27 research outputs found
Comparison of 99mTc-DMSA renal scintigraphy with biochemical and histopathological findings in animal models of acute kidney injury
Biochemical and histological assays are currently
used for the diagnosis and characterization of kidney
injury. The purpose of this study was to compare technetium-
99m-labeled dimercaptosuccinic acid (99mTc-
DMSA) renal scintigraphy, as a non-invasive method, with
common biochemical and histopathological methods in
two animal models of acute kidney injury. Nephrotoxicity
was induced either by gentamicin (100 mg/kg/day for one
week) or unilateral ureteral ligation (UUO). Renal
scintigraphy was performed 1 h after intravenous injection
of 99mTc-DMSA (3 mCi). Furthermore, plasma levels of
blood urea nitrogen (BUN), creatinine, sodium, and
potassium were determined using an autoanalyzer. At the
end of experiments, kidneys were excised for the measurement
of activity uptake (mCi/gr) using a dose calibrator
as well as histopathological examinations with
hematoxylin and eosin (H&E) staining. There was a significant
decrease in 99mTc-DMSA uptake in both gentamicin
(P value = 0.049) and UUO (P value = 0.034)
groups, and it was more significant in the former. The
levels of BUN and creatinine increased in both gentamicin
and UUO groups, while the levels of sodium and potassium
remained unchanged. Furthermore, a strong correlation was
found between DMSA uptake and histopathological findings.
Scintigraphy with 99mTc-DMSA is capable of
detection of kidney injury in both gentamicin and UUO
groups. Moreover, a significant correlation was found
between scintigraphy parameters and histopathological
findings. This suggests 99mTc-DMSA as a non-invasive
method for the evaluation of kidney injury induced by
drugs or anatomical disorders
Review of biomedical ÄŒerenkov luminescence imaging applications
Abstract: ÄŒerenkov radiation is a fascinating optical signal, which has been
exploited for unique diagnostic biological sensing and imaging, with
significantly expanded use just in the last half decade. ÄŒerenkov
Luminescence Imaging (CLI) has desirable capabilities for niche
applications, using specially designed measurement systems that report on
radiation distributions, radiotracer and nanoparticle concentrations, and are
directly applied to procedures such as medicine assessment, endoscopy,
surgery, quality assurance and dosimetry. When compared to the other
imaging tools such as PET and SPECT, CLI can have the key advantage of
lower cost, higher throughput and lower imaging time. CLI can also provide
imaging and dosimetry information from both radioisotopes and linear
accelerator irradiation. The relatively short range of optical photon transport
in tissue means that direct ÄŒerenkov luminescence imaging is restricted to
small animals or near surface human use. Use of ÄŒerenkov-excitation for
additional molecular probes, is now emerging as a key tool for biosensing
or radiosensitization. This review evaluates these new improvements in CLI
for both medical value and biological insigh
Assessment of the maximum uptake time of 99mTc-DMSA in renal scintigraphy in rat
Introduction: The optimal imaging time of a radionuclide scintigraphy is the time at which the organ of interest has the maximum
uptake of the injected radionuclide. This study was performed to investigate the maximum uptake time of 99mTc-DMSA in rat renal
scan.
Methods: Renal scintigraphy was performed with 3 mCi of 99mTc-DMSA. Planar images were acquired every 20 minutes for 8 hours
post-injection using a small-animal SPECT.
Results: Activity and the count rate per pixel (CRPP) of the kidneys peaked 1 h post-injection, plateaued for about 1 h, and declined
time-dependently. Kidney to background ratio (KBR) reached to 61.7% at 1 h after injection and remained almost constant afterwards.
Conclusion: The kidneys had maximum emission and CRPP between 1 to 2 h after 99mTc-DMSA injection, whereas there was no
significant difference between the KBRs after 1 h. Our results showed that image acquisition of 1-2 h post-injection is recommended
for renal scintigraphy with DMSA in rat
Effects of intrathecal opioids use in cesarean section on breastfeeding and newborns’ weight gaining
Objective: To assess the association between intrapartum intrathecal opioid use and breastfeeding and weight gain following cesarean section.
Materials and methods: The prospective double-blinded study was conducted on term pregnant women, undergoing elective cesarean section under spinal anesthesia. They divided into two groups. In the first group, intrathecal Morphine was used to achieve analgesia during or after the operation. The remainder divided into two subgroups, those who did not receive any opioid or those received systemic opioids. Following labor breastfeeding accessed in a follow-up, two month latter.
Results: There was no difference between the demographic variables of the mothers and newborns APGAR score and weight at the time of birth. Breastfeeding rate was similar in intrathecal group in compare with other patents (P value = 0.518). While, the infants’ weight at the end of second month was lower in spinal opioid group (P value = 0.036).
Conclusion: The present study was the first to suggest that spinal (intrathecal) opioids do not have any impact on breastfeeding. However the relationship between spinal anesthesia on weight gaining needs more investigation
The Effect of Electromagnetic Field Generated by a Mobile Phone on the Performance of a SPECT Scanner
Purpose: The aim of the current attempt was quantitative investigation of the
electromagnetic interference (EMI) of amobile phonewith the function of a SPECT
gamma camera during data acquisition.
Materials and Methods:We tested the effect of a mobile phone, in both ringing
mode and standby mode, on one SPECT gamma camera during scanning a cylindrical
phantom containing 5.4 mCi 99mTc. The experiment was performed for
different distances of 10, 12, 14, 16, 18, 20, 25, and 30 cm betweenmobile phone
and head of the scanner, and for different head angles of 0, 30, 60, 90, 120, 150,
and 180 degrees. A RF-EMF meter measured strength of electromagnetic field
throughout the study. Statistically significant decrease in count number was considered
to be electromagnetic interference.
Results: There was significant reduction in the recorded counts during ringing of
the mobile phone in all studied distances. For gamma camera, fixed at a distance,
there was no uniform pattern of reduction of the counts at different angles between
two operation modes of the mobile phone.
Conclusions: A mobile phone, at close distance, can be a sensible source of electromagnetic
field, disturbing the normal function of a gamma camera
Implementation of absolute quantification in small-animal SPECT imaging: Phantom and animal studies
Purpose: Presence of photon attenuation severely challenges quantitative accuracy
in single-photon emission computed tomography (SPECT) imaging. Subsequently,
various attenuation correction methods have been developed to compensate for
this degradation. The present study aims to implement an attenuation correction
method and then to evaluate quantification accuracy of attenuation correction in
small-animal SPECT imaging.
Methods: Images were reconstructed using an iterative reconstruction method
based on the maximum-likelihood expectation maximization (MLEM) algorithm
including resolution recovery. This was implemented in our designed dedicated
small-animal SPECT (HiReSPECT) system. For accurate quantification, the voxel values
were converted to activity concentration via a calculated calibration factor. An
attenuation correction algorithm was developed based on the first-order Chang’s
method. Both phantom study and experimental measurements with four rats were
used in order to validate the proposed method.
Results: The phantom experiments showed that the error of �15.5% in the estimation
of activity concentration in a uniform region was reduced to +5.1% when
attenuation correction was applied. For in vivo studies, the average quantitative
error of �22.8 � 6.3% (ranging from �31.2% to �14.8%) in the uncorrected images
was reduced to +3.5 � 6.7% (ranging from �6.7 to +9.8%) after applying attenuation
correction.
Conclusion: The results indicate that the proposed attenuation correction algorithm
based on the first-order Chang’s method, as implemented in our dedicated small-animal
SPECT system, significantly improves accuracy of the quantitative analysis as
well as the absolute quantification
Implementation of absolute quantification in small-animal SPECT imaging: Phantom and animal studies
Purpose: Presence of photon attenuation severely challenges quantitative accuracy
in single-photon emission computed tomography (SPECT) imaging. Subsequently,
various attenuation correction methods have been developed to compensate for
this degradation. The present study aims to implement an attenuation correction
method and then to evaluate quantification accuracy of attenuation correction in
small-animal SPECT imaging.
Methods: Images were reconstructed using an iterative reconstruction method
based on the maximum-likelihood expectation maximization (MLEM) algorithm
including resolution recovery. This was implemented in our designed dedicated
small-animal SPECT (HiReSPECT) system. For accurate quantification, the voxel values
were converted to activity concentration via a calculated calibration factor. An
attenuation correction algorithm was developed based on the first-order Chang’s
method. Both phantom study and experimental measurements with four rats were
used in order to validate the proposed method.
Results: The phantom experiments showed that the error of �15.5% in the estimation
of activity concentration in a uniform region was reduced to +5.1% when
attenuation correction was applied. For in vivo studies, the average quantitative
error of �22.8 � 6.3% (ranging from �31.2% to �14.8%) in the uncorrected images
was reduced to +3.5 � 6.7% (ranging from �6.7 to +9.8%) after applying attenuation
correction.
Conclusion: The results indicate that the proposed attenuation correction algorithm
based on the first-order Chang’s method, as implemented in our dedicated small-animal
SPECT system, significantly improves accuracy of the quantitative analysis as
well as the absolute quantification
Serological, pathological and scintigraphic assessment of Hemiscorpius lepturus effects on renal dysfunction in rats
Objective(s): Hemiscorpius lepturus is one of the dangerous scorpions of Iran leading to acute kidney injury (AKI) especially in infants. The purpose of this animal study was to compare the serological, pathological and scintigraphic data to quickly predict the occurrence of this disorder.Materials and Methods: In two groups of animals, each contained five rats, H. lepturus venom (1200 µg/Kg) were injected intravenously via the tail vein. At three hours and one week later, 99m Tc-DMSA (3 mCi) was intravenously injected and renal scintigraphy was performed after an hour. Moreover, plasma levels of creatinine, sodium, potassium, and blood urea nitrogen (BUN) were measured. At the end of the study, renal tissues were excised and prepared to perform pathological evaluation after Hematoxylin and Eosin staining.Results: All serological indices were remained unchanged compared to control. A large number of glomerular fibrin thrombi with entrapped red blood cells and simplified tubular epithelium in dilated and ectatic tubules were observed in high power field (×100) four hours after envenomation, which reduced significantly one week later. In our scintigraphic study, there was a statistically significant difference (
Calculation of standardized uptake values (SUVs) and time activity curves (TACs) of mice in FDG-PET
Positron Emission Tomography (PET) with 18Ffluorodeoxyglucose (FDG) is an important imaging practice in cancer diagnosis, staging, treatment planning, and response assessment. Accurate interpretation of PET results requires an understanding of FDG uptake in organs. The time activity curve (TAC) and standardized uptake value (SUV) are the two common tools to measure tracer uptake in regions of interest. The TAC provides information on glucose consumption dynamics, while the SUV involves measuring the amount of tracer taken up by a specific region or volume of interest, and then adjusting the measurement by the amount of tracer injected and the subject’s characteristics. In the current study, we measured the TACs and SUVs of the heart, brain, kidney, and muscle in ten mice injected with FDG over a period of 120 minutes. According to the TACs obtained in this study, the brain has a slower uptake than the other organs with a tendency to keep the FDG for a longer period of time. Also, the SUV of the brain showed a rising trend until the middle of the experiment with a sharp falloff afterwards. The pattern of the curves of the other three organs was almost the same. The findings of this study were in agreement with a similar study on humans and are explained by the metabolic activity and physiology of the organs studied
Fetal Laceration Injury at Caesarean Delivery
 Objective: The purpose of this study was to investigate the incidence, type, location, and risk factors of accidental fetal lacerations during caesarean delivery.
Material and Methods: Total deliveries, caesarean deliveries, and neonatal records for documented accidental fetal lacerations were reviewed retrospectively in four university hospital. Thegestational age, the presenting part of the fetus, the type of incision, and maternal age and parity were recorded. Caesarean deliveries were divided into elective and emergency procedures. Fetal lacerations were grouped according to the location and the need for surgical intervention.
Results: Of 19217 deliveries, 8840 women were delivered by caesarean birth (46%). Neonatal records documented 87 accidental fetal lacerations. Of these accidental lacerations, 16 needed surgical repair and 62 recovered by dressing. Head and neck was the most common site of laceration (64.1%). The overall rate of accidental fetal laceration per caesarean delivery was 0.88%. The rate of emergency caesarean was 45 (56.69%) and for elective procedures was 33 (42.4%). The risk for fetal accidental laceration was higher in foetuses who underwent emergency caesarean birth (P<0.001).
Conclusion: Fetal accidental laceration may occur during caesarean delivery and its incidence is significantly higher during emergency caesarean delivery. The patient should be counselled about the occurrence of fetal laceration during caesarean delivery to avoid litigation