Radioactive Counts Research Articles

Radioactive Parathyroid Adenomas on Sestamibi Scans: Low Parathyroid Hormone Secretory Potential and Large Volume.

BackgroundWe investigated the clinical characteristics of parathyroid adenomas according to radioactivity on 99mTc-methoxyisobutylisonitrile (99mTc-MIBI) single-photon emission computed tomography/computed tomography (SPECT/CT) in primary hyperparathyroidism (PHPT) patients.MethodsThe study included 217 patients diagnosed with PHPT from 2000 to 2019 at Seoul National University Hospital who underwent 99mTc-MIBI SPECT/CT scans. On SPECT/CT, the radioactivity of parathyroid adenomas was measured as the ratio of the mean radioactivity count of the parathyroid adenoma to that of the contralateral thyroid.ResultsTumors were localized by MIBI scans in 190 patients (MIBI [+] group) and by ultrasound or parathyroid four-dimensional CT in 27 patients (MIBI [−] group). The mean age was 55 years, and mean body mass index was 23.4 kg/m2. Patients in the MIBI (+) group had higher parathyroid hormone (iPTH) and lower 25-hydroxy vitamin D levels than those in the MIBI (−) group (168.0 pg/mL [interquartile range, IQR, 111.0 to 250.7] vs. 134.7 pg/mL [IQR, 98.2 to 191.2], P=0.049; 15.4 ng/mL [IQR, 11.1 to 20.8] vs. 21.2 ng/mL [IQR, 13.9 to 24.8], P=0.012, respectively). Patients in the MIBI (+) group had larger tumor volumes, but lower iPTH/volume ratios than those in the MIBI (−) group (1,216.66 [IQR, 513.40 to 2,663.02], 499.82 mm3 [IQR, 167.77 to 1,229.80], P=0.002; 0.18 [IQR, 0.08 to 0.46], 0.40 pg/mL/mm3 [IQR, 0.16 to 1.29], P=0.016, respectively). Adenoma radioactivity was positively correlated with calcium, iPTH, and volume (r=0.180, P=0.020; r=0.208, P=0.006; r=0.288, P<0.001, respectively), but not with iPTH/volume.ConclusionParathyroid adenomas with positive MIBI scans had larger volumes and higher iPTH than adenomas with negative scans, but lower iPTH per unit volume.

Biological role of postoperative low level laser therapy in preventing hydroxyapatite orbital implantation exposure: A case report.

Conjunctival sac stenosis is the contraction of the conjunctival sac as a result of trauma or disease. The aim of the present study was to observe the clinical effects of low-level laser therapy (LLLT) combined with hydroxyapatite (HA) orbital implantation as a treatment strategy for conjunctival sac stenosis. A total of 10 patients with conjunctival sac stenosis were treated with scleral graft transplantation in conjunction with HA implantation and postoperative LLLT. In addition, a rabbit model was used to investigate the biological mechanism underlying the effects of LLLT with the aim of preventing and treating orbital implantation exposure. The right eyeball was removed, orbital implantation performed and LLLT applied to experimental groups. 99mTc-Methyl diphosphonate scanning methods were performed at different timepoints to compare the average radioactivity count of the region of interest between surgical (right) and control (left) eyes (R/L). Histopathological examination was performed 8 weeks post-surgery, followed by analysis of fiber vascularization. Following LLLT, moderate conjunctival wounds were completely healed within 2 weeks and severe stenosis wounds healed within 3 weeks. Following prosthesis implantation in the rabbit model, a significantly elevated R/L ratio was observed after 4 weeks, whereas no significant difference was observed compared with the control group at 6 and 8 weeks postoperatively. Histopathological examination revealed that all implants were fibrotic. Overall, the present study demonstrated that LLLT promoted the survival of conjunctival grafts, stimulated conjunctival incision healing and promoted early vascularization of HA implants. Clinical trial registration no: ChiCTR-DDT-12002660 (www.chictr.org/cn/).

Value of 99mTc-MIBI SPECT/CT in distinguishing between parathyroid lesions and nodular goiter.

Hyperfunctioning parathyroid lesions require surgical resection. 99mTc-methoxyisobutylisonitrile (99mTc-MIBI) single-photon emission computed tomography/computed tomography (SPECT/CT) plays an important role in the diagnosis of parathyroid lesions. Some nodular goiters have a higher uptake of 99mTc-MIBI, which is difficult to distinguish from hyperfunctioning parathyroid lesions. This study aims to explore the value of 99mTc-MIBI SPECT/CT in the differential diagnosis of parathyroid lesions and nodular goiter. This study was a retrospective analysis. A total of 68 patients who were diagnosed as parathyroid lesions by 99mTc-MIBI SPECT/CT were enrolled, with a total of 81 lesions. According to the results of pathological examination after surgical resection, the lesions were divided into a parathyroid lesion group (n=69) and a nodular goiter group (n=12). The target maximum radioactivity count (Tmax) of all lesions was measured. The mean radioactivity count of the aortic arch was used as the background mean radioactivity count (Bmean), and the ratio of the Tmax to Bmean was calculated. The difference in Tmax/Bmean between the 2 groups was compared. The minimum, mean, and maximum of CT density in the lesion were measured. The difference of CT density between the 2 groups was compared. The receiver operating characteristic (ROC) curve of patients with parathyroid lesions and patients with nodular goiter was drawn, and the diagnostic efficacy of each CT density value was evaluated. The 99mTc-MIBI radioactive uptake in parathyroid lesions and nodular goiter lesions was significantly concentrated. The CT density values of the 2 lesions were lower than normal thyroid tissue, and the boundary between the 2 lesions and the thyroid was clear or blurred. There was no significant difference in Tmax/Bmean between the 2 groups (P=0.221). The differences in the minimum, mean and maximum of CT density between the 2 groups were statistically significant (all P<0.05). The diagnostic efficiency of maximum of CT density was the best, area under the ROC curve was 0.894 (P<0.001), the cut-off was 91 HU, the sensitivity was 83.3%, and the specificity was 94.2%. The degree of 99mTc-MIBI radiation uptake in the focus has limited value in differentiating parathyroid lesions from nodular goiter, and the maximum density of CT possesses high diagnostic efficiency.

Quantitative Characterization of the Amount and Length of (1,3)-β-d-glucan for Functional and Mechanistic Analysis of Fungal (1,3)-β-d-glucan Synthase.

(1,3)-β-d-Glucan synthase (GS) is an essential enzyme for fungal cell wall biosynthesis that catalyzes the synthesis of (1,3)-β-d-glucan, a major and vital component of the cell wall. GS is a proven target of antifungal antibiotics including FDA-approved echinocandin derivatives; however, the function and mechanism of GS remain largely uncharacterized due to the absence of informative activity assays. Previously, a radioactive assay and reducing end modification have been used to characterize GS activity. The radioactive assay determines only the total amount of glucan formed through glucose incorporation and does not report the length of the polymers produced. The glucan length has been characterized by reducing end modification, but this method is unsuitable for mechanistic studies due to the very high detection limit of millimolar amounts and the labor intensiveness of the technique. Consequently, fundamental aspects of GS catalysis, such as the polymer length specificity, remain ambiguous. We have developed a size exclusion chromatography (SEC)-based method that allows detailed functional and mechanistic characterization of GS. The approach harnesses the pH-dependent solubility of (1,3)-β-d-glucan, where (1,3)-β-d-glucan forms water-soluble random coils under basic pH conditions, and can be analyzed by SEC using pulsed amperometric detection (PAD) and radioactivity counting (RC). This approach allows quantitative characterization of the total amount and length of glucan produced by GS with minimal workup and a d-glucose (Glc) detection limit of ~100 pmol. Consequently, this approach was successfully used for the kinetic characterization of GS, providing the first detailed mechanistic insight into GS catalysis. Due to its sensitivity, the assay is applicable to the characterization of GS from any fungi and can be adapted to study other polysaccharide synthases.

Redefining Criteria to Ensure Adequate Sentinel Lymph Node Biopsy With Dual Tracer for Breast Cancer

BackgroundFor sentinel lymph node biopsy (SLNB) in patients with breast cancer, the dual tracer of blue dye and radioisotope with the 10% rule that all nodes with radioactive count of 10% or more of the hottest node ex vivo should be removed is widely accepted. However, the cut-off point of radioactivity is being questioned for possibly excessive removal of negative nodes.MethodsTo compare different percentile rules and optimize the criteria for identifying SLNs, we established a database which prospectively collected the radioactivity, status of blue dye and the pathological results of each SLN in breast cancer patients who successfully underwent SLNB with a combination of methylene blue and radioisotope.ResultsA total of 2,529 SLNs from 1,039 patients were identified from August 2010 to August 2019. 16.4% (414/2,529) positive nodes were removed at a cost of 83.6% (2115/2,529) negative nodes removed excessively. Up to 17.9% (375/2,115) negative nodes were removed as radioactively hot nodes without blue staining. By gradually increasing the threshold by each 10%, the number of negative nodes identified reduced by 18.2% (385/2,115) with only three node-positive patients (1.0%) missed to be identified using the “40% + blue” rule. In patients with ≥ 2 SLNs removed, 12.3% (238/1,942) negative nodes avoided unnecessary removal with only 0.8% (2/239) positive patients missed with the “hottest two + blue” rule.ConclusionsOur data indicated that the “40% + blue” rule or the “hottest two + blue” rule for SLNB with the dual tracer of blue dye and radioisotope may be considered as a potential alternative rule to minimize extra nodes resected. Nonetheless, it should be validated by prospective trials with long-term follow-up.

Effect of natural background on detection threshold of radioactive material detection system

In this paper, the relationship between detection limit and error probability is studied based on the statistical law of radioactivity. The conversion method between the lowest detectable radioactivity count and the activity can be obtained, which provides the basis for setting the alarm threshold reasonably.

The Discovery of the Hepatitis D Virus: Three Princes of Serendip and the Recognition of Autoantibodies to Liver-Kidney Microsomes.

The Discovery of the Hepatitis D Virus: Three Princes of Serendip and the Recognition of Autoantibodies to Liver-Kidney Microsomes.

Targeted study of thyroid-stimulating hormone antibody coupled with PLGA-COOH nanoparticles for thyroid cancer

In this study, we aimed to evaluate the effect of all-trans-retinoic acid (PLGA-COOH nanoparticles) on the induction of dedifferentiation of thyroid cancer and the enhancement of iodine uptake. Patients (32 cases) with pathologically confirmed thyroid cancer (24 differentiated and 8 undifferentiated) received all trans-retinoic acid (1.0–1.5 mg/kg) for six weeks. Whole-body imaging was performed after 72 h. Using the American phogamma camera, the radioactivity counts of each pixel in the metastasis was measured by the semi-quantitative method of region of interest (ROI). Changes in uptake radioactivity of the metastases were compared before and after PLGA-COOH nanoparticle induction. The size of the metastasis was determined by ultrasound, X-ray, or computed tomography (CT), and the serum thyroglobulin (TG) was determined by radioimmunoassay. After radioiodine treatment, the average measurable iodine uptake of different sites of metastasis was significantly lower than that before treatment. After 32 patients were treated with PLGA-COOH nanoparticles, the uptake of a single lesion was increased in 14 cases (43.8%), no significant change was found in 7 cases (20.8%), and the uptake of one lesion was decreased in 6 cases (25%). In 827 cases, the metastasis decreased, 12 cases remained unchanged, and 7 cases increased. There was no correlation between the pathological type and the change of a lesion. After induction, serum TG decreased in 12 cases (40%), increased in 11 cases (36.7%), and remained unchanged in 7 cases (23.3%). Serum TG level was not related to a change in iodine uptake ability. In 12 cases (37.5%), two indexes were changed (e.g., increased iodine uptake, reduced ROI, or decreased serum TG). Thyroid-stimulating hormone nano interventional therapy breaks through the single and limitation of traditional treatment of thyroid diseases. PLGA-COOH nanoparticles can play an important role in the differentiation of differentiated thyroid cancer cells and the transformation of undifferentiated thyroid cancer cells. PLGA-COOH nanoparticles provide an effective method to induce the treatment of undifferentiated thyroid cancer.

Accuracy of Sentinel Lymph Node Biopsy in Breast Cancer: Pitfalls in the Application of Single Tracers.

BackgroundRadioisotopes and blue dyes are used as dual tracers in the current gold standard procedure of sentinel lymph node (SLN) biopsy (SLNB) performed for breast cancer. However, the blue dye or the radioisotope as a single tracer is also being applied in some institutes. We aimed to explore the risk factors for the miss-detection of SLNs with the radioisotope and the blue dye and to describe the distribution of SLNs missed by each tracer.Patients and MethodsPatients undergoing SLNB with radioisotope and blue dye as dual mapping agents were enrolled between August 2010 and August 2018. Radioactivity count, blue dye staining status, and size and location of each SLN were prospectively documented.ResultsIn total, 2382 SLNs from 1010 patients were included for statistical analyses. The sentinel node identification rate was 100% for dual tracers, 99.4% for radioisotope, and 89.1% for blue dye. SLN identification using the blue dye was more likely to fail in patients undergoing breast-conserving surgery (p < 0.001) and mastectomy with reconstruction (p = 0.005). Furthermore, miss-detection was significantly more frequent in smaller and uninvolved nodes. Among all SLNs, 8.2% were located in level II and one was in level III. Notably, single tracer of blue dye tended to fail in the detection of lymph nodes in higher levels (p < 0.001).ConclusionThis study explored the association between features and the incidence of the failure to detect SLNs using radioisotope and blue dye. The locations of the miss-detected SLNs are demonstrated to provide a reference for SLNBs conducted using blue dye or radioisotope as a single tracer.

Kinetic Deposition of Polar and Non-polar Lipids on Silicone Hydrogel Contact Lenses

ABSTRACT Purpose: This study investigated kinetic lipid uptake to four silicone hydrogel (SiHy) lenses over a period of four weeks, using an in-vitro radiolabel method. Methods: Four contemporary monthly replacement SiHy lenses (lotrafilcon B, senofilcon C, comfilcon A, samfilcon A) were incubated in three different solutions: 1) An artificial tear solution (ATS) containing 14C-labeled phosphatidylcholine (PC), 2) an ATS containing 14C-cholesteryl oleate (CO) and 3) an ATS containing four 14C-radiolabeled lipids (PC, phosphatidylethanolamine, CO, and cholesterol (total lipid)). After 16 hours, lipids were extracted twice from the lenses with chloroform:methanol and the radioactive counts determined the lipid quantities to simulate 1 day of wear. OPTI-FREE PureMoist (Alcon) was used to clean and disinfect the remaining lenses daily and the lipid quantities were further determined after 2 weeks and 4 weeks. Results: The amount of total lipid increased for all lenses over time (p < .01). After four weeks, total lipid accumulated was 20.26 ± 0.15 µg/lens for senofilcon C, which was significantly higher (p < .01) than all other lens materials (samfilcon A – 17.84 ± 0.21; comfilcon A – 16.65 ± 0.12; lotrafilcon B – 7.41 ± 0.56 µg/lens). CO was highest on lotrafilcon B (1.26 ± 0.13 µg/lens) and senofilcon C attracted the most PC (3.95 ± 0.12 µg/lens) compared to the other materials. Conclusion: The amount of both polar and non-polar lipid deposition on monthly replacement SiHy lenses increased over 4 weeks, with significant differences being seen between lens materials.

A Porous Aromatic Framework Functionalized with Luminescent Iridium(III) Organometallic Complexes for Turn-On Sensing of 99TcO4.

Contamination of 99TcO4-, a problematic radioactive anion in the nuclear fuel cycle, in groundwater has been observed in a series of legacy nuclear sites, representing a notable radiation hazard and environmental concern. The development of convenient, rapid, and sensitive detection methods is therefore critical for radioactivity control and remediation tasks. Traditional detection methods suffer from clear demerits of either the presence of large interference from coexisting radioactive species (e.g., radioactivity counting methods) or the requirement of extensive instrumentation and analysis procedure (e.g., mass spectrometry). Here, we constructed a luminescent iridium(III) organometallic complex (Ir(ppy)2(bpy)+; ppy = 2-phenylpyridine, bpy = 2,2'-bipyridine)-grafted porous aromatic framework (Ir-PAF) for the first time, which can be utilized for efficient, facile, and selective detection of trace ReO4-/TcO4- in aqueous solutions. Importantly, the luminescence intensity of Ir-PAF is greatly enhanced in the presence of ReO4-/TcO4-, giving rise to a distinct turn-on sensor with the detection limit of 556.9 μg/L. Such a superior detection capability originates from the highly selective and strong interaction between ReO4-/TcO4- and Ir(ppy)2(bpy)+, leading to an efficient pre-enrichment of ReO4-/TcO4- during analysis and subsequently a much weaker nonradiative decay of the luminescence of Ir(ppy)2(bpy)+, as illustrated by density functional theory (DFT) calculation as well as quantum yield and fluorescence lifetime measurements. Successful quantification of trace ReO4- in simulated Hanford low-activity waste (LAW) solution containing large excess of Cl-, NO3-, and NO2- was demonstrated, highlighting the bright future of luminescent PAFs in the area of chemical sensing.

Comparison of 18F-Flurpiridaz and 13N-NH3·H2O PET/CT myocardial perfusion imaging in animal experiments

Objective To explore the biodistribution and quantitative value of 18F-Flurpiridaz in mini-swine, and compare with 13N-NH3·H2O. Methods Ten Bama mini-swine were divided into normal group and myocardial infarction group (n=5 in each group). Normal group was not treated and myocardial infarction group was modeled by thoracotomy and coronary artery ligation. Both groups were preceded by 13N-NH3·H2O imaging, followed by 18F-Flurpiridaz imaging (time interval >40 min). Injection dosage of 2 tracers was the same (185-370 MBq). 18F-Flurpiridaz whole-body PET/CT imaging was also performed in normal group. Biological distribution of 18F-Flurpiridaz was observed, and the ratio of radioactive uptake of 18F-Flurpiridaz between myocardium and adjacent tissues or organs was calculated. Image quality score and rest myocardial blood flow (rMBF) of 2 imaging tracers in normal group were measured and compared. MPI image quality score, cardiac function parameters such as summed rest score (SRS), myocardial infarction area percentage, total perfusion defect (TPD), and left ventricular ejection fraction (LVEF) of 2 imaging tracers were compared in myocardial infarction group. Data was analyzed by paired t test. Results In normal group, 18F-Flurpiridaz in the myocardium was clearly observed, with high radioactive uptake maintaining within 2 h postinjection. The radioactivity count ratios of left ventricular myocardium to cardiac pool, the lungs and liver were high (5.19-12.87, 4.17-50.51, 2.08-6.92). The quality of 18F-Flurpiridaz MPI images in both groups was excellent (10/10). The rMBF (ml·g-1·min-1) in different regions of left ventricle measured by 18F-Flurpiridaz and 13N-NH3·H2O imaging were not significantly different (left anterior descending: 0.98±0.06 vs 0.92±0.13; left circumflex: 0.98±0.05 vs 0.88±0.12; right coronary artery: 0.95±0.07 vs 0.88±0.15; left ventricle: 0.96±0.07 vs 0.90±0.13; t values: from -1.70 to -0.90, all P>0.05). There was no significant difference in SRS, myocardial infarction area percentage, TPD, rMBF or LVEF between 18F-Flurpiridaz and 13N-NH3·H2O (SRS: 10.6±4.1 vs 9.2±4.6; myocardial infarction area percentage: (15.2±9.0)% vs (12.6±6.6)%; TPD: (11.6±6.3)% vs (9.6±3.9)%; LVEF: (68.6±11.1)% vs (71.4±11.3)%; t values: -2.33-2.75, all P>0.05). Conclusions Comparing with 13N-NH3·H2O, 18F-Flurpiridaz has the advantages of good MPI image quality, accurate measurement of cardiac function parameters and quantitative potential of myocardial blood flow, which make it as a promising positron myocardial perfusion imaging agent. Key words: Myocardial perfusion imaging; Pyridazines; Fluorine radioisotopes; Ammonia; Positron-emission tomography; Tomography, X-ray computed; Swine

Preparation and SPECT/CT Imaging of 177Lu-Labeled Peptide Nucleic Acid (PNA) Targeting CITED1: Therapeutic Evaluation in Tumor-Bearing Nude Mice.

PurposeThe expression of Cbp/p300-interacting transactivator with Glu/Asp-rich carboxy-terminal domain 1 (CITED1) is upregulated in papillary thyroid carcinoma (PTC) and mediates cell proliferation and migration. To facilitate early diagnosis and monitoring of recurrent or metastatic PTC, we designed 177Lu-labeled antisense peptide nucleic acid (PNA) targeting CITED1 mRNA to evaluate the therapeutic potential, while analyzing its distribution in nude mice and the characteristics withsingle-photon emission-computed tomography/computed tomography (SPECT/CT) imaging.Materials and Methods177Lu-DOTA-anti-CITED1-PNA (177Lu-asPNA) was obtained by indirect labeling. High-performance liquid chromatography (HPLC) and thin-layer chromatography (TLC) were used to determine the labeling rate and radiochemical purity. The stability of 177Lu-asPNA was evaluated by TLC, and the radioactivity count was measured by a γ counter to calculate its uptake capacity in K1 cells. To analyze the distribution of 177Lu-asPNA in body tissues and organs of nude mice, static single-photon emission-computed tomography (SPECT) imaging and SPECT/CT image fusion were performed. Then, the therapeutic effects of probes were explored by tumor growth curves and survival analysis.ResultsOur probe showed a radiochemical purity of 96.5±0.15% at 1 hr and specific activity of 8.7±0.53 MBq/μg. The uptake rate in the 177Lu-asPNA group was much higher than that in the 177Lu-DOTA-nonsense-PNA (177Lu-nonsense-PNA) and 177Lu-DOTA groups (P<0.05). The biological distribution showed that the tumor/muscle ratio was at its highest at 24 h (4.98±0.34) post-inoculation, with SPECT/CT imaging showing clear tumor development. By measuring tumor volume of tumor-bearing nude mice, the 177Lu-asPNA group showed a significant difference in tumor size 9 days after injection (P < 0.05). Kaplan-Meier survival curves showed that the overall survival rate in the 177Lu-asPNA group was significantly different from those in the DOTA-anti-CITED1-PNA (asPNA) and saline groups (P = 0.002, log-rank test).Conclusion177Lu-asPNA was developed successfully, showing a high labeling rate and good stability. SPECT/CT imaging demonstrated tumor growth in nude mice, which was effectively inhibited by our probe, thus prolonging survival.

Utility of Quantitative SPECT/CT Lymphoscintigraphy in Guiding Sentinel Lymph Node Biopsy in Head and Neck Melanoma.

To investigate the use of advanced SPECT/CT quantification in guiding surgical selection of positive sentinel lymph nodes (SLNs) in head and neck melanoma. We retrospectively reviewed data from patients with cutaneous head and neck melanoma who underwent lymphoscintigraphy with SPECT/CT prior to SLN biopsy (SLNB). Quantification of radiotracer uptake from SPECT/CT data was performed using in-house segmentation software. SLNs identified using SPECT/CT were compared to SLNs identified surgically using an intraoperative γ-probe. A radioactivity count threshold using SPECT/CT for detecting a positive SLN was calculated. One hundred and five patients were included. Median number of SLNs detected was 3/patient with SPECT/CT and 2/patient with intraoperative γ-probe. The hottest node identified by SPECT/CT and intraoperative γ-probe were identical in 85% of patients. All 20 histologically positive SLNs were identified by SPECT/CT and γ-probe. On follow-up, all nodal recurrences occurred at lymph node levels with the hottest node identified by SPECT/CT and either the hottest or second hottest node identified by γ-probe during SLNB. Using our data, a SPECT/CT radioactivity count threshold of 20% would eliminate the unnecessary removal of 11% of SPECT/CT identified nodes and 12% of intraoperatively detected nodes. Utilizing SPECT/CT quantification, we propose that a radioactivity count threshold can be developed to help guide the selective removal of lymph nodes in head and neck SLNB. Furthermore, the nodal level containing the hottest node identified by SPECT/CT quantification must be thoroughly investigated for SLNs and undergo careful follow-up and surveillance for recurrence.

Sentinel Lymph Node Technique in Apparent Early Ovarian Cancer: Laparoscopic Technique

To demonstrate the feasibility of laparoscopic sentinel lymph node technique in presumed early-stage ovarian cancer. Video illustrating the laparoscopic performance of the sentinel lymph node technique in ovarian cancer. The Oncologic Gynecology Department at the University Hospital La Fe. Candidates for the technique presented an apparent early stage ovarian cancer. The technique was performed in the context of a clinical trial called SENTOV (NCT03452982). To date, lymphadenectomy is recommended after the diagnosis of apparent early-stage ovarian cancer as part of the surgical staging. Minimally invasive surgery can be considered for the purpose of restaging [1]. Up to 14% of the patients are upstaged because of positive lymph nodes after pelvic and para-aortic lymphadenectomy [2]. Regarding low-grade tumors, a lower rate of lymph node involvement has been reported [3]. Sentinel lymph node technique has been reported to be feasible in a recent pilot study [4]. Two clinical trials (Sentinel Lymph Node in Early Ovarian Cancer and Sentine Lymph Node in Early Ovarian Cancer) are currently ongoing to clarify the use of sentinel lymph node technique in early ovarian cancer. The injection points were at the infundibulopelvic and ovarian ligament stumps. Two hundred microliters of saline solution containing 37 MBq of technetium-99m nanocolloid followed by 0.5 mL of indocyanine green (ICG) was injected subperitoneally. We used a 27 G needle at each injection point. Immediately after injection and also at 15 and 30 minutes after injection, the operative field was checked guided by the acoustic signal of the gamma probe and the near-infrared camera. We performed a minimum dissection looking for the sentinel lymph node or nodes in the pelvic and para-aortic region. Any lymph node with a remarkable radioactivity count as high as 10 times the background and/or dyed with ICG was considered a sentinel lymph node and was harvested separately. A systematic surgical staging was performed after the sentinel lymph node procedure was completed. Because of its small size, the ICG molecule is not caught in the lymph node valve system and keeps migrating when performing lymphography. An exhaustive direct view of the dye path is required to avoid misleading detection of the real sentinel lymph node. This theoretical problem is resolved by the use of the 99mTC-nanocolloid. This tracer gets trapped into the lymph node valve system because of its molecular size and does not keep migrating as does ICG. As such, a combination of both methods is proposed. Laparoscopic performance of sentinel lymph node technique in ovarian cancer seems to achievable. Between 2017 and 2019, this procedure was performed in 30 patients (13 laparoscopic), in the context of our pilot experience [4] and the Sentinel Lymph Node in Early Ovarian Cancer clinical trial (NCT03452982).

68Ga-labeled ubiquicidin for monitoring of mouse infected with Staphylococcus aureus

Ubiquicidin is a cationic, antimicrobial peptide found in the innate hose defence against pathogens. The peptide selectively interacts with the surface of microorganism. This work aimed to develop the radiopharmaceutical for infection imaging using antimicrobial peptide. Optimum labelling condition to obtain radiopharmaceutical purity (RCP) of 68Ga-DOTA-ubiquicidin (29-41) more than 90% was evaluated. The RCP more than 95% was achievable with 30 micrograms peptide at solution reaction pH 4. Stability testing of the labelled peptide was also studied by resembling to in vitro condition using fresh frozen human plasma. The radiolabelled peptide retained its RCP >90% after 4 hours of incubation. Animal study was performed in infected and sterile inflamed mice groups with Staphylococcus aureus or sterilized S. aureus at the left thigh 24 hours prior administration of 68Ga-DOTA-UBI. Radioactivity count rate at the infected or sterilized inflamed site of the left thigh of each mouse was compared and normalized with radioactivity count accumulated in normal muscle of its right thigh. Accumulation of 68Ga-DOTA-UBI in muscle of infected mice was significantly greater than the sterile inflamed mice; 4.62 ± 3.44 and 1.53 ± 1.73, respectively, at 1 hour post injection. These results showed the efficacy of 68Ga-DOTA-UBI as a radiopharmaceutical for monitoring of bacterial infection.

Impact of Gas Flow and Humidity on Trans-Nasal Aerosol Deposition via Nasal Cannula in Adults: A Randomized Cross-Over Study.

Background: Trans-nasal pulmonary aerosol delivery using high flow nasal cannula (HFNC) devices is described with the administration of high gas flows exceeding patient inspiratory flow (HF) and with lower flows (LF). The aim of this pilot clinical trial was to compare deposition and distribution of radiolabeled aerosol via nasal cannula in healthy adults across three rates of gas flow delivered with active heated humidification, and to further identify the impact of aerosol administration without heated humidity. Methods: Twenty-three (23) healthy adults (16F) were randomized to receive aerosol with active heated humidification or unheated oxygen at gas flows of 10 L/min (n = 8), 30 L/min (n = 7), or 50 L/min (n = 8). Diethylenetriaminepentaacetic acid labeled with 1 millicurie (37 MBq) of Technetium-99m (DTPA-Tc99m) was mixed with NaCl to a fill volume of 1 mL, and administered via mesh nebulizer placed at the inlet of the humidifier. Radioactivity counts were performed using a gamma camera and the regions of interest (ROIs) were delimited with counts from the lungs, upper airways, stomach, nebulizer, circuit, and expiratory filter. A mass balance was calculated and each compartment was expressed as a percentage of the total. Results: Lung deposition (mean ± SD) with heated humidified gas was greater at 10 L/min than 30 L/min or 50 L/min (17.2 ± 6.8%, 5.71 ± 2.04%, and 3.46 ± 1.24%, respectively; p = 0.0001). Using unheated carrier gas, a lung dose of aerosol was similar to the active heated humidification condition at 10 L/min, but greater at 30 and 50 L/min (p = 0.011). Administered gas flow and lung deposition were negatively correlated (r = −0.880, p < 0.001). Conclusions: Both flow and active heated humidity inversely impact aerosol delivery through HFNC. Nevertheless, aerosol administration across the range of commonly used flows can provide measurable levels of lung deposition in healthy adult subjects (NCT 02519465).

Correlations between striatal dopamine transporter distribution, glucose metabolism and clinical symptoms in Parkinson′s disease

Objective To investigate the correlations among striatal dopamine transporter (DAT) distribution, glucose metabolism and Parkinson′s disease (PD) clinical symptoms. Methods Twenty-five clinically confirmed idiopathic PD patients (17 males, 8 females, age: (59.8±9.2) years) who underwent 11C-2-beta-carbomethoxy-3-beta-(4-fluorophenyl)tropane (CFT) and 18F-fluorodeoxyglucose (FDG) PET imaging from January 2015 to December 2016 were reviewed. The detailed clinical scores were systematically collected from all patients. Correlations between DAT distribution, glucose metabolism and clinical symptoms were evaluated at global and voxel levels using Pearson correlation analysis. Results There were significantly positive correlations between the PD-related pattern (PDRP) value and unified PD rating scale (UPDRS) motor scores, non-motor symptoms scale (NMSS) scores, activity of daily living scale (ADL) scores (r values: 0.580, 0.522, 0.557, all P 0.05). The CFT uptake of ipsilateral caudate nucleus and anterior putamen were negatively correlated with ADL scores (r values: -0.502, -0.522, both P 0.05). The presence of the significant correlations between UPDRS motor scores, ADL scores and the CFT radioactive count were confirmed in left caudate nucleus and left putamen (r values: from -0.90 to -0.47, all P<0.05). The metabolic PET imaging disclosed a set of brain regions correlating with the clinical symptoms. The presence of significant correlations between the metabolic PET imaging and CFT uptake were confirmed in bilateral caudate nucleus (r values: 0.47-0.90, both P<0.01), precentral gyrus and insula (r values: -0.90 to -0.47, all P<0.01). Conclusion The correlations between DAT distribution, glucose metabolism and PD clinical symptoms are complicated, which promote the understanding in the proper application of dopaminergic and metabolic PET imaging in PD and offer more evidences in PD pathophysiological mechanisms. Key words: Parkinson disease; Dopamine plasma membrane transport proteins; Signs and symptoms; Positron-emission computed; Deoxyglucose

Effect of excessive iodine intake on the 99Tcm-pertechnetate uptake function of thyroid and the related mechanism

Objective To study the influence of excessive iodine intake on the 99Tcm-pertechnetate uptake function of thyroid and explore the related mechanism. Methods A total of 150 male Wistar rats were divided into normal iodine group (NI group) and 4 high iodine (HI) groups (10HI, 50HI, 100HI and 500HI group) with completely random method. Each group included 30 rats. Rats in HI groups were intragastrically administrated with different concentrations of KIO3, and rats in NI group were administrated with the same amount of distilled water. After a 7 d HI diet, each group was randomly divided into 3 subgroups: 7 d group (HI diet for 7 d), 10 d group (HI diet for 7 d + limiting iodine for 3 d) and 14 d group (HI diet for 7 d + limiting iodine for 7 d). All rats were given 1.85 MBq 99TcmO4-, then the thyroid glands were isolated and weighed 20 min post-injection. The radioactive counts were measured and the thyroid uptake percentage activity of injected dose per gram of tissue (%ID/g) of 99TcmO4- for each sample was calculated. Sodium-iodide symporter (NIS) expression level was analyzed by Western blot. One-way analysis of variance or Welch test was used to compare the differences among groups, and Spearman rank correlation analysis was also used. Results At the same observation time, the %ID/g of 99TcmO4- and NIS expression among different HI groups were statistically significant (F values: 48.825-119.219, all P 0.05). Significant differences of %ID/g of 99TcmO4- and NIS expression were found among different time subgroups in 50HI, 100HI and 500HI groups (F values: 10.442-90.408, all P<0.01). Spearman correlation analysis showed that the concentration of iodine correlated negatively with %ID/g of 99TcmO4- and NIS expression (rs values: -0.853 and -0.950, both P<0.01), while the %ID/g of 99TcmO4- and NIS expression was positively correlated (rs=0.925, P<0.01). Conclusions Excessive iodine intake can inhibit thyroid uptake of 99TcmO4- in rats, which is associated with the down-regulation of NIS expression. The degree of inhibition correlates positively with iodine concentration, and correlates negatively with NIS expression. The degree of recovery of NIS and %ID/g of 99TcmO4- may relate to the time of limiting the iodine intake. Key words: Thyroid gland; Sodium pertechnetate Tc 99m; Iodine; Rats; Sodium/iodide symporter

Quantitative measurement of standardized uptake value of lumbar vertebra by 99Tcm-MDP bone imaging with SPECT/CT

Objective To explore the quantitative determination of standardized uptake value (SUV) of lumbar vertebra by 99Tcm-methylene diphosphonate (MDP) bone imaging with SPECT/CT. Methods A total of 90 patients (16 males, 74 females, age: (60.0±11.2) years) who underwent 99Tcm-MDP bone imaging and local lumbar SPECT/CT imaging from May 2017 to November 2017 were retrospectively analyzed. CT attenuation correction, scatter correction and 3-dimensional ordered subset expectation maximization (3D-OSEM) reconstruction were used. The radioactive counts of lumbar vertebra L1-L4 in patients with high MDP-uptake (including degenerative changes and bone metastases) and patients with non-high MDP-uptake (including osteoporosis and non-osteoporosis) were measured. Basing on that, the radioactivity of unit volume in lumbar and lesion was calculated and converted to SUV. The difference of SUV for lumbar and lesions from different types of patients was analyzed, and the correlation between lumbar SUV and varies of parameters were also analyzed. Data were analyzed by two-sample t test and Pearson correlation analysis. Results The mean SUV (SUVmean) and maximum SUV (SUVmax) of L1-L4 in 54 patients with non-high MDP-uptake were 4.64±1.03 and 7.09±1.61 respectively. They were positively correlated with bone mineral content, CT value and body weight (r values: 0.433-0.700, all P<0.05), and negatively correlated with age (r values: -0.514 and -0.456, both P<0.001). The SUVmean and SUVmax of patients with osteoporosis were 3.81±0.76 and 5.86±1.34 respectively, which were significantly lower than those of non-osteoporosis (5.13±0.84 and 7.82±1.30; t values: -5.892 and -5.240, both P<0.001). The SUVmean and SUVmax of 37 metastases were 16.40±6.07 and 24.25±11.35 respectively in 16 patients, which were significantly higher than those in patients with degenerative changes (20 patients with 27 lesions; 9.30±3.16 and 13.48±5.21; t values: 6.074 and 5.083, both P<0.001). Conclusion Based on the specific reconstruction algorithm and correction method, the SUV of lumbar vertebra on 99Tcm-MDP SPECT/CT bone imaging can be obtained, and the bone mineral metabolism can be reflected. Key words: Lumbar vertebrae; Radionuclide imaging; Technetium Tc 99m medronate; Tomography, emission-computed, single-photon; Tomography, X-ray computed