• Nuclear Medicine and Molecular Imaging
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• v.42 no.3
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• pp.185-191
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• 2008

While indirect targeting strategies using reporter-genes are taking center stage in current molecular imaging research, another vital strategy has long involved direct imaging of specific receptors using radiolabeled ligands. Recently, there is renewal of immense interest in this area with particular attention to the epidermal growth factor receptor (EGFR), a transmembrane glycoprotein critically involved in the regulation of many cellular functions and malignancies. Recently, two novel classes of EGFR-targeting anticancer drugs have entered clinical trials with great expectations. These are monoclonal antibodies such as cetuximab that target the extracellular domain, and small molecule tyrosine kinase inhibitors such as gefitinib (lressa) and erlotinib (Tarceva) that target the catalytic domain of the receptor. However, early results have showed disappointing survival benefits, disclosing a major challenge for this therapeutic strategy; namely, the need to identify tumors that are most likely to respond to the agents. To address this important clinical issue, several noninvasive imaging techniques are under investigation including radiolabeled probes based on small molecule tyrosine kinase inhibitors, anti-EGFR antibodies, and EGF peptides. This review describes the current status, limitations, and future prospects in the development of radiotracer methods for EGFR imaging.

• Journal of the Korean Society of Radiology
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• v.8 no.3
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• pp.123-136
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• 2014

In this paper, we study to classify molecular imaging and applications to predict future. Molecular imaging in vivo at the cellular level and the molecular level changes taking place to be imaged, that is molecular cell biology and imaging technology combined with the development of the new field. Molecular imaging is used fluorescence, bioluminescence, SPECT, PET, MRI, Ultrasound and other imaging technologies. That is applied to monitoring of gene therapy, cell tracking and monitoring of cell therapy, antibody imaging, drug development, molecular interaction picture, the near-infrared fluorescence imaging of cancer using fluorescence, bacteria using tumor-targeting imaging, therapeutic early assessment, prediction and therapy. The future of molecular imaging would be developed through fused interdisciplinary research and mutual cooperation, which molecular cell biology, genetics, chemistry, physics, computer science, biomedical engineering, nuclear medicine, radiology, clinical medicine, etc. The advent of molecular imaging will be possible to early diagnosis and personalized treatment of disease in the future.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.1 no.2
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• pp.118-122
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• 2015

Suicidal gene therapy is based on the transduction of tumor cells with "suicide" genes encoding for prodrug-activating enzymes that render target cells susceptible to prodrug treatment. Suicidal gene therapy results in the death of tumor with the expression of gene encoding enzyme that converts non-toxic prodrug into cytotoxic product. Cytochrome P450 4B1 (CYP4B1) activates 4-ipomeanol (4-IPO) or 2-aminoanthracene (2-AA) to cytotoxic furane epoxide and unsaturated dialdehyde intermediate.In this study, therapeutic effects of suicidal gene therapy with rabbit CYP4B1/2-AA or 4-IPO system were evaluated in HT-29 (human colon cancer cell). pcDNA-CYP4B1 vector was transfected into HT-29 by lipofection and stable transfectant was selected by treatment of hygromycin ($500{\mu}g/mL$) for 3 weeks. Reverse transcription polymerase chain reaction (RT-PCR) analysis was performed for confirmation of CYP4B1 expression in CYP4B1 gene transduced cell. The cytotoxic effects of CYP4B1 transduced cell were determined using dye-exclusion assay after treatment of 2-AA or 4-IPO for 96 hrs. Dye-exclusion assay showed that $IC_{50}$ of HT-29 and CYP4B1 transduced HT-29 was 0.01 mM and 0.003 mM after 4-IPO or 2-AA treatment at 96 hrs exposure, respectively. In conclusion, CYP4B1 based prodrug gene therapy probably have the potential for treatment of colorectal adenocarcinoma.

• The Korean Journal of Urological Oncology
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• 제15권3호
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• pp.131-136
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• 2017

Purpose: The aim of this study is to investigate the criteria of biochemical recurrence (BCR) and follow-up periods and methods with and without blood and imaging test of urologic oncology before established guidelines of prostate cancer in Korea. Materials and Methods: In December 2015, we sent the questionnaire to urologic oncologist in academic hospital and received the answer from 108 urologic oncologist (50%). Also, we analyzed the data of 1,141 patients underwent radical prostatectomy in 2005 from Korean Medical Insurance. Results: In follow-up, 72 physicians (66.7%) performed blood test every 3 months, 51 physicians (47.2%) performed imaging study in case of BCR. Bone scan was the most common imaging study in the follow-up (74 physicians, 68.5%). But, bone scan was only performed in case of BCR (43 physicians, 39.8%). The criteria of BCR was PSA 0.2 ng/mL (75 physician, 69.4%), 76 physicians (70.4%) was performed different follow-up according to risk of patients. In Korean Medical Insurance data analysis, PSA were performed average 2 times every year and magnetic resonance imaging, computed tomography, Bone scan were performed average 0.1, 0.2, 0.1 times every year, respectively. Conclusions: The criteria of BCR and the follow-up of prostate cancer patients in Korea were similar Korean prostate cancer guidelines. Blood and imaging test might be increased compared to 10 years ago, it is necessary to compare the Korean Medical Insurance data between 10 years ago and present.

• Korean Journal of Radiology
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• v.22 no.4
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• pp.559-567
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• 2021

Objective: To evaluate the impact of multiparametric magnetic resonance imaging (mpMRI) before confirmatory prostate biopsy in patients under active surveillance (AS). Materials and Methods: This retrospective study included 170 patients with Gleason grade 6 prostate cancer initially enrolled in an AS program between 2011 and 2019. Prostate mpMRI was performed using a 1.5 tesla (T) magnetic resonance imaging system with a 16-channel phased-array body coil. The protocol included T1-weighted, T2-weighted, diffusion-weighted, and dynamic contrast-enhanced imaging sequences. Uroradiology reports generated by a specialist were based on prostate imaging-reporting and data system (PI-RADS) version 2. Univariate and multivariate analyses were performed based on regression models. Results: The reclassification rate at confirmatory biopsy was higher in patients with suspicious lesions on mpMRI (PI-RADS score ≥ 3) (n = 47) than in patients with non-suspicious mpMRIs (n = 61) and who did not undergo mpMRIs (n = 62) (66%, 26.2%, and 24.2%, respectively; p < 0.001). On multivariate analysis, presence of a suspicious mpMRI finding (PI-RADS score ≥ 3) was associated (adjusted odds ratio: 4.72) with the risk of reclassification at confirmatory biopsy after adjusting for the main variables (age, prostate-specific antigen density, number of positive cores, number of previous biopsies, and clinical stage). Presence of a suspicious mpMRI finding (adjusted hazard ratio: 2.62) was also associated with the risk of progression to active treatment during the follow-up. Conclusion: Inclusion of mpMRI before the confirmatory biopsy is useful to stratify the risk of reclassification during the biopsy as well as to evaluate the risk of progression to active treatment during follow-up.

• Bulletin of the Korean Chemical Society
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• v.25 no.4
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• pp.506-510
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• 2004

There have been intensive studies concerning $[^{11}F]$choline ($[^{11}F]$methyldimethyl( ${\beta}$ -hydroxyethyl) ammonium) (1) which is known as a very effective tracer in imaging various human tumors localized in brain, lung, esophagus, rectum, prostate and urinary bladder using Positron Emission Tomography (PET) and there is increasing interest in $^{18}F$ labelled choline (2) and proved to be useful to visualize prostate cancer. We have prepared six $^{18}F$ labelled alkyl choline derivatives (3a-3c, 4a-4c) from ditosylated and dibrominated alkanes in moderate yields. The six alkyl tosylate or bromate ammonium salts have been synthesized as precursors. Radiofluorination was achieved by the treatment of precursors with $^{18}F$ - in the presence of Kryptofix-2.2.2.. The labeling yields varied ranging from 7 to 25%.

• Nuclear Medicine and Molecular Imaging
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• v.40 no.5
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• pp.237-242
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• 2006

Knowledge of molecular mechanisms governing malignant transformation brings new opportunities for therapeutic intervention against cancer using novel approaches. One of them is gene therapy based on the transfer of genetic material to an organism with the aim of correcting a disease. The application of gene therapy to the cancer treatment has led to the development of new experimental approaches such as suicidal gene therapy, inhibition of oncogenes and restoration of tumor-suppressor genes. Suicidal gene therapy is based on the expression in tumor cells of a gene encoding an enzyme that converts a prodrug into a toxic product. Representative suicidal genes are Herpes simplex virus type 1 thymidine kinase (HSV1-tk) and cytosine deaminase (CD). Especially, physicians and scientists of nuclear medicine field take an interest In suicidal gene therapy because they can monitor the location and magnitude, and duration of expression of HSV1-tk and CD by PET scanner.

• Investigative Magnetic Resonance Imaging
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• v.22 no.4
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• pp.272-276
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• 2018

Extra-articular tenosynovial giant cell tumor (TS-GCT) in retropharyngeal space is a rare case. We found only two case reports in the literature, in which one was located in retropharynx or prevertebral space of the cervical spine. We describe a rare case of TS-GCT in the retropharynx, which was initially misdiagnosed as oropharyngeal cancer. Furthermore, we want to assure that extraarticular diffuse type TS-GCT should be considered in the differential diagnosis of lesions showing low signal intensity in MRI scan.

• Journal of Digestive Cancer Research
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• v.10 no.1
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• pp.16-21
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• 2022

Diagnosis of gastric subepithelial tumors (SETs) is sometimes difficult with conventional endoscopy or tissue sampling with standard biopsy, so non-invasive imaging modalities such as endoscopic ultrasound (EUS) and computed tomography are used to evaluate the characteristics of SETs features (size, location, originating layer, echogenicity, shape). However imaging modalities alone is not able to distinguish among all types of SETs, so histology is the gold standard for obtaining the final diagnosis. For tissue sampling, mucosal cutting biopsy and mucosal incision-assisted biopsy and EUS-guided fine-needle aspiration or biopsy (EUS-FNA or EUS-FNB) is commonly recommended. Endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) are used for resection of SETs involving the mucosal and superficial submucosal layers, could not treat adequately and safely the SETs involving the deep mucosa and muscularis propria. Submucosal tunneling endoscopic resection (STER) and endoscopic full-thickness resection (EFTR) is used as a therapeutic option for the treatment of SETs with the development of reliable endoscopic closure techniques and tools.

• Clinical Endoscopy
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• v.57 no.5
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• pp.559-570
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• 2024

The literature pertaining to surveillance following treatment for esophageal squamous cell carcinoma (SCC) was reviewed and summarized, encompassing the current status and future perspectives. Analysis of the standardized mortality and incidence ratios for these cancers indicates an elevated risk of cancer in the oral cavity, pharynx, larynx, and lungs among patients with esophageal SCC compared to the general population. To enhance the efficacy of surveillance for these metachronous cancers, risk stratification is needed. Various factors, including multiple Lugol-voiding lesions, multiple foci of dilated vascular areas, young age, and high mean corpuscular volume, have been identified as predictors of metachronous SCCs. Current practice involves stratifying the risk of metachronous esophageal and head/neck SCCs based on the presence of multiple Lugol-voiding lesions. Endoscopic surveillance, scheduled 6-12 months post-endoscopic resection, has demonstrated effectiveness, with over 90% of metachronous esophageal SCCs treatable through minimally invasive modalities. Narrow-band imaging emerges as the preferred surveillance method for esophageal and head/neck SCC based on comparative studies of various imaging techniques. Innovative approaches, such as artificial intelligence-assisted detection systems and radiofrequency ablation of high-risk background mucosa, may improve outcomes in patients following endoscopic resection.