Nailfold capillaroscopy findings of interstitial pneumonia with autoimmune features

Background/Aims@#We evaluated nailfold capillaroscopy (NFC) of interstitial pneumonia with autoimmune features (IPAF) and compared it with that of patients with connective tissue disease-interstitial lung disease (CTD-ILD) and idiopathic interstitial pneumonia (IIP). @*Methods@#Patients with newly diagnosed as ILD were evaluated using NFC. Baseline demographic, clinical, serological, and high-resolution CT findings were collected. NFC was semi-quantitatively scored with six domains ranging from 0 to 18. In addition, the overall patterns (sclerodermaon-scleroderma patterns) were determined. @*Results@#A total of 81 patients (31 with CTD-ILD, 18 with IPAF, and 32 with IIP) were included. The non-specific interstitial pneumonia pattern was the most common ILD pattern in the CTD-ILD and IPAF groups, whereas the usual interstitial pneumonia pattern was the most common in the IIP group. The semi-quantitative score of the CTD-ILD group was higher than that of the IPAF or IIP groups (5.8 vs 4.2 vs 3.0, p < 0.001, respectively). Giant capillaries and haemorrhages were more frequently present in the CTD-ILD and IPAF groups than in the IIP group. A scleroderma pattern was present in 27.8% of the IPAF group, whereas none of the IIP patients showed a scleroderma pattern. @*Conclusions@#NFC findings may be useful in classifying patients with ILD into CTD-ILD/IPAF/IIP.

A Brief History of Nuclear Medicine Physics, Instrumentation, and Data Sciences in Korea / 대한핵의학회잡지

We review the history of nuclear medicine physics, instrumentation, and data sciences in Korea to commemorate the 60 th anniversary of the Korean Society of Nuclear Medicine. In the 1970s and 1980s, the development of SPECT, nuclear stethoscope, and bone densitometry systems, as well as kidney and cardiac image analysis technology, marked the beginning of nuclear medicine physics and engineering in Korea. With the introduction of PET and cyclotron in Korea in 1994, nuclear medicine imaging research was further activated. With the support of large-scale government projects, the development of gamma camera, SPECT, and PET systems was carried out. Exploiting the use of PET scanners in conjunction with cyclotrons, extensive studies on myocardial blood flow quantification and brain image analysis were also actively pursued. In 2005, Korea’s first domestic cyclotron succeeded in producing radioactive isotopes, and the cyclotron was provided to six universities and university hospitals, thereby facilitating the nationwide supply of PET radiopharmaceuticals. Since the late 2000s, research on PET/MRI has been actively conducted, and the advanced research results of Korean scientists in the fields of silicon photomultiplier PET and simultaneous PET/MRI have attracted significant attention from the academic community.Currently, Korean researchers are actively involved in endeavors to solve a variety of complex problems in nuclear medicine using artificial intelligence and deep learning technologies.

Liquid biopsy using extracellular vesicle–derived DNA in lung adenocarcinoma

Blood liquid biopsy has emerged as a way of overcoming the clinical limitations of repeat biopsy by testing for the presence of acquired resistance mutations to therapeutic agents. Despite its merits of repeatability and non-invasiveness, this method is currently only used as a supplemental test due to a relatively low sensitivity rate of 50%–60%, and cannot replace tissue biopsy. The circulating tumor DNAs used in blood liquid biopsies are passive products of fragmented DNA with a short half-life released following tumor cell death; the low sensitivity seen with liquid blood biopsy results from this instability, which makes increasing the sensitivity of this test fundamentally difficult. Extracellular vesicles (EVs) are ideal carriers of cancer biomarkers, as cancer cells secret an abundance of EVs, and the contents of tumor cell-originated EVs reflect the molecular and genetic composition of parental cells. In addition, EV-derived DNAs (EV DNAs) consist of large-sized genomic DNAs and tumor-specific oncogenic mutant DNAs. For these reasons, liquid biopsy using EV DNA has the potential to overcome issues arising from tissue shortages associated with small biopsies, which are often seen in lung cancer patients, and the biopsy product can be used in other diagnostic methods, such as epidermal growth factor receptor (EGFR) mutation testing and next-generation sequencing (NGS). A higher sensitivity can be achieved when EV DNAs obtained from bronchoalveolar lavage fluid (BALF) are used rather than those from blood. BALF, when obtained close to the tumor site, is a promising liquid biopsy tool, as it enables the gathering of both cellular and non-cellular fractions of the tumor microenvironment, and provides increased diagnostic sensitivity when compared to blood.

Liquid biopsy using extracellular vesicle–derived DNA in lung adenocarcinoma

Blood liquid biopsy has emerged as a way of overcoming the clinical limitations of repeat biopsy by testing for the presence of acquired resistance mutations to therapeutic agents. Despite its merits of repeatability and non-invasiveness, this method is currently only used as a supplemental test due to a relatively low sensitivity rate of 50%–60%, and cannot replace tissue biopsy. The circulating tumor DNAs used in blood liquid biopsies are passive products of fragmented DNA with a short half-life released following tumor cell death; the low sensitivity seen with liquid blood biopsy results from this instability, which makes increasing the sensitivity of this test fundamentally difficult. Extracellular vesicles (EVs) are ideal carriers of cancer biomarkers, as cancer cells secret an abundance of EVs, and the contents of tumor cell-originated EVs reflect the molecular and genetic composition of parental cells. In addition, EV-derived DNAs (EV DNAs) consist of large-sized genomic DNAs and tumor-specific oncogenic mutant DNAs. For these reasons, liquid biopsy using EV DNA has the potential to overcome issues arising from tissue shortages associated with small biopsies, which are often seen in lung cancer patients, and the biopsy product can be used in other diagnostic methods, such as epidermal growth factor receptor (EGFR) mutation testing and next-generation sequencing (NGS). A higher sensitivity can be achieved when EV DNAs obtained from bronchoalveolar lavage fluid (BALF) are used rather than those from blood. BALF, when obtained close to the tumor site, is a promising liquid biopsy tool, as it enables the gathering of both cellular and non-cellular fractions of the tumor microenvironment, and provides increased diagnostic sensitivity when compared to blood.

Detection of EGFR and KRAS Mutation by Pyrosequencing Analysis in Cytologic Samples of Non-Small Cell Lung Cancer

EGFR and KRAS mutations are two of the most common mutations that are present in lung cancer. Screening and detecting these mutations are of issue these days, and many different methods and tissue samples are currently used to effectively detect these two mutations. In this study, we aimed to evaluate the testing for EGFR and KRAS mutations by pyrosequencing method, and compared the yield of cytology versus histology specimens in a consecutive series of patients with lung cancer. We retrospectively reviewed EGFR and KRAS mutation results of 399 (patients with EGFR mutation test) and 323 patients (patients with KRAS mutation test) diagnosed with lung cancer in Konkuk University Medical Center from 2008 to 2014. Among them, 60 patients had received both EGFR and KRAS mutation studies. We compared the detection rate of EGFR and KRAS tests in cytology, biopsy, and resection specimens. EGFR and KRAS mutations were detected in 29.8% and 8.7% of total patients, and the positive mutation results of EGFR and KRAS were mutually exclusive. The detection rate of EGFR mutation in cytology was higher than non-cytology (biopsy or resection) materials (cytology: 48.5%, non-cytology: 26.1%), and the detection rate of KRAS mutation in cytology specimens was comparable to non-cytology specimens (cytology: 8.3%, non-cytology: 8.7%). We suggest that cytology specimens are good alternatives that can readily substitute tissue samples for testing both EGFR and KRAS mutations. Moreover, pyrosequencing method is highly sensitive in detecting EGFR and KRAS mutations in lung cancer patients.

Efficacy of epidermal growth factor receptor-tyrosine kinase inhibitors for patient with leptomeningeal metastasis of epidermal growth factor receptor mutant non-small cell lung cancer / 영남의대학술지

We report on a 64-year-old man with leptomeningeal metastasis (LM) from an epidermal growth factor receptor (EGFR)-mutated adenocarcinoma of the lung. He was treated with paclitaxel, cisplatin. After completion of chemotherapy, he complained of headache, nausea, and vomiting. EGFR-mutated tumor cells were identified from the cerebrospinal fluid (CSF). Second-line therapy with gefitinib, methotrexate was started. After receiving gefitinib for 4 weeks, he had no more headaches or vomiting. Eleven months after initiation of gefitinib, he developed headache and nausea. Chest computed tomography showed aggravation of bone metastasis. Third-line therapy was started with gemcitabine and carboplatin. Two weeks later, he experienced disorientation. After a fourth relapse within the central nervous system, the therapy was switched to erlotinib and significant improvement of LM was achieved. This case shows that LM can be diagnosed by detecting EGFR mutation in CSF and EGFR tyrosine kinase inhibitors are effective for LM from EGFR mutant non-small cell lung cancer.

A Case of Cryptogenic Organizing Pneumonia after Transarterial Chemoembolization for the Treatment of Hepatocellular Carcinoma / 결핵및호흡기질환

Cryptogenic organizing pneumonia (COP) is an inflammatory lung disease involving the distal bronchioles, respiratory bronchioles, bronchiolar ducts, and alveolae. The etiology is usually unknown; however, there are several known causes and associated systemic diseases. Corticosteroid therapy is the best treatment option and the prognosis of COP is good, with recovery in up to 80% of patients. We described a patient with in-operable hepatocellular carcinoma (HCC) undergoing chemoembolization with doxorubicin in a drug-eluting bead (DEB). COP developed in the patient after chemoembolization but resolved spontaneously in several months.

Bilateral Internal Auditory Canal Metastasis of Non-small Cell Lung Cancer / Journal of the Korean Cancer Association, 대한암학회지

We report on a patient with brain metastasis involving bilateral internal auditory canal from non-small cell lung cancer (NSCLC). A 49-year-old woman who had been diagnosed with NSCLC (T2aN1M0) complained of persistent vertigo and bilateral tinnitus for three months. The patient had refused all treatments, including surgery and chemotherapy; however, she sought alternative medicine. The patient's hearing loss showed rapid progression bilaterally, and rotatory vertigo with peripheral-type nystagmus developed. Magnetic resonance imaging of the brain showed irregular nodular enhancement within both internal auditory canals with leptomeningeal enhancement and multiple intracranial metastasis. The patient was treated with epidermal growth factor receptor-tyrosine kinase inhibitor, and the tumor showed partial response. This was a rare case of multiple brain metastases involving bilateral internal auditory canal from known NSCLC presenting with vertigo and hearing loss.

Bilateral Ovarian Metastases from ALK Rearranged Non-Small Cell Lung Cancer / 결핵및호흡기질환

Anaplastic lymphoma kinase (ALK) rearrangement, is a kind of driver mutation, accounts for 3%-5% of non-small cell lung cancer (NSCLC). NSCLC patients harboring ALK fusion genes have distinct clinical features and good response to ALK inhibitors. Metastasis from lung cancer to the ovary has rarely been known. We report a case of a 54-year-old woman with bilateral ovarian metastases from ALK rearranged NSCLC. She underwent bilateral salpingo-oophorectomy for ovary masses, which were progressed after cytotoxic chemotherapy although primary lung mass was decreased. Histopathological examination of the ovary tumor showed characteristic adenocarcinoma patterns of the lung and ALK rearrangement.

A Case of Congenital Cystic Adenomatoid Malformation Infected with Mycobacterium avium-intracellulare Complex / 결핵및호흡기질환

We present a case of congenital cystic adenomatoid malformation (CCAM) in a 25-year-old male who was presented with chronic cough. Chest radiography revealed an abnormal mass-like shadow in the right lower pulmonary zone. A contrast enhanced computed tomography showed an 11 cm solid, cystic mixed mass on the right lower lobe. A right lower lobectomy was performed by video-assisted thoracoscopic surgery without complications. The gross specimen showed a massive cavitation with multiloculated cysts of varying size, consistent with CCAM, along with noticeable granulomatous inflammation. Non-tuberculosis mycobacteria were isolated from a bronchial wash specimen, and the resected tissue homogenates were positive for Mycobacterium avium-intracellulare complex by polymerase chain reaction.

Annual Change of Peak Expiratory Flow Rate in Asthma and COPD / 결핵및호흡기질환

BACKGROUND: Measurement of peak expiratory flow rate (PEFR) in a follow-up examination for a chronic airway disease is useful because it has the advantages of being a simple measurement and can be repeated during examination. The aim of this study was to examine the annual decrease of PEFR in asthma and chronic obstructive pulmonary disease (COPD) patients and to confirm the factors which influence this decrease. METHODS: From May, 2003 to September, 2010, the annual decrease of PEFR was obtained from asthma and COPD patients attending an outpatient pulmonary clinic. PEFR was measured using a Mini-Wright peak flow meter (Clement Clarke International Ltd. UK), and we conducted an analysis of factors that influence the change of PEFR and its average values. RESULTS: The results showed an annual decrease of 1.70+/-12.86 L/min the asthmatic patients and an annual decrease of 10.3+/-7.32 L/min in the COPD patients. Age and FEV1 were the predictive factors influencing change in asthma, and FEV1 and smoking were the predictive factors influencing change in COPD. CONCLUSION: We confirmed the annual decreasing PEFR in patients with chronic airway disease and identified factors that work in conjunction with FEV1 to influence the change.

Effective Detective Quantum Efficiency (eDQE) Evaluation for the Influence of Focal Spot Size and Magnification on the Digital Radiography System / 의학물리

The magnification technique has recently become popular in bone radiography, mammography and other diagnostic examination. However, because of the finite size of X-ray focal spot, the magnification influences various imaging properties with resolution, noise and contrast. The purpose of study is to investigate the influence of magnification and focal spot size on digital imaging system using eDQE (effective detective quantum efficiency). Effective DQE is a metric reflecting overall system response including focal spot blur, magnification, scatter and grid response. The adult chest phantom employed in the Food and Drug Administration (FDA) was used to derive eDQE from eMTF (effective modulation transfer function), eNPS (effective noise power spectrum), scatter fraction and transmission fraction. According to results, spatial frequencies that eMTF is 10% with the magnification factor of 1.2, 1.4, 1.6, 1.8 and 2.0 are 2.76, 2.21, 1.78, 1.49 and 1.26 lp/mm respectively using small focal spot. The spatial frequencies that eMTF is 10% with the magnification factor of 1.2, 1.4, 1.6, 1.8 and 2.0 are 2.21, 1.66, 1.25, 0.93 and 0.73 lp/mm respectively using large focal spot. The eMTFs and eDQEs decreases with increasing magnification factor. Although there are no significant differences with focal spot size on eDQE (0), the eDQEs drops more sharply with large focal spot than small focal spot. The magnification imaging can enlarge the small size lesion and improve the contrast due to decrease of effective noise and scatter with air-gap effect. The enlargement of the image size can be helpful for visual detection of small image. However, focal spot blurring caused by finite size of focal spot shows more significant impact on spatial resolution than the improvement of other metrics resulted by magnification effect. Based on these results, appropriate magnification factor and focal spot size should be established to perform magnification imaging with digital radiography system.

No Significance of the Free Cortisol Index Compared to Total Cortisol in Critically Ill Patients

BACKGROUND: Some patients exhibit an inadequate response of cortisol to stressful conditions; this state is known as critical illness-related corticosteroid insufficiency. These patients have low serum binding protein concentrations, thereby suggesting that total serum cortisol may not be reflective of circulating cortisol activity. As the free cortisol index (FCI = total cortisol/corticosteroid-binding globulin) has been correlated with serum free cortisol, we measured FCI in Korean patients for the first time. In this study, we attempted to determine whether FCI was superior to total cortisol in predicting 30-day mortality. METHODS: We recruited 65 critically ill patients with relatively high Acute Physiology, Age and Chronic Health Evaluation (APACHE III) scores. Fourteen patients with pituitary disease but normal pituitary function were recruited from outpatient clinics. Total cortisol and corticosteroid-binding globulin were measured in patients and controls during the short Synacthen test. RESULTS: The basal cortisol level and basal FCI level were higher in patients (n = 65) than in healthy controls (P < 0.001, respectively). We found that total cortisol was strongly correlated with FCI (P < 0.001) in critically ill patients; however, neither total cortisol nor FCI were associated with 30-day mortality among patients. Only severe clinical criteria (such as APACHE-III scores and low albumin) were associated with 30-day mortality. CONCLUSION: Our results do not suggest that FCI is more accurate than total cortisol in predicting clinical outcomes in critically ill patients.

Comparative Analysis of Peptide Nucleic Acid (PNA)-Mediated Real-Time PCR Clamping and DNA Direct Sequencing for EGFR Mutation Detection / 결핵및호흡기질환

BACKGROUND: Although the gold standard method for research trials on epidermal growth factor receptor (EGFR) mutations has been direct sequencing, this approach has the limitations of low sensitivity and of being time-consuming. Peptide nucleic acid (PNA)-mediated polymerase chain reaction (PCR) clamping is known to be a more sensitive detection tool. The aim of this study was to compare the detection rate of EGFR mutation and EGFR-tyrosine kinase inhibitor (TKI) responsiveness according to EGFR mutation status using both methodologies. METHODS: Clinical specimens from 112 NSCLC patients were analyzed for EGFR mutations in exons 18, 19, 20, and 21. All clinical data and tumor specimens were obtained from 3 university hospitals in Korea. After genomic DNA was extracted from paraffin-embedded tissue specimens, both PNA-mediated PCR clamping and direct-sequencing were performed. The results and clinical response to EGFR-TKIs were compared. RESULTS: Sequencing revealed a total of 35 (22.9%) mutations: 8 missense mutations in exon 21 and 26 deletion mutations in exon 19. PNA-mediated PCR clamping showed the presence of genomic alterations in 45 (28.3%) samples, including the 32 identified by sequencing plus 13 additional samples (6 in exon 19 and 7 in exon 21). CONCLUSION: PNA-mediated PCR clamping is simple and rapid, as well as a more sensitive method for screening of genomic alterations in EGFR gene compared to direct sequencing. This data suggests that PNA-mediated PCR clamping should be implemented as a useful screening tool for detection of EGFR mutations in clinical setting.

Comparative Analysis of Peptide Nucleic Acid (PNA)-Mediated Real-Time PCR Clamping and DNA Direct Sequencing for EGFR Mutation Detection / 결핵및호흡기질환

BACKGROUND: Although the gold standard method for research trials on epidermal growth factor receptor (EGFR) mutations has been direct sequencing, this approach has the limitations of low sensitivity and of being time-consuming. Peptide nucleic acid (PNA)-mediated polymerase chain reaction (PCR) clamping is known to be a more sensitive detection tool. The aim of this study was to compare the detection rate of EGFR mutation and EGFR-tyrosine kinase inhibitor (TKI) responsiveness according to EGFR mutation status using both methodologies. METHODS: Clinical specimens from 112 NSCLC patients were analyzed for EGFR mutations in exons 18, 19, 20, and 21. All clinical data and tumor specimens were obtained from 3 university hospitals in Korea. After genomic DNA was extracted from paraffin-embedded tissue specimens, both PNA-mediated PCR clamping and direct-sequencing were performed. The results and clinical response to EGFR-TKIs were compared. RESULTS: Sequencing revealed a total of 35 (22.9%) mutations: 8 missense mutations in exon 21 and 26 deletion mutations in exon 19. PNA-mediated PCR clamping showed the presence of genomic alterations in 45 (28.3%) samples, including the 32 identified by sequencing plus 13 additional samples (6 in exon 19 and 7 in exon 21). CONCLUSION: PNA-mediated PCR clamping is simple and rapid, as well as a more sensitive method for screening of genomic alterations in EGFR gene compared to direct sequencing. This data suggests that PNA-mediated PCR clamping should be implemented as a useful screening tool for detection of EGFR mutations in clinical setting.

Usefulness of Vibration Response Imaging (VRI) for Pneumonia Patients / 결핵및호흡기질환

BACKGROUND: Pneumonia is commonly seen in outpatient clinics. it is widely known as the most common cause of death from infectious disease. Pneumonia has been diagnosed by its typical symptoms, chest X-ray and blood tests. However, both chest X-rays and blood tests have limitations in diagnosis. Thus primary care clinicians usually have been constrained due to a lack of adequate diagnostic tools. Vibration response imaging (VRI) is a newly emerging diagnostic modality, and its procedure is non-invasive, radiation-free, and easy to handle. This study was designed to evaluate the diagnostic usefulness of the VRI test among pneumonia patients and to consider its correlation with other conventional tests such as Chest X-ray, laboratory tests and clinical symptoms. METHODS: VRI was performed in 46 patients diagnosed with pneumonia in Konkuk University Medical Center. VRI was assessed in a private and quiet room twice: before and after the treatment. Sensors for VRI were placed on a patient's back at regular intervals; they detected pulmonary vibration energy produced when respiration occurred and presented as specific images. Any modifications either in chest X-ray, C-reactive protein (CRP), white blood cell count (WBC) or body temperature were compared with changes in VRI image during a given time course. RESULTS: VRI, chest X-ray and CRP scores were significantly improved after treatment. Correlation between VRI and other tests was not clearly indicated among all patients. But relatively severe pneumonia patients showed correlations between VRI and chest X-ray, as well as between VRI and CRP. CONCLUSION: This study demonstrates that VRI can be safely applied to patients with pneumonia.

A Case of Yellow Nail Syndrome: Misdiagnosis as Congestive Heart Failure / 결핵및호흡기질환

Yellow nail syndrome (YNS) is a rare disorder of unknown cause associated with yellow nails, lymphedema and respiratory manifestations. It was first described by Samman and White in 1964, and to date, approximately 150 cases have been reported. The diagnosis of YNS is essentially a clinical one and based on the presence of characteristic findings. We report a case of YNS of a 62-year-old female who presented with a 4-month history of dyspnea and recurrent pleural effusion. The patient had a 5-year history of leg swelling and dyspnea. She had been managed with medications for congestive heart failure (CHF) for two years and she was referred to our hospital for further evaluation and management.

Survey of Technical Parameters for Pediatric Chest X-ray Imaging by Using Effective DQE and Dose / 의학물리

The purpose of this study was to investigate the effect of various technical parameters for the dose optimization in pediatric chest radiological examinations by evaluating effective dose and effective detective quantum efficiency (eDQE) including the scatter radiation from the object, the blur caused by the focal spot, geometric magnification and detector characteristics. For the tube voltages ranging from 40 to 90 kVp in 10 kVp increments at the FDD of 100, 110, 120, 150, 180 cm, the eDQE was evaluated at the same effective dose. The results showed that the eDQE was largest at 60 kVp when compares the eDQE at different tube voltage. Especially, the eDQE was considerably higher without the use of an anti-scatter grid on equivalent effective dose. This indicates that the reducing the scatter radiation did not compensate for the loss of absorbed effective photons in the grid. When the grid is not used the eDQE increased with increasing FDD because of the greater effective modulation transfer function (eMTF). However, most of major hospitals in Korea employed a short FDD of 100 cm with an anti-scatter grid for the chest radiological examination of a 15 month old infant. As a result, the entrance surface air kerma (ESAK) values for the hospitals of this survey exceeded the Korean DRL (diagnostic reference level) of 100 microGy. Therefore, appropriate technical parameters should be established to perform pediatric chest examinations on children of different ages. The results of this study may serve as a baseline to establish detailed reference level of pediatric dose for different ages.

PNA-Mediated PCR Clamping for the Detection of EGFR Mutations in Non-Small Cell Lung Cancer / 결핵및호흡기질환

BACKGROUND: Recent studies have demonstrated that the epidermal growth factor receptor (EGFR) genotype is the most important predictive marker to EGFR-tyrosine kinase inhibitors (TKIs) and first-line gefitinib treatment will be approved in the near future for use in non-small cell lung cancer (NSCLC) patients with the EGFR mutation. Direct sequencing is known to be the standard for detecting EGFR mutations; however, it has limited sensitivity. Peptide nucleic acids (PNA)-mediated PCR clamping method is a newly introduced method for analyzing EGFR mutations with increased sensitivity and stability. METHODS: A total of 71 NSCLC patients were analyzed for EGFR mutations using the PNA-mediated PCR clamping technique. Sixty-nine patients were analyzed for clinicopathologic correlation with EGFR genotype; 2 patients with indeterminate results were excluded. In order to determine EGFR-TKI drug response, 57 patients (42 gefitinib, 15 erlotinib) were included in the analysis. RESULTS: The EGFR mutation rate was 47.8%. Being female, a non-smoker, and having adenocarcinoma were favorable clinicopathologic factors, as expected. However, more than a few smokers (33.3%), male (28.1%), and patients with non-adenocarcinoma (28.6%) had the EGFR mutation. Having a combination of favorable clinicopathologic factors did not increase the EGFR mutation rate significantly. Drug response to EGFR-TKIs showed significant differences depending on the EGFR genotype; ORR was 14.3% for wild type vs 69.0% for mutant type; DCR is 28.6% for wild type vs 96.6% for mutant type. The median EGFR-TKI treatment duration is 7.6 months for mutant type group and 1.4 months for wild type group. CONCLUSION: EGFR genotype determined using the PNA-mediated PCR clamping method is significantly correlated with the clinical EGFR-TKI responses and PNA-mediated PCR.

Performance Measurement of Siemens Inveon PET Scanner for Small Animal Imaging / 의학물리

Inveon PET is a recently developed preclinical PET system for small animal. This study was conducted to measure the performance of Inveon PET as recommended by the NEMA NU 4-2008. We measured the spatial resolution, the sensitivity, the scatter fraction and the NECR using a F-18 source. A 3.432 ns coincidence window was used. A 1 mm3 sized F-18 point source was used for the measurement of spatial resolution within an energy window of 350~625 keV. PET acquisition was performed to obtain the spatial resolution from the center to the 5 cm offset toward the edge of the transverse FOV. Sensitivity, scatter fraction, and NECR were measured within an energy window of 350~750 keV. For measuring the sensitivity, a F-18 line source (length: 12.7 cm) was used with concentric 5 aluminum tubes. For the acquisition of the scatter fraction and the NECR, two NEMA scatter phantoms (rat: 50 mm in diameter, 150 mm in length; mouse: 25 mm in diameter, 70 mm in length) were used and the data for 14 half-lives (25.6 hr) was obtained using the F-18 line source (rat: 316 MBq, mouse: 206 MBq). The spatial resolution of the F-18 point source was 1.53, 1.50 and 2.33 mm in the radial, tangential and axial directions, respectively. The volumetric resolution was 5.43 mm3 in the center. The absolute sensitivity was 6.61%. The peak NECR was 486 kcps @121 MBq (rat phantom), and 1056 kcps @128 MBq (mouse phantom). The values of the scatter fraction were 20.59% and 7.93% in the rat and mouse phantoms, respectively. The performances of the Inveon animal PET scanner were measured in this study. This scanner will be useful for animal imaging.