The Utility of Sulfur Colloid Imaging to Differentiate Charcot's Neuroarthropathy from Osteomyelitis: A Case Study.

Charcot's neuroarthropathy and osteomyelitis can have similar initial presentations. The ability to differentiate between the two pathologic conditions is essential, as each requires different treatment. We present a case of a 53-year-old woman with pain, swelling, and warmth in her left first metatarsophalangeal joint and first tarsometatarsal joint. Radiographs showed comminuted fractures at the base of the first metatarsal. Osteomyelitis was suspected by the primary team based on physical findings and a history of previous first metatarsophalangeal joint arthrodesis. A triphasic bone scan and an indium white blood cell scan were positive for osteomyelitis. The podiatric medical team was suspicious for possible Charcot's neuroarthropathy based on physical findings and uncontrolled blood glucose levels at the time of her previous arthrodesis. A sulfur colloid scan was performed and compared with an indium scan, which showed no evidence of osteomyelitis. This case demonstrates the usefulness of sulfur colloid imaging compared with an indium white blood cell scan to differentiate osteomyelitis from Charcot's neuroarthropathy. This case also highlights the importance of using clinical judgment to make the correct diagnosis.

Acute Effect of E-Cigarette Inhalation on Mucociliary Clearance in E-Cigarette Users.

Background: Recent studies show e-cigarette (EC) users have increased rates of chronic bronchitic symptoms that may be associated with depressed mucociliary clearance (MCC). Little is known about the acute or chronic effects of EC inhalation on in vivo MCC. Methods: In vivo MCC was measured in young adult vapers (n = 5 males, mean age = 21) after controlled inhalation of a radiolabeled (Tc99m sulfur colloid) aerosol. Whole-lung clearance of radiolabeled deposited particles was measured over a 90-minute period for baseline MCC and associated with controlled periodic vaping over the first 60 minutes of MCC measurements. The vaping challenge was administered from a fourth generation box mod EC containing unflavored e-liquid (65% propylene glycol/35% vegetable glycerin, 3 mg/mL freebase nicotine). The challenge was administered at the start of each 10-minute interval of MCC measurements and consisted of 1 puff every 30 seconds for 5 minutes (i.e., 10 puffs for each 10-minute period for a total of 60 puffs during the initial 60 minutes of MCC measurements). Results: Compared with baseline, peripheral lung average clearance (%) over the 90 minutes of MCC measures was enhanced, associated with EC challenge, 12 (±6) versus 24 (±6), respectively (p < 0.05 by Wilcoxon signed-rank test). Conclusions: Acute enhancement of in vivo MCC during EC challenge is contrary to recent studies showing nicotine-associated slowing of ciliary beat and mucus transport at higher nicotine levels than those used here. However, our findings are consistent with an acute increase in fluid volume and mucin secretion to the bronchial airway surface that is likely short lived. Research reported in this publication was supported by the National Institutes of Health R01HL139369 and registered with ClinicalTrials.gov (NCT03700892).

Evaluation of three different 99mTc-based mock-venom agents for lymphoscintigraphy studies in preclinical models of peripheral snakebite envenomation.

Snakebite envenomation is one of the major public health concerns across many countries; with the WHO designating it as a 'priority neglected tropical disease' and stressing for a need to develop novel therapeutic strategies to reduce death and disability rate by end of 2030. Since a major component of venom; the high molecular weight (HMw) toxins enter the bloodstream through lymphatic system, research is focusing on modulating the lymphatic flow rate after topical application of suitable drug candidates. Present study compared the suitability of three radiopharmaceutical agents, namely 99mTc-Sulfur colloid (SC), 99mTc-Phytate (Phy) and 99mTc-Human serum albumin (HSA), to be used as mock-venom agent in studying modulation in lymphatic flow rate in preclinical models of peripheral snakebite envenomation using lymphoscintigraphy studies. The study was performed in 72 Sprague Dawley rats; divided into six groups of 12 rats each. Control groups were given intradermal injection (1.29-1.48 MBq in 100 µl normal saline) of either 99mTc-Phy/ 99mTc-SC/ 99mTc-HSA into the tail as 'mock-venom'. In respective test groups, commercially available topical formulation (Anobliss® Cream) containing Nifedipine (Nif; 0.3% w/w) and Lidocaine (Lid; 1.5% w/w) was applied topically over the animals' lower body (tail and hind limbs) immediately within 20s of administering intradermal injection of the radiopharmaceutical. Any modulation in lymph transit time from periphery to systemic circulation was assessed using lymphoscintigraphy by taking dynamic gamma-scintigraphy images of 60s each till 1 h post-injection of the test radiopharmaceuticals. Significant difference in movement of the three radiopharmaceuticals was noted in terms of their lymphatic movement. 99mTc-Phy did not show significant travel through the lymphatics and the liver was faintly visualized in control as well as test intervention groups. In case of 99mTc-SC, significant changes in movement of the radiotracer after topical application of Nif/Lid in the test intervention groups were clearly noted in comparison to control (P < 0.05). Multiple numbers of lymph nodes (LNs) could be clearly visualized in control (5 ± 1 LNs) and test intervention groups (3 ± 1 LNs). Liver uptake was more prominent in control animals and it reduced significantly in test intervention groups. On the other hand, 99mTc-HSA showed lesser number of lymph nodes and higher accumulation in liver as compared to 99mTc-SC, suggesting very fast movement of this radiopharmaceutical. Results indicates that 99mTc-SC could be used as a suitable agent to mimic lymphatic transit behavior of HMw toxin components of snake venom and could therefore be used as a model in studying the effect of any test pharmacological intervention in modulating lymphatic transit rate. Additional advantage could be a significant reduction in the need for sacrificing large number of animals, particularly during initial screening phase of drug development cycle.

Hot or not? Investigating radiation safety and policy updating for the appropriate storage of radioactive specimens at Mount Sinai Hospital.

PURPOSE: The current hospital policy for this study is stringent regarding the storage of radioactive sentinel lymph node (SLN) specimens, which requires the storage time of 24 hours before being handled by Pathology. Additional labeling along with separate containment of these specimens can be forgone if negligible radiation levels are found. The objective of this study was to determine whether the storage time needed for resected radioactive breast and primary site specimens to decay to twice the background radiation levels is less than 24 hours. METHODS: The investigators retrieved breast and primary site SLN specimens from the Pathology department on the same day of the biopsy. A dose calibrator was used to measure the dose, specimen, and concurrent background radioactivity in Megabecquerels (MBq). Radioactive decay calculations were used to further investigate when specimen activities reached twice the background levels. A retrospective analysis was performed using a one-sample t-test to determine if the time to reach double the background activity was significantly different from 24 hours. This study pertained to workflow optimization; thus, general procedure consent forms were sufficient. Both patient confidentiality and privacy were protected. The investigators followed the necessary radiation safety measures. RESULTS: The mean time for specimens to reach twice the background level of radioactivity was 3.99 hours, significantly less than current storage time of 24 hours (p < 0.001). The mean time point for the SLNs to reach 1/16th of the original activity was 7.78 hours (p < 0.001). The average node activity was 0.14 MBq. CONCLUSION: The average sentinel node activity was less than 1 exemption quantity and the time to reach less than twice the background levels was significantly less than 24 hours, meaning that radioactive labels are not needed, and the 24-hour overnight specimen storage can be mitigated.

Pneumatic compression therapy using the EQ Press accelerates lymphatic flow in healthy equine forelimbs as determined by lymphoscintigraphy.

OBJECTIVE: Limb lymphedema in horses can be debilitating and painful. Pneumatic compression therapy has shown significant benefits for people suffering from lymphedema. The objective of this study was to determine the effect of a novel, equine-specific pneumatic compression device on the lymphatic flow of healthy horse forelimbs as determined by Tc-99m sulfur colloid lymphoscintigraphy. ANIMALS: 6 healthy Thoroughbreds. PROCEDURES: In a randomized crossover design, horses underwent bilateral forelimb lymphoscintigraphy following subcutaneous injection of Tc-99m sulfur colloid at the coronary band as untreated control or with pneumatic compression therapy using the EQ Press. Lateral, static images were obtained of the distal limb (time 0 to 60 minutes) and proximal limb (time 30 to 60 minutes) using a standard gamma camera. Lymphatic flow was determined by assigning a score to the time point at which Tc-99m sulfur colloid was first visualized at the level of the accessory carpal bone (1 to 7) in the distal limb and the cubital lymph node (1 to 4) in the proximal limb. RESULTS: EQ Press treatment led to a significantly faster lymphatic flow of Tc-99m sulfur colloid to the predetermined anatomic locations of the accessory carpal bone (P = .002) in the distal limb and the cubital lymph node (P = .001) in the proximal limb. CLINICAL RELEVANCE: Pneumatic compression therapy as provided by an equine-specific device encouraged lymphatic flow in healthy, nonedematous equine forelimbs. These data support further study of the EQ Press for pneumatic compression therapy in horses clinically affected by lymphedema and lymphatic drainage disorders.

Evaluation of Preoperative and Intraoperative Mobile Gamma Camera Imaging in Sentinel Lymph Node Biopsy for Melanoma Independent of Preoperative Lymphoscintigraphy.

INTRODUCTION: Sentinel lymph node biopsy (SLNB) is a standard practice for staging cutaneous melanoma. High false-negative rates have an increased interest in adjunctive techniques for localizing SLNs. Mobile gamma cameras (MGCs) represent potential tools to enhance SLNB performance. METHODS: An institutional review board approval was obtained for this study (ClinicalTrials.gov ID NCT01531608). After obtaining informed consent, 20 eligible melanoma patients underwent 99mTc sulfur colloid injection and standard lymphoscintigraphy with a fixed gamma camera (FGC). A survey using a 20 cm square MGC, performed immediately preoperatively by the study surgeon, was used to establish an operative plan while blinded to the FGC results. Subsequently, SLNB was performed using a gamma probe and a novel 6 cm diameter handheld MGC. RESULTS: A total of 24 SLN basins were detected by FGC. Prior to unblinding, all 24 basins were identified with the preoperative MGC and the operative plan established by preoperative MGC imaging was confirmed accurate by review of the FGC images. All individual sentinel lymph nodes were identified during intraoperative MGC imaging, and in 5/24 (21%) cases, surgeon-reported additional clinically useful information was obtained from the MGC. CONCLUSIONS: Preoperative MGC images provide information consistent with FGC images for planning SLNB and in some cases provide additional information that aided in surgical decision-making.

NANOCIS®: Possible errors in the summary of product characteristics quality control method and a suggested alternative method.

BACKGROUND: Determination of the radiochemical purity of [99mTc]NANOCIS® was performed using the procedure described in the Summary of Product Characteristics (SPC). In contrast to the clinical findings of thyroid gland accumulation indicating free [99mTc] pertechnetate, the QC results showed no free [99mTc]pertechnetate. This discrepancy prompted us to further investigate the described QC procedure. The aim of our study is to develop a correct QC procedure for [99mTc]NANOCIS®. METHOD AND MATERIALS: After 99mTc-labelling performed in accordance with the SPC, QC was performed on two stationary phases (Whatman No. 1 and ITLC-SA) with both wet and dry application spots. RESULTS: All QC samples prepared using the method described in the SPC (Whatman No. 1 with dry application spot) indicated an acceptable labelling with a radiochemical purity over 99 %. The QC methods performed using non-SPC described methods (Whatman No. 1 with wet application spot, ITLC-SA with wet and dry application spot), show more impurities, resulting in radiochemical purity ranging between 68 % and 99 %. All results from the three QC procedures not outlined in the SPC resulted in comparable results. When comparing the QC results with imaging of the thyroid gland, if the correct TLC method is used, a clear connection was observed between low radiochemical purity, as a result of free [99mTc]pertechnetate present in the prepared radiopharmaceutical, and visualisation of the thyroid gland, due to thyroid uptake of the free [99mTc]pertechnetate. CONCLUSION: Drying the application spot on Whatman No. 1 paper indicates erroneous high labelling. To obtain a correct QC result, either an analytical method using Whatman No. 1 papers without drying of the application spot or a method using instant thin layer chromatography with a silica acid coating (ITLC-SA) should be used.

99mTc-Sulfur Colloid SPECT/CT in Diagnosis of Splenogonadal Fusion.

A congenital abnormal connection between an accessory spleen and a gonad is called splenogonadal fusion. The parent of a 3-y-old boy brought him to King Saud Medical City because he had left scrotal swelling that had begun 1 y previously. 99mTc-sulfur colloid (SC) imaging has superior sensitivity and specificity in targeting the liver, spleen, and bone marrow, in that these are the only organs that 99mTc-SC can visualize. Furthermore, if these tissues appear anywhere other than their usual locations, such as in the case of an accessory spleen, 99mTc-SC imaging can identify them even without biopsy or-in the case of splenogonadal fusion-orchiectomy. In the current case, the patient underwent laparoscopy, the masses were removed, and orchiectomy was avoided. Histopathologic examination confirmed normal splenic tissue, matching the imaging results.

How much time is enough? Sentinel lymph node mapping time depends on the radiotracer agent.

BACKGROUND: In 2014, technetium-99m tilmanocept (TcTM) replaced technetium-99m sulfur colloid (TcSC) as the standard lymphoscintigraphy (LS) mapping agent in melanoma patients undergoing sentinel lymph node biopsy (SLNB). The aim of this study was to examine differences in mapping time, intra-operative identification of sentinel lymph node (SLN), and false negative rate (FNR) between patients who underwent SLNB with TcTM compared to TcSC. METHODS: Patients who underwent SLNB between 2010 and 2018 were retrospectively identified. Patient demographic, tumor, and imaging data was stratified by receipt of TcSC (n = 258) or TcTM (n = 133). Student's t test and χ2 test were used to compare characteristics and outcomes. RESULTS: Both cohorts were similar in demographic, primary tumor characteristics, and total number of SLN identified (TcTM 3.56 vs. TcSC 3.28, p = 0.244). TcTM was associated with significantly shorter LS mapping times (51.8 vs. 195.1 min, p < 0.01). There was no significant difference in the number of patients with positive SLN (TcTM 11.3 vs. TcSC 17.4%, p = 0.109) and the FNR was similar between both groups (TcTM 25% vs. TcSC 22%). CONCLUSION: TcTM was associated with significantly shorter LS mapping time while identifying similar numbers of SLN. Our results support further study to ensure similar FNR and oncologic outcomes between agents.

Optimal timing of imaging in gastric emptying scintigraphy for the detection of delayed emptying.

OBJECTIVE: The purpose of this study was to evaluate a standard 4-h imaging protocol for gastric emptying scintigraphy (GES) in detecting delayed gastric emptying (GE). SUBJECTS AND METHODS: Gamma camera imaging was performed in the anterior and posterior views at 0, 0.5, 1, 1.5, 2, 2.5 and 4-h as per established Miami method (MIA) and National Standard Protocol (NSP), in accordance with the consensus guidelines of the ANMS/SNM [SNMMI] Societies. Patients (N=1002) received a standardized solid meal radiolabeled with 1mCi of technetium-99 (99mTc) sulfur colloid. Quantitative analysis was performed using geometric mean calculation of decay-corrected counts at each imaging time point, expressed as percent emptying or retention. RESULTS: In our patient cohort, 21% had delayed GE at 4h, whereas 79% had normal emptying with less than 10% retention at 4h. There was a 25% increase in delayed GE studies at 4h versus 2h. From those patients who had delayed GE at 2h, 30% normalized at 4h, while 10% of patients with normal GE at 2h became delayed at 4h thus indicating that more studies changed from abnormal to normal than from normal to abnormal at 4h. Greater than 90% GE was found in 9% of patients at 2 h and 25% of patients at 2.5h and this persisted at 4h. The study at 2h as compared with 4h, had 56% sensitivity, 95% specificity, 70% PPV and 91% NPV. CONCLUSION: The 4-h imaging was very important in detecting cases that were delayed at 2h but normalized at 4h, and also cases with normal GE at 2h that became abnormal at 4h. These findings support the ANMS/SNM [SNMMI] recommendations. Gastric emptying value ≥90% at 2.5h can be used as threshold in predicting normal GE and the study could be terminated without additional imaging.

Chylopericardium Due to Residual Lymphangiomyoma Detected on 99mTc-Sulfur Colloid Lymphoscintigraphy.

ABSTRACT: Lymphangiomyomas are relatively rare, benign neoplasms. Many patients present with symptoms including effusions, and some cases are incidentally detected. Surgical excision is the treatment of choice, but because of its location, complete surgical resection of a lymphangioma can be technically difficult, and recurrent cases can present with symptoms including effusions. 99mTc-sulfur colloid scan can be used to confirm the leak and nature of the effusion fluid. Here, we present an 8-year-old girl with recurrent pleural and pericardial effusions after lymphocele excision and total pericardiectomy. 99mTc-sulfur colloid lymphoscintigraphy was done to rule out secondary chylopericardium.

Bilateral Peritoneoscrotal Communication-"Chicken Leg" Appearance Demonstrated on 99mTc-Sulfur Colloid Scintigraphy.

Continuous ambulatory peritoneal dialysis is a convenient alternate form of treatment in patients receiving hemodialysis for renal failure. Sometimes during the procedure, patients may develop scrotal swelling because of patent processus vaginalis. The diagnostic utility of the peritoneal scintigraphy, an infrequently performed nuclear medicine scan to identify peritoneoscrotal communication, has been reported by many authors. Most of the previous case reports in the literature demonstrated unilateral peritoneoscrotal communication. We present an interesting Tc-sulfur colloid peritoneal scintigraphic image finding of bilateral peritoneoscrotal communication in a 67-year-old man who developed scrotal swelling while undergoing continuous ambulatory peritoneal dialysis.

Sentinel lymph node detection differs when comparing lymphoscintigraphy to lymphography using water soluble iodinated contrast medium and digital radiography in dogs.

Sentinel lymph node (SLN) mapping by various means has become standard of care in certain types of human cancers and is receiving more attention in veterinary oncology. Current SLN mapping techniques can be costly and often require advanced imaging equipment. The objective of this prospective, method comparison study was to compare an SLN mapping protocol of lymphoscintigraphy to lymphography using water soluble iodinated contrast medium (WIC) and digital radiography for identification of an SLN. Lymphoscintigraphy and lymphography were performed on eight healthy purpose-bred dogs using technetium-99m sulfur colloid and WIC injected into the subcutaneous tissues in a four-quadrant technique around a predefined area of skin on the brachium. Images were obtained using a gamma camera and digital radiography at different time points post-injection. Image sequences were evaluated by one of two American College of Veterinary Radiology board-certified veterinary radiologists. Data obtained were compared between methods using descriptive statistics. An SLN was identified in all dogs with lymphoscintigraphy and seven of eight dogs with lymphography. Agreement between results of the lymphoscintigraphy and lymphography studies was a complete match in three dogs, a partial match in four dogs, and no match in one dog. The SLN detected differed based on the imaging modality used.

99mTc-sodium phytate is a valid alternative to the gold-standard 99mTc-sulfur colloid in the measurement of gastric emptying among healthy multi-ethnic Asian population: results of a randomized cross-over trial.

BACKGROUND: It is unclear if the 99mTc-sodium phytate (99mTc-SP) is as reliable as the gold-standard 99mTc-sulfur colloid (99mTc-SC) for gastric emptying scintigraphy (GES). This study is aimed to compare the emptying rates of both radiotracers in a prospective, randomized cross-over trial and to determine the normative data of a healthy multi-ethnic Asian population. METHODS: Out of the 44 healthy individuals screened, 31 (14 females; mean age: 28.4 ± 7.0 years) were enrolled and underwent GES using the standardized egg-white meal. All participants were randomly assigned to either 99mTc-SP or 99mTc-SC on the first GES session before crossed over to the other formulation after 2 weeks. RESULTS: Both kits achieved the radiochemical purities of > 95%. The median rate (95th upper normative limit) of gastric emptying, reported as total gastric meal retention between 99mTc-SP and 99mTc-SC, was found to be comparable at all measured time points: 0.5 h [85.0% (96.6%) vs. 82.0% (94.0%)], 1 h [70.0% (86.4%) vs. 65.0% (86.6%)], 2 h [31.0% (55.8%) vs. 25.0% (64.4%)], 3 h [7.0% (26.3%) vs. 5.0% (29.9%)], and 4 h [3.0% (10.3%) vs. 2.0% (9.9%)]; P > 0.05. In addition, both radiotracers correlated well (Kendall's Tau (τ) coefficient = 0.498, P < 0.001) and presented with a good agreement at the 4th-hour time frame based on the Bland-Altman plot analysis. CONCLUSIONS: 99mTc-SP is a valid radiotracer alternative to 99mTc-SC for routine GES examination. The normative values for both radiotracers have also been determined for the healthy multi-ethnic Asian population. TRIAL REGISTRATION: This trial was registered retrospectively in the Thai Clinical Trials Registry on May 23rd, 2020 (Identifier: TCTR20200526004; http://www.clinicaltrials.in.th/index.php?tp=regtrials&menu=trialsearch&smenu=fulltext&task=search&task2=view1&id=6296 ).

The effect of surgery on lymphoscintigraphy drainage patterns from the canine brachium in a simulated tumor model.

OBJECTIVE: To determine the effect of surgery on lymphoscintigraphy drainage patterns from the canine brachium. STUDY DESIGN: Experimental study. ANIMALS: Eight healthy research beagles. METHODS: A predefined area of skin measuring 2 × 1.5 cm in dimension was designated on either the right or left brachium. Preoperative lymphoscintigraphy was performed with technetium sulfur colloid injected into the subcutaneous tissues around the predefined anatomic location in a four-quadrant technique. Dogs underwent surgery for excision of the predefined area of skin, subcutis, and fascia of the lateral head of the triceps muscle with 1-cm margins. Eighteen days after surgery, lymphoscintigraphy was again performed with technetium sulfur colloid injected into the subcutaneous tissues around the surgical scar in a four-quadrant technique. RESULTS: Sentinel lymph nodes were identified in eight of eight dogs preoperatively and in eight of eight dogs postoperatively. Agreement between the results of the preoperative and postoperative lymphoscintigraphy studies was identified as complete in four of eight dogs and partial in four of eight dogs. Sentinel lymph node identification occurred immediately in three of eight dogs preoperatively and in eight of eight dogs postoperatively. CONCLUSION: Sentinel lymph node identification occurred faster postoperatively. Agreement or partial agreement between the results of the preoperative and postoperative lymphoscintigraphy studies was observed in eight of eight dogs. CLINICAL SIGNIFICANCE: Surgery appears to have an effect on lymphoscintigraphy drainage patterns. Additional studies are required to compare preoperative and postoperative sentinel lymph node mapping patterns in tumor-bearing dogs. However, this study provides preliminary information regarding the effect of surgery on sentinel lymph node identification.

Metastatic and non-metastatic sentinel inguinofemoral lymph nodes in vulvar cancer show an increased lymphangiogenesis.

INTRODUCTION AND OBJECTIVE: Lymph node involvement is a strong predictor of disease recurrence and patient survival in vulvar cancer. The aim of the study was to evaluate the feasibility of sentinel lymph node (SLN) screening, the incidence of skip metastases, and lymph node lymphangiogenesis. MATERIAL AND METHODS: Fifty-five patients participated in this prospective, single centre study. A double SLN screening method was employed using radiocolloid (technetium-99 sulfur colloid) and 1.0% Isosulfan Blue. Immunohistochemistry, using a mouse monoclonal antibody against D2-40, was used to evaluate lymphatic vessel density (LVD). All calculations were performed using STATISTICA software v. 10 (StatSoft, USA, 2011); p < 0.05 was considered significant. RESULTS: Using both methods of SLN detection, 100% accuracy was achieved, and skip metastases were diagnosed in only one woman (1.82%). Peri-tumour median LVD was significantly increased compared with matched intra-tumour samples (p < 0.001), while median LVD was significantly lower in negative, compared with positive SLN, regardless of whether matched non-SLN were negative (p < 0.001) or positive (p = 0.005). Metastatic SLN exhibited significantly higher median LVD compared with matched negative non-SLN (p = 0.015), while no significant difference in median LVD was detected between positive SLN and matched positive non-SLN. However, negative SLN had a significantly higher median LVD compared with matched negative non-SLN (p = 0.012). CONCLUSIONS: SLN detection is a safe and feasible procedure in vulvar cancer. In patients without nodular involvement, SLN, compared with non-SLN, exhibited significantly higher median LVD, which may be an indication of its preparation to host metastases, and thus requires further investigation.

Buffering the Suffering of Breast Lymphoscintigraphy.

Breast lymphoscintigraphy with 99mTc-sulfur colloid is frequently performed before breast-conserving surgery to delineate drainage to a sentinel node. Tracer injection for lymphoscintigraphy can be painful. Our aims were to determine whether administering a solution of buffered lidocaine immediately before lymphoscintigraphy injection could both reduce the patients' pain and increase nuclear medicine technologists' satisfaction with performing the procedure. Methods: A pain scale survey was obtained from patients undergoing breast lymphoscintigraphy with or without buffered lidocaine. Our nuclear medicine technologists were also surveyed for their satisfaction with the procedure, both with and without the addition of buffered lidocaine. Results: The patients' reported pain decreased by 86% with the addition of buffered lidocaine. Technologist satisfaction with performing the procedure increased by 36%. Conclusion: Lidocaine buffered with sodium bicarbonate injected before lymphoscintigraphy significantly reduces pain experienced by the patient and improves nuclear medicine technologist satisfaction in performing the procedure.

Using gastric emptying scintigraphy to evaluate antral contractions and duodenal bolus propagation.

Our aim was to investigate the feasibility of measuring antral contractions and duodenal bolus propagation (DBP) during dynamic antral contraction scintigraphy (DACS) as an assessment of antro-pyloro-duodenal coordination (APDC). Gastric emptying scintigraphy (GES) with DACS was performed with Tc-99m sulfur colloid (SC) using increasing doses of 74 MBq (2 mCi) for 10 subjects, 185 MBq (5 mCi) for 11, and 370 MBq (10 mCi) for 11. DACS was performed for 10 min after static images at 0, 30, 60, 120, 180, and 240 min in anterior and right anterior oblique (RAO) projections. Best projection and lowest dose of Tc-99m SC were assessed visually. DBP were quantified utilizing duodenal activity peaks from a region of interest in the first portion of the duodenum. DBP was better visualized in the RAO projection than anterior projection and using 185 MBq (5 mCi) and 370 MBq (10 mCi) compared with 74 MBq (2 mCi). DBP showed infrequent and irregular bolus transfers from the antrum to the duodenum. Antral activity peaks at 60 min averaged 2.91 ± 0.66 per minute and duodenum bolus peaks 0.36 ± 0.18 per minute (ratio 0.36/2.91 = 0.12). DBP activity peaks can be measured during GES with DACS but requires a 185-MBq (5 mCi) dose of Tc-99m SC radiolabeled test meal for adequate DBP signal detection and is better imaged in RAO than anterior projection. DBPs over the first 60 min postmeal ingestion are infrequent with only 12% of the antral contractions propagating into the duodenum. This methodology appears promising to assess APDC.NEW & NOTEWORTHY This study shows that duodenal bolus propagations after meal ingestion can be measured during gastric emptying scintigraphy using dynamic scintigraphy. Duodenal bolus propagation over the first 60 min postmeal ingestion are infrequent with only 12% of the antral contractions propagating into the duodenum. This methodology appears promising to assess antropyloroduodenal coordination in patients with unexplained symptoms of upper gastrointestinal dysmotility.

FDG PET/CT of Infection: Should It Replace Labeled Leukocyte Scintigraphy of Inpatients?

OBJECTIVE. The purpose of this study was to compare the sensitivity, specificity, and helpfulness to referring clinicians of labeled leukocyte scintigraphy versus FDG PET/CT in inpatients with suspected infection. MATERIALS AND METHODS. In this retrospective study, labeled leukocyte scintigraphy and FDG PET/CT examinations performed from 2009 to 2017 for suspected infection in inpatients were identified. Sensitivity, specificity, and helpfulness of PET/CT versus labeled leukocyte scintigraphy were calculated by means of a mixed generalized linear model. Number of yearly tests and radiopharmaceutical costs were also assessed. RESULTS. Fifty-seven patients (30 men, 27 women; median age, 65 years; range, 21-91 years) underwent whole-body labeled leukocyte scintigraphy. Forty-two patients (30 male patients, 12 female patients; median age, 62.5 years; range, 12-91 years) underwent PET/CT for suspected infection. Labeled leukocyte scintigraphy was 66.7% sensitive, whereas the sensitivity of PET/CT was 89.7% (p = 0.0485). The higher sensitivity of PET/CT did not come at a cost to specificity, which was 73.3% as opposed to 76.9% for labeled leukocyte scintigraphy (p = 0.8050). The odds of a positive study being helpful increased 4.6-fold for PET/CT versus labeled leukocyte scintigraphy (p = 0.0412). From 2009 to 2011, 33 labeled leukocyte scintigraphic examinations were performed versus two PET/CT examinations; and from 2012 to 2014, 16 labeled leukocyte scintigraphic versus 22 PET/CT examinations; from 2015 to 2017, eight labeled leukocyte scintigraphic versus 18 PET/CT examinations. The cost of labeled leukocytes increased between 2009 and 2017, but that of FDG decreased. By 2017, a labeled leukocyte radiopharmaceutical dose was approximately 10 times the cost of an FDG dose. CONCLUSION. PET/CT was more sensitive than and as specific as labeled leukocyte scintigraphy for identifying a source of infection in inpatients, and it was more helpful to referring clinicians. Use of PET/CT increased over time and was associated with substantial savings in radiopharmaceutical cost.