Importancia de los radiotrazadores MDP, DTPA, MIBI marcados con Tc99m en diagnóstico de medicina nuclear / Importance of Tc99m-labeled MDP, DTPA, MIBI radiotracers in nuclear medicine diagnostics / Importância dos radiotraçadores MDP, DTPA e MIBI marcados com Tc99m em diagnósticos de medicina nuclear

La medicina nuclear utiliza radiofármacos, conocidos como radiotrazadores, para evaluar la función y el metabolismo de órganos y sistemas del cuerpo. Objetivo. Examinar la relevancia de los radiotrazadores MDP, DTPA y MIBI, marcados con tecnecio-99m (Tc99m), en el diagnóstico en medicina nuclear. Metodología. Se siguió el método PRISMA para identificar estudios publicados entre 2010 y 2022. Las bases de datos consultadas incluyeron Dialnet, Elsevier, Research, Redalyc, PubMed, Google Académico y Scielo. Se utilizaron descriptores específicos como "radiotrazadores Tc99m", "MDP", "DTPA", "MIBI", y "medicina nuclear", centrando la búsqueda en diagnóstico y excluyendo propósitos terapéuticos. Resultados. De 14 estudios analizados, se observó una predominancia en investigaciones sobre radiotrazadores MDP y MIBI marcados con Tc99m, enfocándose en diagnósticos relacionados con lesiones paratiroideas, hiperparatiroidismo, enfermedades esqueléticas, enfermedad arterial coronaria y perfusión miocárdica. Conclusiones. Los radiotrazadores MDP, DTPA y MIBI marcados con Tc99m demuestran eficacia en diversas aplicaciones diagnósticas, incluyendo la localización de adenomas paratiroideos y la detección de condiciones como el mieloma múltiple. A pesar de sus beneficios, es crucial continuar investigando y desarrollando nuevos radiofármacos para expandir su utilidad clínica y mejorar aún más la atención médica en el campo de la medicina nuclear.

Nuclear medicine uses radiopharmaceuticals, known as radiotracers, to assess the function and metabolism of organs and body systems. Objective. To examine the relevance of technetium-99m (Tc99m)-labeled MDP, DTPA, and MIBI radiotracers in nuclear medicine diagnostics. Methodology. The PRISMA method was followed to identify studies published between 2010 and 2022. The databases consulted included Dialnet, Elsevier, Research, Redalyc, PubMed, Google Scholar and Scielo. Specific descriptors such as "Tc99m radiotracers", "MDP", "DTPA", "MIBI", and "nuclear medicine" were used, focusing the search on diagnosis and excluding therapeutic purposes. Results. Of 14 studies analyzed, there was a predominance of research on Tc99m-labeled MDP and MIBI radiotracers, focusing on diagnoses related to parathyroid lesions, hyperparathyroidism, skeletal diseases, coronary artery disease, and myocardial perfusion. Conclusions. Tc99m-labeled MDP, DTPA, and MIBI radiotracers demonstrate efficacy in a variety of diagnostic applications, including localization of parathyroid adenomas and detection of conditions such as multiple myeloma. Despite their benefits, it is crucial to continue researching and developing new radiopharmaceuticals to expand their clinical utility and further improve medical care in the field of nuclear medicine.

A medicina nuclear utiliza radiofármacos, conhecidos como radiotraçadores, para avaliar a função e o metabolismo de órgãos e sistemas corporais. Objetivo. Examinar a importância dos radiotraçadores MDP, DTPA e MIBI, marcados com tecnécio-99m (Tc99m), em diagnósticos de medicina nuclear. Metodologia. O método PRISMA foi usado para identificar estudos publicados entre 2010 e 2022. Os bancos de dados consultados incluíram Dialnet, Elsevier, Research, Redalyc, PubMed, Google Scholar e Scielo. Foram utilizados descritores específicos como "radiotraçadores Tc99m", "MDP", "DTPA", "MIBI" e "medicina nuclear", concentrando a busca em fins diagnósticos e excluindo fins terapêuticos. Resultados. Dos 14 estudos analisados, houve predomínio de pesquisas com os radiotraçadores MDP e MIBI marcados com Tc99m, com foco em diagnósticos relacionados a lesões da paratireoide, hiperparatireoidismo, doenças esqueléticas, doença arterial coronariana e perfusão miocárdica. Conclusões. Os radiotraçadores MDP, DTPA e MIBI marcados com Tc99m demonstram eficácia em uma variedade de aplicações diagnósticas, incluindo a localização de adenomas de paratireoide e a detecção de doenças como o mieloma múltiplo. Apesar de seus benefícios, é fundamental continuar a pesquisa e o desenvolvimento de novos radiofármacos para expandir sua utilidade clínica e melhorar ainda mais o atendimento médico no campo da medicina nuclear.

Comparison of GFR measurement with a two-blood sample technique using [99mTc]Tc-DTPA vs. creatinine-based equations in potential kidney donors / Comparação da medição da TFG com uma técnica com duas amostras de sangue usando [99mTc]Tc-DTPA vs. equações baseadas em creatinina em potenciais doadores de rim

ABSTRACT Introduction: Accurate determination of glomerular filtration rate (GFR) is crucial for selection of kidney donors. Nuclear medicine methods are considered accurate in measuring GFR but are not always easily available. The four-variable Modification of Diet in Renal Disease (MDRD4), Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI), and Full Age Spectrum (FAS) formulas are common equations for estimating GFR and are recommended for initial assessment of kidney donors. The aim of this study was to evaluate the performance of these GFR estimation equations compared with technetium-99m diethylenetriaminepentaacetic acid ([99mTc]Tc-DTPA) clearance. Methods: We compared GFR estimation by [99mTc]Tc-DTPA clearance using a two-blood sample method with estimation by MDRD4, CKD-EPI, and FAS creatinine-based equations in a population of healthy potential kidney donors. Results: A total of 195 potential kidney donors (68.2% female; mean age 49 years, range 21-75 years) were included in this study. Mean [99mTc]Tc-DTPA measured GFR (mGFR) was 101.5 ± 19.1 mL/min/1.73 m2. All three equations underestimated the GFR value measured by [99mTc]Tc-DTPA (MDRD4: -11.5 ± 18.8 mL/min/1.73 m2; CKD-EPI: -5.0 ± 17.4 mL/min/1.73 m2; FAS: -8.3 ± 17.4 mL/min/1.73 m2). Accuracy within 30% and 10% of the measured GFR value was highest for CKD-EPI. Conclusion: The CKD-EPI equation showed better performance in estimating GFR in healthy potential kidney donors, proving to be a more accurate tool in the initial assessment of kidney donors. However, creatinine-based equations tended to underestimate kidney function. Therefore, GFR should be confirmed by another method in potential kidney donors.

RESUMO Introdução: Determinar precisamente a taxa de filtração glomerular (TFG) é crucial para seleção de doadores de rim. Métodos de medicina nuclear são considerados precisos na medição da TFG, mas nem sempre estão facilmente disponíveis. As fórmulas Modification of Diet in Renal Disease de 4 variáveis (MDRD4), Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI), e Full Age Spectrum (FAS) são equações comuns para estimar a TFG, sendo recomendadas para avaliação inicial dos doadores. Este estudo visou avaliar o desempenho destas equações de estimativa da TFG em comparação com o clearance do tecnécio-99m-ácido dietilenotriaminopentacético ([99mTc]Tc-DTPA). Métodos: Comparamos a TFG por clearance de [99mTc]Tc-DTPA usando um método com duas amostras de sangue com estimativa da TFG pelas equações MDRD4, CKD-EPI e FAS baseadas em creatinina em uma população de potenciais doadores saudáveis. Resultados: Incluiu-se 195 potenciais doadores de rim (68,2% mulheres; idade média de 49 anos, intervalo 21-75 anos). A TFG média medida por [99mTc]Tc-DTPA foi 101,5 ± 19,1 mL/min/1,73m2. As três equações subestimaram o valor da TFG medida por [99mTc]Tc-DTPA (MDRD4: -11,5 ± 18,8 mL/min/1,73 m2; CKD-EPI: -5,0 ± 17,4 mL/min/1,73 m2; FAS: -8,3 ± 17,4 mL/min/1,73 m2). A precisão dentro de 30% e 10% do valor da TFG medida foi maior para CKD-EPI. Conclusão: A equação CKD-EPI mostrou melhor desempenho na estimativa da TFG em potenciais doadores de rim saudáveis, revelando-se uma ferramenta mais precisa na avaliação inicial dos doadores. Entretanto, equações baseadas em creatinina tendem a subestimar a função renal. Portanto, a TFG deve ser confirmada por outro método em potenciais doadores.

Pancreatitis aguda en el escenario de hipercalcemia por hiperparatiroidismo primario / Acute pancreatitis in the setting of hypercalcemia due to primary hyperparathyroidism

Introducción: describir el caso de un paciente con pancreatitis aguda secundaria a hipercalcemia por hiperparatiroidismo prImario. Esta es una causa poco frecuente de pancreatitis, asociada a morbimortalidad significativa en caso de no ser diagnosticada oportunamente Caso clínico: un hombre de 44 años, con antecedente de pancreatitis de presunto origen biliar que había requerido previamente colecistectomía, consultó por dolor abdominal y náuseas. Los estudios complementarios fueron compatibles con un nuevo episodio de pancreatitis aguda. Presentaba hipercalcemia y hormona paratiroidea (PTH) elevada, configurando hiperparatiroidismo primario. La gammagrafía informó hallazgos compatibles con adenoma paratiroideo. Se inició tratamiento con reanimación hídrica y analgesia con adecuada disminución de calcio sérico y resolución de dolor abdominal. Después de la paratiroidectomía se logró normalizar los niveles de calcio y PTH. Discusión: la pancreatitis aguda es una condición potencialmente fatal, por lo que la sospecha de causas poco frecuentes como la hipercalcemia debe tenerse en cuenta. El tratamiento de la hipercalcemia por adenoma paratiroideo se basa en reanimación hídrica adecuada y manejo quirúrgico del adenoma, con el fin de evitar recurrencia de pancreatitis y mortalidad. (AU)

Introduction: we describe the case of a patient with acute pancreatitis secondary to hypercalcemia due to primary hyperparathyroidism. This is a rare cause of pancreatitis associated with significant morbidity and mortality if not diagnosed in time. Clinical case: a 44-year-old man with a history of pancreatitis of presumed biliary origin, which had previously required cholecystectomy, consulted for abdominal pain and nausea. The laboratory findings were compatible with a new episode of acute pancreatitis. He presented hypercalcemia and an elevated parathyroid hormone (PTH), configuring primary hyperparathyroidism. Scintigraphy was performed, yielding findings compatible with parathyroid adenoma. Treatment with fluid resuscitation and analgesia was started, resulting in an adequate decrease in serum calcium and resolution of abdominal pain. After parathyroidectomy, calcium and PTH levels were normalized. Discussion: acute pancreatitis is a potentially fatal condition; therefore the suspicion of rare causes, such as hypercalcemia, should be considered. The treatment of hypercalcemia due to parathyroid adenoma is based on adequate fluid resuscitation and surgical management of the adenoma, to avoid recurrence of pancreatitis and death. (AU)

Morphometric examination of the trachea and bronchi in follow-up computed tomography scans of COVID-19 patients / Examen morfométrico de la tráquea y los bronquios en tomografías computarizadas de seguimiento de pacientes con COVID-19

SUMMARY: The purpose of this study is to evaluate changes in the trachea and bronchi using 3-dimensional reconstruction images obtained from the initial and follow-up computed tomography (CT) scans of COVID-19 patients. A hundred COVID-19 patients over the age of 18 were included in our study. CT images were transferred to Mimics software, and a 3-dimensional reconstruction of the trachea and bronchi was performed. The initial and follow-up CT images of COVID-19 patients were graded as none (grade 0), mild (grade 1), moderate (grade 2), and severe (grade 3) according to the total lung severity score. The patients were divided into progression and regression groups according to the grade increase/decrease between the initial and follow-up CTs. Moreover, the patients were divided into groups as 0-2 weeks, 2-4 weeks, 4-12 weeks, and over 12 weeks according to the duration between the initial and follow-up CTs. The mean cross-sectional area, circumference, and diameter measurements of the right upper lobar bronchus, intermediate bronchus, middle lobar bronchus, and left lower lobar bronchus decreased in the follow-up CTs of the progression group. This decrease was not found to be statistically significant. In the follow-up CTs of the regression group, the left upper lobar bronchus and left lower lobar bronchus measurements increased but not statistically significant. Upon comparing the onset of the disease and the follow-up period, statistically significant changes did not occur in the trachea, main bronchus, and lobar bronchus of COVID-19 patients.

El propósito de este estudio fue evaluar los cambios en la tráquea y los bronquios utilizando imágenes de reconstrucción tridimensionales obtenidas de las tomografías computarizadas (TC) iniciales y de seguimiento de pacientes con COVID-19. En nuestro estudio se incluyeron 100 pacientes con COVID-19 mayores de 18 años. Las imágenes de TC se transfirieron al software Mimics y se realizó una reconstrucción tridimensional de la tráquea y los bronquios. Las imágenes de TC iniciales y de seguimiento de los pacientes con COVID-19 se calificaron como ninguna (grado 0), leve (grado 1), moderada (grado 2) y grave (grado 3) según la puntuación total de gravedad pulmonar. Los pacientes se dividieron en grupos de progresión y regresión según el aumento/disminución del grado entre las TC iniciales y de seguimiento. Además, los pacientes se dividieron en grupos de 0 a 2 semanas, de 2 a 4 semanas, de 4 a 12 semanas y de más de 12 semanas según la duración entre la TC inicial y la de seguimiento. Las mediciones medias del área transversal, la circunferencia y el diámetro del bronquio lobar superior derecho, el bronquio intermedio, el bronquio lobar medio y el bronquio lobar inferior izquierdo disminuyeron en las TC de seguimiento del grupo de progresión. No se encontró que esta disminución fuera estadísticamente significativa. En las TC de seguimiento del grupo de regresión, las mediciones del bronquio lobar superior izquierdo y del bronquio lobar inferior izquierdo aumentaron pero no fueron estadísticamente significativas. Al comparar el inicio de la enfermedad y el período de seguimiento, no ocurrieron cambios estadísticamente significativos en la tráquea, el bronquio principal y el bronquio lobar de los pacientes con COVID-19.

Arteritis de Takayasu como hallazgo incidental en un paciente con enfermedad celiaca: la importancia de la tomografía computarizada por emisión de positrones / Takayasu's arteritis as an incidental finding in a patient with celiac disease: the importance of positron emission computed tomography

Resumen Introducción: La arteritis de Takayasu es una vasculitis de grandes vasos que afecta a las arterias elásticas de gran calibre, fundamentalmente la aorta y sus ramas principales. Ocurre frecuentemente en mujeres entre los 20-30 años, por lo que es muy infrecuente en la edad pediátrica. Caso clínico: Se presenta el caso de una paciente de 15 años en seguimiento desde los 9 años por enfermedad celiaca. A los 13 años se detectó anemia de trastornos crónicos, elevación de proteína C reactiva y velocidad de sedimentación globular. La paciente permaneció en todo momento asintomática. Tras descartar otros procesos, se solicitó tomografía computarizada por emisión de positrones (PET-TC), donde se detectaron lesiones compatibles con vasculitis de grandes vasos. La valoración por Cardiología evidenció un aneurisma en coronaria derecha. Se realizó angio-TC, que sugirió arteritis de Takayasu tipo III. Conclusiones: Es frecuente un retraso en el diagnóstico de la arteritis de Takayasu en los pacientes pediátricos. En este caso se encontraron lesiones de la fase II sin la presencia de síntomas correspondientes a la fase I. El PET-TC permitió el diagnóstico de vasculitis, clave para el diagnóstico de la paciente.

Abstract Background: Takayasu arteritis is a large-vessel vasculitis which affects large-caliber elastic arteries, primarily the aorta and its main branches. It mainly affects women between 20-30 years, so it is rare in children. Case report: We describe the case of a 15-year-old female who was followed up since she was 9 years old due to celiac disease. At the age of 13, anaemia of chronic disorders associated to elevated C-reactive protein and erythrocyte sedimentation were detected. The patient remained asymptomatic. After excluding other diseases, we requested a positron emission computed tomography (PET-CT); lesions compatible with large-vessel vasculitis were detected. Cardiology evaluation showed an aneurysm in the right coronary artery. Angio-CT suggested Takayasu type III arteritis. Conclusions: The delay in the diagnosis of Takayasu arteritis in pediatric patients is quite common. In this case, we have found phase II lesions, with no previous phase I symptoms. However, PET-CT allowed the diagnosis of vasculitis, key to the diagnosis of the patient.

Tc-99m scan for pediatric bleeding Meckel diverticulum: a systematic review and meta-analysis

Abstract Objective: Meckel diverticulum (MD) is a common malformation of the digestive tract, often accompanied by serious complications. It is important to find safe and effective diagnostic methods for screening MD. The aim of this study was to evaluate the effectiveness of a technetium-99m (Tc-99m) scan for pediatric bleeding MD. Methods: The authors conducted a systematic review of studies published in PubMed, Embase, and Web of Science before 1 January 2023. Studies based on PICOS were included in this systematic review. The flow chart was made by PRISMA software. The quality of included studies was assessed by RevMan5 software (QUADAS-2: Quality Assessment of Diagnostic Accuracy Studies-2). The sensitivity, specificity, and other measurements of accuracy were pooled using Stata/SE 12.0 software. Results: Sixteen studies with 1115 children were included in this systematic review. A randomized-effects model was used for the meta-analysis because of significant heterogeneity. The combined sensitivity and specificity were 0.80 [Confidence Interval (95% CI, 0.73-0.86) and 0.95 (95% CI, 0.86-0.98)], respectively. The area under the curve (AUC) was 0.88 (95% CI, 0.85-0.90). Publication bias (Begg's test p = 0.053) was observed. Conclusion: Tc-99m scan has high specificity, but moderate sensitivity, which is always influenced by some factors. Hence, the Tc-99m scan has some limitations in the diagnosis of pediatric bleeding MD.

Lamivudine-based two-drug regimens with dolutegravir or protease inhibitor: Virological suppression in spite of previous therapy failure or renal dysfunction

Abstract Background Two-Drug Regimens (2DR) have proven effective in clinical trials but real-world data, especially in resource-limited settings, is limited. Objectives To evaluate viral suppression of lamivudine-based 2DR, with dolutegravir or ritonavir-boosted protease inhibitor (lopinavir/r, atazanavir/r or darunavir/r), among all cases regardless of selection criteria. Patients and methods A retrospective study, conducted in an HIV clinic in the metropolitan area of São Paulo, Brazil. Per-protocol failure was defined as viremia above 200 copies/mL at outcome. Intention-To-Treat-Exposed (ITT-E) failure was considered for those who initiated 2DR but subsequently had either (i) Delay over 30 days in Antiretroviral Treatment (ART) dispensation, (ii) ART changed or (iii) Viremia > 200 copies/mL in the last observation using 2DR. Results Out of 278 patients initiating 2DR, 99.6% had viremia below 200 copies/mL at last observation, 97.8% below 50 copies/mL. Lamivudine resistance, either documented (M184V) or presumed (viremia > 200 copies/mL over a month using 3TC) was present in 11% of cases that showed lower suppression rates (97%), but with no significant hazard ratio to fail per ITT-E (1.24, p= 0.78). Decreased kidney function, present in 18 cases, showed of 4.69 hazard ratio (p= 0.02) per ITT-E for failure (3/18). As per protocol analysis, three failures occurred, none with renal dysfunction. Conclusions The 2DR is feasible, with robust suppression rates, even when 3TC resistance or renal dysfunction is present, and close monitoring of these cases may guarantee long-term suppression.

Clinical application of normalized residual activity as a semiquantitative adjunct in assessing renal emptying in pediatric diuretic scans

Background@#The most recent pediatric diuretic imaging guidelines recommend the use of normalized residual activity (NORA) as a semiquantitative index of renal tracer drainage. It is defined as the ratio of post-void renal counts to 1-2 minute post-injection renal counts, with values less than 1 indicative of good drainage. We present two instances where NORA calculation was adjunctive in the evaluation of obstructive uropathy. @*Case Presentation@#The first patient was a 3-month-old male with left-sided congenital hydronephrosis. On dynamic imaging, the diseased kidney showed adequate perfusion and parenchymal extraction; moderate to severe pelvicalyceal tracer retention exhibited good response to diuretic. The pre-diuretic NORA of 1.62 declined to 0.28 after furosemide challenge, concordant with imaging findings that were negative for obstruction. The second patient was a 7-week-old male, also with congenital hydronephrosis of the left kidney. Dynamic images showed the diseased kidney with diminished perfusion and function, as well as pelvicalyceal tracer retention which became more severe after the diuretic was given. The pre-diuretic NORA was 1.81, which became 1.18 post-diuretic. This inadequate decline supplemented imaging findings pointing to significant obstruction. Other semiquantitative parameters have preceded NORA; however, clearance half-time is not validated as a marker of obstructive uropathy in infants and children, and output efficiency requires specialized software to calculate. Standardization of NORA determination is largely provided for by the guidelines recommending a perirenal background region of interest, as well as minimizing the interval between starting camera acquisition and injecting the tracer. @*Conclusion@#Semiquantitative analysis through NORA calculation gives relevant supporting information in the reporting of renal tracer drainage among pediatric patients. Further studies are needed to ascertain its applicability among adults and its diagnostic value in a larger sample of affected Filipino children.

Application of diuretic renal scintigraphy in the treatment of infants with severe hydronephrosis / 中华核医学与分子影像杂志

Objective:To explore the differences of renal dynamic imaging parameters between operation group and non-operation group in infants with severe hydronephrosis, so as to accumulate theoretical basis for diuretic renal scintigraphy to help the treatment decision making.Methods:A total of 107 infants (age: 3(2, 6) months; 90 males and 17 females) with severe hydronephrosis, who underwent diuretic renal scintigraphy between March 2018 and October 2021 in Shanxi Children′s Hospital were retrospectively reviewed. All patients were diagnosed with ureteropelvic junction obstruction and divided into operation group ( n=87) and no-operation group ( n=20). The differences of differential renal function (DRF), peak time, half-time and drainage curve between the two groups were compared with the independent-sample t test or χ2 test, and the correlation between the renal function of the affected side and the anteroposterior pelvic diameter (APD) was analyzed with Pearson correlation analysis. Results:The operation group included 17 patients with DRF<40%, 60 patients with DRF between 40%-55%, and 10 patients with DRF>55%(supernormal renal function). The 40%-55% was considered as normal DBF, and the rest were abnormal. Infants with abnormal renal function in the operation group ( n=27) were more than those in the non-operation group ( n=3), but there was no statistical difference ( χ2=2.07, P=0.150). The proportion of obstruction curve in the operation group (85.1%, 74/87) was significantly higher than that in the non-operation group (55.0%, 11/20; χ2=7.24, P=0.007). Compared with the non-operation group, the peak time of affected kidney in the operation group was significantly longer ((22.77±7.52) vs (15.26±10.29) min; t=3.78, P<0.001), as well as the peak time of contralateral kidney ((11.25±8.47) vs (6.65±5.75) min; t=2.30, P=0.023). There was a negative correlation between the DRF of the affected side and the APD ( r=-0.48, P<0.001). Conclusions:The DBF is mostly in the normal range in infants with severe hydronephrosis, and supernormal renal function is common. The previous operation indication (DRF<40%) is not suitable for the infants, and it needs to be analyzed combined with the type of curve and the APD determined by color Doppler ultrasound. The prolongation of contralateral renal peak time may be an important parameter for the surgical evaluation of severe hydronephrosis in infants.

Application of 99Tc m-MIBI SPECT/CT imaging in patients with primary cervical dystonia / 中华核医学与分子影像杂志

Objective:To evaluate the value of 99Tc m-methoxyisobutylisonitrile(MIBI) SPECT/CT imaging for the identification of dystonic muscles in patients with primary cervical dystonia (PCD). Methods:A total of 10 patients with PCD (3 males, 7 females, age (47.3±9.9) years) and 10 healthy subjects (4 males, 6 females, age (43.5±9.4) years; control group) between August 2019 and October 2021 in China-Japan Friendship Hospital were enrolled prospectively. All subjects underwent 99Tc m-MIBI SPECT/CT scan. The SUV max of 8 bilateral representative muscles, including rectus capitis posterior major, obliquus capitis inferior, splenius capitis, semispinalis, sternocleidomastoid, trapezius, musculus scalenus muscle and levator scapulae were evaluated in control group. In PCD group, muscles with abnormal uptake were determined. ROI was drawn and SUV max was measured. Independent-sample t test was used to analyze the differences of SUV max between normal and abnormal muscles. The detecting rates of neck MRI and SPECT/CT for abnormal muscles were analyzed by χ2 test. Results:Normal muscles of healthy subjects showed mild symmetrical radioactivity distribution, with the SUV max of 1.10±0.19. A total of 60 muscles with abnormal uptake in 10 patients were found, including 7 rectus capitis posterior major, 10 obliquus capitis inferior, 8 splenius capitis, 8 semispinalis, 10 sternocleidomastoid, 5 trapezius, 3 musculus scalenus muscle and 9 levator scapulae. The SUV max of muscles with abnormal uptake was 1.81±0.43, which was higher than that of normal muscles ( t=17.05, P<0.001). Only 30 pieces abnormal hypertrophy muscle were found by neck MRI, and the detecting rate was much lower than that of SPECT/CT (18.75%(30/160) vs 37.50%(60/160); χ2=28.03, P<0.001). Conclusion:99Tc m-MIBI SPECT/CT may be a useful method for identifying dystonic muscles and a guide to precision therapy in patients with PCD.

Application and progress of 99Tc m-GSA and 99Tc m-mebrofenin hepatobiliary scintigraphy in liver reserve function assessment / 中华核医学与分子影像杂志

The liver reserve function refers to the compensatory ability to maintain liver function after damage, providing implication for the resection of hepatic malignant tumor. Hepatobiliary scintigraphy imaging can provide quantitative evaluation of liver blood perfusion, and has advantages on the evaluation of liver reserve function and the prediction of postoperative complications. 99Tc m-galactosyl serum albumin (GSA) and 99Tc m-mebrofenin are commonly used imaging agents for hepatobiliary scintigraphy imaging assessment of liver reserve function. This article reviews the application and progress of hepatobiliary scintigraphy in liver reserve function assessment.

Evaluation of the efficacy of balloon pulmonary angioplasty in chronic thromboembolic pulmonary hypertension using pulmonary perfusion tomography imaging / 中华核医学与分子影像杂志

Objective:To evaluate the efficacy of balloon pulmonary angioplasty (BPA) in chronic thromboembolic pulmonary hypertension (CTEPH) using 99Tc m-macroaggregated albumin (MAA) pulmonary perfusion tomography imaging. Methods:Twenty-five patients (4 males, 21 females; age (56.5±12.3) years) with CTEPH who underwent BPA from January 2017 to April 2020 in Beijing Chaoyang Hospital, Capital Medical University were enrolled retrospectively. Effect of BPA on the improvement of pulmonary lobe/pulmonary segment perfusion was analyzed, and the proportions of improved and unimproved pulmonary lobe/pulmonary segment perfusion by BPA were calculated. The percentages of perfusion defect scores (PPDs%) of lung perfusion tomography imaging before BPA and after 4-6 times BPA were compared and analyzed (paired t test). The correlations between PPDs% and mean pulmonary artery pressure (mPAP) before BPA and after BPA were analyzed respectively, and the correlation between decreased percentage of PPDs% and decreased percentage of mPAP after BPA were also analyzed (Pearson correlation analysis). Results:Among 150 lobes of 25 patients, 96.00%(144/150) lobes showed perfusion abnormalities before BPA. After BPA, 11.11%(16/144) showed complete improvement, 57.64%(83/144) showed partial improvement, and 31.25%(45/144) showed no improvement. Among 450 pulmonary segments of 25 patients, 62.44%(281/450) showed perfusion abnormalities before BPA. After BPA, 30.60%(86/281), 37.37%(105/281), 32.03%(90/281) showed complete, partial and no improvement, respectively. The post-BPA PPDs% was significantly lower than that of pre-BPA ((39.08±10.88)% vs (57.88±10.46)%; t=10.40, P<0.001). The post-BPA mPAP was significantly lower than that of pre-BPA ((32.36±10.57) vs (49.08±10.23) mmHg; 1 mmHg=0.133 kPa; t=10.25, P<0.001). There was no significant correlation between PPDs% and mPAP either before BPA ( r=0.01, P=0.953) or after BPA ( r=0.27, P=0.199), but there was a positive correlation between the changes of PPDs% and mPAP ( r=0.40, P=0.045). Conclusions:BPA can significantly improve the pulmonary perfusion and reduce mPAP in CTEPH patients. Pulmonary perfusion tomography imaging can be used to evaluate the efficacy of BPA in CTEPH.

Sestamibi scan in renal parathyroidectomy: a worthwhile preoperative exam? / Cintilografia com sestamibi na paratireoidectomia renal: um exame pré‐operatório que vale a pena?

Abstract Introduction Surgical treatment of hyperparathyroidism related to chronic kidney disease is a real challenge for Brazilian public health care. High cost medications and long waiting lines to perform preoperative exams, especially technetium Tc 99m Sestamibi (MIBI) are some of the reasons. Despite the reality that the aid of localization exams are questionable in this scenario, doctors are too apprehensive in performing surgery without it. Objective The study aimed at evaluating the efficacy of surgery for renal hyperparathyroidism without preoperative MIBI. Methods A total of 114 patients were surgically treated. Total parathyroidectomy with autotransplantation and subtotal parathyroidectomy were carried out without preoperative MIBI. Results and conclusion Among the 114 patients undergoing surgery, 37 had secondary hyperparathyroidism in dialysis replacement, and 77 patients had post-renal transplant persistent disease. We were successful in 107 cases with only 7 failures (93.8% of success rate). Among these failures, only one parathyroid gland was not found in 4 cases, 2 parathyroid glands were not found in 2 cases and in 1 patient the 4 glands were found but this patient remained hypercalcemic and a postoperative diagnosis of supernumerary parathyroid gland was made. Surgery for treatment of renal hyperparathyroidism proved to be an effective (93.8%) and reproductible procedure, even without MIBI.

Resumo Introdução O tratamento cirúrgico do hiperparatireoidismo relacionado à doença renal crônica é um verdadeiro desafio para a saúde pública brasileira. Medicamentos de alto custo e longas filas de espera para exames pré‐operatórios, principalmente a cintilografia com tecnécio Tc‐99m Sestamibi, MIBI, são alguns dos motivos. Apesar da contribuição de exames de localização ser questionável nesse cenário, os médicos ficam muito apreensivos por fazer uma cirurgia sem ele. Objetivo Avaliar a eficácia da cirurgia para hiperparatireoidismo renal sem o MIBI pré‐operatório. Método Foram tratados cirurgicamente 114 pacientes. A paratireoidectomia total com autotransplante e a paratireoidectomia subtotal foram feitas sem MIBI pré‐operatório. Resultados e conclusão Entre os 114 pacientes submetidos à cirurgia, 37 apresentavam hiperparatireoidismo secundário em reposição dialítica e 77 doença persistente pós‐transplante renal. Tivemos sucesso em 107 casos, com apenas 7 falhas (93,8% de taxa de sucesso). Entre essas falhas, uma glândula paratireoide não foi encontrada em 4 casos, 2 glândulas paratireoides não foram encontradas em 2 casos e em um paciente as 4 glândulas foram encontradas, mas ele permaneceu hipercalcêmico com diagnóstico pós‐operatório de glândula paratireoide supranumerária. A cirurgia para tratamento do hiperparatireoidismo renal mostrou‐se um procedimento eficaz (93,8%) e reprodutível mesmo sem MIBI.

Morphometric analysis of the mandibular lingual foramina using cone-beam computed tomography in elderly Korean / Análisis morfométrico de los forámenes linguales mandibulares mediante tomografía computarizada de haz cónico en adultos mayores coreanos

SUMMARY: The aim of this study was to determine the morphologic characteristics of the lingual foramen and lateral lingual foramen using cone-beam CT in elderly Korean. Cone-beam CT images were obtained from 80 Korean older than 50 years (mean age, 65.2 years). The prevalence of the lingual and lateral lingual foramina at the lingual aspect of the mandible was determined. The diameter and height to the upper margin of the foramina from the mandibular inferior margin, and the bone height to the alveolar crest from the mandibular inferior margin were measured. In addition, the location of the lateral lingual foramen, the direction of its canal, and the presence of communication with the mandibular canal were evaluated. All of elderly Korean possessed at least one lingual foramen, with two or three foramina occurring in 77.5 % of Korean. A lateral lingual foramen was observed in 91.3 % of Korean, with the prevalence being highest at the second premolar in dentulous cases (21.6 %; 33/153). The very high frequencies of these foramina were attributable to high frequencies of relatively small-diameter inferior lingual foramen and lateral lingual foramen in the incisor region. The prevalence of a large-diameter (≥1 mm) superior lingual foramen was high, at 31.0 %. A large-diameter lateral lingual foramen in the premolar region occurred at a frequency of 17.0 %; communication with the mandibular canal was observed in 70.0 % of these cases. These quantitative data on the lingual and lateral lingual foramina of the mandible provide valuable information that could help to avoid surgical complications during implant placement in elderly Korean.

RESUMEN: El objetivo de este estudio fue determinar las características morfológicas del foramen lingual y del foramen lingual lateral mediante TC de haz cónico en adultos mayores coreanos. Se obtuvieron imágenes de TC de haz cónico de 80 coreanos mayores de 50 años (edad media, 65,2 años). Se determinó la prevalencia de los forámenes linguales y linguales laterales en la cara lingual de la mandíbula. Se midió el diámetro y la altura hasta el margen superior de los forámenes desde el margen inferior mandibular, y la altura ósea hasta la cresta alveolar desde el margen inferior mandibular. Además, se evaluó la ubicación del foramen lingual lateral, la dirección de su canal y la presencia de comunicación con el canal mandibular. Todos los adultos mayores coreanos tenían al menos un foramen lingual, con dos o tres forámenes en el 77,5 %. Se observó un foramen lingual lateral en el 91,3 %, siendo la prevalencia más alta en el segundo premolar en casos dentados (21,6 %; 33/ 153). Las mayores frecuencias de estos forámenes se atribuyeron a altas frecuencias de foramen lingual inferior y foramen lingual lateral de diámetro relativamente pequeño en la región de los incisivos. La prevalencia de un foramen lingual superior de gran diámetro (≥1 mm) fue alta, del 31,0 %. Un foramen lingual lateral de gran diámetro en la región premolar ocurrió con una frecuencia del 17,0 %; se observó comunicación con el canal mandibular en el 70,0 % de estos casos. Estos datos cuantitativos sobre los forámenes linguales y linguales laterales de la mandíbula proporcionan información valiosa que podría ayudar a evitar complicaciones quirúrgicas durante la colocación de implantes en adultos mayores coreanos.

Estudio preclínico en primate no-humano con [18F]Fluorotimidina. dosimetría y biodistribución / [18F]Fluorothymidine preclinical study in non-human primate. Dosimetry and biodistribution

Resumen En el linfoma Hodgkin, la tomografía por emisión de positrones (PET-TC) forma parte de los nuevos algoritmos diagnósticos y de valoración de respuesta al tratamiento como método eficaz para evaluar supervivencia y pronóstico de la enfermedad, ya sea a través del PET-TC interino con 2-[18F]fluoro- 2-desoxi-D-glucosa, ([18F]FDG), como también del PET-TC al final de la terapéutica. Sin embargo, la [18F]FDG presenta una baja especificidad en linfoma no Hodgkin de grandes células B. Ante la aprobación en nuestro país del radiotrazador 3´-desoxi-3´-[18F]fluorotimidina, [18F]FLT, indicador de proliferación celular de fase S, éste resultaría un prometedor radiofármaco de uso diagnóstico frente a [18F]FDG. Por lo tanto, el objetivo de este estudio fue valorar la utilización de [18F]FLT mediante un modelo animal en primates no humanos Sapajus cay. Se obtuvieron imágenes de cuerpo entero para evaluar la biodistribución y realizar un cálculo dosimétrico en la médula ósea, dado que este es un órgano crítico por la permanencia del radiofármaco. Para órganos de inte rés, se trazaron curvas de actividad en función del tiempo y se calculó la actividad acumulada normalizada. La dosis media absorbida en la médula ósea se determinó aplicando el esquema conocido como Medical Internal Radiation Dosimetry (MIRD). La dosis media obtenida en el modelo animal por unidad de actividad administrada fue de 8.7 μGy/MBq. Este resultado se extrapoló a un modelo humano adulto resultando en 32 μGy/MBq, de lo que se desprende que PET-TC con [18F]FLT es una herramienta segura para uso diagnóstico y de seguimiento en pacientes con enfermedad oncológica linfoproliferativa u otros tumores sólidos.

Abstract Positron emission tomography-computed tomography (PET-CT) is part of the new diagnostic and therapeutic algorithms for Hodgkin lymphoma. PET-CT is a valuable tool for the assessment of treatment response and prognosis, both by means of interim PET-CT with 2-[ 18F]fluoro-2-deoxy-D-glucose ([18F]FDG) as well as end of treatment (EOT) PET-CT. Given the low specificity of [ 18F]FDG for the diffuse large B cell lymphoma (DLBCL), there is an emerging need for a more specific radiopharmaceutical agent. The recent approval of the radiotracer 3´-deoxy-[18F]-3´-flourothymidine ([18F]FLT), a phase-S mitosis cell proliferation marker, for clinical application in our country, shows as a promising radiopharmaceutical for diagnostic use with incremental value over [18F]FDG. In this study, non-human primates (Sapajus cay) were studied. PET-CT study was performed after the injection of [18F]FLT. Whole-body images were obtained to evaluate the biodistribution and to calculate the dosimetry of bone marrow, as this is a critic organ to this radiotracer. Time-activity curves were traced, normalized activity uptake of the organs of interest were calculated, and mean absorbed dose was also calculated using the established Medical Internal Radiation Dosimetry (MIRD) scheme. The mean dose obtained in the animal model per unit of activity administered was 8.7 μGy/MBq. This result was extrapolated to an adult human model resulting in 32 μGy/MBq, thereby suggesting that [18F]FLT is a secure diagnostic tool to be used on the tracing of patients with DLBCL.

Clinical application of 99Tc m-sulfur colloid lymphoscintigraphy in the diagnosis of lower limb lymphedema after gynecological tumor surgery / 肿瘤研究与临床

Objective:To explore the significance of 99Tc m-sulfur colloid lymphoscintigraphy in the diagnosis of lower limb lymphedema after gynecological tumor surgery. Methods:The clinical data of patients with lower limb lymphedema after gynecological tumor surgery in Union Hospital Affiliated to Tongji Medical College of Huazhong University of Science and Technology from May 2015 to October 2019 were retrospectively analyzed. 99Tc m-sulfur colloid lymphoscintigraphy was performed in all patients. The results of lymphatic vessel imaging, lymph node imaging and their combination in the diagnosis of lower limb lymphedema were analyzed. The diagnostic efficacy of lymphatic vessel imaging alone, lymph node imaging alone and their combination was evaluated by the receiver operating characteristic (ROC) curve and the area under the curve (AUC), and the Youden index, sensitivity and specificity were calculated. Results:Among the 100 lower limbs of 50 patients, 56 limbs had lymphedema and 44 limbs had no obvious edema. When diagnosis was based on abnormal lymphatic vessel imaging alone, among 56 lower limbs with lymphedema, lower limbs lymphatic vessel imaging was positive in 38 (67.9%) and negative in 18 (32.1%); among 44 lower limbs without obvious edema, lower limbs lymphatic vessel imaging was positive in 6 (13.6%) and negative in 38 (86.4%); the sensitivity was 67.9%, the specificity was 86.4%, and the Youden index was 0.543. When diagnosis was based on abnormal lymph node imaging alone, among 56 lower limbs with lymphedema, lower limbs lymph node imaging was positive in 42 (75.0%) and negative in 14 (25.0%); among 44 lower limbs without obvious edema, lower limbs lymph node imaging was positive in 13 (29.5%) and negative in 31 (70.5%); the sensitivity was 75.0%, the specificity was 70.5%, and the Youden index was 0.455. When diagnosis was based on the combination of lymphatic vessel imaging and lymph node imaging, among 56 lower limbs with lymphedema, lymphatic vessel imaging and lymph node imaging were positive in 48 (85.7%) and negative in 8 (14.3%); among 44 lower limbs without obvious edema, lymphatic vessel imaging and lymph node imaging were positive in 14 (31.8%) and negative in 30 (68.2%); the sensitivity was 85.7%, the specificity was 68.2%, and the Youden index was 0.539. The AUC for the combined diagnosis of lymphatic vessel imaging and lymph node imaging was 0.781, the AUC for the diagnosis of abnormal lymphatic vessel imaging was 0.771, and the AUC for the diagnosis of abnormal lymph node imaging was 0.739 (all P < 0.01). Conclusions:99Tc m-sulfur colloid lymphoscintigraphy is of great help in the diagnosis of lower limb lymphedema after operation of gynecological tumors. The combination of lymph node imaging and lymphatic vessel imaging is more effective in the diagnosis of lower limb lymphedema.

Comparison of IQ-SPECT and low energy high-resolution collimator SPECT in clinical application / 中华核医学与分子影像杂志

Objective:To investigate differences in cardiac function and perfusion parameters measured by IQ-SPECT and low energy high-resolution (LEHR)-SPECT, as well as effects of scattering correction (SC) and CT attenuation correction (AC) on myocardial perfusion imaging.Methods:From May 2020 to September 2020, 80 patients (58 males, 22 females, age (57±10) years) who underwent SPECT myocardial perfusion imaging were retrospectively enrolled in Fuwai Hospital. According to the standardized left ventricular end-diastolic diameter of body surface measured by two-dimensional echocardiography, patients were divided into 2 groups: A group ( n=34) with significantly enlarged left ventricle and B group ( n=46) with no significant enlargement of left ventricle. LEHR-SPECT and IQ-SPECT gated myocardial perfusion imaging were performed in all patients. Left ventricular end-diastolic volume (EDV), end-systolic volume (ESV), ejection fraction (EF), summed rest score (SRS) and total perfusion defect (TPD) were measured. Parameters measured by two methods and differences before and after SC and AC were compared by using paired t test and Wilcoxon signed rank test. The correlation was analyzed by Pearson correlation or Spearman rank correlation analyses, and the consistency was analyzed by Bland-Altman analysis. Results:In A group, EDV, EF and SRS measured by IQ-SPECT were significantly lower than those assessed by LEHR-SPECT after SC and AC (EDV: (257±137) vs (276±154) ml, EF: (21±11)% vs (26±13)%, SRS: 17(6, 25) vs 18(8, 28); t values: -2.63, -7.46, z=-2.14, all P<0.05); all parameters measured by LEHR-SPECT and IQ-SPECT had well correlation ( r values: 0.965, 0.969, 0.967, rs values: 0.920, 0.960, all P<0.001) and consistency. In B group, EDV and EF measured by IQ-SPECT were significantly lower than those assessed by LEHR-SPECT after SC and AC (EDV: (96±40) vs (107±39) ml, EF: (46±15)% vs (54±16)%; t values: -6.23, -10.71, both P=0.001); SRS and TPD measured by IQ-SPECT after SC and AC were significantly lower than non-SC and non-AC (SRS: 2(1, 4) vs 5(3, 11), TPD: (3%(1%, 5%) vs 7%(3%, 12%); z values: -4.11, -4.16, both P<0.001); all parameters measured by LEHR-SPECT and IQ-SPECT had well correlation ( r values: 0.956, 0.978, 0.958, rs values: 0.926, 0.944, all P<0.001) and consistency. Conclusions:There are good correlation and consistency of left ventricular function and myocardial perfusion parameters acquired by IQ-SPECT and LEHR-SPECT. Moreover, IQ-SPECT is able to shorten acquisition time, resulting in great potential in clinical application.

Serially evaluation of changes in myocardial perfusion, hibernation myocardium and left ventricular function in the development of chronic coronary artery occlusion by gated SPECT perfusion and gated PET imaging in pigs / 中华核医学与分子影像杂志

Objective:To serially characterize the myocardial perfusion, myocardial hibernation and left ventricular (LV) function as well as LV remodeling in progressive coronary artery stenosis in Chinese mini-pigs.Methods:In 8 Chinese mini-pigs (5 males, 3 females; age: 10 months), chronic progression of coronary stenosis and finally occlusion was established using Ameroid constrictor implantation at the 1 cm below the bifurcation of the first diagonal branch of the left anterior descending (LAD) artery. Serial gated 99Tc m-methoxyisobutylisonitrile(MIBI) SPECT/CT, gated 18F-FDG PET/CT imaging and coronary angiography (CAG) were performed before surgery and at the 1st, 4th and 8th week after surgery. Longitudinally, total perfusion defect (TPD), LV ejection fraction (LVEF), LV end-diastolic volume (LVEDV), LV end-systolic volume (LVESV), summed motion score (SMS), summed thickening score (STS) and hibernating myocardium (HM) were analyzed. Repeated measures analysis of variance, Kruskal-Wallis rank sum test and Bonferroni correction method were used to analyze data. Results:One mini-pig died of infection after the Ameroid constrictor implantation. In the remaining 7 mini-pigs, TPD was progressively increased with time prolonged (0, 12.0%(0, 33.0%), (41.1±23.7)% and (49.3±24.5)%; H=17.03, P=0.001); Compared with HM before the surgery (100%), HM was gradually reduced from the 1st (21.0%(6.0%, 100%)) to the 4th (18.0%(3.0%, 33.0%)) week after surgery, and then increased to the 8th week after surgery ((23.0±15.4)%; H=13.09, P=0.004), but there was no significant difference between the 1st and 4th week, or between the 4th and 8th week after surgery (both P>0.05 (Bonferroni correction method)). Accordingly, LVEF gradually decreased ((73.7±8.4)%, (63.7±19.1)%, (53.7±14.6)% and (49.9±15.4)%; F=6.22, P=0.004). LVEDV (9.0(6.0, 21.0), (31.4±16.3), (32.9±17.4) and (36.4±17.5) ml; H=8.58, P=0.035)and LVESV ((3.8±3.2), (15.9±15.3), 12.0(10.0, 17.0)and (19.3±10.9) ml; H=10.51, P=0.015) gradually increased. SMS and STS continuously increased as well ( H values: 16.49, 13.33, P values: 0.001, 0.004). Conclusions:With the progression of coronary artery stenosis to occlusion, myocardial perfusion is gradually decreased, while the global and regional LV function, LV remodeling are gradually aggravated, and HM is gradually reduced. After the chronic coronary artery occlusion, myocardial perfusion has a trend to be improved and HM is gradually recovered.

Assessment of left ventricular diastolic dyssynchrony and its influencing factors early after acute myocardial infarction by SPECT gated myocardial perfusion imaging: an experimental study / 中华核医学与分子影像杂志

Objective:To evaluate the left ventricular diastolic dyssynchrony (LVDD) and its influencing factors early after acute myocardial infarction (AMI) using phase analysis of SPECT gated myocardial perfusion imaging (GMPI).Methods:Bama miniature swines ( n=16) were subjected to establish AMI models. GMPI was performed before and 1 d after AMI to obtain the extent of myocardial perfusion defect (Extent, %) and left ventricular systolic dyssynchrony (LVSD)/LVDD parameters, namely the phase histogram bandwidth (PBW) and phase standard deviation (PSD). Meanwhile, left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVESV), left ventricular ejection fraction (LVEF), and the ratio of early to late peak mitral diastolic flow (E/A) were obtained by echocardiography. Independent-sample t test, paired t test and Pearson correlation analysis were used to analyze the data. Results:Sixteen AMI swines were successfully created. Compared to baseline, Extent, LVEDV and LVESV significantly increased on 1 d after AMI ( t values: -11.14, -4.55, -6.12, all P<0.001), while LVEF and E/A significantly decreased ( t values: 10.16, 2.18, P<0.001, P=0.046). GMPI showed that the LVDD parameters PBW and PSD increased significantly on 1 d after AMI when compared to those at baseline((142.25±72.06)° vs (33.06±8.98)°, (56.15±26.71)° vs (12.51±5.13)°; t values: -6.11, -6.60, both P<0.001). There were significant differences between LVSD parameters and LVDD parameters (PBW: (109.06±62.40)° vs (142.25±72.06)°, PSD: (44.40±25.61)° vs (56.15±26.71)°; t values: -2.73, -2.20, P values: 0.016, 0.044). LVDD parameters PBW, PSD were negatively correlated with E/A after AMI ( r values: -0.569, -0.566, P values: 0.021, 0.022), and positively correlated with the Extent ( r values: 0.717, 0.634, P values: 0.002, 0.008). The phase analysis of SPECT GMPI to evaluate LVDD showed good intra-observer and inter-observe reproducibility (intraclass correlation coefficient (ICC): 0.953-0.984, all P<0.001). Conclusions:LVDD occurs early on 1 d after AMI, and can reflect left ventricular diastolic dysfunction. The Extent is correlated with LVDD significantly. Phase analysis of SPECT GMPI is an accurate method to evaluate LVDD and left ventricular diastolic function.

Automatic diagnosis and assessment of bone metastases on bone scans based on deep learning / 中华核医学与分子影像杂志

Objective:To develop an approach for the automatic diagnosis of bone metastasis and to design a parameter of quantitative evaluation for tumor burden on bone scans based on deep learning technology.Methods:A total of 621 cases (389 males, 232 females, age: 12-93 years) of bone scan images from the Department of Nuclear Medicine in Tenth People′s Hospital of Tongji University from March 2018 to July 2019 were retrospectively analyzed. Images were divided into bone metastasis group and non-bone metastasis group. Eighty percent of the cases were randomly extracted from both groups as the training set, and the rest of cases were used as the test set. A deep residual convolutional neural network ResNet34 was used to construct the classification model and the segmentation model. The sensitivity, specificity and accuracy were calculated and the performance differences of the classification model in different age groups (15 cases of <50 years, 75 cases of ≥50 and <70 years, 33 cases of ≥70 years) were analyzed. The regions of metastatic bone lesions were automatically segmented by the segmentation model. The Dice coefficient was used to evaluate the effect of the segmentation model and the manual labeled results. Finally, the bone scans tumor burden index (BSTBI) was calculated to assess the tumor burden of bone metastases.Results:There were 280 cases with bone metastases and 341 cases with non-bone metastases, including 498 in training set and 123 in test set. The classification model could accurately identify bone metastases, with the sensitivity, specificity and accuracy of 92.59%(50/54), 85.51%(59/69) and 88.62%(109/123), respectively, and it performed best in the <50 years group (sensitivity, 2/2; specificity, 12/13; accuracy, 14/15). The specificity in the ≥70 years group (8/12) was the lowest. The Dice coefficient of bone metastatic area and bladder area were 0.739 and 0.925 in the segmentation model, which performed similarly in the three age groups. Preliminary results showed that the value of BSTBI increased with the increase of the number of bone metastatic lesions and the degree of 99Tc m-MDP uptake. The machine learning model in this study took (0.48±0.07) s for the entire analysis process from input to the final BSTBI calculation. Conclusions:The deep learning based on automatic diagnosis framework for bone metastases can automatically and accurately identify segment bone metastases and calculate tumor burden. It provides a new way for the interpretation of bone scans. The proposed BSTBI may be used as a quantitative evaluation indicator in the future to assess the tumor burden of bone metastases based on bone scans.