99m Technetium-HMPAO-labeled platelet scan in practice: Preparation, quality control, and biodistribution studies

Abstract There is no biodistribution or imaging data on 99mtechnetium (Tc)-hexamethyl propylamine oxime (HMPAO)-labeled platelets in the literature. The current study aimed to present updated information about the clinical procedures for preparation and use of labeled platelets. Following two-step centrifugation at 1500 and 2500 rpm, the platelets were extracted from whole blood into platelet-rich plasma (PRP) above the buffy coat and then from PRP into a platelet pellet at the bottom of the tube. The 99mTc-HMPAO-labeled platelets were inspected for purity, viability, release of 99mTc from platelets, and sterility. Also, microscopic examination and thin layer chromatography (TLC) were performed. Biodistribution was assessed following necropsy in BALB/c mice and through imaging of New Zealand rabbits. The separation ratio was estimated at 98%, and radiochemical purity was measured to be 80%. The labeling efficiency was above 30% in more than half of the assays (range: 17-43%). The release of 99mTc from platelets was 9% per hour at 37ºC. After 24 hours, stability was estimated at 54% in the human serum. The target organs of mice included the spleen and liver. In rabbits, the imaging results indicated liver as the target organ. Thyroid uptake was negligible up to 90 minutes. Based on the findings, extraction of platelets and labeling them with 99mTc-HMPAO is a feasible and safe approach in routine practice.

Usefulness of hybrid SPECT/CT for the 99mTc-HMPAO-labeled leukocyte scintigraphy in a case of cranial osteomyelitis

Cranial osteomyelitis is a potentially fatal lesion. White blood cell scanning (WBC) with 99mTc-hexamethylpropylene amine oxime (HMPAO) has proven highly sensitive and specific in the diagnosis and follow-up of patients with suspected osteomyelitis. In this report we show the usefulness of SPECT and transmission CT performed simultaneously using a hybrid imaging device for the functional anatomic mapping of soft tissue and cranial bone infections. 99mTc-HMPAO-labeled leukocytes scintigraphy was performed on an elderly diabetic man with an intracranial mass lesion and with suspected temporal bone infection. Planar scans were acquired 30 min, 4 h, and 24 h after injection. SPECT/CT was obtained 6 h after tracer injection, using a dual-head camera coupled with a low-power X-ray tube. The scintigraphic results were matched with the results of surgery and of clinical follow-up. The planar images alone were true-positives for abscess in this patient. SPECT/CT improves the accuracy of99mTc-HMPAO scintigraphy especially in discriminating between soft-tissue and bone involvement. In fact, SPECT/CT also showed temporal bone osteomyelitis. This result indicates that SPECT/CT performed using a hybrid device can improve imaging with 99mTc-HMPAO-labeled leukocytes in patients with suspected osteomyelitis by providing accurate anatomic localization and precise definition of the extent of infection.

A Case of Actinobacillus actinomycetemcomitans Bacteremia Associated with Permanent Pacemaker Lead Infection / 감염과화학요법

A 73-year-old man was admitted for intermittent episodes of fever and chills for 3 months. He had been implanted with a permanent pacemaker to control tachy-bradycardia syndrome 7 months before admission. Blood cultures were positive for Actinobacillus actinomycetemcomitans and a 99mTc-hexamethylpropylene amine oxime (99mTc-HMPAO) WBC scan revealed inflammation on the pacemaker lead in extracardiac site. Oral examination revealed several dental caries. The patient was treated with intravenous ceftriaxone, followed by oral ciprofloxacin without removal of the infected pacemaker lead. He was doing well 10 months without febrile episodes after discontinuation of antibiotics. This report describes the first case of A. actinomycetemcomitans bacteremia associated with a pacemaker lead and localized by 99mTc-HMPAO WBC scan

A Case of Actinobacillus actinomycetemcomitans Bacteremia Associated with Permanent Pacemaker Lead Infection / 감염과화학요법

A 73-year-old man was admitted for intermittent episodes of fever and chills for 3 months. He had been implanted with a permanent pacemaker to control tachy-bradycardia syndrome 7 months before admission. Blood cultures were positive for Actinobacillus actinomycetemcomitans and a 99mTc-hexamethylpropylene amine oxime (99mTc-HMPAO) WBC scan revealed inflammation on the pacemaker lead in extracardiac site. Oral examination revealed several dental caries. The patient was treated with intravenous ceftriaxone, followed by oral ciprofloxacin without removal of the infected pacemaker lead. He was doing well 10 months without febrile episodes after discontinuation of antibiotics. This report describes the first case of A. actinomycetemcomitans bacteremia associated with a pacemaker lead and localized by 99mTc-HMPAO WBC scan

Migration of 99mTc-Hexamethylpropylene Amine Oxime (HMPAO) Labeled Immature and Mature Dendritic Cells in the Mouse / 대한핵의학회잡지

PURPOSE: The purpose of this study is to evaluate migration of technetium-99m hexamethylpropylene amine oxime (99mTc-HMPAO) labeled immature and mature dendritic cells (DC) in the mouse. METHODS: DC were collected from bone marrow (BM) of tibiae and femurs of mice. Immature and mature DC from BM cells were radiolabeled with 99mTc-HMPAO. To evaluate the functional and phenotypic changes of DC from radiolabeling, the allogeneic mixed lymphocyte reaction (MLR) and fluorescence-activated cell sorting (FACS) analysis were performed before and after labeling with 99mTc-HMPAO. Migration of intravenously injected DC (iv-DC) was assessed by serial gamma camera images of mice with or without subcutaneous tumor. Percent injected dose per gram (%ID/g) was calculated in lungs, liver, spleen, kidneys, and tumor through dissection of each mice after 24 hours of injection. RESULTS: Labeling efficiency of immature and mature DC were 60.4 +/- 5.4% and 61.8 +/- 6.7%, respectively. Iv-DC initially appeared in the lungs, then redistributed mainly to liver and spleen. Migration of mature DC to spleen was significantly higher than that of immature DC (38.3 +/- 4.0 % vs. 32.2 +/- 4.1 % in control group, 40.4 +/- 4.1% vs. 35.9 +/- 3.8 % in tumor group; p< 0.05). Migration to tumor was also significantly higher in mature DC than in immature DC (2.4 +/- 0.3% vs 1.7 +/- 0.2%; p=0.034). CONCLUSION: Assessment of migration pattern of DC in mice was possible using 99mTc-HMPAO labeled immature and mature DC. Migration of mature DC to spleen and tumor was higher than that of immature DC when they were i.v. injected.

Prediction of Prognosis by Acetazolamide Brain Perfusion SPECT in Patients with Arteriovenous Malformation / 대한핵의학회잡지

After surgical operation in patients with arteriovenous malformation (AVM), normal pressure perfusion breakthrough (NPPB) is one of the major complications. Brain perfusion SPECT with acetazolamide stress was known to be useful to evaluate the vascular reserve in several neurological and neurosurgical conditions. The authors performed acetazolamide brain perfusion SPECT in patients with AVM and compared the brain perfusion in the post-operative clinical courses. The acetazolamide brain perfusion SPECT was helpful in defining the prognosis of the patients with AVM. We describe 4 patients with AVM who had acetazolamide brain perfusion SPECT to examine the prognosis.

Optimization of Correction Factor for Linearization with Tc-99m HM PAO and Tc-99m ECD Brain SPECT / 영남의대학술지

No abstract available.

Comparison of the Findings of DDST (II), Brain SPECT and Brain MRI in Cerebral Palsy Children

OBJECTIVE: To evaluate the clinical values of the DDST II (Denver Developmental Screening Test, 2nd revision), 99mTc HMPAO brain single photon emission computed tomography (SPECT) findings and brain magnetic resonance imaging (MRI) in the assessment of cerebral palsy children. METHOD: Twenty-two children with cerebral palsy were investigated. Four profiles of DDST (II) were summated to a monthly age according to each developmental status. 99mTc HMPAO brain SPECT imagings were analyzed for the calculation of the perfusion defect indices. The clinical severities were scored as mild to severe, and were compared to a motor age of Maryland criteria. The presence of abnormal findings of brain MRI was also checked. RESULTS: (1) The gross and fine motor profiles of DDST (II) were significantly different between normal and abnormal findings of the brain SPECT in cerebral palsy children. (2) The region of interests ROIs in brain SPECT correlated with many profiles of DDST (II), 1) prefrontal area of the brain SPECT and language profile of DDST (II), 2) premotor area and gross motor/language profile, 3) thalamic area and social-personal profile, 4) basal ganglia area and gross motor/language proflie. respectively. (3) There was no relationship between each profile of DDST (II) and brain MRI findings. CONCLUSION: The DDST (II) and Brain SPECT seemes to be more useful than the brain MRI for the functional assessment of cerebral palsy children.

Experimental evaluation of brain spect using d,1 -HMPAO99mTc in dogs. Anatomo-physiological implications / Avaliação experimental de "spect" cerebral mediante utilização do d,1 - HMPAO 99mTc em cães. Considerações anátomo-fisiológicas

Technetium-99m-d,1-hexamethylpropyleamine oxime (99mTc-HMPAO) is an important radiopharmaceutical used for both brain SPECT imaging and "in vitro" labelling of white blood cells. An increasing utilization of this radiopharmaceutical for studies of several neurologic and psychiatric diseases in humans, lead us to the preparation of the kits of HMPAO to be labeled with technetium-99m. This paper presents animal experimental studies with d,l-HMPAO99mTc prepared from liofilized kits developed in our laboratories and also comparison to those commercially available. The brain scans have been done initially in rabbits, however better results were obtained with dogs. Six mongrel dogs clinically qualited as normals, were used in order to get scintigraphic brain pictures and washout curves of region of interest (ROIs). The value of experimental studies in animals and the considerable reduction in price of the so obtained radiopharmaceutical, have shown the viability of such procedure in the clinical practice as well in the veterinary clinic of small animals. By the other side, the perfusion of d,l-HMPAO99mTc showed that such a product concentrates at the same time in the cerebral area and nasal fossa, showing evidence of similar structures as the hemato encephalic barrier, also in the nasal area.

O d,1 - Hexametilpropileno oxima marcado com o tecnécio-99m(99mTc-HMPAO) é um importante radiofármaco usado tanto para imagens tomográficas cerebrais quanto na marcação in vitro" de leucócitos. A crescente utilização deste radiofármaco no estudo de doenças neurológicas no homem levou-nos à obtenção de "kits" de HMPAO para ser marcado pelo tecnécio-99m. Neste trabalho apresentamos o estudo experimental efetuado com "kits" liofilizados de d,1 HMPAO99mTc desenvolvidos em nossos laboratórios, comparando inclusive com aqueles encontrados no comércio. As imagens cerebrais inicialmente foram feitas em coelhos, entretanto os melhores resultados foram obtidos em cães. Assim, selecionaram-se seis cães sem raça definida, considerados clinicamente normais para obtenção das imagens cintilográficas do cérebro e o washout das regiões de interesse (ROls). Os estudos experimentais em animais e a considerável redução do custo do radiofármaco mostrou-nos a possibilidade da utilização destes exames na clínica veterinária, especialmente de pequenos animais. Por outro lado, a perfusão do d,l HMPAO99mTc mostra que a concentração do radiofármaco se faz ao mesmo tempo na região do cérebro e nas fossas nasais, demonstrando a existência de estruturas iguais às da barreira hemo-encefálica nesta última região.

Diagnosis of Cerebrovascular Disease Using 99mTc-HMPAO SPECT

A new radiopharmaceutical, technetium-99m hexamethylpropyleneamine oxime(99mTc-HMPAO), has been reported to cross the blood-brain-barrier and to distribute in brain in proportion to regional blood flow. Measurement of cerebral blood flow with single photon emixxion computed tomography(SPECT) was performed using 99mTc-HMPO in 46 patients and clinical analysis was done. Decreased regional cerebral perfusion was observed in 41 cases. Moreover eight cases of them who had normal X-ray C-T scan revealed positive finding on SPECT. We porpose that 99mTc-HMPAO SPECT seems to be a useful diagnostic method for evaluation of ischemic cerebral lesions.