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Positron emission tomography (PET) can be utilized in particle beam therapy to verify the dose distribution of the target volume as well as the accuracy of the treatment. We present an in-beam PET scanner that can be integrated into a particle beam therapy system. The proposed PET scanner consisted of 14 detector modules arranged in a C-shape to avoid blockage of the particle beam line by the detector modules. Each detector module was composed of a 9×9 array of 4.0 mm×4.0 mm×20.0 mm LYSO crystals optically coupled to four 29-mm-diameter PMTs using the photomultiplier-quadrant-sharing (PQS) technique. In this study, a Geant4 Application for Tomographic Emission (GATE) simulation study was conducted to design a C-shaped PET scanner and then experimental evaluation of the proposed design was performed. The spatial resolution and sensitivity were measured according to NEMA NU2-2007 standards and were 6.1 mm and 5.61 cps/kBq, respectively, which is in good agreement with our simulation, with an error rate of 12.0%. Taken together, our results demonstrate the feasibility of the proposed C-shaped in-beam PET system, which we expect will be useful for measuring dose distribution in particle therapy. [ABSTRACT FROM AUTHOR]

We assessed the role of F-18 FDG PET/CT in evaluating isolated extra-axillary lymph node recurrences in postoperative breast cancer patients and its prognostic value on clinical outcome. We reviewed PET/CT scans of postoperative breast cancer patients performed at our institution between July 2003 and February 2012. We recorded PET/CT findings, clinicopathologic variables and treatment modalities. We analyzed metabolic parameters from PET/CT and clinicopathologic variables with respect to progression free survival (PFS). A total of 3561 PET/CT scans were performed in 1906 postoperative breast cancer patients with a median interval of 43 month from curative surgery. Fifty seven patients (2.99%) demonstrated isolated extra-axillary nodal recurrences (n=85) on PET/CT (internal mammary node recurrences in 28, supraclavicular 24, infraclavicular 4, interpectoral 8, cervical 12, and mediastinal 9).The median SUVmax was 7.8 (range, 1.8~19.0), and the median node size was 15 mm (range, 6~38 mm). All recurrences were nonpalpable. Based on PET/CT findings, 53 out of 57 patients with extra-axillary node recurrences underwent subsequent chemotherapy/radiation therapy. The estimated 3-year PFS rate was 48.6%. Cutoff points of SUVmax 2.7 and size 14 mm were the best discriminative values for predicting clinical outcome. SUVmax and size of extra-axillary nodal recurrences were significantly correlated to PFS on univariate and multivariate analyses (p<0.001 and p=0.019, respectively). [ABSTRACT FROM AUTHOR]

We assessed the role of F-18 FDG PET/CT in evaluating isolated extra-axillary lymph node recurrences in postoperative breast cancer patients and its prognostic value on clinical outcome. We reviewed PET/CT scans of postoperative breast cancer patients performed at our institution between July 2003 and February 2012. We recorded PET/CT findings, clinicopathologic variables and treatment modalities. We analyzed metabolic parameters from PET/CT and clinicopathologic variables with respect to progression free survival (PFS). A total of 3561 PET/CT scans were performed in 1906 postoperative breast cancer patients with a median interval of 43 month from curative surgery. Fifty seven patients (2.99%) demonstrated isolated extra-axillary nodal recurrences (n=85) on PET/CT (internal mammary node recurrences in 28, supraclavicular 24, infraclavicular 4, interpectoral 8, cervical 12, and mediastinal 9).The median SUVmax was 7.8 (range, 1.8~19.0), and the median node size was 15 mm (range, 6~38 mm). All recurrences were nonpalpable. Based on PET/CT findings, 53 out of 57 patients with extra-axillary node recurrences underwent subsequent chemotherapy/radiation therapy. The estimated 3-year PFS rate was 48.6%. Cutoff points of SUVmax 2.7 and size 14 mm were the best discriminative values for predicting clinical outcome. SUVmax and size of extra-axillary nodal recurrences were significantly correlated to PFS on univariate and multivariate analyses (p<0.001 and p=0.019, respectively). [ABSTRACT FROM AUTHOR]

Abstract: In recent years, there has been an increasing interest in the magnetic resonance (MR)-compatible positron emission tomography (PET) scanners for both clinical and preclinical practice. The aim of this study was to design a novel PET detector module using a segmented block crystal readout with an array of multi-pixel photon counters (MPPCs). A 16.5×16.5×10.0mm3 LSO block was segmented into an 11×11 array, and reflective material was used to fill in the cuts to optically isolate the elements. The block was attached to a 4×4 MPPC array (Hamamatsu S11064) of 3.0×3.0mm2 detectors to give a total effective area of 144mm2. To visualize all the individual detector elements in this 11×11 detector module, the depth of the cuts was optimized by DETECT2000 simulations. The depth of the cuts determines the spread of scintillation light onto the MPPC array. The accuracy of positioning was evaluated by varying the depth of the cuts from 0.0 to 10.0mm in steps of 0.5mm. A spatial resolution of 1.5mm was achieved using the optimized partially segmented block detector. The simulation results of this study can be used effectively as a guide for parameter optimization for the development of a partially segmented block detector for high-resolution MR-compatible PET scanners. [Copyright &y& Elsevier]

Abstract: In recent years, small-animal PET scanners with depth of interaction (DOI) capability have been developed for molecular imaging research. The aim of this study is to perform simulations to design a high performance small-animal PET, called TraPET. TraPET has an inner diameter of 76.21mm with 6 dual-layer phoswich detector modules. Each module is composed of a 5.0-mm-thick trapezoidal-monolithic-LSO crystal with a front face (surface facing toward the inside of the scanner) of 44.0×44.0mm2 and a back face of 50.0×50.0mm2 and a 25×25 array of LuYAP crystals with a 2.0×2.0mm2 sensitive area with a 15.0mm thickness. DOI information is extracted by a pulse shape discrimination method. The ability of event positioning in the trapezoidal-monolithic-LSO was evaluated by modeling the light distribution in the crystal using DETECT2000 and a 16×16 array of silicon photo-multipliers (SiPMs), with a 3.0mm pixel size, selected as the photo-sensor. Also, the sensitivity and gap filling effect between modules were simulated using the Monte Carlo code, GATE. The new detector showed higher and more uniform sensitivity, as compared to scanners with rectangular-shaped detectors, because the trapezoidal-monolithic-LSO minimizes the dead space within the detector ring. In conclusion, our new detector proved to be a reliable design for small-animal PET with high spatial resolution by DOI information, and high sensitivity by high filling fraction. [Copyright &y& Elsevier]

Abstract: We have built a four-layer detector to obtain depth of interaction (DOI) information in which all four layers have a relative offset of half a crystal pitch with each other. The main characteristics of the detector, especially the energy and spatial resolutions, strongly depend on the crystal surface treatments. As a part of the development of an animal PET, we have investigated the effect of crystal surface treatment on detector performances using Monte Carlo simulations in order to optimize the surface conditions of crystals composing a four-layer detector. The proposed detector consists of four LYSO layers with crystal dimensions of 1.5×1.5×7.0 and 1.5×1.5×5.0mm3. A simulation tool (DETECT2000) was used and validated against the experimental results; flood images were acquired by a prototype module. Flood images were simulated by varying the surface treatment of the crystals. The optimal surface conditions of the four-layer crystals were derived for a small animal PET with a view towards achieving high sensitivity, as well as high and uniform radial resolution. [ABSTRACT FROM AUTHOR]

Abstract: In our previous work, the new detector module with depth of interaction (DOI) based on a quasi-monolithic crystal array and maximum-likelihood position-estimation (MLPE) algorithm was designed and the methodology for 3D event positioning in the detector was established by using Monte Carlo simulation. The aim of this study was to evaluate the performance of our detector module experimentally. The detector module consisted of a 1D array of eight LYSO crystals of 20.0(X)×2.0(Y)×10.0(Z)mm3, optically coupled to a Hamamatsu H7546B position sensitive photomultiplier tube (PSPMT). The PSPMT was read out using a resistive charge divider, which multiplexes 64 anodes into 8(X)+8(Y) channels. Gaussian-based MLPE methods have been implemented using experimentally measured detector response functions (DRFs). The results demonstrated that the detector module could identify the position of the gamma ray interaction inside the crystal in all three directions. The new DOI detector for a small animal PET was developed and verified experimentally with a view towards achieving high sensitivity as well as high and uniform radial resolution. [ABSTRACT FROM AUTHOR]

Abstract: Objectives: This study aimed to determine whether regional cerebral blood flow (rCBF) is abnormal in patients who have Transient Global Amnesia (TGA). Methods: We obtained noninvasive rCBF measurements using Tc-99m-ethyl cysteinate diamer Single Photon Emission Computed Tomography (SPECT) in 7 patients diagnosed with TGA within 4 days of onset of the amnestic episode while the patients were still symptomatic and in 17 age-matched healthy control subjects. We assessed memory functioning using the Hopkins''s Verbal Learning Test (HVLT) and Statistical Parametric Mapping to compare rCBF across diagnostic groups. Results: The patients with TGA were significantly impaired in their performance on the 20-minute delayed recall of the HVLT. They also exhibited significantly decreased rCBF on their SPECT scans in the inferior and middle frontal gyrus bilaterally, with more prominent left-sided reductions in the superior temporal, precentral, and postcentral gyri, as well as increased rCBF primarily in the right hemisphere within the middle temporal, superior temporal, and inferior frontal gyri, cerebellum, and thalamus, compared with the normal control group. Conclusion: These findings suggest that lateralized abnormalities in brain functioning are an important component of the pathophysiology of TGA. Lateralized abnormalities may disrupt functions that are relatively specific to the left hemisphere, including receptive language, symbolic representation, and the processing of local features in the environment, while preserving anterograde memory processes. Increased flow to the right hemisphere centered on regions that subserve the functions of expressive language and visuospatial processing, and may represent processes that compensate for flow reductions to the left hemisphere. [Copyright &y& Elsevier]

Abstract: We report a new design of a detector module with depth of interaction (DOI) based on a quasi-monolithic LSO crystal, a multi-channel sensor, and maximum-likelihood position-estimation (MLPE) algorithm. Light transport and detection were modeled in a quasi-monolithic crystal using DETECT2000 code, with lookup tables (LUTs) built by simulation. Events were well separated by applying the MLPE method within 2.0mm spatial resolution in both trans-axial and DOI directions. These results demonstrate that the proposed detector provides dependable positioning capability for small animal positron emission tomography (PET). [Copyright &y& Elsevier]

Distinct brain alterations in response to traumatic events may render trauma-exposed individuals either resilient or vulnerable to posttraumatic stress disorder (PTSD). This study compared regional cerebral metabolic rate of glucose (rCMRglu) among trauma-exposed individuals with current PTSD (PTSD group, n = 61), those without current PTSD (Resilience/Recovery group, n = 26), and trauma-unexposed controls (Control group, n = 54). All participants underwent brain [18F]-fluorodeoxyglucose positron emission tomography (FDG-PET) scans. Voxel-wise group differences in rCMRglu among the three groups were evaluated. Associations between rCMRglu and both PTSD severity and resilience were examined. The rCMRglu in the right anterior insula and adjacent prefrontal and striatal areas was lower in the PTSD group, while higher in the Resilience/Recovery group, compared to the Control group. In addition, the lower glucose metabolism of these areas was associated with higher severity and less improvement in PTSD symptoms in the PTSD group, while the higher levels of rCMRglu were correlated with stronger resilience in the Resilience/Recovery group. This study suggests distinct roles of the anterior insula in response to trauma between the PTSD and Resilience/Recovery groups. Heightened rCMRglu in the anterior insular regions may reflect an underlying mechanism of resilience against traumatic stress, while reduced rCMRglu may indicate vulnerability to PTSD. [ABSTRACT FROM AUTHOR]

Preclinical studies have suggested that low-intensity transcranial focused ultrasound (tFUS) may have therapeutic potential for Alzheimer's disease (AD) by opening the blood–brain barrier (BBB), reducing amyloid pathology, and improving cognition. This study investigated the effects of tFUS on BBB opening, regional cerebral metabolic rate of glucose (rCMRglu), and cognitive function in AD patients. Eight patients with AD received image-guided tFUS to the right hippocampus immediately after intravenous injection of microbubble ultrasound contrast agents. Patients completed magnetic resonance imaging (MRI), 18F-fluoro-2-deoxyglucose positron emission tomography (PET), and cognitive assessments before and after the sonication. No evidence of transient BBB opening was found on T1 dynamic contrast-enhanced MRI. However, immediate recall (p = 0.03) and recognition memory (p = 0.02) were significantly improved on the verbal learning test. PET image analysis demonstrated increased rCMRglu in the right hippocampus (p = 0.001). In addition, increases of hippocampal rCMRglu were correlated with improvement in recognition memory (Spearman's ρ = 0.77, p = 0.02). No adverse event was observed. Our results suggest that tFUS to the hippocampus of AD patients may improve rCMRglu of the target area and memory in the short term, even without BBB opening. Further larger sham-controlled trials with loger follow-up are warranted to evaluate the efficacy and safety of tFUS in patients with AD. [ABSTRACT FROM AUTHOR]

We developed a depth of interaction (DOI) positron emission tomography (PET) detector using depth-dependent reflector patterns in a discrete crystal array. Due to the different reflector patterns at depth, light distribution was changed relative to depth. As a preliminary experiment, we measured DOI detector module crystal identification performance. The crystal consisted of a 9×9 array of 2 mmx2 mmx20 mm lutetium-yttrium oxyorthosilicate (LYSO) crystals. The crystal array was optically coupled to a 64-channel position-sensitive photomultiplier tube with a 2 mmx2 mm anode size and an 18.1 mmx18.1 mm effective area. We obtained the flood image with an Anger-type calculation. DOI layers and 9×9 pixels were well distinguished in the obtained images. Preclinical PET scanners based on this detector design offer the prospect of high and uniform spatial resolution. [ABSTRACT FROM AUTHOR]

Purpose: We evaluated the prognostic value of pretreatment F-fluorodeoxyglucose positron emission tomography with computed tomography (FDG PET/CT) in patients with Barcelona Clinic Liver Cancer (BCLC) stage 0 or A hepatocellular carcinoma (HCC) who had received curative treatment or transarterial chemoembolization (TACE). Methods: Between 2009 and 2010, 317 patients diagnosed with HCC at seven hospitals were enrolled. Among these, 195 patients underwent curative treatments including resection, liver transplantation, and radiofrequency ablation. TACE was performed in 122 patients. The tumor-to-normal liver standardized uptake value ratio (TLR) of the primary tumor was measured using pretreatment FDG PET/CT. The prognostic significance of TLR and other clinical variables was assessed using Cox regression models. Differences in the overall survival (OS) associated with TLR or other significant clinical factors were examined using the Kaplan-Meier method. Results: Over a median follow-up period of 46 months, 77 patients died from cancer. In the curative cohort, higher TLR (≥2) was significantly associated with death (hazard ratio [HR] = 2.68; 95 % CI, 1.16-6.15; P = 0.020) in multivariable analysis. Patients with a higher TLR had significantly worse OS than patients with a lower TLR (5-year overall survival, 61 % vs. 79.4 %; P = 0.006). In the TACE cohort, the Model for End-Stage Liver Disease (MELD) score (≥8) was a significant independent prognostic factor for OS (HR = 3.34; 95 % CI, 1.49-7.48; P = 0.003), whereas TLR was not associated with OS. The Kaplan-Meier curves showed significantly poorer OS in patients with higher MELD scores (≥8) than in those with lower MELD scores (5-year survival rate, 33.1 % vs. 79.6 %; P < 0.001). Conclusions: Pretreatment TLR measured using FDG PET/CT was an independent prognostic factor for OS in patients with BCLC stage 0 or A HCC undergoing curative treatment. In contrast, underlying liver function appeared to be important in predicting the prognosis of patients undergoing TACE. [ABSTRACT FROM AUTHOR]

Background: Some groups have focused on the detection and management of subjective memory impairment (SMI) as the stage that precedes mild cognitive impairment (MCI). However, there have been few clinical studies that have examined biomarkers of SMI to date.Purpose: To investigate the differences in glucose metabolism as a prodromal marker of dementia in patients with SMI, MCI, and healthy controls using brain F-18 fluoro-2-deoxyglucose positron emission tomography (FDG-PET).Material and Methods: Sixty-eight consecutive patients with SMI, 47 patients with MCI, and 42 age-matched healthy subjects were recruited. All subjects underwent FDG-PET and detailed neuropsychological testing. FDG-PET images were analyzed using the statistical parametric mapping (SPM) program.Results: FDG-PET analysis showed glucose hypometabolism in the periventricular regions of patients with SMI and in the parietal, precentral frontal, and periventricular regions of patients with MCI compared with healthy controls. Interestingly, hypometabolism on FDG-PET was noted in the parietal and precentral frontal regions in MCI patients compared to SMI patients.Conclusion: The results suggest that hypometabolism in the periventricular regions as seen on FDG-PET may play a role as a predictive biomarker of pre-dementia, and the extension of reduced glucose metabolism into parietal regions likely reflects progression of cognitive deterioration. [ABSTRACT FROM AUTHOR]

Background: There is growing evidence that essential tremor (ET) is a multiple-system disorder. Previous PET studies in ET typically have measured brain oxygen consumption and cerebral blood flow. Purpose: To compare ET patients with control subjects to investigate any regional change in cerebral glucose metabolism through statistical parametric mapping (SPM) analysis of F-18-fluorodeoxyglucose positron emission tomography (F-18-FDG-PET). Material and Methods: We studied 17 patients with ET (17 men; mean age, 67.3 ± 4.8 years) and age-sex matched normal subjects. All subjects underwent FDG-PET imaging, and evaluated severity of tremor symptoms was measured as score on the Fahn-Tolosa-Marin rating scale (FTM). We also evaluated detailed the medical history and neurological examinations in all patients. Results: The mean age of tremor onset was 57.6 ± 12.9 years and the mean FTM score was 15.1 ± 4.9. Brain FDG-PET analysis demonstrated hypometabolism in the medial frontal lobe, medial temporal lobe, and the precuneus of parietal lobe. However, there was no significant difference of glucose metabolism in the cerebellum. Conclusion: We propose that motor symptom of ET are caused by electrophysiological disturbances within cortical-cerebellar networks, rather than degenerative process of cerebellum, because the metabolism of the cerebellum was normal at rest. Furthermore, the abnormal glucose metabolism in the cerebral regions that do not mainly participate in motor function suggest that these regions may play a role as early markers of non-motor manifestations. [ABSTRACT FROM AUTHOR]

This study introduces a depth-encoding PET detector inserting a glass plate between the pixilated scintillation crystal layers. The principle of the proposed design was that the relative amount of light received by each photosensor will be altered by using the glass plate. This change in the light distribution can generate a pattern diagram of the 2D flood histogram that identifies depth position as well as X-Y position of \gamma–ray interaction. A Monte Carlo simulation was conducted for the assessment of the DOI-PET detector of 4 \times 4 array photosensor coupled with 2-layers of LSO arrays which consist of 4 \times 4 arrays of 3 \times 3 \times 10~\mm^3 discrete crystals. The traced light distribution for each event was converted by the modified resistive charge division networks into the 2D flood histogram. Optical glass plates with 11 different thicknesses that range from 0 to 10 mm with a 1 mm step were modeled. This was done, to estimate the thickness which allows the extraction of the depth information from the 2D flood histogram. An experimental study was performed to acquire the flood histograms of the DOI-PET detectors with 3 and 5 mm thick glass plate. The effect of glass plate on light loss and count rate loss were assessed for two detector configurations with and without glass plate. The simulation results showed that the flood histogram without overlapping of each crystal position can be generated for the detectors by inserting the glass plates with thickness of 3\sim 10~\mm. They were also demonstrated in the acquired representative flood histograms which were obtained by the experimental study. The light and count rate losses measured from DOI-PET detector with 3 mm thick glass plate was \sim 5\% and \sim 2\%, respectively. This study demonstrated that the proposed DOI-PET detector can extract the 3D \gamma -ray interaction position without considerable performance degradations of PET detector from the 2D flood histogram. [ABSTRACT FROM AUTHOR]

Abstract: DIP is a heterogeneous clinical syndrome; some patients develop persistent and worsening of parkinsonian symptoms after discontinuation of the offending drug, or Parkinson''s disease (PD) reappears later after a full remission from DIP. However, it is difficult to predict the prognosis in patients with DIP. Herein, we evaluated whether the combined use of 18F-N-(3-fluoropropyl)-2beta-carbon ethoxy-3beta-(4-iodophenyl) nortropane (FP-CIT) PET and cardiac MIBG scintigraphy can be used to help distinguish the prognosis in patients with DIP. Among 20 patients enrolled, 16 showed normal DAT uptake and normal myocardial sympathetic innervation. After withdrawal of the suspected drugs, the patients experienced a clinical remission of parkinsonian motor symptoms within 3 months and did not experience any new movement symptoms after at least 2 years of follow-up. Two patients with a moderate decrease in DAT uptake and impaired sympathetic denervation showed worsening of motor manifestations 3 months after discontinuation of the drugs. Another two patients with normal DAT uptake and decreased MIBG uptake, presented full remission of motor symptoms within 2 months after discontinuation of the drugs. However, these two patients eventually developed parkinsonism within 2 years of the follow-up period. The follow-up scans revealed severe decreased DAT uptake in the putamen and similar ranges of cardiac sympathetic denervation. The results suggest that the combined use of these techniques can predict the prognosis of DIP and suggest a proper therapeutic plan for DIP. [Copyright &y& Elsevier]

The testis shows physiologic uptake in flourine-18 fluorodeoxyglucose (F-18 FDG) positron emission tomography (PET). The purpose of this study was to examine the degree of FDG uptake of normal testis on PET/computed tomography (CT), especially in relationship to various clinical parameters. We obtained the maximum standardized uptake value (SUVmax) and the mean standardized uptake value (SUVmean) of each testis from PET/CT of 166 healthy men. We also calculated the testis-to-muscle (T/M) ratio, defined as the SUVmean of the testis divided by the SUVmean of the right thigh muscle. Subjects completed a questionnaire on their medical history and sexual habits, including frequency of sexual intercourse, latest date of sexual intercourse, and vasectomy history. We then evaluated the association between imaging parameters and sexual habits. The mean age of subjects was 48 ± 10 years (range, 21-74), and the mean volume of each testis was 17.1 ± 4.5 cm3 (range, 7.4-32.4). The mean SUVmax was 3.6 ± 0.5 (range, 2.2-5.5), the mean SUVmean was 2.5 ± 0.4 (range, 1.6-3.8), and the mean T/M ratio was 4.2 ± 0.8 (range, 2.3-7.3). Of the 166 subjects, 51 reported having sexual intercourse zero times per month and 109 had sexual intercourse at least per month. The interval between the latest date of sexual intercourse and PET/CT was less than 3 days in 48 subjects; between 3 days and 1 month in 58; and greater than 1 month in 60. Twenty subjects were currently vasectomized. The T/M ratio was significantly correlated with age ( P = 0.040) but not with sexual habits. On the PET/CT, normal testicular FDG uptake decreased as age increased. © 2012 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 22, 245-249, 2012 [ABSTRACT FROM AUTHOR]

Small-animal positron emission tomography (PET) systems are useful functional imaging systems for pathology and pharmacology research. However, conventional small-animal PET systems show degradation with regard to spatial resolution and sensitivity when small objects are image with a scanner having large diameter. In this study, to overcome this limitation, we propose a small-animal PET using an adjustable gantry and a depth-of-interaction (DOI) detector. The adjustable gantry allows the field of view (FOV) to be changed depending on object size to increase the solid-angle coverage and improve sensitivity. In addition, detector modules are arranged in a square shape to fill gaps between the detector module as well as in the corners to achieve higher sensitivity. To overcome the parallax error that occurs in the square-shaped gantry with long and thin crystal elements, a DOI detector is employed using a depth-dependent reflector pattern. The adjustable-gantry PET (AGPET) system is designed by GATE Monte Carlo simulation and evaluated by comparison with conventional small-animal PET systems, such as Inveon and PETbox, in terms of spatial resolution and sensitivity. The DOI detector blocks were composed of two 8 × 8 SiPM arrays coupled to two blocks of 12 × 12 lutetium-yttrium oxyorthosilicate (LYSO) crystals of size 2.1 × 2. 1 × 20 mm3. The signals of the detector blocks are fed to a data acquisition system based on field-programmable gate array, and the position, energy, and time information were recorded. The detector module performance is analyzed by the peak-to-valley ratio (PVR), distance-to-width ratio (DWR), energy resolution, and timing resolution. The results demonstrate that the proposed AGPET potentially provide higher sensitivity and resolution for small animal imaging. • Development of small animal PET system with adjustable gantry. • Investigation of the depth of interaction method using depth-dependent reflector. • Evaluation of small animal PET system using Monte Carlo simulation. [ABSTRACT FROM AUTHOR]