Post-mortem redistribution of 3,4-methylenedioxymethamphetamine (MDMA, "ecstasy") in the rabbit. Part II: post-mortem infusion in trachea or stomach

Drug concentrations in autopsy samples can also be influenced by post-mortem gastric diffusion when the stomach contains a substantial amount of the drug or by diffusion from the trachea when agonal aspiration or post-mortem regurgitation of vomit occurs. This was studied in a rabbit animal model in which MDMA solutions were infused post mortem either in the trachea or in the stomach. At 24, 48 or 72 h post mortem, samples including cardiac blood, vitreous humour, urine, bile, gastric content and several tissues were taken for toxicological analysis. After post-mortem tracheal infusion, MDMA can easily diffuse not only into the lungs but also in great quantities into the cardiac blood and, to a lesser extent, into the cardiac muscle. MDMA was also found in the closely adjacent diaphragm and in the upper abdominal organs, including the liver and the stomach. Following post-mortem infusion into the stomach, considerable MDMA levels were found in cardiac blood and muscle, both lungs, diaphragm and liver tissue when the solution was concentrated nearby the lower oesophageal sphincter. However, when the MDMA solution was present deeper in the stomach, MDMA levels were high in the spleen and the liver and relatively low in cardiac blood and muscle. In both experiments, MDA levels in most tissues were low or below the limit of quantitation, but were substantial in cardiac blood and muscle, lungs and diaphragm, indicating that MDMA can be metabolised to MDA after death. These results in the rabbit model indicate that the diffusion of MDMA out of the stomach content, or due to aspirated vomit and gastro-oesophageal reflux can lead to considerable post-mortem redistribution and thus should be taken into account in current forensic practice in order to draw the right conclusions when a peripheral blood sample is not available.     

Is vitreous humour useful for the interpretation of 3,4-methylenedioxymethamphetamine (MDMA) blood levels?

As drug instability and redistribution are factors known to affect the interpretation of post-mortem blood levels, we questioned whether post-mortem vitreous humour concentrations could be useful as predictors for the MDMA load at the time of death. In a first series of in vivo experiments using rabbits, 3,4-methylenedioxy-methamphetamine (MDMA) concentrations in plasma, blood and vitreous humour were studied as a function of time after intravenous (iv) administration of MDMA. Equilibration between the vascular compartment and vitreous humour was attained about 1 h after iv MDMA administration. In a second series of experiments, the post-mortem stability of MDMA in vitreous humour in relation to ambient temperature was investigated. Post-mortem MDMA concentrations in vitreous humour were closer to the ante-mortem blood levels when compared to cardiac blood samples. These preliminary investigations in the rabbit model indicate that measurements of vitreous humour concentrations could also be of interest for predicting the blood concentration at the time of death in humans. Received: 15 September 1999 / Accepted: 7 January 2000     

Post-mortem redistribution of 3,4-methylenedioxymethamphetamine (MDMA, "ecstasy") in the rabbit. Part I: experimental approach after in vivo intravenous infusion

Post-mortem redistribution is known to influence blood and tissue levels of various drugs. An animal model was used in an attempt to elucidate this problem for the amphetamine analogue, 3,4-methylenedioxymethamphetamine (MDMA). Rabbits received 1 mg/kg MDMA intravenously (iv) and were killed 2 h later in order to simulate the state of complete distribution in the body. MDMA and 3,4-methylenedioxyamphetamine (MDA) concentrations were determined in blood, urine, bile, vitreous humour, and various tissues (eye globe walls, brain, cardiac muscle, lungs, liver, kidneys, iliopsoas muscle and adipose tissue) using a high pressure liquid chromatographic (HPLC) procedure with fluorescence detection. In the first group (control group, sampling immediately post mortem) considerable MDMA concentrations were found in the brain and both lungs. In addition, our data indicate the elimination of MDMA by hepatic biotransformation and excretion via the bile. When the animals were preserved either 24 or 72 h post mortem (second group), an increase of MDMA and MDA levels in the liver and the eye globe walls was noticed. In the lungs, on the other hand, they tended to decline as a function of increasing post-mortem interval. MDMA levels in cardiac and iliopsoas muscle were fairly comparable and remained stable up to 72 h after death. In the third group, ligation of the large vessels around the heart took place immediately post mortem, but significant differences in blood and tissue MDMA concentrations between rabbits of group 2 and 3 could not be demonstrated. We therefore conclude that post-mortem redistribution of MDMA at the cellular level (viz. by pure diffusion gradient from higher to lower concentrations) is more important than its redistribution via the vascular pathway. Finally, MDA levels were relatively low in all samples, thus indicating that this is not a major metabolite in the rabbit, at least within the first 2 h after administration.     

Ocular disposition of diazepam in rabbits: understanding its level in vitreous humour for forensic applications

The disadvantages associated with routine toxicological samples, such as blood samples, have encouraged the forensic toxicologist to use vitreous humour as an alternative matrix. However, its use is still limited. The reason for this is the lack of a systematic study in this domain. Moreover, the phenomena of drug disposition in ocular tissues are mostly unexplored. This paper presents a controlled study to investigate the distribution of diazepam in post-mortem blood, vitreous humour and ocular tissues using rabbit as an animal model. This study reveals that diazepam levels in vitreous and aqueous humour increase with their decrease in whole blood at post-mortem. A further study on the distribution of diazepam in ocular tissues reveals that the anterior and posterior segment tissues might be responsible for the increase in diazepam levels in aqueous humour and vitreous humour respectively. The present study strengthens the possibility of using vitreous humour as a complementary sample to blood in forensic toxicological investigations.     

Relationship between post-mortem interval and creatine concentration in vitreous humour and cerebrospinal fluid

Many chemical-based methods have been examined for determination of the post-mortem interval (PMI) using body fluid. However, creatine, a non-protein nitrogen, has hardly been investigated over the last 20 years, even though the possibility of using it for PMI determination has been reported. The aim of the present study was to assess if creatine in vitreous humour and cerebrospinal fluid (CSF) correlates with PMI. Fifty-one subjects underwent vitreous humour and 56 subjects underwent CSF creatine measurement, respectively. The results showed that the creatine concentration increased linearly in the CSF and vitreous humour until about 50 and 90 hours after death, respectively. In particular, the creatine concentration in CSF (Pearson correlation = 0.79, p < 0.01) until 50 hours post-mortem was more strongly correlated with PMI than that in vitreous humour (Pearson correlation = 0.55, p < 0.01). Regarding the vitreous humour creatine concentration and PMI, our results showed a broad range at 24 hours post-mortem.     

Capillary zone electrophoresis and artificial neural networks for estimation of the post-mortem interval (PMI) using electrolytes measurements in human vitreous humour

Determination of electrolyte concentrations (mainly potassium) in vitreous humour has long been considered an important tool in human death investigations for the estimation of the post-mortem interval (PMI). On the basis of its well known potential in ion analysis, capillary zone electrophoresis (CZE) has recently been applied to achieve a rapid and simultaneous determination of inorganic ions in this extracellular fluid. In the present work, artificial neural networks (ANN) were applied for modelling of the relationship of multicomponent CZE analysis of K⁺, NH₄ ⁺, Na⁺, and Ba²⁺ ions in vitreous humour with PMI. In a study based on 61 cases with different causes of death and a known PMI ranging from 3 to 144 h, the use of ANNs considering all inorganic ion data from the human vitreous humour, achieved a substantial improvement of post-mortem interval prediction. Good linear correlation was observed (r ² = 0.98) and in comparison to the traditional linear least squares (LLS) method applied only to K⁺ levels in the vitreous humour, the prediction of PMI with ANN was improved by a factor of 5 from ≈± 15 h to less than 3 h. Received: 23 January 2001 / Accepted: 29 May 2001     

Diffusion as a mechanism of postmortem drug redistribution: An experimental study in rats

Summary In some cases of drug overdose there is a reservoir of unabsorbed drug in the stomach and gut. Furthermore, agonal aspiration might establish a second reservoir in the lungs. Two experimental rat models were used to study if diffusion from these reservoirs could contribute to the phenomenon of postmortem drug redistribution. Overnight fasted rats were sacrificed by CO₂ and 75 mg of amitriptyline (AMI) was administered by a gastric tube. In the first series (n = 19), the tubes were removed after AMI administration. In the second series (n = 17), the trachea was ligated and cut prior to drug administration to prevent airways contamination. The rats were left at room temperature on their back for a period of 5, 10, 24, 48, 96 up to 192 h and samples of heart blood, blood from the inferior vena cava, tissue samples from heart, lungs, different liver lobes, kidney and psoas muscle were taken. In both series of rats we observed that as early as 5 h postmortem increasing concentrations of amitriptyline were found in the liver lobes lying closest to the stomach. In rats where the trachea was not ligated, drug contamination of the lungs also resulted in an increase in drug concentration within 5 h in heart blood and heart muscle. In rats where the trachea had been ligated, amitriptyline was found in the lungs after 96 h postmortem. The main metabolite nortriptyline was also detected. We concluded that postmortem diffusion from the gastrointestinal tract could be a major mechanism behind the phenomenon of postmortem redistribution of drugs in human case material, and that agonal aspiration may be followed by a rapid increase in postmortem drug concentration in autopsy samples.      

Estimation of post-mortem interval: A comparison between cerebrospinal fluid and vitreous humour chemistry

Accurate estimation of post-mortem interval is of great importance in medico-legal autopsy cases. The present study is intended to compare the accuracy of estimating post-mortem interval from biochemical parameters of vitreous humour and cerebrospinal fluid (CSF). Both the fluids were collected from 100 medico-legal autopsies with known time of death and analysed for potassium, glucose, sodium, calcium, urea and creatinine. The current study found that vitreous humour is a better fluid in comparison to CSF for estimation of post-mortem interval. It is also observed that among the statistically significant parameters in both the fluids, level of potassium and sodium in vitreous humour are giving more accurate results in comparison to their corresponding parameters in CSF while accuracy of glucose is more or less same in both the fluid. Nevertheless potassium concentration in vitreous humour is a single best time honoured parameter to estimate post-mortem interval.     

A comparative study of five fatal cases of Taxus poisoning

The study presents five fatal cases of poisoning with Taxus spp., all of which were suicides of young people aged between 16 and 26 years. Yew leaves were consumed in four fatalities, whereas a mash from Taxus was ingested in one case. No relevant concentrations of alcohol, narcotic drugs, and pharmaceuticals were determined in postmortem toxicological screening. At forensic autopsy, a widely dilated pupil was found in two decedents. Furthermore, autopsy showed unspecific findings of intoxication in all cases: acute blood congestion of lungs, liver, kidney, and brain as well as dilated cardiac ventricles. No signs of violence could be found in any of the fatalities. Yew leaves were identified in four cases in the stomach and duodenum. 3,5-Dimethoxyphenol, the aglycon of the Taxus ingredient taxicatine, was determined as toxicological evidence for the absorption of yew ingredients. Taxus intoxication could be confirmed by 3,5-dimethoxyphenol concentrations in cardiac blood between 31 and 528 ng/ml for all cases. 3,5-Dimethoxyphenol was also detected in stomach contents as well as in urine, liver, kidneys, and brain samples. Based on the different concentrations of 3,5-dimethoxyphenol determined in the cardiac blood samples, it was concluded that the form of ingestion plays a decisive role in the process of poisoning. Finally, a toxic range for Taxus poisoning based on 3,5-dimethoxyphenol as marker substance is proposed as orientation.     

不同标准X射线RQR辐射场刻度眼晶状体当量剂量Hp(3)比较研究

目的通过在不同标准X射线RQR辐射场对Hp(3)进行刻度,并对刻度结果进行比较,探究国内标准X射线RQR辐射场刻度Hp(3)的可行性。方法选择直径20 cm、高20 cm的柱模,分别选取国内外标准X射线RQR辐射场对同一TLD进行Hp(3)的刻度,选择射线包括RQR4(60 kV)、RQR7(90 kV)、RQR9(120 kV),刻度内容包括能量响应、角度响应和线性响应。结果在能量响应方面,TLD对国内外标准X射线RQR辐射场响应均较好,响应值与照射值差异均在10%以内。在角度响应方面,TLD在国外辐射场响应值较好,响应值与照射值差异均在6%以内。而在国内辐射场,TLD在20°响应值偏低,响应值与照射值差异>10%。在线性响应方面,TLD在国内和国外标准X射线RQR辐射场拟合程度均较好。结论本研究的各项检测结果表明,国内标准X射线RQR辐射场可以对TLD进行Hp(3)的刻度。     

Biodistribution and radiation dosimetry of the norepinephrine transporter radioligand (<Emphasis Type="Italic">S</Emphasis>,<Emphasis Type="Italic">S</Emphasis>)-[<Superscript>18</Superscript>F]FMeNER-D<Subscript>2</Subscript>: a human whole-body PET study

Purpose (S,S)-[¹⁸F]FMeNER-D₂ is a recently developed positron-emission tomography (PET) radioligand for in vivo quantification of the norepinephrine transporter system. The aim of this study was to provide dosimetry estimates for (S,S)-[¹⁸F]FMeNER-D₂ based on human whole-body PET measurements. Methods PET scans were performed for a total of 6.4 h after the injection of 168.9 ± 31.5 MBq of (S,S)-[¹⁸F]FMeNER-D₂ in four healthy male subjects. Volumes of interest were drawn on the coronal images. Estimates of the absorbed dose of radiation were calculated using the OLINDA software. Results Uptake was largest in lungs, followed by liver, bladder, brain and other organs. Peak values of the percent injected dose (%ID) at a time after radioligand injection were calculated for the lung (21.6%ID at 0.3 h), liver (5.1%ID at 0.3 h), bladder (12.2%ID at 6 h) and brain (2.3%ID at 0.3 h). The largest absorbed dose was found in the urinary bladder wall (0.039 mGy/MBq). The calculated effective dose was 0.017 mSv/MBq. Conclusion Based on the distribution and dose estimates, the estimated radiation burden of (S,S)-[¹⁸F]FMeNER-D₂ is lower than that of [¹⁸F]FDG. The radioligand would allow multiple PET examinations in the same research subject per year.     

Structural modification of receptor-binding technetium-99m complexes in order to improve brain uptake

Low brain uptake is a generally accepted problem in developing technetium-99m brain receptor imaging agents. For a class of potential 5-HT_2A receptorbinding agents we tried to improve the original low brain uptake of 0.4% injected dose (ID) in rats 5 min p.i. by modifying the lipophilic properties of the molecules. Because of the presence of a protonable nitrogen, which according to the pK _a value leads to ionization of the molecule at blood pH, the pK _a value was considered to be the parameter most suitable for adjustment of lipophilicity. Insertion of ether-oxygen in the molecule of five candidates lowers the apparent pK _a value from 10.0 to 8.3 and dramatically increases the brain uptake to 1.3% ID at 5 min. The direct relationship between brain uptake and apparent pK _a cannot be simply explained by the increase in the pK _a-governed proportion of the neutral species.     

Influence of the nature of death in biochemical analysis of the vitreous humour for the estimation of post-mortem interval

ABSTRACT

Post-mortem biochemistry as a tool for the establishment of post-mortem interval (PMI) and the nature of death is very useful in Legal Medicine. Currently, several matrices are used for these investigations, although vitreous humour is the most useful for biochemical analysis due to its stability and low susceptibility to autolytic changes. The purpose of this study was to analyse to what extent the nature of death could influence in the measurement of parameters such us potassium (K⁺), hypoxanthine (Hx) and uric acid in the establishment of PMI. Samples of vitreous humour were collected from the eyes of 250 dead bodies (174 males, 76 females) with a mean age of 58.75 ± 20.84 years, mean PMI of 15.56 ± 6.21 hours post-mortem (hpm) and different causes of death, including natural (n = 148) and violent (n = 101) deaths. The vitreous humour was treated and the resultant supernatant was used for the biochemical analysis. Multichannel Autoanalyser was used to determine the concentrations of K⁺ and uric acid (mmol/L), and Hx (µmol/L) was quantified by HPLC-UV. The results showed the measurement of K⁺, Hx and uric acid together could be a complementary tool for establishing the PMI because these parameters provide good results.     

Imaging the norepinephrine transporter with positron emission tomography: initial human studies with (<Emphasis Type="Italic">S,S</Emphasis>)-[<Superscript>18</Superscript>F]FMeNER-D<Subscript>2</Subscript>

Introduction (S,S)-[¹⁸F]FMeNER-D₂ is a recently developed positron emission tomography (PET) ligand for in vivo quantification of norepinephrine transporter. A monkey occupancy study with the radioligand indicated that (S,S)-[¹⁸F]FMeNER-D₂ can be useful for quantitative PET analysis. In this preliminary study, regional distributions in the living human brain were evaluated. Materials and methods Brain PET measurements were performed for a total of 255 min after the injection of 188.3 ± 5.7 MBq of (S,S)-[¹⁸F]FMeNER-D₂ in four healthy male subjects. Regions of interests were drawn on the thalamus and the caudate in the coregistered MRI/PET images. Results (S,S)-[¹⁸F]FMeNER-D₂ displayed good brain penetration and selective retention in regions rich in norepinephrine reuptake sites. The transient peak equilibrium was reached during the PET measurements. The ratios of radioactivity uptake in the thalamus to that in the caudate were 1.50 ± 0.06 for the time period of 90–255 min. Conclusion The present preliminary investigation indicates that (S,S)-[¹⁸F]FMeNER-D₂ has suitable characteristics for probing the norepinephrine reuptake system with PET in the human brain.     

Radiation dosimetry of <Emphasis Type="Italic">N</Emphasis>-([<Superscript>11</Superscript>C]methyl)benperidol as determined by whole-body PET imaging of primates

Purpose N-([¹¹C]methyl)benperidol ([¹¹C]NMB) can be used for positron emission tomography (PET) measurements of D₂-like dopamine receptor binding in vivo. We report the absorbed radiation dosimetry of i.v.-administered ¹¹C-NMB, a critical step before applying this radioligand to imaging studies in humans. Materials and methods Whole-body PET imaging with a CTI/Siemens ECAT 953B scanner was done in a male and a female baboon. After i.v. injection of 444–1221 MBq of ¹¹C-NMB, sequential images taken from the head to the pelvis were collected for 3 h. Volumes of interest (VOIs) were identified that entirely encompassed small organs (whole brain, striatum, eyes, and myocardium). Large organs (liver, lungs, kidneys, lower large intestine, and urinary bladder) were sampled by drawing representative regions within the organ volume. Time–activity curves for each VOI were extracted from the PET, and organ residence times were calculated by analytical integration of a multi-exponential fit of the time–activity curves. Human radiation doses were estimated using OLINDA/EXM 1.0 and the standard human model. Results Highest retention was observed in the blood and liver, each with total residence times of 1.5 min. The highest absorbed radiation doses were to the heart (10.5 mGy/kBq) and kidney (9.19 mGy/kBq), making these the critical organs for [¹¹C]NMB. A heart absorption of 50 mGy would result from an injected dose of 4,762 MBq [¹¹C]NMB. Conclusions Thus, this study suggests that up to 4,762 MBq of [¹¹C]NMB can be safely administered to human subjects for PET studies. Total body dose and effective dose for [¹¹C]NMB are 2.82 mGy/kBq and 3.7 mSv/kBq, respectively.     

Quantitative determination of taxine B in body fluids by LC–MS–MS

A new specific and sensitive LC–MS–MS method for the detection of taxine B and isotaxine B, the main toxic pseudo-alkaloids from yew (Taxus sp.), in biological samples (blood, urine, gastric content) was developed. Biological samples were prepared for LC–MS–MS by means of solid-phase extraction (SPE) procedure and yielded a recovery of 86%. Chromatographic separation was achieved using an RP₁₈ column. Detection of taxine B and isotaxine B was performed using multiple reaction monitoring with m/z 584.2 as precursor ion, i.e. [M+H]⁺, of both isomers and m/z 194.3 and m/z 107.1 as product ions after collision-induced dissociation. Docetaxel was applied as internal standard. The method was fully validated for the analysis of blood samples. Linearity was proven in the range from 0.1–500 ng/g. The limit of detection and the limit of quantitation are 0.4 and 2 ng/g, respectively. The method was applied to the determination of taxine B and isotaxine B in four fatal cases (two humans, two horses) with suspected yew intoxication. Blood levels were 105, 168, 174 and 212 ng/g.     

In vitro formation of ethanol in autopsy samples containing fluoride ions

We present a case of a death of a diabetic man where the concentration of ethanol in post-mortem blood rose from 0.4 g/l 2 days after autopsy to 3.5 g/l 10 days after autopsy. The presence of fluoride ions in this blood sample was determined with ion chromatography and verified that fluoride ions were added to the vials. The concentrations of free fluoride, corresponding to 0.21 and 0.25% w/v potassium fluoride in blood and urine, respectively, were somewhat lower than the recommended 1% w/v. However, the amount of fluoride ions bound to calcium, proteins and other compounds in the samples is unknown. The blood sample was also subject to microbiological examination, which revealed growth of bacteria. In addition, a very high concentration of glucose was found in vitreous humour from the deceased. To determine whether the ethanol detected at the first analysis was of ante-mortem origin, ethyl glucuronide was analysed. Its absence, in the blood as well as the urine sample, strongly supported the theory that, in this case, all the ethanol detected was formed post-mortem. This case showed that ethanol may be formed in vitro at a very high concentration, despite the verified presence of fluoride ions. Possible reasons for this unusual formation of ethanol were the abundant presence of bacteria, a high level of glucose and, possibly, an insufficient amount of fluoride added to the vials.     

FDG—a marker of tumour hypoxia? A comparison with [18F]fluoromisonidazole and pO2-polarography in metastatic head and neck cancer

Purpose Experimental data suggest that the accumulation of [¹⁸F]fluorodeoxyglucose (FDG) in malignant tumours is related to regional hypoxia. The aim of this study was to evaluate the clinical potential of FDG positron emission tomography (PET) to assess tumour hypoxia in comparison with [¹⁸F]fluoromisonidazole (FMISO) PET and pO₂-polarography. Methods Twenty-four patients with head and neck malignancies underwent FDG PET, FMISO PET, and pO₂-polarography within 1 week. Parameters of pO₂-polarography were the relative frequency of pO₂ readings ≤2.5 mmHg, ≤5 mmHg and ≤10 mmHg, respectively, as well as the mean and median pO₂. Results We observed a moderate correlation of the maximum standardised uptake value (SUV) of FDG with the tumour to blood ratio of FMISO at 2 h (R=0.53, p<0.05). However, SUV of FDG was similar in hypoxic and normoxic tumours as defined by pO₂-polarography (6.9±3.2 vs 6.2±3.0, NS), and the FDG uptake was not correlated with the results of pO₂-polarography. The retention of FMISO was significantly higher in hypoxic tumours than in normoxic tumours (tumour to muscle ratio at 2 h: 1.8±0.4 vs 1.4±0.1, p<0.05), and the FMISO tumour to muscle ratio showed a strong correlation with the frequency of pO₂ readings ≤5 mmHg (R=0.80, p<0.001). Conclusion These results support the hypothesis that tumour hypoxia has an effect on glucose metabolism. However, other factors affecting FDG uptake may be more predominant in chronic hypoxia, and thus FDG PET cannot reliably differentiate hypoxic from normoxic tumours.     

Radio-iodine therapy and <Emphasis Type="Italic">Helicobacter pylori</Emphasis> infection

Background  Helicobacter pylori is the most important cause of gastritis and related morbidities. Following consumption, radioactive iodine accumulates considerably in the stomach. On the basis of this observation, we decided to determine whether the high radiation induced by radio-iodine in the stomach is effective in the eradication of this infection. Methods  All consecutive patients with differentiated thyroid carcinoma, who were referred for radio-iodine therapy [dose 117.1 ± 24.4 mCi (4.3 ± 0.9 GBq), range 100–200 mCi (3.7–7.4 GBq)], were enrolled. To detect H. pylori infection, the urease breath test (UBT) was performed 1-2 h before radio-iodine consumption and the test was repeated 2 months later. Results  Of 88 patients, 71 had pre-treatment positive UBT. Of these, 23 patients had negative post-treatment result, which means a significant reduction (26.1%, 95% CI 16.8–35.5%) in the number of positive UBT results in our treated population (32.4% of UBT-positive cases became UBT-negative). Conclusions  Considering the high prevalence of reinfection in developing countries, the therapeutic benefit would have been more considerable if the second UBT had been done with a lag time of less than 2 months. Although radio-iodine therapy is not a logical method for the treatment of patients suffering from H. pylori, our finding provides indirect evidence about the radiosensitivity of bacteria, the future clinical applications of which need to be further evaluated. Also this finding can be useful for the food industry, where radiation is used widely to sterilize food. Regarding the possibility of H. pylori suppression, we recommend not using UBT for screening for the infection for at least within 2 months following radio-iodine therapy.     

Non-invasive estimation of hepatic blood perfusion from H2 15O PET images using tissue-derived arterial and portal input functions

Purpose  The liver is perfused through the portal vein and the hepatic artery. When its perfusion is assessed using positron emission tomography (PET) and ¹⁵O-labeled water (H₂ ¹⁵O), calculations require a dual blood input function (DIF), i.e., arterial and portal blood activity curves. The former can be generally obtained invasively, but blood withdrawal from the portal vein is not feasible in humans. The aim of the present study was to develop a new technique to estimate quantitative liver perfusion from H₂ ¹⁵O PET images with a completely non-invasive approach. Methods  We studied normal pigs (n = 14) in which arterial and portal blood tracer concentrations and Doppler ultrasonography flow rates were determined invasively to serve as reference measurements. Our technique consisted of using model DIF to create tissue model function and the latter method to simultaneously fit multiple liver time–activity curves from images. The parameters obtained reproduced the DIF. Simulation studies were performed to examine the magnitude of potential biases in the flow values and to optimize the extraction of multiple tissue curves from the image. Results  The simulation showed that the error associated with assumed parameters was <10%, and the optimal number of tissue curves was between 10 and 20. The estimated DIFs were well reproduced against the measured ones. In addition, the calculated liver perfusion values were not different between the methods and showed a tight correlation (r = 0.90). Conclusion  In conclusion, our results demonstrate that DIF can be estimated directly from tissue curves obtained through H₂ ¹⁵O PET imaging. This suggests the possibility to enable completely non-invasive technique to assess liver perfusion in patho-physiological studies.