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The residence time distribution (RTD) is very reliable, providing valuable information about the performance of process equipment such as reactors and columns. The aim of this work is to study the effect of agitation in the hydrodynamic column of flow-rig. In this case, residence time distribution (RTD) is determined using the radiotracer approach. The radiotracer is the Technetium Tc-99m with half decay 6 h. It also emits gamma rays with an energy of 0.140 MeV. 2 mL of approximately 9 mCi activity Tc-99m was injected inside the column. The results show that in the conditions studied the column presents the anomaly, dead volume. The Intensity function A(t) confirms this result. Agitation has a beneficial effect in the reduction of dead volume. To revise the conception of the column or study other parameters like the variation flow rate can reduce or eliminate the dead volume. The RTD model indicated the column behaved as a Plug flow reactor (PFR) with mixing cells in serie (J = 4) model and the RTD experiment verified the model well. [ABSTRACT FROM AUTHOR]

Extracellular vesicles derived from human umbilical cord-derived mesenchymal stem cells (UCMSC-EVs) have been postulated to have therapeutic potential for various diseases. However, the biodistribution and pharmacokinetics of these vesicles are still unclear. For a better understanding of the in vivo properties of UCMSC-EVs, in the present study, these vesicles were first radiolabeled with Technetium-99m (99mTc-UCMSC-EVs) and evaluated using in vivo single photon emission computed tomography (SPECT) imaging and biodistribution experiments. SPECT images demonstrated that the liver and spleen tissues mainly took up the 99mTc-UCMSC-EVs. The biodistribution study observed slight uptake in the thyroid and stomach, indicating that 99mTc-UCMSC-EVs was stable at 24 h in vivo. The pharmacokinetic analyses of the blood half-life demonstrated the quick distribution phase (0.85 ± 0.28 min) and elimination phase (25.22 ± 20.76 min) in mice. This study provides a convenient and efficient method for 99mTc-UCMSC-EVs preparation without disturbing their properties. In conclusion, the biodistribution, quick elimination, and suitable stability in vivo of 99mTc-UCMSC-EVs were quantified by the noninvasive imaging and pharmacokinetic analyses, which provides useful information for indication selection, dosage protocol design, and toxicity assessment in future applications.

Abstract Background Soluble oligomeric forms of Tau protein have emerged as crucial players in the propagation of Tau pathology in Alzheimer’s disease (AD). Our objective is to introduce a single-domain antibody (sdAb) named 2C5 as a novel radiotracer for the efficient detection and longitudinal monitoring of oligomeric Tau species in the human brain. Methods The development and production of 2C5 involved llama immunization with the largest human Tau isoform oligomers of different maturation states. Subsequently, 2C5 underwent comprehensive in vitro characterization for affinity and specificity via Enzyme-Linked Immunosorbent Assay and immunohistochemistry on human brain slices. Technetium-99m was employed to radiolabel 2C5, followed by its administration to healthy mice for biodistribution analysis. Results 2C5 exhibited robust binding affinity towards Tau oligomers (Kd = 6.280 nM ± 0.557) and to Tau fibers (Kd = 5.024 nM ± 0.453), with relatively weaker binding observed for native Tau protein (Kd = 1791 nM ± 8.714) and amyloid peptide (Kd > 10,000 nM). Remarkably, this SdAb facilitated immuno-histological labeling of pathological forms of Tau in neurons and neuritic plaques, yielding a high-contrast outcome in AD patients, closely mirroring the performance of reference antibodies AT8 and T22. Furthermore, 2C5 SdAb was successfully radiolabeled with 99mTc, preserving stability for up to 6 h post-radiolabeling (radiochemical purity > 93%). However, following intravenous injection into healthy mice, the predominant uptake occurred in kidneys, amounting to 115.32 ± 3.67, 97.70 ± 43.14 and 168.20 ± 34.52% of injected dose per gram (% ID/g) at 5, 10 and 45 min respectively. Conversely, brain uptake remained minimal at all measured time points, registering at 0.17 ± 0.03, 0.12 ± 0.07 and 0.02 ± 0.01% ID/g at 5, 10 and 45 min post-injection respectively. Conclusion 2C5 demonstrates excellent affinity and specificity for pathological Tau oligomers, particularly in their early stages of oligomerization. However, the current limitation of insufficient blood–brain barrier penetration necessitates further modifications before considering its application in nuclear medicine imaging for humans.

To calculate the contribution of absorbed dose by organs in the biokinetics of Tc-99m when used for radiodiagnosis of the adult male heart employing a Matlab program. Methods: The absorbed self-dose of the adult male heart and absorbed dose by organs in the biokinetics of the heart when administering Tc-99m are estimated using the MIRD formalism and the Cristy-Eckerman representation, which have been employed to develop the algorithm in Matlab. Results: The results indicate that electron capture emissions of 1.446 (mGy/MBq) and Auger electrons of 0.062 (mGy/MBq) are entirely directed towards the target organ (heart) and contribute 29.33% and 1.25% respectively to its total dose. Additionally, the dosimetric contributions of biokinetic organs correspond to characteristic radiation emissions and gamma photons at 2.578 (mGy/MBq) for Tc-99m, representing 52.29% of its total dose. Conclusion: These dosimetric contributions are significant in estimating the total absorbed dose by the heart in adult males and should not be disregarded. [ABSTRACT FROM AUTHOR]

The neurotensin subtype 1 receptor (NTS1R) is overexpressed in a number of human tumors, thereby representing a valid target for cancer theranostics with radiolabeled neurotensin (NT) analogs like [99mTc]Tc-DT1 (DT1, N4-Gly7-NT(8-13)). Thus far, the fast degradation of intravenously injected NT–radioligands by neprilysin (NEP) and angiotensin-converting enzyme (ACE) has compromised their clinical applicability. Aiming at metabolic stability enhancements, we herein introduce (i) DT7 ([DAsn14]DT1) and (ii) DT8 ([β-Homoleucine13]DT1), modified at the C-terminus, along with (iii) DT9 ([(palmitoyl)Lys7]DT1), carrying an albumin-binding domain (ABD) at Lys7. The biological profiles of the new [99mTc]Tc–radioligands were compared with [99mTc]Tc-DT1, using NTS1R-expressing AsPC-1 cells and mice models without or during NEP/ACE inhibition. The radioligands showed enhanced in vivo stability vs. [99mTc]Tc-DT1, with [99mTc]Tc-DT9 displaying full resistance to both peptidases. Furthermore, [99mTc]Tc-DT9 achieved the highest cell internalization and tumor uptake even without NEP/ACE-inhibition but with unfavorably high background radioactivity levels. Hence, unlike C-terminal modification, the introduction of a pendant ABD group in the linker turned out to be the most promising strategy toward metabolic stability, cell uptake, and tumor accumulation of [99mTc]Tc-DT1 mimics. To improve the observed suboptimal pharmacokinetics of [99mTc]Tc-DT9, the replacement of palmitoyl on Lys7 by other ABD groups is currently being pursued. [ABSTRACT FROM AUTHOR]

Abstract New modes of production and supply of short-lived radioisotopes using accelerators are becoming attractive alternatives to the use of nuclear reactors. In this study, the use of a compact accelerator neutron source (CANS) was implemented to explore the production of 99mTc and 101Tc. Irradiations were performed with neutrons generated from a 16.5 MeV cyclotron utilising the 18O(p, n)18F reaction during routine 18F-fluorodeoxyglucose (FDG) production in a commercial radiopharmacy. Natural molybdenum targets in metal form were employed for the production of several Tc isotopes interest via (n, γ) reactions on 98Mo and 100Mo. The production of 99mTc and 101Tc under these conditions is considered and discussed.

New modes of production and supply of short-lived radioisotopes using accelerators are becoming attractive alternatives to the use of nuclear reactors. In this study, the use of a compact accelerator neutron source (CANS) was implemented to explore the production of 99mTc and 101Tc. Irradiations were performed with neutrons generated from a 16.5 MeV cyclotron utilising the 18O(p, n)18F reaction during routine 18F-fluorodeoxyglucose (FDG) production in a commercial radiopharmacy. Natural molybdenum targets in metal form were employed for the production of several Tc isotopes interest via (n, γ) reactions on 98Mo and 100Mo. The production of 99mTc and 101Tc under these conditions is considered and discussed. [ABSTRACT FROM AUTHOR]

The aim of the presented work was to develop folate based radiolabeled compound intended to be used as diagnostic aid for the various folate-receptor overexpressing cancers eg. breast cancer, brain tumors, lung cancer etc. Folate was directly radiolabeled with Tc-99m using Quality-by-Design and encapsulated in micellar nanocarriers. The authors are of the view that the stable radiolabeled folate could be of potential diagnostic value in cancers overexpressing folate receptors thereby opening novel possibilities to diagnostic applications of radiolabeled folate. Folic acid was directly radiolabeled with Tc-99m utilizing a quality by design approach. The experimental trials were designed using the Box-Behenken design with the concentration of drug, concentration of reducing agent and the incubation time as dependent variable and percent radiolabeling as the response for the same. The applied design in the method section was validated with a series of experiments and the percent labeling of the FA with Tc-99m was found to be around 94%. The radiolabeled compound was imperilled to stability evaluation by incubating the same with serum and physiological pH and the same was found to be stable at the end of 4h. On subjecting to DTPA challenge test, the compound displayed no change in the radiolabeling percentage thereby indicating the robustness of the formed Tc-99m-FA complex, The radiolabeled Tc-99m-FA was further encapsulated into micellar nanocarriers and the same were also found to be robust and stable. • Nuclear medicine is an influential tool, which upon combination with the existing chemotherapeutic drugs could be used for the diagnostic/theranostic applications. • Folate radiolabeled with Tc-99m can aid as an excellent diagnostic tracer for the tumors formed by the folate-receptor overexpressing cancers cells. [ABSTRACT FROM AUTHOR]

A micro-SPECT system having spatial resolution of 2.5 mm is presented. The system has a field of vision about 57 × 57 mm. Results of tomographic reconstruction of calibration phantoms using Tc-99m solution are outlined. The design of phantoms that can be used to assess performance of SPECT system having a narrow field of vision is given. [ABSTRACT FROM AUTHOR]

Over the past decade, [ 68 Ga]Ga-FAPI-04 positron emission tomography (PET)/CT imaging has been widely used for the treatment of various tumors. However, the application of 99m TC-labeled fibroblast activation protein inhibitors in tumors has been less studied. Our team previously demonstrated the safe biological distribution of [ 99m Tc]Tc-DP-FAPI in the human body. Based on this, this study reports the accuracy of [ 99m Tc]Tc-DP-FAPI in the imaging diagnosis of gastrointestinal tumors and compares it with that of [ 68 Ga]Ga-FAPI-04 to evaluate the differences. A total of 24 patients with clinically diagnosed gastrointestinal tumors were prospectively included. All patients received [ 99m Tc]Tc-DP-FAPI quantitative SPECT/CT imaging on the first day and [ 68 Ga]Ga-FAPI-04 PET/CT imaging on the second day. And the effectiveness of the two imaging probes in detecting suspicious lesions was analyzed and compared. The primary tumors of all 24 patients were well detected by two imaging probes, and the sensitivity of [ 99m Tc]Tc-DP-FAPI and [ 68 Ga]Ga-FAPI-04 to the primary lesions was 100%. [ 99m Tc]Tc-DP-FAPI examined 21 lymph nodes with a sensitivity and specificity of 32.8% and 10.9%, and [ 68 Ga]Ga-FAPI-04 detected 57 lymph nodes with a sensitivity and specificity of 89.1% and 67.2%, respectively. Three distant metastases were detected by [ 99m Tc]Tc-DP-FAPI and nine metastases by [ 68 Ga]Ga-FAPI-04. The study showed that [ 99m Tc]Tc-DP-FAPI is highly sensitive to detecting primary lesions of gastrointestinal tumors. Compared with [ 68 Ga]Ga-FAPI-04, [ 99m Tc]Tc-DP-FAPI has the same sensitivity in detecting primary tumors but has certain limitations in detecting metastases. [ 99m Tc]Tc-DP-FAPI is of great value for preliminary screening of tumor lesions and early diagnosis of disease in patients who are suspected of having gastrointestinal tumors.

Extracellular vesicles derived from human umbilical cord-derived mesenchymal stem cells (UCMSC-EVs) have been postulated to have therapeutic potential for various diseases. However, the biodistribution and pharmacokinetics of these vesicles are still unclear. For a better understanding of the in vivo properties of UCMSC-EVs, in the present study, these vesicles were first radiolabeled with Technetium-99m ( 99m Tc-UCMSC-EVs) and evaluated using in vivo single photon emission computed tomography (SPECT) imaging and biodistribution experiments. SPECT images demonstrated that the liver and spleen tissues mainly took up the 99m Tc-UCMSC-EVs. The biodistribution study observed slight uptake in the thyroid and stomach, indicating that 99m Tc-UCMSC-EVs was stable at 24 h in vivo. The pharmacokinetic analyses of the blood half-life demonstrated the quick distribution phase (0.85 ± 0.28 min) and elimination phase (25.22 ± 20.76 min) in mice. This study provides a convenient and efficient method for 99m Tc-UCMSC-EVs preparation without disturbing their properties. In conclusion, the biodistribution, quick elimination, and suitable stability in vivo of 99m Tc-UCMSC-EVs were quantified by the noninvasive imaging and pharmacokinetic analyses, which provides useful information for indication selection, dosage protocol design, and toxicity assessment in future applications., (© 2024 The Authors. Published by Elsevier B.V. on behalf of Chang Gung University. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).)

The neurotensin subtype 1 receptor (NTS1R) is overexpressed in a number of human tumors, thereby representing a valid target for cancer theranostics with radiolabeled neurotensin (NT) analogs like [99mTc]Tc-DT1 (DT1, N4-Gly7-NT(8-13)). Thus far, the fast degradation of intravenously injected NT–radioligands by neprilysin (NEP) and angiotensin-converting enzyme (ACE) has compromised their clinical applicability. Aiming at metabolic stability enhancements, we herein introduce (i) DT7 ([DAsn14]DT1) and (ii) DT8 ([β-Homoleucine13]DT1), modified at the C-terminus, along with (iii) DT9 ([(palmitoyl)Lys7]DT1), carrying an albumin-binding domain (ABD) at Lys7. The biological profiles of the new [99mTc]Tc–radioligands were compared with [99mTc]Tc-DT1, using NTS1R-expressing AsPC-1 cells and mice models without or during NEP/ACE inhibition. The radioligands showed enhanced in vivo stability vs. [99mTc]Tc-DT1, with [99mTc]Tc-DT9 displaying full resistance to both peptidases. Furthermore, [99mTc]Tc-DT9 achieved the highest cell internalization and tumor uptake even without NEP/ACE-inhibition but with unfavorably high background radioactivity levels. Hence, unlike C-terminal modification, the introduction of a pendant ABD group in the linker turned out to be the most promising strategy toward metabolic stability, cell uptake, and tumor accumulation of [99mTc]Tc-DT1 mimics. To improve the observed suboptimal pharmacokinetics of [99mTc]Tc-DT9, the replacement of palmitoyl on Lys7 by other ABD groups is currently being pursued.

This study was designed to indicate the cardiotoxicity due to 99mTc-MIBI injection in myocardial perfusion imaging in wistar Rats. In addition, protective effect of hesperidin/diosmin compound (HDC) against the cardiotoxicity was evaluated. Twenty five male rats were randomly divided into five groups. The rats in Group 1 (control) only received PBS. For Group 2 (HDC only) the rats treated with only HDC. The rats in Group 3 (radiation) received PBS before injection and exposure to 1 mCi 99mTc-MIBI. The rats in Group 4 (HDC + radiation) treated with HDC before exposure. For Group 5 (radiation + HDC) the rats were exposed and thereafter administered HDC. The Animals of this study were orally administered 100 mg/kg/day of the HDC for 7 days. Then, the rats were sacrificed and afterwards their heart tissues were carefully extracted for biochemical and histopathological evaluations. According to our results in the radiation group, the rate of rupture of cardiomyocyte fibers was higher than other groups, and in some fibers, the presence of lymphocytes was observed. Relative improvement was observed in radiation + HDC group compared to the radiation group and also a small number of cardiomyocyte fibers were torn and in some fibers, the presence of lymphocytes was observed, which was less than the model group. Collagen deposition significantly increased in radiation group compared to control group (P < 0.05). It can be seen that the percentage of collagen deposition decreased substantially in the group treated with HDC before or after radiation compared to radiation group (P < 0.05). The MDA activities significantly reduced (P < 0.05) in both (HDC + radiation) and (radiation + HDC) groups. SOD activity significantly increased in both (radiation + HDC) and (HDC + radiation) groups compared to that of radiation group (P < 0.05). It could be concluded that the HDC is safe and promising useful therapeutic agent in radiation induced cardiotoxicity for patients undergoing nuclear medicine procedures. [ABSTRACT FROM AUTHOR]

Tc-99m is the most important nuclear medicine radioisotope produced from the decay of Mo-99. Currently, Iran's demand for Mo-99 is 120 Ci per week. More than 90% of the Mo-99 in the world is produced via U-235 fission. The supply chain of this radioisotope includes the Uranium target supplier, the nuclear reactor, the Mo-99 processing facility, and the Mo-99/Tc-99m generator manufacturer. Investigation of the domestic existing facilities of Iran shows that its production is feasible inside the country. The present study focuses on the Mo-99 production chain in Iran and presents the appropriate radiochemical method. Uranium targets in the miniplate form with irradiation capability in TRR were accepted as feed for processing unit facilities. According to the special limitations of Iran, the Modified AMOR process, which is a combination of AMOR and ROMOL processes, is identified as the appropriate method for the available U3O8-Al/Al targets. The researches and the experimental activities are proposed based on this method.

The aim of the work presented in this manuscript was to radiolabel methotrexate and prepare radiolabeled methotrexate micelles, an antifolate drug with Tc-99m using QbD approach. The radiolabeling was executed using the experimental design and the radiolabeled drug was further encapsulated in micelles. The authors are of the view that the radiolabeled MTX could be used to target the folate receptor overexpressing cancers such as the kidney, colorectal, breast, brain etc thereby opening newer possibilities to the theranostic applications of the formed conjugate. • Nuclear medicine is a powerful tool which when clubbed with chemotherapeutics can be used for diagnostic and/or therapeutic purpose. • Methotrexate radiolabeled with Tc-99m can serve purpose of both, chemotheraphy as well as diagnostic radiotracer. • Tc-99m radiolabeled methotrexate loaded in micelles can be an efficient aid in targeting cancers overexpressing folate receptors. The experiments were successfully conducted using experimental design involving Box-Behenken Design and the radiolabeling efficiency of the Tc-99m-MTX was found to be around 93%. The Tc-99m-MTX was subjected to stability tests by incubating with serum and in physiological pH solution and the same was found to be stable. The radiochemical stability of the Tc-99m-MTX was evaluated using DTPA challenge test and it was found that upon incubating with various concentration of DTPA, the percent radiolabeling of the MTX changed only slightly indicating the radiochemical stability of the formed radiolabeled MTX conjugate. The Tc-99m-MTX loaded micelles were also evaluated for stability and the same were found to be radiochemical stable. [ABSTRACT FROM AUTHOR]

Study Design: Although prone position is considered as a complementary protocol in myocardial perfusion imaging (MPI), there is no consensus on its capability to find coronary artery disease (CAD), independently. The primary aim of this review was to report pooled sensitivity and specificity for prone position MPI in detection of CAD. In addition, the results were compared to the supine position's performance. Methods: Electronic bibliographic databases, The Cochrane Library, Web of Science (Science and Social Science Citation Index), Scopus, PubMed, and EMBASE until the end of June 2020 were searched. Studies were included based on the inclusion criteria of (1) evaluated the prone position MPI, (2) defined CAD with coronary angiography (CAG), using the threshold of ≥ 50% stenosis, (3) Adequate data were provided to extract the diagnostic performance. QUADAS-2 tool was utilized to assess the quality of included studies. Pooled sensitivity and specificity were calculated for prone and supine positions, separately. The hierarchical summary ROC curves were also drawn. Results: Ten individual studies with the data of the 1490 patients for the prone position and 1138 patients for the supine position were included. Pooled sensitivity and specificity for the prone position were 83% and 79%, respectively. These results were calculated for the supine position as the sensitivity of 86% and specificity of 67%. The pooled sensitivity and specificity of the prone position in detecting the right coronary artery territory defects were 70% and 84%, in turn. Conclusion: In the suspicion for the CAD, prone position with comparable sensitivity and higher specificity can be an acceptable alternative to the supine position as the standard method. Also, in the cases of possible defects in the RCA territory, prone position showed to be a superior standard. [ABSTRACT FROM AUTHOR]

Background: The [99mTc][Tc(N)(PNP)] system, where PNP is a bisphosphinoamine, is an interesting platform for the development of tumor 'receptor-specific' agents. Here, we compared the reactivity and impact of three [Tc(N)(PNP)] frameworks on the stability, receptor targeting properties, biodistribution, and metabolism of the corresponding [99mTc][Tc(N)(PNP)]-tagged cRGDfK peptide to determine the best performing agent and to select the framework useful for the preparation of [99mTc][Tc(N)(PNP)]-housing molecular targeting agents. Methods: cRGDfK pentapeptide was conjugated to Cys and labeled with each [Tc(N)(PNP)] framework. Radioconjugates were assessed for their lipophilicity, stability, in vitro and in vivo targeting properties, and performance. Results: All compounds were equally synthetically accessible and easy to purify (RCY ≥ 95%). The main influences of the synthon on the targeting peptide were observed in in vitro cell binding and in vivo. Conclusions: The variation in the substituents on the phosphorus atoms of the PNP enables a fine tuning of the biological features of the radioconjugates. ws[99mTc][Tc(N)(PNP3OH)]– and [99mTc][Tc(N)(PNP3)]– are better performing synthons in terms of labeling efficiency and in vivo performance than the [99mTc][Tc(N)(PNP43)] framework and are therefore more suitable for further radiopharmaceutical purposes. Furthermore, the good labeling properties of the ws[99mTc][Tc(N)(PNP3OH)]– framework can be exploited to extend this technology to the labeling of temperature-sensitive biomolecules suitable for SPECT imaging. [ABSTRACT FROM AUTHOR]

Purpose: Neck dissection (ND), whether therapeutic or elective, is an essential component of the treatment of head and neck squamous cell carcinoma (HNSCC). Due to altered anatomy and fibrosis caused by initial treatments, surgeons face challenges during salvage ND. A combination of Technetium-99 m and indocyanine green (ICG) previously used in the sentinel lymph node (SLN) biopsy for oral cavity cancers, may be useful in different types of neck surgeries. We aimed to show the additional advantage of this combination in detecting HNSCC and thyroid cancer recurrences, as well as individual lymphatic drainage in elective ND. Methods: We retrospectively reviewed medical records of patients, underwent neck surgery guided with ICG and Tc-99 m, in Hacettepe University Hospital between June 2018 and December 2020. In a total of 28 patients, intraoperative gamma probes were paired with near infrared (NIR) cameras. Patients are divided into two groups: neck surgery with recurrent occult lesion localization (NS- ROLL) (n: 14) and ND with SLN screening (ND-SLNS) (n: 14). Results: Among all 14 patients in NS-ROLL group, recurrent diseases, hidden behind tissues were 100% successfully localized. In ND-SLNS group, 238 lymph nodes were harvested, metastasis rate was 31.3% (10/32) in sentinel nodes. SLNS revealed 100% accuracy in detecting metastasis in clinically N0 neck (10/238). Contralateral lymphatic drainage was observed in three patients (lateral-sided oral cavity SCC). In two patients (floor of mouth), three sentinel nodes were detected by NIR only. Conclusion: The use of ICG-radiotracer provides additional value in disease removal for both primary and recurrent tumors of the head and neck. [ABSTRACT FROM AUTHOR]

Introduction: Endometriosis is a gynecological disease and disorder that occurs when endometrial cells are shed through the fallopian tubes and are implanted on the surfaces of pelvis and abdomen. They form lesions that respond to hormones of the menstural cycle and will stimulate inflammation. It is controversial whether [99mTc]Tc-RBC scan would be sufficient for localizing bleeding sites. This study evaluated the value of [99mTc]Tc-RBC in diagnosing endometriosis. Methods: Twenty patients were included in the study for endometriosis localization. Between the 2nd and the 5th days of menstruation, when the lesions were highly activated, [99mTc]Tc-RBC scan was performed and compared with TVUS, pelvic MRI and laparoscopic surgery findings. Scans of the patients were reported by two nuclear medicine specialists who were blind to patients' history. Results: The patients' age range was 21-48 years (mean age: 35±8.79). The sensitivity, specificity, positive predictive value and negative predictive value for the right pelvic bleeding sites were 73.3%, 80.0%, 91.7% and 50%, respectively while the corresponding indices on the opposite pelvic site were find to be 87.5%, 75.0%, 93.0% and 60%, respectively. Conclusion: Radiolabeled red blood cell scintigraphy has the potential to be used as an alternative procedure for diagnosing endometriosis. [ABSTRACT FROM AUTHOR]

The purpose of this study was to develop a multifunctional theranostic probe for imaging (magnetic resonance imaging [MRI] and single‐photon emission computed tomography [SPECT]) and therapy (photodynamic therapy). For this purpose, Tc‐99m‐labeled lupulone‐conjugated Fe3O4@TiO2 nanocomposites (99mTc‐DTPA‐Fe3O4@TiO2‐HLP and 99mTc‐DTPA‐Fe3O4@TiO2‐ALP nanocomposites) were synthesized. The average diameter of the nanocomposites was 171 ± 20 nm as seen on transmission electron microscopy images. Fe3O4@TiO2 nanocomposites exhibited fluorescence spectra at an emission wavelength of 314 nm. Lupulone‐conjugated Fe3O4@TiO2 nanocomposites were spherical‐shaped with a suitable dispersion and without visible aggregation, and their radiolabeling yields were over 85%. Healthy (RWPE‐1 normal human prostate epithelial cell line) and cancer prostate cell lines (PC‐3 human prostate cancer cell line) were used to determine the in vitro biological behavior of the nanocomposites. The PC‐3 cells treated with lupulone‐conjugated Fe3O4@TiO2 nanocomposites showed a lower cell viability compared with RWPE‐1 cells treated with lupulone‐conjugated Fe3O4@TiO2 nanocomposites. Lupulone‐modified Fe3O4@TiO2 nanocomposites may serve in the future as a multifunctional probe for positron emission tomography (PET)/MRI, photodynamic therapy, and hyperthermia therapy of cancer. [ABSTRACT FROM AUTHOR]

Background: The [99mTc][Tc(N)(PNP)] system, where PNP is a bisphosphinoamine, is an interesting platform for the development of tumor ‘receptor-specific’ agents. Here, we compared the reactivity and impact of three [Tc(N)(PNP)] frameworks on the stability, receptor targeting properties, biodistribution, and metabolism of the corresponding [99mTc][Tc(N)(PNP)]-tagged cRGDfK peptide to determine the best performing agent and to select the framework useful for the preparation of [99mTc][Tc(N)(PNP)]-housing molecular targeting agents. Methods: cRGDfK pentapeptide was conjugated to Cys and labeled with each [Tc(N)(PNP)] framework. Radioconjugates were assessed for their lipophilicity, stability, in vitro and in vivo targeting properties, and performance. Results: All compounds were equally synthetically accessible and easy to purify (RCY ≥ 95%). The main influences of the synthon on the targeting peptide were observed in in vitro cell binding and in vivo. Conclusions: The variation in the substituents on the phosphorus atoms of the PNP enables a fine tuning of the biological features of the radioconjugates. ws[99mTc][Tc(N)(PNP3OH)]– and [99mTc][Tc(N)(PNP3)]– are better performing synthons in terms of labeling efficiency and in vivo performance than the [99mTc][Tc(N)(PNP43)] framework and are therefore more suitable for further radiopharmaceutical purposes. Furthermore, the good labeling properties of the ws[99mTc][Tc(N)(PNP3OH)]– framework can be exploited to extend this technology to the labeling of temperature-sensitive biomolecules suitable for SPECT imaging.

The objective of this study was to report the synthesis and characteristics of a dual modality imaging agent, Tc‐99m GRFLTGGTGRLLRIS‐GHEG‐ECG‐K(‐5‐carboxy‐X‐rhodamine)‐NH2 (GRFLT‐ECG‐ROX), and to verify its feasibility as both molecular imaging and intraoperative guidance agent. GRFLT‐ECG‐ROX was synthesized using Fmoc solid‐phase peptide synthesis. Radiolabeling of GRFLT‐ECG‐ROX with Tc‐99m was accomplished using ligand exchange via tartrate. Binding affinity and in vitro cellular uptake studies were performed. Gamma camera imaging, biodistribution, and ex vivo imaging studies were performed using LNCaP and PC‐3 tumor‐bearing murine models. Surgical removal of tumor nodules in murine models with peritoneal carcinomatosis was performed under a fluorescence imaging system. After radiolabeling procedures with Tc‐99m, Tc‐99m GRFLT‐ECG‐ROX complexes were prepared in high yield (>96%). The binding affinity value (Kd) of Tc‐99m GRFLT‐ECG‐ROX for LNCaP cells was estimated to be 9.5 ± 1.3 nM. In gamma camera imaging, the tumor to normal muscle uptake ratios of Tc‐99m GRFLT‐ECG‐ROX increased with time (3.1 ± 0.2, 4.0 ± 0.4, and 6.3 ± 0.9 at 1, 2, and 3 h, respectively). Under real‐time optical imaging, the removal of visible nodules was successfully performed. Thus, Tc‐99m GRFLT‐ECG‐ROX could provide both preoperative molecular imaging and fluorescence imaging guidance for tumor removal. [ABSTRACT FROM AUTHOR]

Technetium-99m (Tc-99m) labeled tetrofosmin kit has been widely used in hospitals including in Indonesia. Usually, tetrofosmin kits and Tc-99m pertechnetate are supplied separately, but recently there has been a new trend where Tc-99m tetrofosmin is supplied in the form of the ready-to-inject product. To prepare such a product it has to be proven that tetrofosmin can be labeled with high activity of Tc-99m and the resulted Tc-99m tetrofosmin, remains stable within shipping time until being used in hospitals. In this investigation, locally produced tetrofosmin kits were labeled with various radioactivity of Tc-99m ranging from 150 mCi to 400 mCi, their radiolabeling yields or radiochemical purity was analyzed using SepPak C18 column, and the radiochemical stability was assessed within 30 hours. The worst storage condition was also studied by analyzing its radiochemical purity after being stored at extreme temperatures for several hours. The results showed that tetrofosmin kit can be highly labeled with up to 415 mCi of Tc-99m, and stable up to 30 hours in room temperature, and there is a tendency that higher radioactivity leads to more decreasing in radiochemical purity. Stability study in extreme temperatures showed that the product can withstand its stability within 6 hours in 40°C, but it decreased rapidly to less than 70% within 1 hour when stored in 50°C. It concludes that the quality of Tc-99m tetrofosmin as an injectable radiopharmaceutical can be maintained during transportation by storing it at cool temperature.

Background: The SMARTZOOM multifocal collimator from Siemens Healthcare was developed to improve the γ-photon sensitivity in myocardial perfusion imaging without truncating the field of view. As part of the IQ-SPECT package, it may be used to reduce radiopharmaceutical dose to patients, as well as acquisition time. The aim of this study was twofold: (1) to evaluate the influence of dose reduction in semi-automated MPI scoring, with focus on different strategies for the choice of normal data (count-matched, full-count), and (2) to evaluate the effect of dose reduction afforded by Siemens' IQ-SPECT package. Methods: 50 patients underwent Tc-99m-sestamibi one-day stress/rest SPECT/CT. Multiple levels of count reduction were generated using binomial thinning. Using Corridor 4DM, summed stress score (SSS) was calculated using either count-matched or full-count normal data. Studies were classified as low-risk (SSS < 4) or intermediate/high-risk (SSS ≥ 4). Results: Count reduction using count-matched normal data increases false-normal rate and decreases sensitivity. With full-count normal data, count reduction increases false-hypoperfusion rate, leading to decreased specificity. Altogether, rate of reclassification was significant at roughly 67% dose and below. Conclusion: Significant bias results from count level of normal data relative to actual patient data. Compared to standard LEHR, IQ-SPECT should allow for significant dose reduction. [ABSTRACT FROM AUTHOR]

Abstract Background Image-based measurement of absorbed dose of Ra-223 dichloride may be useful in predicting therapeutic outcome in patients with castration-resistant prostate cancer (CRPC). In general, SPECT has been found to be more accurate than planar imaging in terms of lesion-based analysis. The aims of this study were to assess the feasibility and clinical usefulness of Ra-223 SPECT. The energy spectrum of Ra-223 and SPECT images of a cylindrical phantom with a hot rod were obtained to determine the collimator candidates and energy window settings suitable for clinical Ra-223 SPECT (basic study A). Another phantom with a tube-shaped chamber and two spheres simulating bowel activity and metastatic lesions in the lumbar spine was scanned with medium-energy general-purpose (MEGP) and high-energy general-purpose (HEGP) collimators (basic study B). Ten patients with CRPC underwent SPECT imaging 2 h after Ra-223 injection successively with MEGP and HEGP collimators in random order for 30 min each. Lesion detectability and semi-quantitative analyses of bone metastasis (i.e. lesion-to-background ratio (LBR)) were performed compared to Tc-99m HMDP SPECT. Results Basic study A revealed that an 84-keV photopeak ± 20% using the HEGP collimator offers better SPECT image quality than the other imaging conditions. Basic study B showed that uptake in one of the spheres was overestimated by overlapped activity of the tube-shaped chamber in planar imaging whereas the spheres had similar counts and significantly higher sphere-to-background ratio in SPECT. On both planar and SPECT images, HEGP gave higher image contrast than MEGP (p

Technetium-99m labeled radiopharmaceutical is commonly used in nuclear medicines as a diagnostic agent, by mixing the sterile kit with Tc-99m. Manufacturing of kits requires an aseptic facility which need to be well designed and maintained according to cGMP, since mostly kits can not be terminally sterilized. Radiopharmaceuticals as pharmaceuticals containing radionuclide is assumed to have an autosterilization property, but correlation between radioactivity and capability of killing microorganisms has to be studied so far. The aim of this study is to investigate the effect of radioactivity on the autosterilization process of radiopharmaceuticals. The study was carried out by adding Tc-99m of various radioactivity into non-sterile tetrofosmin kits, then the samples were tested for sterility. Sterile tetrofosmin kit and non-sterile kit with no Tc-99m added will be used as a negative control and positive control respectively. The sterility was tested using standard direct inoculation method, by inoculating samples in culture media for both bacteria and fungi and observing qualitatively within 14 days. The results showed that the samples with radioactivity of 1, 3 and 5 mCi changed the clarity of the media to turbid, conformed with the performance of positive controls but samples with radioactivity of 10 mCi and 20 mCi did not change the clarity of the media, conformed with the performance of negative control, indicating neither growth of bacteria nor fungi. It is concluded that Tc-99m behaves as an autosterilizing agent at certain radioactivity. Therefore the preparation of Tc-99m radiopharmaceutical can be considered as terminal sterilization rather than aseptic preparation.

The shortage of nuclear-reactor-based Tc-99m supply has led to increased research on cyclotron-based Tc-99m production. In this paper, Tc-99m radionuclides produced by a 11-MeV proton cyclotron is theoretically discussed in terms of the optimum thickness of natMo, natMoO3, and enriched 100Mo targets; expected impurities; and radioactivity yields of several (p,2n), (p,n), and (p,γ) based nuclear reactions. The SRIM 2013 codes and TALYS 2014 codes are employed to calculate the range of 11-MeV proton beams in the Mo-based targets and the excitation functions of the selected nuclear reactions, respectively. The calculated results indicate that 94m,95m,96mTc radionuclides would give rise to radionuclide impurities at the end of irradiation for natMo targets, whereas no significant impurities were theoretically detected for the enriched 100Mo target. At the end of bombardment, nearly 42.18 GBq/µA.hr of Tc-99m radionuclide is predicted to result in the 11-MeV proton-irradiated 100Mo target.

To date, myocardial perfusion (MP) has been utilized to assess the adequacy of blood flow to the myocardium in order to determine the ischemic heart diseases. With the advent of SPECT/CT, MP became the most common investigation in the field of nuclear cardiology with more accuracy and details. Thallium-201 and Technetium-99m (Tc-99m) have been early used in cardiac nuclear imaging. Half-life of Tc-99m is 6 h, and its energy is 140 keV, while the half-life of Tl-201 is as longer as 73 h, its X-ray energies range between 69 and 81 kV in addition to gamma rays of 135 keV and 167 keV. The purpose of the present study was to explore the radiation dose rates emitted from the patients following Tc-99m sestamibi injection. To achieve that, the radiation emanated to the environment was measured at different distances from patients and various time intervals for 20 patients using GM counter. The mean radioactivity administered to the patients was 391.1 MBq (10.6 mCi), with a range between 276.8 MBq to maximum of 515.4 MBq. Radiation dose rate was found 9.07 μSv h−1 at 1 m distance from the patient's chest level after 7.6 min, then decayed to 7.93 μSv h−1 after 36.5 min, and 7.83 μSv h−1 later to 66.4 min. It was concluded that 1 m distance from the patients sounds sensibly adequate to maintain the occupational dose within the safe limit following Tc-99m sestamibi injection, while verification of public dose rate ≤ 1 μSv h−1 at 1 m distance from the patient prolongs to 14 h following Tc-99m injection. [ABSTRACT FROM AUTHOR]

Objective: Folate receptor (FR) is an ideal target for cancer imaging because it is frequently overexpressed in major types of human tumor, whereas its expression in normal organs is highly limited. Combining nuclear and fluorescence-imaging techniques provides a novel approach for cancer imaging and monitoring the surgery. The objective of this study was to report the synthesis and characteristics of a dual-modality imaging agent, Tc-99m Folate-Gly-His-Glu-Gly-Glu-Cys-Gly-Lys(-5-carboxy-X-rhodamine)-NH2 (Folate-ECG-ROX), and verify its feasibility as both molecular imaging agent and intra-operative guidance.Methods: Folate-ECG-ROX was synthesized using Fmoc solid-phase peptide synthesis. Radiolabeling of Folate-ECG-ROX with Tc-99m was done using ligand exchange via tartrate. Binding affinity and in vitro cellular uptake studies were performed. Gamma camera imaging, biodistribution and ex vivo imaging studies were performed using KB and HT-1080 tumor-bearing murine models. Tumor tissue slides were prepared and analyzed with immunohistochemistry staining and confocal microscopy. Surgical removal of tumor nodules in murine models with peritoneal carcinomatosis was performed under the fluorescence-imaging system.Results: After radiolabeling procedures with Tc-99m, Tc-99m Folate-ECG-ROX complexes were prepared in high yield (> 97%). The binding affinity value (Kd) of Tc-99m Folate-ECG-ROX for KB cells was estimated to be 6.9 ± 0.9 nM. In gamma camera imaging, tumor to normal muscle uptake ratio of Tc-99m Folate-ECG-ROX increased with time (3.4 ± 0.4, 4.4 ± 0.7, and 6.6 ± 0.8 at 1, 2, and 3 h, respectively). In biodistribution study, %IA/g for KB tumor was 2.50 ± 0.80 and 4.08 ± 1.16 at 1 and 3 h, respectively. Confocal microscopy with immunohistochemistry staining detected strong Tc-99m Folate-ECG-ROX fluorescence within KB tumor tissue which is correlating with the fluorescent activity of anti-FR antibody. Under real-time optical imaging, the removal of visible nodules was successfully performed.Conclusions: In vivo and in vitro studies revealed substantial and specific uptake of Tc-99m Folate-ECG-ROX in FR-positive tumors. Thus, Tc-99m Folate-ECG-ROX could provide both pre-operative molecular imaging and fluorescence image-guidance for tumor. [ABSTRACT FROM AUTHOR]

Single-photon emission computed tomography/computed tomography (SPECT/CT) is an already established nuclear imaging modality. Co-registration of functional information (SPECT) with anatomical images (CT) paved the way to the wider application of SPECT. Recent advancements in quantitative SPECT/CT have made it possible to incorporate quantitative parameters, such as standardized uptake value (SUV) or %injected dose (%ID), in gamma camera imaging. This is indeed a paradigm shift in gamma camera imaging from qualitative to quantitative evaluation. In fact, such quantitative approaches of nuclear imaging have only been accomplished for positron emission tomography (PET) technology. Attenuation correction, scatter correction, and resolution recovery are the three main features that enabled quantitative SPECT/CT. Further technical improvements are being achieved for partial-volume correction, motion correction, and dead-time correction. The reported clinical applications for quantitative SPECT/CT are mainly related to Tc-99m-labeled radiopharmaceuticals: Tc-99m diphosphonate for bone/joint diseases, Tc-99m pertechnetate for thyroid function, and Tc-99m diethylenetriaminepentaacetic acid for measurement of glomerular filtration rate. Dosimetry before trans-arterial radio-embolization is also a promising application for Tc-99m macro-aggregated albumin. In this review, clinical applications of Tc-99m quantitative SPECT/CT will be discussed. [ABSTRACT FROM AUTHOR]

An aqueous solution of 99mTc was standardized by means of 4πce(LS)-γ and 4πce(PC)-γ coincidence counting. The activity concentration was obtained by efficiency extrapolation relying on four different variation techniques. In both setups, fast digitizers were used for data acquisition. Detected events were recorded in list mode format, and their coincidence relationship was analyzed in the subsequent offline analysis. The combined result was used to participate in an international comparison using the Transfer Instrument of the International Reference System. • 99mTc was standardized by 4πce(LS)-γ and 4πce(PC)-γ coincidence counting. • Digitizer-based DAQ in combination with offline coincidence analysis was used. • Activity concentration was derived by various efficiency variation methods. • The results from different methods are in good agreement with each other. [ABSTRACT FROM AUTHOR]

Recently, radiolabelled antagonists targeting somatostatin receptors subtype 2 (SST2) in neuroendocrine neoplasms demonstrated certain superior properties over agonists. Within the ERA-PerMED project “TECANT” two 99mTc-Tetramine (N4)-derivatized SST2 antagonists (TECANT-1 and TECANT-2) were studied for the selection of the best candidate for clinical translation. Receptor-affinity, internalization and dissociation studies were performed in human embryonic kidney-293 (HEK293) cells transfected with the human SST2 (HEK-SST2). Log D, protein binding and stability in human serum were assessed. Biodistribution and SPECT/CT studies were carried out in nude mice bearing HEK-SST2 xenografts, together with dosimetric estimations from mouse-to-man. [99mTc]Tc-TECANT-1 showed higher hydrophilicity and lower protein binding than [99mTc]-TECANT-2, while stability was comparable. Both radiotracers revealed similar binding affinity, while [99mTc]Tc-TECANT-1 had higher cellular uptake (>50%, at 2 h/37 °C) and lower dissociation rate (99mTc]Tc-TECANT-1 showed lower blood values, kidney and muscles uptake, whereas tumour uptake was comparable to [99mTc]Tc-TECANT-2. SPECT/CT imaging confirmed the biodistribution results, providing the best tumour-to-background image contrast for [99mTc]Tc-TECANT-1 at 4 h post-injection (p.i.). The estimated radiation dose amounted to approximately 6 µSv/MBq for both radiotracers. This preclinical study provided the basis of selection of [99mTc]Tc-TECANT-1 for clinical translation of the first 99mTc-based SST2 antagonist.

We present a 74-year-old woman with primary hyperparathyroidism, with elevated parathyroid hormone and calcium. Tc-99m-methoxyisobutyl isonitrile (sestamibi) planar imaging showed a focus of uptake over the inferior aspect of the right submandibular gland that was localized on the single-photon emission computed tomography with CT. [ABSTRACT FROM AUTHOR]

Purpose: We developed a Tc-99m and fluorescence-labeled peptide, Tc-99m TAMRA-GHEG-ECG-GNQWFI, to target tumor cells, and evaluated the diagnostic performance as a dual-modality imaging agent for tumor in a murine model.Methods: TAMRA-GHEG-ECG-GNQWFI was synthesized using Fmoc solid-phase peptide synthesis. Radiolabeling of TAMRA-GHEG-ECG-GNQWFI with Tc-99m was done using ligand exchange via tartrate. Binding affinity and in vitro cellular uptake studies were performed. Gamma camera imaging, biodistribution, and ex vivo imaging studies were performed in murine models with U87MG tumors. Tumor tissue slides were prepared and analyzed with immunohistochemistry using confocal microscopy.Results: After radiolabeling procedures with Tc-99m, Tc-99m TAMRA-GHEG-ECG-GNQWFI complexes were prepared in high yield (> 95%). The Kd of Tc-99m TAMRA-GHEG-ECG-GNQWFI determined by saturation binding was 29.5 ± 4.5 nM. Confocal microscopy images of U87MG cells incubated with TAMRA-GHEG-ECG-GNQWFI showed strong fluorescence in the cytoplasm. Gamma camera imaging revealed substantial uptake of Tc-99m TAMRA-GHEG-ECG-GNQWFI in tumors. Tumor uptake was effectively blocked by the co-injection of an excess concentration of GNQWFI. Specific uptake of Tc-99m TAMRA-GHEG-ECG-GNQWFI was assessed by biodistribution, ex vivo imaging, and immunohistochemistry stain studies.Conclusions: In vivo and in vitro studies revealed substantial and specific uptake of Tc-99m TAMRA-GHEG-ECG-GNQWFI in tumor cells. Tc-99m TAMRA-GHEG-ECG-GNQWFI could be a good candidate dual-modality imaging agent for tumors. [ABSTRACT FROM AUTHOR]

Introduction Radionuclides for leucocyte kinetic studies have progressed from non-gamma emitting cell-labelling radionuclides through gamma emitting nuclides that allow imaging of leucocyte kinetics, to the next goal of positron emission tomography (PET). Sources of data Mostly the authors’ own studies, following on from studies of the early pioneers. Areas of controversy From early imaging studies, it appeared that the majority of the marginated granulocyte pool was located in the lungs. However, later work disputed this by demonstrating the exquisite sensitivity of granulocytes to ex vivo isolation and labelling, and that excessive lung activity is artefactual. Areas of agreement Following refinement of labelling techniques, it was shown that the majority of marginated granulocytes are located in the spleen and bone marrow. The majority of leucocytes have a pulmonary vascular transit time only a few seconds longer than erythrocytes. The minority showing slow transit, ~5% in healthy persons, is increased in systemic inflammatory disorders that cause neutrophil priming and loss of deformability. Using a range of imaging techniques, including gamma camera imaging, whole-body counting and single photon-emission computerized tomography, labelled granulocytes were subsequently used to image pulmonary trafficking in lobar pneumonia, bronchiectasis, chronic obstructive pulmonary disease and adult respiratory distress syndrome. Growing points More recently, eosinophils have been separated in pure form using magnetic bead technology for the study of eosinophil trafficking in asthma. Areas timely for developing research These include advancement of eosinophil imaging, development of monocyte labelling, development of cell labelling with PET tracers and the tracking of lymphocytes. [ABSTRACT FROM AUTHOR]

We developed a Tc‐99m and TAMRA‐labeled peptide, Tc‐99m arginine‐arginine‐leucine (RRL) peptide (TAMRA‐GHEG‐ECG‐RRL), to target tumor cells and evaluated the diagnostic performance of Tc‐99m TAMRA‐GHEG‐ECG‐RRL as a dual‐modality imaging agent for tumor in a murine model. TAMRA‐GHEG‐ECG‐RRL was synthesized using Fmoc solid‐phase peptide synthesis. Binding affinity and in vitro cellular uptake studies were performed. Gamma camera imaging, biodistribution, and ex vivo imaging studies were performed in murine models with PC‐3 tumors. Tumor tissue slides were prepared and analyzed with immunohistochemistry using confocal microscopy. After radiolabeling procedures with Tc‐99m, Tc‐99m TAMRA‐GHEG‐ECG‐RRL complexes were prepared in high yield (>96%). The Kd of Tc‐99m TAMRA‐GHEG‐ECG‐RRL determined by saturation binding was 41.7 ± 7.8 nM. Confocal microscopy images of PC‐3 cells incubated with TAMRA‐GHEG‐ECG‐RRL showed strong fluorescence in the cytoplasm. Gamma camera imaging revealed substantial uptake of Tc‐99m TAMRA‐GHEG‐ECG‐RRL in tumors. Tumor uptake was effectively blocked by the coinjection of an excess concentration of RRL. Specific uptake of Tc‐99m TAMRA‐GHEG‐ECG‐RRL was confirmed by biodistribution, ex vivo imaging, and immunohistochemistry stain studies. In conclusion, in vivo and in vitro studies revealed substantial uptake of Tc‐99m TAMRA‐GHEG‐ECG‐RRL in tumors. Tc‐99m TAMRA‐GHEG‐ECG‐RRL has potential as a dual‐modality tumor imaging agent. [ABSTRACT FROM AUTHOR]

In this study Isoniazid (INH) as one of the first line drugs in treatment of Tuberculosis was investigated to be loaded in Solid Lipid Nanoparticles (SLNs) for reducing hepatotoxicity as well as prolonging drug release. High shear homogenization method was performed to prepare INH SLNs. To compare biodistribution of INH before and after loading in SLNs, INH was labeled by Technetium 99 (Tc99) after derivatization. The particle size of the prepared SLNs was 167 and 200 nm before and after lyophilization, respectively. Loading efficiency was calculated using the reverse method and release study was performed by using the dialysis sack method. Loading efficiency was 98%, and more than 85% of the loaded drug released in 3 h. Differential Scanning calorimeter (DSC) studies were performed for evaluating of the probability of happening hydrogen bonds or other chemical interactions between cholesterol as carrier and isoniazid as active pharmaceutical ingredient. The results could support the probability of hydrogen bond formation between cholesterol and INH. Gamma Scintigraphy studies showed that after administering INH SLNs, longer drug retention in the body was obtained compared to free INH. Quantitative gamma counting showed that the concentration of INH in the liver and intestines could be decreased by using nanotechnology. [ABSTRACT FROM AUTHOR]

Purpose: Nanotheranostic platforms, i.e., the combination of both therapeutic and diagnostic agents on a single platform, are emerging as an interesting tool for the personalized cancer medicine. Therefore, the aim of this work was to evaluate the in vivo properties of a Tc-99m-labeled nanostructured lipid carrier (NLC) formulation, co-loaded with doxorubicin (DOX) and docosahexaenoic acid (DHA), for theranostic applications.Procedures: NLC-DHA-DOX were prepared busing the hot melting homogenization method using an emulsification-ultrasound and were radiolabeled with Tc-99m. Biodistribution studies, scintigraphic images, and antitumor activity were performed in 4T1 tumor-bearing mice.Results: NCL was successfully radiolabeled with Tc-99m. Blood clearance showed a relatively long half-life, with blood levels decaying in a biphasic manner (T1/2 α = 38.7 min; T1/2 β = 516.5 min). The biodistribution profile and scintigraphic images showed higher tumor uptake compared to contralateral muscle in all time-points investigated. Antitumor activity studies showed a substantial tumor growth inhibition ratio for NLC-DHA-DOX formulation. In addition, the formulation showed more favorable toxicity profiles when compared to equivalent doses of free administered drugs, being able to reduce heart and liver damage.Conclusions: Therefore, NLC-DHA-DOX formulation demonstrated feasibility in breast cancer treatment and diagnosis/monitoring, leading to a new possibility of a theranostic platform. [ABSTRACT FROM AUTHOR]

Background: Jerusalem artichoke [JA] is a rich source of dietary fiber. Previous reports showed that JA influence delayed gastric emptying by prolonging gastric emptying, resulting in extending satiety.This property may be beneficial for current lifestyle of the working women who need simple and convenient form of energy supply but provide the effect of weight controlling at the same time. Objective: The present study aimed to label JA with 99mTc-pertechnetate and to evaluatethe effect of JA formulation in a snack bar (JASB) on gastric emptying and satiety in healthy female subjects. Materials and Methods: JASB and control snack bar [CSB] were prepared by mixing JA syrup with SnCl2 0.1 mg for 15 minutes, and subsequently adding 99mTc-pertechnetate 1 mCi. The incubation time was 10 minutes at room temperature. The labeled 99mTc-JASB mixture were then put in a rectangular mold and baked in an oven at 180°C for 20 minutes. A randomized double-blinded crossover design study was conducted to evaluate the gastric emptying process in vivo. Thirty healthy female participants whose average age was 29.1±1.95 year were recruited for this study. The participants were instructed to consume JASB and then to stand in an upright position. For gastric emptying analysis, scintigraphic method was used. Sequential data acquisition was performed in upright 45 degree left anterior oblique (45° LAO) position for 4 hours. Participants were also asked to describe their satiety by making a vertical mark on 100-mm visual analogue scales [VAS] during data acquisition. This procedure was repeated for each subject but after consuming CSB. Results: The 99mTc-Jerusalem artichoke was successfully labeled with radiochemical purity of more than 90%. The gastric emptying half time and percent gastric of JASB were significantly greater than CSB (p<0.05). The satiety at these intervals were also notably distinctive (p<0.05) between JASB and CSB. In JASB studies, the gastric emptying exhibited a strong positive correlation with satiety (R2 = 0.89, p<0.05). Conclusion: JA plays a key part in delaying gastric emptying of consumed snack bar, resulting in prolonged subjects' satiety. [ABSTRACT FROM AUTHOR]