a radiopharmaceutical must involve considering and addressing some limitations such as its retention by unintended organs, which can influence patient and worker safety, imaging findings, and diagnostic and therapeutic accuracy. This paper presents data on the changing biodistribution, localization, stability, and accuracy patterns of radiopharmaceuticals by liposome encapsulation.

Methods: Data are presented for 5 male New Zealand white rabbits. They were injected intravenously with the ^99mTc-liposomes encapsulated MIBI through a marginal ear vein, and whole-body images were acquired using a dual-head gamma camera. Cationic PEGylated liposomes were prepared using the conventional thin-film-hydration method. The liposomes were tested for particle size, zeta potential, high-performance-liquid-chromatography (HPLC), and toxicity.

Results: The liver activity was slightly greater than or equivalent to heart uptake, using ^99mTcsestamibi, MIBI, without liposome as a reference. The absorbed doses in myocardium cells after injecting rabbits with ^99mTc-MIBI labeled with free positive lower pH liposomes was greater than in the liver, whereas ^99mTc labeled with encapsulated MIBI within positive liposomes showed a significantly higher heart-to-liver ratio. The heart-to-spleen activity uptake ratio in ^99mTc-MIBI was higher than or equal to one but increased in ^99mTc labeled with MIBI and free positive liposomes. Injecting rabbits with ^99mTc labeled with encapsulated MIBI raised myocardium uptake to 2-4 times more than the spleen. Heart-to-bowel activity began to rise with 99m Tc-labeld-MIBI and liposomes.

Conclusion: This study provides findings in radiopharmaceutical biodistribution using liposomal agents. Adding free liposomes using a pH gradient technique enhanced the uptake and localization of the radiotracer. However, tracer encapsulation during the formation of the liposomes showed even better specificity.

Background: Myelosuppression is common and threatening during tumor treatment. However, the effect of radiation on bone marrow activity, especially leukocyte count, has been underestimated in cervical cancer. The aim of this study was to evaluate the severity of radiotherapy- induced acute leukopenia and its relationship with intestinal toxicity.

Methods: The clinical data of 59 patients who underwent conventional radiation alone for cervical cancer were retrospectively analyzed. The patients had normal leukocyte count on admission, and the blood cell count, gross tumor volume (GTV) dose, and intestinal toxicity were evaluated.

Results: During radiotherapy (RT), 47 patients (79.7%) developed into leukopenia, with 38.3% mild and 61.7% moderate. The mean time for leukopenia was 9 days. Compared with leukopenianegative patients, leukopenia-positive ones had lower baseline leukocyte count, while neutrophil/ lymphocyte (NLR) and monocyte/lymphocyte (MLR) showed no significance. Logistic regression analysis indicated that excluding the factors for age, body mass index (BMI), TNM stage, surgery and GTV dose, baseline leukocyte count was an important independent predictor of leukopenia (OR=0.383). During RT, a significant reduction was found in leukocyte, neutrophil and lymphocyte count at week 2 while monocyte count after 2 weeks. Furthermore, NLR and MLR showed a significant and sustained upward trend. About 54.2% of patients had gastrointestinal symptoms. However, no significant relevance was noted between leukocyte count as well as NLR/MLR and intestinal toxicity, indicating leukopenia may not be the main factor causing and aggravating gastrointestinal reaction in cervical cancer.

Conclusion: Our results suggest the underrated high prevalence and severity of leukopenia in cervical cancer patients receiving RT, and those with low baseline leukocyte count are more likely for leukopenia, for whom early prevention of infection may be needed during RT.

Introduction: F18 and Ga68 radioisotopes are used in PET imaging for prostate cancer. It was aimed to calculate the prostate, testicle and bladder effective doses (ED) caused by F18 and Ga68 used in prostate cancer imaging with PET/CT via simulation with the GATE toolkit and evaluate the ED in terms of fertility.

Methods: The prostate, testicle and bladder were defined together with their geometric properties and densities in GATE simulation. F18 and Ga68 with activity of 277.5 MBq and 151.7 MBq were identified in the prostate as a source organ. The ED, uncertainties, and S values were taken as an output file in the TXT format with the DoseActors command. S values were used for validation of the simulation.

Results: The ED of the prostate, total testicle and bladder for F18 were found to be 6.627E-04 ± 1.799E-06, 12.74E-07 ± 4.11E-08 and 1.617E-05 ± 4.317E-09 (Gy/s), respectively. The ED of the prostate, total testicle, and bladder for Ga68 were found to be 9.195E-04 ± 2.660E-06, 6.54E-07 ± 2.93E-08 and 4.290E-05 ± 6.936E-09 (Gy/s), respectively.

Conclusion: It was found that Ga68 produced high prostate and bladder ED, and F18 produced high testicular ED. In terms of male fertility, Ga68 seems to be a good alternative because it produces low testicular doses. The ED of the testicle both F18 and Ga68 were below the reported spermatogonia and azoospermia dose.

Background: During the development of novel Re-188 radiopharmaceuticals, it was discovered that no calibration settings were published to calibrate Re-188 on the Capintec CRC-25PET dose calibrator.

Methods: Sodium [¹⁸⁸Re]perrhenate was eluted from an OncoBeta ¹⁸⁸W/¹⁸⁸Re generator to measure activity on a Capintec CRC-25R dose calibrator using established dose calibrator settings provided by the manufacturer. The eluent was then used to tune the calibra on settings on a Capintec CRC-25PET dose calibrator, accounting for geometry. Radionuclidic purity of the [¹⁸⁸Re]perrhenate source was verified via gamma spectroscopy.

Results: The calibrator number for Re-188 was determined to be 469 x 10 for the Capintec CRC-25PET dose calibrator, which differed from the manufacturer provided calibra on number of 496 x 10 for the Capintec CRC-25R dose calibra on model. W-188 breakthrough was characterised as < 0.01%.

Conclusion: This previously unreported calibration number can be used to determine the activity of Re- 188 labelled radiopharmaceuticals using the Capintec CRC-25PET dose calibrator model.