• Korean Journal of Materials Research
• /
• v.3 no.5
• /
• pp.443-450
• /
• 1993

Self-alignment gatc Schottky contact structure on Si- implanted GaAs was formed by plasma enhanced chemical vapor dcposirion. Tungsten nitride thin films (ahclut 1600$\AA$) \vcre dopositcd on GaAs at $350^{\circ}C$ in order to fahricarc GaAs 1Cs and ttwn rapidly annealed at $750^{\circ}C$ to $900^{\circ}C$. Thermal charac tcristics of PECVD)-$W_{67}N_{43}$/GaAs structure were investigated by X-ray diffraction, photolumintesccnce. and optical deep level transient specrroscopy. Results revealed that $W_{67}N_{33}$ gate was more thermally sta ble with GaAs substrate than W gate and Si atoms implanted In $W_{67}N_{33}$/GaAs structure became morr active than those In W/GaAs after annealing. I-V characteristics of $W_{67}N_{33}$/GaAs diod c exhibired a nearly ideal diode behavior. The termal stability of $W_{67}N_{33}$/GaAs diode was better than that of W/GaAs diode with the post annealing at temperatures from 800 to $900^{\circ}C$ for 20s without As overpressure.

• The Korean Journal of Nuclear Medicine
• /
• v.36 no.2
• /
• pp.140-142
• /
• 2002

A 67-year-old woman who had undergone anterior resection for a moderately differentiated adenocarcinoma of the rectum and wedge resection for liver metastasis presented with hematogenous lung metastasis. Metastatic pulmonary nodules in both lung fields were shown on plain chest radiograph and CT. Ga-67 SPECT images revealed accumulation of radioactivity corresponding to the pulmonary nodules. The authors present an unusual case of accumulation of Ga-67 in metastatic pulmonary nodules in a patient with a moderately differentiated adenocarcinoma of the rectum.

• The Korean Journal of Nuclear Medicine
• /
• v.23 no.1
• /
• pp.27-33
• /
• 1989

The relationship between angiographic findings and those of $^{67}Ga$ scan was evaluated in 30 patients with primary hepatocellular carcinoma diagnosed by either pathological examination or laboratory, radiologic findings. Twenty-three cases revealed hot activities on $^{67}Ga$ scan and definite tumor stains on angiography. Main findings of $^{67}Ga$ scans of 7 cases were isoactivity in 5 and cold area in 2, 5 of which revealed faint or no tumor stain on angiography. Cold areas within the primary hepatocellular carcinoma were noted in 9 cases by $^{67}Ga$ scan. In 6 cases these were due to tumor necrosis. Remaining 3 cases had arterioportal shunt, portal vein thrombosis and one had necrosis as well. These results indicate that gallium uptake of primary hepatocellular carcinoma seems to be relatively correlated with tumor stains on angiography. It is well known that the necrotic portion of primary hepatocellular carcinoma does not uptake gallium and it's the main cause of cold areas on $^{67}Ga$ scan. And we suspect that the hemodynamic changes of primary hepatocellular carcinoma such as large arterioportal shunt, portal vein thromosis may cause the decreased activity on $^{67}Ga$ scan.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.40 no.7
• /
• pp.486-493
• /
• 2003

Schottky type A $l_{0.33}$G $a_{0.67}$N ultraviolet photodetectors were fabricated on the MOCVD grown AlGaN/ $n^{＋}$-GaN and AlGaN/AlGaN interlayer/ $n^{＋}$-GaN structures. The grown layers have the carrier concentrations of -$10^{18}$, and the mobilities were 236 and 269 $\textrm{cm}^2$/V.s, respectively. After mesa etching by ICP etching system, the Si3N4 layer was deposited for passivation between the contacts and Ti/AL/Ni/Au and Pt were deposited for ohmic and Schottky contact, respectively. The fabricated Pt/A $l_{0.33}$G $a_{0.67}$N Schottky diode revealed a leakage current of 1 nA for samples with interlayer and 0.1$\mu\textrm{A}$ for samples without interlayer at a reverse bias of -5 V. In optical measurement, the Pt/A $l_{0.33}$G $a_{0.67}$N diode with interlayer showed a cut-off wavelength of 300 nm, a prominent responsivity of 0.15 A/W at 280 nm and a UV-visible extinction ratio of 1.5x$10^4./TEX>.

• The Korean Journal of Nuclear Medicine
• /
• v.22 no.1
• /
• pp.93-98
• /
• 1988

$^{67}Ga$ scintigraphy has been used in the evaluation of sarcoidosis, particularly for delineating sites of involvement and grading activity. Three patients admitted in SNUH between Jan. 1986 and Jun. 1987 were diagnosed as sarcoidosis after clinical examination and $^{67}Ga$ scintigraphy. $^{67}Ga$ scintigraphy disclosed increased uptake of radioactivity in both hilar region, mediastinum, both lacrimal glands and parotid glands prior to treatment. In one case after prednisolon therapy, there was definit improvement of clinical findings and $^{67}Ga$ scintigraphy was normalized.

• The Korean Journal of Nuclear Medicine
• /
• v.22 no.1
• /
• pp.77-81
• /
• 1988

Tumor localizing properties of $^{67}Ga$ citrate and $^{169}Yb$ citrate were studies with sarcoma 180 bearing mice. To compare precisely the accumulation of $^{67}Ga$ citrate and $^{169}Yb$ citrate in tumor tissue itself, $^{67}Ga$ and l63yb were administered simultaneously as a mixture of same chemical form of citrate. The yield of $^{169}Yb$ labeled citrated and the of radiopharmaceuticals purity was identified more than 90% by chromatography on silica gel plates. $^{67}Ga$ and $^{169}Yb$ were injected into mice and the mice were killed at 3, 24, and 48 hours following intraperitoneal injection of the radiopharmaceuticals. The retention value of $^{67}Ga$ and $^{169}Yb$ in tumor was similar but they differ from each other markedly in normal tissue distribution. $^{169}Yb$ citrate is cleared up from blood more rapidly than $^{67}Ga$ citrate, and a high tumor to blood ratio is achieved shortly after injection.

• The Korean Journal of Nuclear Medicine
• /
• v.24 no.2
• /
• pp.337-342
• /
• 1990

A case of a 39-year-old man with granulocytic sarcoma documented by positive Ga-67 scan is described and brief review of literature was performed. He was diagnosed as acute myelogenous leukemia and got complete remission with antileukemic chemotherapy for 7 months. On admission, picture of his bone marrow and peripheral blood showed remission state of leukemia. Radiologic examinations were performed for evaluation of lesions in head and chest, and findings of granulocytic sarcoma were suspected. So we got $^{67}Ga-citrate$ scan and pleural biopsy for identification of causes of intractable pleural effusion and skin lesion. Myeloblastomas (or granular sarcomas) proved by pleural biopsy were correctly identified by $^{67}Ga-citrate$ scan, and disease extent was clearly delineated. We believe that $^{67}Ga-scintigraphy$ is very helpful in localizing and follow-up evaluation of granulocytic sarcoma.

• Nuclear Medicine and Molecular Imaging
• /
• v.43 no.4
• /
• pp.366-367
• /
• 2009

Ga-67 scintigraphy demonstrated increased uptake in the lungs and stomach in a 26-year-old man with hypercalcemia. A primitive neuroectodermal tumor was confirmed by bone marrow examination. Tc-99m MDP uptake in the same locations as Ga-67 revealed by bone scintigraphy was consistent with metastatic calcification. Although the mechanism of Ga-67 uptake in metastatic calcification is not understood, the presence of an inflammatory process is suggested.

• Proceedings of the Optical Society of Korea Conference
• /
• 1997.08a
• /
• pp.67-67
• /
• 1997

• The Korean Journal of Nuclear Medicine
• /
• v.26 no.2
• /
• pp.318-326
• /
• 1992

Ga-67 citrate scan has been requested for detection or follow-up of inflammatory or neoplastic disease. Visualization of Ga-67 citrate in the kidneys at 48 and 72 hr post injection is usually interpreted as evidence of renal pathology. But precise mechanisms of abnormal Ga-67 uptake in kidneys were unknown. We undertook a study to determine the clinical value of Ga-67 citrate imaging of the kidneys in 68 patients with primary or secondary nephropathy confirmed by renal biopsy and 66 control patients without renal disease. Renal uptake in 48 to 72 hr images was graded as follows: Grade 0=back-ground activity:1=faint uptake greater than background;2=definite uptake, but less than lumbar vertebrae; 3=same uptake as lumbar vertebrae, but less than liver; 4=same or higher uptake than liver. The results were as follows. 1) 42 of 65 (62%) patients with noninfectious nephritis showed grade 2 or higher Ga-67 renal uptake but only 10 percent of control patients showed similar uptake. 2) In 14 patients with systemic lupus erythematosus, 8 of 9 (89%) patients with lupus nephritis exhibited marked renal uptake 3) 36 of 41 patients (88%) with combined nephrotic syndrome showed Grade 2 or higher renal uptake. 4) Renal Ga-67 uptake was correlated with clinical severity of nephrotic syndrome determined by serum albumin level, 24 hr urine protein excretion and serum lipid levels. 5) After complete remission of nephrotic syndrome, renal uptake in all 8 patients who were initially Grade 3 or 4, decreased to Grade 1 or 0. In conclusion, we think that the mechanism of renal Ga-67 uptake in nephrotic syndrome might be related to the pathogenesis of nephrotic syndrome. In systemic lupus erythematosus, Ga-67 citrate scan is useful in predicting renal involvement.