Brain SPECT Imaging Research Articles

SU-C-9A-07: Fabrication and Calibration of a Novel High-Sensitivity Collimator for Brain SPECT Imaging

Purpose: We have designed a novel collimator for brain SPECT imaging that yields greatly increased sensitivity near the center of the brain without loss of resolution. The collimator was manufactured and initial evaluation has been completed. Methods: The collimator was time-consuming and challenging to build. Because our desired hole pattern required substantial variations in hole angle, we designed two supporting plates to securely position about 34,000 hexagonal, slightly tapered, 75-mm long steel pins. The holes in the plates were modeled to yield the desired focal length, hole length and septal thickness. Molten lead was poured in between the plates, and all pins were removed after cooling. The sensitivity gain compared to a fan-beam collimator was measured using a point source placed along the central ray at several distances from the collimator face. Visual inspection of the holes was not possible as the collimator was sealed so it could be safely mounted on a SPECT system. Therefore, we prepared a 2D array of 768, ∼48μCi Tc-99m point sources, separated by 1.6 cm. The array was imaged for 10 minutes at 4 shifted locations to reduce sampling distance to 8 mm. Results: The sensitivity of the novel cone-beam collimator varied with distancemore » from the detector face; it was higher than that of the fan-beam collimator by factors ranging from 3 to 176. Examination of the projections of the 4×768 point sources revealed that fewer than 2% of the holes were fully or partially blocked, which indicates that the intensive manual fabrication process was very successful. Conclusion: We have designed and manufactured a novel collimator for brain SPECT imaging. As expected, the sensitivity is much higher than that of a fan-beam collimator. Because of differences between the manufactured collimator and its design, reconstruction of the data will require a measured system function.« less

Ioflupane I123 Injection (DaTscanTM) SPECT Brain Imaging in Patients with Movement Disorders and/or Dementia: Preliminary Report

Early and accurate diagnosis of movement disorders and dementia is critically important to ensure patients receive appropriate treatment. Ioflupane I123 injection (ioflupane (123I) or (123I) FP-CIT or DaTscanTM or DaTscanTM) is approved in Europe and the US for diagnostic use only, for detecting loss of functional dopaminergic neuron terminals in the striatum in patients with clinically uncertain parkinsonian syndromes (PS), including those at an early stage, to help differentiate essential tremor (ET) from PS related to Parkinson’s disease (PD), multiple system atrophy (MSA), and progressive supranuclear palsy (PSP). (Figure 1) Ioflupane (123I) is unable to discriminate between PD, MSA, and PSP. In Europe, Ioflupane (123I) is also approving to help differentiate probable dementia with Lewy bodies (DLB) from Alzheimer’s disease (AD). Ioflupane (123I) is not able to discriminate between dementia with Lewy bodies and Parkinson’s disease dementia (Table 1).

Influences of reconstruction and attenuation correction in brain SPECT images obtained by the hybrid SPECT/CT device: evaluation with a 3-dimensional brain phantom.

The aim of this study was to evaluate the influences of reconstruction and attenuation correction on the differences in the radioactivity distributions in (123)I brain SPECT obtained by the hybrid SPECT/CT device. We used the 3-dimensional (3D) brain phantom, which imitates the precise structure of gray matter, white matter and bone regions. It was filled with (123)I solution (20.1 kBq/mL) in the gray matter region and with K2HPO4 in the bone region. The SPECT/CT data were acquired by the hybrid SPECT/CT device. SPECT images were reconstructed by using filtered back projection with uniform attenuation correction (FBP-uAC), 3D ordered-subsets expectation-maximization with uniform AC (3D-OSEM-uAC) and 3D OSEM with CT-based non-uniform AC (3D-OSEM-CTAC). We evaluated the differences in the radioactivity distributions among these reconstruction methods using a 3D digital phantom, which was developed from CT images of the 3D brain phantom, as a reference. The normalized mean square error (NMSE) and regional radioactivity were calculated to evaluate the similarity of SPECT images to the 3D digital phantom. The NMSE values were 0.0811 in FBP-uAC, 0.0914 in 3D-OSEM-uAC and 0.0766 in 3D-OSEM-CTAC. The regional radioactivity of FBP-uAC was 11.5% lower in the middle cerebral artery territory, and that of 3D-OSEM-uAC was 5.8% higher in the anterior cerebral artery territory, compared with the digital phantom. On the other hand, that of 3D-OSEM-CTAC was 1.8% lower in all brain areas. By using the hybrid SPECT/CT device, the brain SPECT reconstructed by 3D-OSEM with CT attenuation correction can provide an accurate assessment of the distribution of brain radioactivity.

Integrated Analysis of [123I]FP-CIT (DaTscan; Ioflupane I123 Injection) SPECT Brain Imaging - Diagnostic Effectiveness in Patients with Movement Disorders and/or Dementia (S8.004)

Integrated Analysis of [123I]FP-CIT (DaTscan; Ioflupane I123 Injection) SPECT Brain Imaging - Diagnostic Effectiveness in Patients with Movement Disorders and/or Dementia (S8.004)

Early detection of subjective memory impairment in Parkinson's disease using cerebral perfusion SPECT.

Cognitive dysfunction is a common feature of Parkinson's disease (PD). Recent research has focused on the detection and management of subjective memory impairment (SMI) as the stage that precedes mild cognitive impairment (MCI). Nevertheless, few clinical studies have biomarkers of SMI in PD. Therefore, this study was designed to investigate differences in perfusion brain SPECT between PD with SMI (PD+SMI) and PD without SMI (PD-SMI) to identify a potential prodromal biomarker of progression to dementia in patients with PD. In this study, 30 PD patients with SMI and 24 PD patients without SMI have been recruited. All subjects underwent perfusion brain SPECT and neuropsychological testing. Brain SPECT images were analyzed by using the SPM program and comparing between patients with PD+SMI and PD-SMI. The PD+SMI and PD-SMI groups did not differ in any neuropsychological tests, except for MMSE. Despite a significant difference in MMSE scores, all scores of both groups were in the normal range. Brain SPECT analysis of PD+SMI patients showed hypoperfusion in the frontal and inferior temporal regions, anterior cingulate and thalamus compared with PD-SMI patients. This pilot study investigated the role of decreased brain perfusion SPECT findings in PD+SMI patients compared with PD-SMI patients as a predictive biomarker of pre-dementia as the stage that precedes MCI in PD. Larger, prospective studies are warranted for further investigation of the pathophysiology of neuronal systems during cognitive decline.

Brain SPECT Imaging of Ictal Smile Seizure

"Ictal smile" is defined as a facial expression during a seizure, which usually translates happiness, clearly distinct from a tonic deviation of the mouth or other abnormal tonic-clonic movements involving the face, not associated to any happiness emotion (Epilepsia. 1998;39:1357-1360). It is a rare condition (6%-10% of patients; Epilepsia. 1998;39:1357-1360) and seems to be related to seizures arising from temporal or frontal regions (Brain. 2003;126:2121-2138).Anecdotal reports of brain perfusion SPECT performed during ictal and interictal phases (Epilepsia. 1998;39:1357-1360) do not supply, unfortunately, imaging documentation. Thus, we report the first evidence of brain perfusion abnormalities induced by ictal smile seizure.

Brain SPECT Imaging with Acetazolamide Challenge

The patient was a 69-y-old man who, 37 d earlier, had a 4-d-long evolving onset of headache, dizziness, acute personality changes, visual changes, and weakness. Unspecified imaging was obtained at an outside facility, and he was diagnosed with an intracerebral stenosis. Subsequently, he was given

Improving the Convergence Rate in Affine Registration of PET and SPECT Brain Images Using Histogram Equalization

A procedure to improve the convergence rate for affine registration methods of medical brain images when the images differ greatly from the template is presented. The methodology is based on a histogram matching of the source images with respect to the reference brain template before proceeding with the affine registration. The preprocessed source brain images are spatially normalized to a template using a general affine model with 12 parameters. A sum of squared differences between the source images and the template is considered as objective function, and a Gauss-Newton optimization algorithm is used to find the minimum of the cost function. Using histogram equalization as a preprocessing step improves the convergence rate in the affine registration algorithm of brain images as we show in this work using SPECT and PET brain images.

Application of Empirical Mode Decomposition (EMD) on DaTSCAN SPECT images to explore Parkinson Disease

Parkinsonism is the second most common neurodegenerative disorder. It includes several pathologies with similar symptoms, what makes the diagnosis really difficult. I-ioflupane allows to obtain in vivo images of the brain that can be used to assist the PS diagnosis and provides a way to improve its accuracy. In this paper a new method for brain SPECT image feature extraction is shown. This novel Computer Aided Diagnosis (CAD) system is based on the Empirical Mode Decomposition (EMD), which decomposes any non-linear and non-stationary time series into a small number of oscillatory Intrinsic Mode Functions (IMF) a monotonous Residuum. A 80-DaTSCAN image database from the “Virgen de las Nieves” Hospital in Granada (Spain) was used to evaluate this method, yielding up to 95% accuracy, which greatly improves the baseline Voxel-As-Feature (VAF) approach.

The comparison of pre- and post-treatment 99mTc HMPAO brain SPECT images in patients with obsessive-compulsive disorder

The objective of the present study was to compare brain activation in patients with obsessive-compulsive disorder (OCD) who received pharmacotherapy (selective serotonin reuptake inhibitor (SSRI) or a SSRI–risperidone combination) with that in healthy controls using 99mTc-hexamethyl propyleneamine oxime (HMPAO) brain single photon emission tomography (SPECT). Twelve OCD patients achieving clinical response (seven SSRI responders, five patients responded to SSRI plus risperidone) underwent post-treatment SPECT scan. The baseline regional cerebral blood flow (rCBF) was significantly reduced in a large part of the cerebral cortex and the left cingulate gyrus in OCD patients compared with controls. After a 50% reduction of the OCD symptoms, bilaterally increased rCBF in the thalamus showed a significant effect of time in both of the patient groups. In the remitted state, although rCBF in the cingulate gyrus did not differ in SSRI responders compared with controls, patients who responded to the combination of SSRI+ risperidone showed significant hypoperfusion in the left anterior cingulate gyrus. SSRI responders had normalized rCBF in the frontal region relative to the control group. Consequently, based on our results, we attribute the observed thalamic rCBF alteration to SSRI treatment. Our results also suggested that brain perfusion changes associated with clinical remission may differ across patient subgroups.

Linear intensity normalization of FP-CIT SPECT brain images using the α-stable distribution

In this work, a linear procedure to perform the intensity normalization of FP-CIT SPECT brain images is presented. This proposed methodology is based on the fact that the histogram of intensity values can be fitted accurately using a positive skewed α-stable distribution. Then, the predicted α-stable parameters and the location-scale property are used to linearly transform the intensity values in each voxel. This transformation is performed such that the new histograms in each image have a pre-specified α-stable distribution with desired location and dispersion values. The proposed methodology is compared with a similar approach assuming Gaussian distribution and the widely used specific-to-nonspecific ratio. In this work, we show that the linear normalization method using the α-stable distribution outperforms those existing methods.

SPECT Brain Imaging in Chronic Lyme Disease

Lyme disease is an infectious disease that frequently involves the central nervous system, leading to cognitive and/or mood dysfunction. The basis for these symptoms remains to be defined but may be the result of a vasculitis or metabolic abnormality secondary to the infection. SPECT scans of the brain might provide an objective measure of abnormalities present in patients with otherwise difficult to objectify clinical findings. The objective of this study was to determine the frequency, location, and severity of abnormalities in SPECT scans of the brain of patients with chronic Lyme disease. A total of 183 individuals who met the clinical definition of chronic Lyme disease underwent SPECT scanning of the brain using Tc and standard nuclear imagine techniques. Abnormalities of perfusion to affected areas of the brain were defined as mild, moderate, or severe. Of all patients, 75% demonstrated abnormalities in perfusion to various areas of the brain, most notably the frontal, temporal, and parietal lobes. Patients considered to be seropositive and those considered seronegative had similar rates, types, and severity of perfusion defects. Abnormalities of MRI of the brain were seen in 14% of patients. Treatment with antibiotics, especially those with intracellular-penetrating activity, resulted in resolution or improvement of abnormalities in 70% of patients over a 1- to 2-year period. Brain SPECT scans are abnormal in most patients with chronic Lyme disease, and these scans can be used to provide objective evidence in support of the clinical diagnosis. The use of certain antibiotic regimens seems to provide improvement in both clinical status and SPECT scans.

Component-based technique for determining the effects of acupuncture for fighting migraine using SPECT images

In this work, SPECT brain images are analyzed automatically in order to determine the effects of acupuncture applied for fighting migraine. For this purpose, two different groups of patients are randomly collected and received verum and sham acupuncture, respectively. Changes in the brain perfusion patterns can be measured quantitatively by dealing with the images in a classification context. A classification scheme consisting of a component-based feature extraction technique in combination with Support Vector Machines allows us to accurately determine the regions of interest (ROIs) where acupuncture produced more intense effects, and whether these effects are correlated with a decrease or an increase of the brain activity. Effects produced by verum and sham acupuncture are studied, and the best method for intensity normalization is discussed. The result is a complete, objective system which can be used for general purposes in the visual assessment of perfusion images.

Correlation between neuropsychological tests and hypoperfusion in MCI patients: anatomical labeling using xjView and Talairach Daemon Software

Statistical analysis of brain perfusion SPECT images has shown mild to severe abnormalities, consistent with cortical dysfunctions in the brain. Recently, functional brain imaging such as fMRI, PET and SPECT is increasingly used for diagnosis of MCI. In this study, we calculate the correlation with perfusion of brain SPECT and neuropsychological test scores of patients by SPM analysis to evaluate the relationship with cerebral hypoperfusion and cognitive dysfunction in MCI patients. Anatomical labeling was performed automatically using the Talairach Daemon (TD) and xjView. Ninety-three patients (mean age 67.2 ± 7.42 years; 59 women and 34 men) with MCI were selected and examined by the comprehensive neuropsychological test. Tc-99m-HMPAO brain SPECT images were acquired on the patients using a two-head gamma camera. We analyzed the brain image of MCI patients by SPM8 software, and observed the anatomical correlated region, between the neuropsychological tests and cerebral hypoperfusion. The SPM8 tool provided correlation between neuropsychological score and brain perfusion by simple regression method. The neuropsychological test included attention, language function, visuospatial function, memory, frontal executive function, depression score and general cognitive function. Percentage of voxels with correlated area to the whole brain was calculated and the values by Rey complex figure test (CFT) copy score, MMSE score, Seoul verbal learning test (SVLT) immediate recall score and Rey CFT delayed recall score were 15.3, 12.33, 10.59 and 8.45 %, respectively. Rey CFT copy score was correlated with perfusion in the left middle temporal gyrus (BA 21), right inferior frontal gyrus (BA 45), right lingual gyrus, left lingual gyrus (BA 18), right postcentral gyrus (BA 40), right cingulate gyrus (BA 31) and left thalamus (pulvinar) with p < 0.01 FDR. The correlation related to MMSE included left parahippocampal gyrus, right fusiform gyrus and right middle frontal gyrus (BA 46). SVLT immediate recall score was correlated with left superior temporal gyrus and Rey CFT delayed recall score was correlated with left inferior frontal gyrus (BA 47), right inferior frontal gyrus, and left lentiform nucleus. Visuospatial and general cognitive dysfunctions in the patients with MCI were most correlated with cerebral hypoperfusion. Rey CFT copy and MMSE scores were more strongly correlated with blood perfusion of the brain than with other neuropsychological test scores. xjView was a useful tool to find out the anatomical name of the selected voxel or clusters and to display the cluster's anatomical information and list all cluster information and could be used instead of TD Client.

On the empirical mode decomposition applied to the analysis of brain SPECT images

In this paper we propose a novel method for brain SPECT image feature extraction based on the empirical mode decomposition (EMD). The proposed method applied to assist the diagnosis of Alzheimer Disease (AD) selects the most discriminant voxels for support vector machine (SVM) classification from the transformed EMD feature space. In particular, the combination of frequency components of the EMD transformation are found to retain regional differences in functional activity which is characteristic of AD. In general, the EMD represents a fully data-driven, unsupervised and additive signal decomposition and does not need any a priori defined basis system. Several experiments were carried out on a balanced SPECT database collected from the “Virgen de las Nieves” Hospital in Granada (Spain), containing 96 recordings and yielding up to 100% maximum accuracy and 93.52±4.92% on average, with a acceptable biased estimate of the cross-validation (CV) true error, in separating AD and normal controls on this SPECT database. In this way, we achieve the “gold standard” labeling outperforming recently proposed CAD systems.

MR Imaging–Based Correction for Partial Volume Effect Improves Detectability of Intractable Epileptogenic Foci on Iodine 123 Iomazenil Brain SPECT Images: An Extended Study with a Larger Sample Size

It has been suggested, on the basis of a previous pilot study conducted in a small number of patients, that MR imaging-based PVE correction in I-123 iomazenil brain SPECT improves the detectability of cortical epileptogenic foci. In the present study, we performed an investigation by using a larger sample size to establish the effectiveness of the PVE correction and to conduct a detailed evaluation based on the histologic classification of lesions. Seventy-five patients (male/female, 37/38; age, 28 ± 12 years) with intractable epilepsy who had undergone surgical treatment were enrolled in this study. I-123 iomazenil SPECT and MR imaging examinations were performed before the operation in all patients. I-123 iomazenil SPECT images with and without MR imaging-based PVE correction were assessed visually and by semiquantitative analysis based on the AI(%) of the SPECT count in the resected lesions. The sensitivity, specificity, and accuracy of foci detection by visual assessment were significantly higher after PVE correction compared with the values obtained before the correction. The results of the semiquantitative analysis revealed that the asymmetry of the SPECT counts was significantly increased after the PVE correction in the surgically resected lesions in cases of mesial temporal sclerosis, tumor, and malformations of cortical development. The effectiveness of MR imaging-based PVE correction in I-123 iomazenil brain SPECT in improving the detection of cortical epileptogenic foci with abnormal histologic findings was established by our investigation conducted on a large sample size.

Estimation of 123I-IMP Arterial Blood Activity Using 123I-IMP Acquisition Data From the Lungs and Brain Without Any Blood Sampling

The conventional methods for the estimation of regional cerebral blood flow (rCBF) using ¹²³I-labeled N-isopropyl-p-iodoamphetamine (¹²³I IMP) autoradiography (ARG) require continuous or 1-point arterial blood sampling. Patients who need rCBF quantification benefit from the avoidance of arterial puncture. In this study, we attempted to develop a method without any blood sampling to estimate ¹²³I IMP activity in the arterial blood sample at 10 minutes after injection of ¹²³I IMP (Ca10) for the purpose of rCBF quantification. For the evaluation of validity of this method, the mean of rCBFs in various regions of the brain (mean CBF) calculated by ¹²³I IMP ARG method using the estimated Ca10 was compared with that calculated using the Ca10 directly measured with the actual arterial blood sample. Both groups of the mean CBF values were also compared with those measured by O-15 H₂O PET ARG method. I-123 IMP ARG study was applied to 23 patients, and O-15 H₂O PET ARG was applied to 20 patients of them. Dynamic images of the lungs, time series of static images of the brain, and brain SPECT images were acquired after injection of ¹²³I IMP. Arterial blood sampling was done 10 minutes after injection of ¹²³I IMP. Multiple regression analysis was used to estimate Ca10 using 5 parameters from the lung washout counts, time series of brain static counts, and brain SPECT average counts as the explanatory variables and the Ca10 directly measured with the actual arterial blood sample as the objective variable, and the regression equation was calculated. The regression equation was calculated by multiple regression analysis as follows: Estimated Ca10 = (2.09 × 10⁻² · LW3) - (2.29 × 10⁻⁴ · Cb5) - (9.87 × 10⁻³ · Cbpre-SPECT) + (1.06 · CbSPECTav) + (1.03 × 10⁻² · Cbpost-SPECT) + 165 (counts/s/g), where LW3: lung washout count at 3 minutes after injection, Cb5: brain count at 5 minutes, Cb pre-SPECT: brain count before SPECT, Cb SPECT av: average brain count during SPECT, and Cb post-SPECT: brain count after SPECT. The estimated Ca10 values closely correlated with the directly measured Ca10 values (r = 0.907, P < 0.01). The mean CBF values (mL/min/100 g) calculated by ¹²³I IMP ARG method using the estimated Ca10 also closely correlated with those calculated using the directly measured Ca10 (r = 0.818, P < 0.01). The mean CBF values calculated by the ¹²³I IMP ARG method using either the directly measured or the estimated Ca10 significantly correlated (r = 0.698 and 0.590, respectively; P < 0.01) with those measured by O-15 H₂O PET ARG method. The ¹²³I IMP arterial blood activity can be estimated reliably without any blood sampling using the ¹²³I IMP acquisition data from the lungs and brain. This method can serve for a convenient and noninvasive rCBF quantification technique instead of the conventional methods requiring arterial blood sampling.

Biodistribution and dosimetry of 123I-mZIENT: a novel ligand for imaging serotonin transporters

123I-labelled mZIENT (2β-carbomethoxy-3β-(3′-((Z)-2-iodoethenyl)phenyl)nortropane) has been developed as a radioligand for the serotonin transporter. The aim of this preliminary study was to assess its whole-body biodistribution in humans and estimate dosimetry. Three healthy controls and three patients receiving selective serotonin reuptake inhibitor (SSRI) therapy for depression were included (two men, four women, age range 41-56 years). Whole-body imaging, brain SPECT imaging and blood and urine sampling were performed. Whole-body images were analysed using regions of interest (ROIs), time-activity curves were derived using compartmental analysis and dosimetry estimated using OLINDA software. Brain ROI analysis was performed to obtain specific-to-nonspecific binding ratios in the midbrain, thalamus and striatum. Initial high uptake in the lungs decreased in later images. Lower uptake was seen in the brain, liver and intestines. Excretion was primarily through the urinary system. The effective dose was estimated to be of the order of 0.03 mSv/MBq. The organ receiving the highest absorbed dose was the lower large intestine wall. Uptake in the brain was consistent with the known SERT distribution with higher specific-to-nonspecific binding in the midbrain, thalamus and striatum in healthy controls compared with patients receiving SSRI therapy. ¹²³I-mZIENT may be a promising radioligand for imaging the serotonin transporters in humans with acceptable dosimetry.

The Clinical Utility of Brain SPECT Imaging in Process Addictions

Brain SPECT imaging is a nuclear medicine study that uses isotopes bound to neurospecific pharmaceuticals to evaluate regional cerebral blood flow (rCBF) and indirectly metabolic activity. With current available technology and knowledge SPECT has the potential to add important clinical information to benefit patient care in many different areas of a substance abuse practice, including in the area of process addictions. This article explores the ways brain SPECT has the potential to be useful to clinicians in helping to understand and direct treatment for complex cases of obesity and sexual addictions. Areas where SPECT can add value include helping clinicians ask better questions, helping them in making more complete diagnoses, evaluating underlying brain systems pathology, decreasing stigma and increasing compliance, and visualizing effectiveness via follow-up evaluations. In particular, SPECT can help in identifying and assessing the issue of brain trauma and toxicity in process addictions, which may be significant contributing factors in treatment failure. Three illustrative case histories will be given.

99m Tc-HMPAO in Brain SPECT Imaging; Feasibility of Ultra-Utilization of the Cold kit with higher 99mTc activities - A Chromatographic Study.

Brain SPECT imaging has become one of the most interesting subjects for most specialists in nuclear medicine because of its ability to present clear and detailed data about the brain anatomy and function, allowing the specialist to obtain the greatest sensitivity and specificity for disease detection (Catafau, 2001). Technetium-99m complex of hexamethyl propylene amineoxime (HMPAO) (which is called also exametazime) is widely used as an efficient brain perfusion agent due to the ability of the primary 99mTc-HMPAO complex to penetrate the intact blood-brain barrier (BBB) which is believed to be attributed to its lipophilic property (Hung, 1994). The primary lipophilic 99mTc-HMPAO complex is inherently unstable and rapidly converts to a secondary less lipophilic complex. Retention in the brain results from the inability of the secondary complex to cross the blood-brain barrier (Ponto, 1990). Thus, we have here one more impurity ligand in addition to the 2 other persisting impurities which are the free and hydrolyzed-reduced technetium. The radiochemical purity of the 99mTc-HMPAO preparation could be recognized by using a combination of three thin layer chromatographic (TLC) systems (Tikofsky, 1993). HMPAO commercial kits are one of the most expensive materials in nuclear medicine, in addition to that; the added Tc-99m activities proposed by the commercial venders can be enough to perform only 2 patient studies per vial which is not cost effective especially in developing countries that obstacles depending on brain SPECT as a routine imaging protocol. To overcome this, there are two postulated solutions; one is to collect a larger number of patients per session which is not practical as it may take several weeks to have a good number of patients especially in small NM facilities, the other solution is to do a cold kit fractionation which is best idea allowing having secured single patient doses at different times; however, this method needs a well trained personnel to perform it. These two solutions are still not fully applicable because of the limited Tc-99m capacity of the HMPAO vial; this motivated us to study the effect of adding up to 200% of the recommended activity to one of the commercial kits which will allow us to know to which activity limit we can have a safe preparation and if we exceeds these limits what will be the produced impurities out of this, and hence, the preparation is modifiable and recoverable or not