• The Korean Journal of Nuclear Medicine
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• v.33 no.4
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• pp.352-361
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• 1999

Purpose: Carotid endarterectomy nay benefit patients with bilateral carotid stenosis by improving cerebro-vascular hemodynamics of ipsilateral as well as contralateral cerebral hemispheres. We investigated cerebro-vascular hemodynamics after carotid endarterectomy in patients with contralateral carotid occlusion by acetazolamide stress brain SPECT. Materials and Methods: Subjects were 14 symptomatic patients (all men, mean age 66 yrs) with carotid stenosis (>50%) with contralateral carotid occlusion. Acetazolamide stress Tc-99m ECD brain SPECTs were performed within 2 weeks before and after carotid endarterectomy using one day protocol. Cerebral blood flow (CBF) and cerebrovascular reserve (CVR) were assessed visually. In 12 patients, correlation between the patency of proximal anterior cerebral or anterior communicating arteries (A1/A-comm) and the improvement of CBF or CVR after endarterectomy was assessed. Results: Preoperative SPECT showed reduced CBF in 2 ipsilateral and 10 contralateral hemispheres. CVR was reduced in 4 ipsilateral and 9 contralateral hemispheres. Of 12 hemispheres with reduced CBF, 2 hemispheres (16.7%) showed improvement of CBF after endarterectomy. However, reduced CVR was improved in all 4 ipsilateral and 7 of 9 (78%) of contralateral hemispheres after endarterectomy. Three of4 with stenotic Al/A-comm and 4 of 8 with patent A1/A-comm had reduced contralateral CVR. Reduced contralateral CVR improved in all 3 patients with stenotic A1/A-comm and 3 of 4 with patent A1/A-comm. Conclusion: Acetazolamide stress brain SPECT demonstrated improvement of compromised cerebrovascular reserve in not only ipsilateral but also contralateral hemispheres of patients with contralateral carotid occlusion after carotid endarterectomy, and may, therefore, be useful for evaluating cerebral blood flow and cerebrovascular reserve after carotid endarterectomy.

• The Korean Journal of Nuclear Medicine
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• v.37 no.6
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• pp.382-392
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• 2003

Purpose: Uptakes of Tc-99m MIBI (MIBI) and Tc-99m tetrofosmin (tetrofosmin) in human non-small cell lung cancer A549, multidrug-resistance associated protein (MRP) expressing cell, were investigated in vitro and in vivo. Materials and Methods: Western blot analysis and immunohistochemistry were used for detection of MRP in A549 cells with anti-MRPr1 antibody. Cellular uptakes of two tracers were evaluated at $100{\mu}M$ of verapamil (Vrp), $50{\mu}M$ of cyclosporin A (CsA) and $25{\mu}M$ of butoxysulfoximide (BSO) after incubation with MIBI and tetrofosmin for 30 and 50 min at $37^{\circ}C$, using single cell suspensions at $1{\times}10^6cells/ml$. Radioactivities in supernatants and pellets were measured with gamma well counter. A549 cells were inoculated in each flanks of 24 nude mice. Group 1 (Gr1) and Gr3 mice were treated with only MIBI or tetrofosmin, and Gr2 and Gr4 mice were treated with 70mg/kg of CsA i.p. for 1 hour before injection of 370KBq of MIBI or tetrofosmin. Mice were sacrificed at 10, 60 and 240 min. Radioactivities of organs and tumors were expressed as percentage injected dose per gram of tissue (%ID/gm). Results: Western blot analysis of the A549 cells detected expression of MRPr1 (190 kDa) and immunohistochemical staining of tumor tissue for MRPr1 revealed brownish staining in cell membrane but not P-gp. Upon incubating A549 cells for 60 min with MIBI and tetrofosmin, cellular uptake of MIBI was higher than that of tetrofosmin. Coincubation with modulators resulted in an increase in cellular uptakes of MIBI and tetrofosmin. Percentage increase of MIBI was higher than that of tetrofosmin with Vrp by 623% and 427%, CsA by 753% and 629% and BSO by 219% and 140%, respectively. There was no significant difference in tumoral uptakes of MIBI and tetrofosmin between Gr1 and Gr3. Percentage increases in MIBI (114% at 10 min, 257% at 60 min, 396% at 240 min) and tetrofosmin uptake (110% at 10 min, 205% at 60 min, 410% at 240 min) were progressively higher by the time up to 240 min with CsA. Conclusion: These results indicate that MIBI and tetrofosmin are suitable tracers for imaging MRP-mediated drug resistance in A549 tumors. MIBI may be a better tracer than tetrofosmin for evaluating MRP reversal effect of modulators.

• The Korean Journal of Nuclear Medicine
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• v.37 no.2
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• pp.83-93
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• 2003

Background: Lung-to-heart uptake ratio (LHR) in $^{201}Tl-chloride$ myocardial perfusion scan is believed to be a reliable marker for left ventricular (LV) dysfunction, but the clinical value of LHR is controversial for $^{99m}Tc-MIBI$ imaging. Furthermore, most of results suggesting lung uptake of $^{99m}Tc-MIBI$ as a potential marker for LV dysfunction used immediate post-stress images, instead of routine images acquired 1 hour after tracer injection. The goal of our study was to investigate whether LHR evaluated with routine gated $^{99m}Tc-MIBI$ imaging can reflect the degree of perfusion defect or left ventricular performance. Subjects and Methods: 241 patients underwent exercise $^{99m}Tc-MIBI$ myocardial SPECT were classified into normal myocardial perfusion (NP, n=135) and abnormal myocardial perfusion (AP, n=106) group according to the presence of perfusion defect. LHR was calculated from anterior projection image taken at 1-hour after injection. Two legions of interest (ROIs) were placed on left lung above LV and on myocardium showing the highest radioactivity. Subjects were classified by left ventricular ejection fraction (LVEF), as Gr-I: >50%, Gr-II: 36-50%, Gr-III: <36% and by summed stress score (SSS), as Gr-A: <4, Gr-B: 4-8, Gr-C: 9-13, Gr-D: >13, LHR was compared among these groups. Results: In NP group(n=135), LHR, were higher in men than women ($men:\;0.311{\pm}0.03,\;women:\;0.296{\pm}0.03,\;p<0.05$). Significant difference, in LHR were found between NP and AP groups both for men and women ($men:\;0.311{\pm}0.03\;vs\;.\;0.331{\pm}0.06,\;women:\;0.296{\pm}0.03\;vs.\;0.321{\pm}0.07.\;p<0.05$). There were weak negative correlation between LHR and LVEF (r=-0.342, p<0.05) and weak positive correlation between LHR and SSS (r=0.478, p<0.05) in men, but not in women (LVEF: r=-0.279, p=0.100, SSS: r=0.276, p=0.103). Increased LHR was defined when for more than mean + 2SD value ($men{\geq}0.38,\;women{\geq}0.37$) of the LHR of the subject with normal perfusion. Increased LHR were observed more frequently in subjects with lower LVEF (Gr-I: 11.1%, Gr-II: 27.0%, Gr-III: 35.4%, p<0.05) and higher SSS(Gr-A: 14.0%, Gr-B: 5.7%, Gr-C: 18.2%, Gr-D: 40.7%, p<0.05). Conclusions: LHRs obtained from routine $^{99m}Tc-MIBI$ gated SPECT images were weakly correlated with LVEF and perfusion defect. Although significant overlaps were observed between normal and abnormal perfusion group, LHRs could be used as an indirect marker of severe perfusion defect or reduced left ventricular function.

• The Korean Journal of Nuclear Medicine
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• v.37 no.2
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• pp.110-119
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• 2003

Purpose: Radioiodine (I-131) therapy is an effective modality to reduce both recurrence and mortality rates in differentiated thyroid cancer. Whether higher doses shows higher therapeutic responses was still debatable. The purpose of this study was to validate curve-fitting (CF) method measuring maximum permissible dose (MPD) by a biological dosimetry using metaphase analysis of peripheral blood lymphocytes. Materials and Methods: Therapeutic effects of MPD was evaluated in 58 patients (49 females and 9 males, mean age $50{\pm}11$ years) of papillary thyroid cancer. Among them 43 patients were treated with ${\Leq}7.4GBq$, while 15 patients with ${\geq}9.25GBq$. The former was defined as low-dose group, and the latter high-dose group. Therapeutic response was defined as complete response when complete disappearance of lesions on follow-up I-131 scan and undetectable serum thyroglobulin levels were found. Statistical comparison between groups were done using chi-square test. P value less than 0.05 was regarded as statistically significant. Results: MPD measured by CF method using tracer and therapeutic doses were $13.3{\pm}1.9\;and\;13.8{\pm}2.1GBq$, respectively (p=0.20). They showed a significant correlation (r=0.8, p<0.0001). Exposed doses to blood measured by CF and biological methods were $1.54{\pm}0.03\;and\;1.78{\pm}0.03Gy$ (p=0.01). They also showed a significant correlation (r=0.86, p=0.01). High-dose group showed a significantly higher rate of complete response (12/15, 80%) as compared to the low-dose group (22/43, 51.2%) (p=0.05). While occurrence of side effects was not different between two groups (40% vs. 30.2%, p=0.46). Conclusion: Measurement of MPD using CF method is reliable, and the high-dose I-131 therapy using MPD gains significantly higher therapeutic effects as compared with low-dose therapy.

• The Korean Journal of Nuclear Medicine
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• v.34 no.5
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• pp.393-402
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• 2000

Purpose: Tc-99m-MIBI (MIBI) and Tc-99m-Tetrofosmin (TF) are commonly used for scintimammog (SMM). We compared the diagnostic ability of SMM using Tc-99m-MIBI and Tc-99m-TF for the diagnosis of breast mass. Materials and Methods: The study subjects were comprised of 123 breast lesior 86 normal breasts of 114 patients who underwent SMM. Bilateral prone images and anterior supine images obtained at 5 minutes and 1 or 3 hours after intravenous injection of 740 MBq of either MIBI or TF. of tumors were not significantly different between the MIBI and TF groups. First, two observers read the SMM without clinical information (1st interpretation), then read again with information about location (2nd interpretation). Sensitivity and specificity of each radiopharmaceutical for the diagnosis of cancer were evaluated in terms of image acquisition time, tumor size, and location. Results: The SMM a good agreement between two observers for 1st and 2nd interpretation, except for TF SMM at 3 hr. first interpretation, the sensitivities at 5 min, 1 hr, and 3 hr were not significantly different between MIBI TF SMM (81.6%, 80.0%, 60.9% in MIBI vs. 88.9%, 80.6%, 42.9% in TF), although the sensitivities of images were significantly lower than 5 min images in both MIBI and TF SMM. The specificity of TF at was superior to that of MIBI (81.5%, 90.0%, 82.9% in MIBI vs. 96.7%, 100%, 90.0% in TF, p<0.01 MIBI TF at 5 min). For the second interpretation with information of mass location, the sensitivities at 3 hr were significantly lower than 5 min images (86.8%, 86.7%, 78.3% in MIBI vs. 88.9%, 93.5%, 57.1% between MIBI and TF SMM. However, there was no significant difference in the specificity (60.0%, 75.0% for MIBI vs. 86.7%, 100%, 100% for TF). MIBI and TF SMM showed lower sensitivities for the with less than 1 cm than tumors with more than 1 cm. However, the location of tumors did not sensitivity and specificity between MIBI and TF SMM. Conclusion: The ability for the differential of breast tumor is similar between MIBI and TF SMM, and delayed image is not necessary. TF may be than MIBI considering the specificity of SMM without clinical information and labeling convenience.

• The Korean Journal of Nuclear Medicine Technology
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• v.16 no.2
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• pp.110-114
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• 2012

Purpose : PET/CT is widely used for early checking up of cancer and following up of pre and post operation. Image reconstruction method is advanced with mechanical function. We want to evaluate image quality of each reconstruction program based on time of flight (TOF). Materials and Methods : After acquiring phantom images during 2 minutes with Gemini TF (Philips, USA), Biograph mCT (Siemens, USA) and Discovery 690 (GE, USA), we reconstructed image applied to Astonish TF (Philips, USA), ultraHD PET (Siemens, USA), Sharp IR (GE, USA) and not applied. inside of Flangeless Esser PET phantom (Data Spectrum corp., USA) was filled with $^{18}F$-FDG 1.11 kBq/ml (30 Ci/ml) and 4 hot inserts (8. 12. 16. 25 mm) were filled with 8.88 kBq/ml (240 ${\mu}Ci/ml$) the ratio of background activity and hot inserts activity was 1 : 8. Inside of triple line phantom (Data Spectrum corp., USA) was filled with $^{18}F$-FDG 37 MBq/ml (1 mCi). Three of lines were filled with 0.37 MBq (100 ${\mu}Ci$). Contrast ratio and background variability were acquired from reconstruction image used Flangeless Esser PET phantom and resolution was acquired from reconstruction image used triple line phantom. Results : The contrast ratio of image which was not applied to Astonish TF was 8.69, 12.28, 19.31, 25.80% in phantom lid of which size was 8, 12, 16, 25 mm and it which was applied to Astonish TF was 6.24, 13.24, 19.55, 27.60%. It which was not applied to ultraHD PET was 4.94, 12.68, 22.09, 30.14%, it which was applied to ultraHD PET was 4.76, 13.23, 23.72, 31.65%. It which was not applied to SharpIR was 13.18, 17.44, 28.76, 34.67%, it which was applied to SharpIR was 13.15, 18.32, 30.33, 35.73%. The background variability of image which was not applied to Astonish TF was 5.51, 5.42, 7.13, 6.28%. it which was applied to Astonish TF was 7.81, 7.94, 6.40 6.28%. It which was not applied to ultraHD PET was 6.46, 6.63, 5.33, 5.21%, it which was applied to ultraHD PET was 6.08, 6.08, 4.45, 4.58%. It which was not applied to SharpIR was 5.93, 4.82, 4.45, 5.09%, it which was applied to SharpIR was 4.80, 3.92, 3.63, 4.50%. The resolution of phantom line of which location was upper, center, right, which was not applied to Astonish TF was 10.77, 11.54, 9.34 mm it which was applied to Astonish TF was 9.54, 8.90, 8.88 mm. It which was not applied to ultraHD PET was 7.84, 6.95, 8.32 mm, it which was applied to ultraHD PET was 7.51, 6.66, 8.27 mm. It which was not applied to SharpIR was 9.35, 8.69, 8.99, it which was applied to SharpIR was 9.88, 9.18, 9.00 mm. Conclusion : Image quality was advanced generally while reconstruction program which is based on time of flight was used. Futhermore difference of result compared each manufacture reconstruction program showed up, however this is caused by specification of instrument of each manufacture and difference of reconstruction algorithm. Therefore we need further examination to find out appropriate reconstruction condition while using reconstruction program used for advance of image quality.

• The Korean Journal of Nuclear Medicine
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• v.4 no.1
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• pp.27-36
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• 1970

적혈구(赤血球) 수명의 측정에는 $^{51}Cr$-표지적혈구법(標識赤血球法)이 임상적(臨床的)으로 이용(利用)되고 있으며 이는 이론상(理論上) steady state 즉(卽) 측정기간(測定期間)동안 순환(循環) $^{51}Cr$량(量)-적혈구량(赤血球量)이 일정(一定)할 때에 한(限)하여 유효(有效)하며 unsteady state 때는 true red cell survival을 알기 위하여서는 측정치에 영향을 주는 요인(要因)에 대하여 각각(各各) 교정(校正)해 줄 필요(必要)가 있다. 이 요인(要因)중에 특히 실혈(失血)로 인(因)한 영향에 관(關)하여는 계통적인 연구(硏究)가 적다. 이에 저자(著者)들은 $^{51}Cr$표지적혈구법(標識赤血球法)을 이용(利用)하여 실혈(失血)이 적혈구(赤血球) 수명측정(測定)에 미치는 영향을 인체(人體)에서 실험 관찰하여 몇가지 성적을 얻었다. 연구대상(硏究對象)은 총(總) 56명(名)의 청장년(靑壯年)으로 급성실혈군(急性失血群)과 만성실혈군(慢性失血群)으로 구분(區分)하여 급성실혈군(急性失血群)은 위장출혈등(胃腸出血等)이 없는 2대(代)의 의대생(醫大生)으로 $^{51}Cr$표지적혈구법(標識赤血球法)을 사용하여 적혈구(赤血球) 수명을 측정하는 동안($10{\sim}14$ 일간(日間)) 1일당(日當) 10ml(6명(名)), 25ml(4명(名)), 50ml(4명(名)), 75ml(4명(名)), 100ml(6명(名))를 각각(各各) 사혈(瀉血)한 군(群)과 10일간(日間) 1,000ml를 사혈한 군(群) 즉 200ml씩 5회(回)(4명(名)), 500ml씩 2회(回)(4명(名))로 세분(細分)하였으며 만성실혈군(慢性失血群)은 직업적인 공혈자(供血者)로 반복사혈로 생긴 9명(名)의 빈혈자와 십이지장충증(十二指腸蟲症)에 감염(感染)되어 구충(驅蟲)한 중등도(中等度)의 철결핍성 빈혈환자 7명(名)으로 나누어 관찰하였다. 측정(測定) 방법(方法)으로는 Gray 및 Sterling법(法)을 개설한 방법(方法)으로 $^{51}Cr$표지적혈구(標識赤血球)의 계측시료(計測試料)로서 전혈(全血) 및 적혈구(赤血球)를 사용(使用)하였다. 실험(實驗)성적은 1. 1일당(日當) 실혈량(失血量)이 증가(增加)할수록 적혈구(赤血球)수명($T\frac{1}{2}$)은 짧아짐을 알 수 있었다. 즉(卽) 1일당(日當) $20{\sim}50ml$ 사혈군에서는 $T\frac{1}{2}$이 현저히 짧아지는 rapid phase을 나타내고 1일당(日當) 50ml이상(以上) 사혈군에서는 짧아지는 정도(程度)가 완만한 slow phase을 나타낸다(Fig. 6). 2. 1일량(日量) 10ml 및 25ml식(式) 사혈한 군(群)의 적혈구수명(赤血球壽命)을 측정(測定)하는데 있어 적혈구(赤血球)를 사용하였을 때에는 $T\frac{1}{2}$측 정치에 유의한 차(差)가 없었으며 이 범위 내에서는 Hct., Hb. 및 혈청철치(血淸鐵値)도 역시 유의한 차(差)가 없었다. 3. 1일량(日量) 50ml 및 75ml, 100ml씩 사혈한 군(群)에서는 적혈구(赤血球)만을 사용(使用)하였을 때와 전혈(全血)을 시료(試料)로 하였을 때 사이에 $T\frac{1}{2}$의 측정치에 유의한 차(差)가 있었으며 이 때는 Hct., Hb. 및 혈청철치(血淸鐵値)에도 변화(變化)가 있었다. 즉(卽), 전혈(全血)을 사용한 적혈구(赤血球) 수명($T\frac{1}{2}$)의 측정치가 적혈구(赤血球)만를 사용(使用)한 적혈구(赤血球) 수명($T\frac{1}{2}$)의 측정치 보다 짧았다. 4. 일정(一定)기간(10 일(日)) 사혈의 총량(1000ml)이 같을 매는 200ml를 5회(回) 사혈한 군(群)이나 500ml를 2회(回) 사혈한 군(群) 사이에 적혈구(赤血球) 수명($T\frac{1}{2}$)에 유의(有義)한 차(差)를 볼 수 없었다. 5. 직업적 공혈자의 반복사혈로 인(因)한 만성(慢性) 빈혈환자 9명(名)에서의 $^{51}Cr$적혈구(赤血球)수명($T\frac{1}{2}$) 측정치는 평균(平均) 19.2일(日)로 짧아져 있으나 적혈구수명측정전후(赤血球壽命測定前後)에 충분(充分)한 철제(鐵劑)를 투여(投與)하여 Hct., Hb. 및 혈청철치(血淸鐵値)를 증가(增加)시켰으며 이때 볼 수 있었든 Hct치(値)를 규준(規準)하여 교정한 적혈구(赤血球)수명($T\frac{1}{2}$)은 거의 정상(正常)범위 안에 있어(27.6일(日)) 이러한 인자(因子)를 고려하지 않으면 잘못 이해할 수가 있다. 6. 구충자충(鉤蟲仔蟲)을 구충한 7명(名)의 중등도(中等度) 철(鐵)결핍성 빈혈환자에서의 적혈구(赤血球)수명($T\frac{1}{2}$) 측정치는 25일(日)$\sim$31일(日)로 평균(平均) 28일(日)이었으며, 이때 장 출혈량은 1일(日) $1.0{\sim}3.5ml$이었다. 단시일내의 급성실혈시에는 이와같은 소량의 실혈(失血)도 적혈구(赤血球)수명($T\frac{1}{2}$) 측정치에 영향을 보여 줌을 알 수 있었다. 따라서 이러한 정도의 실혈은 실험오차에 기인하는 것인지 아니면 장기 출혈에서는 이러한 소량의 실혈이 적혈구(赤血球)수명($T\frac{1}{2}$) 측정에 영향을 미치지 않는 것인지는 아직 확실히 말할 수 없다. 8. $^{51}Cr$-표지적혈구(標識赤血球)로 측정한 적혈구(赤血球)수명($T\frac{1}{2}$)은 측정시의 실혈량(失血量)에 큰 영향을 받음을 알 수 있으며 저자(著者)들은 $^{51}Cr$표지적혈구(標識赤血球)를 이용(利用)한 적혈구(赤血球) 수명 측정때 검사기간중 실혈량이 적혈구수명치(赤血球壽命値)에 미치는 관계를 상술(上述)한 실험치(實驗値)를 기초(基礎)로 하여 다음과 같을 교정식(校正式)을 고찰(考察)해 보았다. $^{51}Cr\;T\frac{1}{2}=17.0e^{-0.0495}+18.4e^{-0.000924x}$ 단(但) X : 1일(日) 실혈량(失血量)(단위(單位) ml)

• The Korean Journal of Nuclear Medicine
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• v.33 no.3
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• pp.298-305
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• 1999

Purpose: N-(3-[$^{18}F$]Fluoropropyl)-$2{\beta}$-carbomethoxy-$3{\beta}$-(4-iodophenyl)nortropane [$^{18}F$]FP-CIT) has been shown to be very useful for imaging the dopamine transporter. However, synthesis of this radiotracer is somewhat troublesome. In this study, we used a new method for the preparation of [$^{18}F$]FP-CIT to increase radiochemical yield and effective specific activity. Materials and Methods: [$^{18}F$]FP-CIT was prepared by N-alkylation of nor-${\beta}$-CIT (2 mg) with 3-bromo-1-[$^{18}F$]fluoropropane in the presence of $Et_3N$ (5-6 drops of $DMF/CH_3CN$, $140^{\circ}C$, 20 min). 3-Bromo-1-[$^{18}F$]fluoropropane was synthesized from $5{\mu}L$ of 3-bromo-1-trifluoromethanesulfonyloxypropane (3-bromopropyl-1-triflate) and $nBu_4N^{18}F$ at $80^{\circ}C$. The final compound was purified by reverse phase HPLC and formulated in 13% ethanol in saline. Results: 3-Bromo-1-[$^{18}F$]fluoropropane was obtained from 3-bromopropyl-1-triflate and $nBu_4N^{18}F$ in 77-80% yield. N-Alkylation of nor-${\beta}$-CIT with 3-bromo-1-[$^{18}F$]fluoropropane was carried out at $140^{\circ}C$ using acetonitrile containing a small volume of DMF as the solvents. The overall yield of [$^{18}F$]FP-CIT was 5-10% (decay-corrected) with a radiochemical purity higher than 99% and effective specific activity higher than the one reported in the literature based on their HPLC data. The final [$^{18}F$]FP-CIT solution had the optimal pH (7.0) and it was pyrogen-free. Conclusion: In this study, 3-bromopropyl-1-triflate was used as the precursor for the [$^{18}F$]fluorination reaction and new conditions were developed for purification of [$^{18}F$]FP-CIT by HPLC. We established this new method for the preparation of [$^{18}F$]FP-CIT, which gave high effective specific activity and relatively good yield.

• The Korean Journal of Nuclear Medicine
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• v.32 no.1
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• pp.71-80
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• 1998

This study examines the levels of carbohydrate antigen 19-9(CA19-9) and cancer antigen 125(CA125) in serum and its related factors in healthy Korean population. Although CA19-9 and CA125 have been widely used tumor markers for gastroenteric cancers and ovarian cancer in Western countries, there are no information available on the serum levels of CA19-9 and CA125 in healthy population and the factors affecting the levels of these tumor markers in Korea. A cross-sectional study was performed to measure CA19-9 and CA125 among 76 healthy males and 95 healthy females in Korea. CA19-9 and CA125 were quantitated using solid-phase radioimmunoassay kits. Informations on the factors which might be related to the levels of these markers were collected by questionnaire(e.g., smoking, alcohol consumption, menstruation, oral pill use, breast-feeding history, etc.). There was no statistically significant difference in the mean of CA19-9 concentration between men(10.4 u/ml) and women(10.1 u/ml), whereas the mean of CA125 levels(11.2 u/ml) was higher in women than that(2.5 u/ml) in men. Although there was a statistically significant association between CA19-9 and average number of cigarette consumed per day(r=0.59, p=0.026) and total number of cigarettes consumed in women(r=0.74, p=0.003), the significance disappeared by multiple regression analysis after adjusting age and body mass index. Later age of menopause(p=0.035) and longer duration of breast-feeding(p=0.050) were significant predictors for CA125 levels in women by multiple regression analysis after adjusting age and body mass index. In conclusion, CA19-9 can be used as a stable tumor marker in clinical practices, however, menstruation and breast-feeding should be considered when CA125 is used in women.

• The Korean Journal of Nuclear Medicine
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• v.31 no.1
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• pp.73-82
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• 1997

Regional myocardial blood flow (rMBF) can be noninvasively quantified using N-13 ammonia and dynamic positron emission tomography (PET). The quantitative accuracy of the rMBF values, however, is affected by the distortion of myocardial PET images caused by finite PET image resolution and cardiac motion. Although different methods have been developed to correct the distortion typically classified as partial volume effect and spillover, the methods are too complex to employ in a routine clinical environment. We have developed a refined method incorporating a geometric model of the volume representation of a region-of-interest (ROI) into the two-compartment N-13 ammonia model. In the refined model, partial volume effect and spillover are conveniently corrected by an additional parameter in the mathematical model. To examine the accuracy of this approach, studies were performed in 9 coronary artery disease patients. Dynamic transaxial images (16 frames) were acquired with a GE $Advance^{TM}$ PET scanner simultaneous with intravenous injection of 20 mCi N-13 ammonia. rMBF was examined at rest and during pharmacologically (dipyridamole) induced coronary hyperemia. Three sectorial myocardium (septum, anterior wall and lateral wall) and blood pool time-activity curves were generated using dynamic images from manually drawn ROIs. The accuracy of rMBF values estimated by the refined method was examined by comparing to the values estimated using the conventional two-compartment model without partial volume effect correction rMBF values obtained by the refined method linearly correlated with rMBF values obtained by the conventional method (108 myocardial segments, correlation coefficient (r)=0.88). Additionally, underestimated rMBF values by the conventional method due to partial volume effect were corrected by theoretically predicted amount in the refined method (slope(m)=1.57). Spillover fraction estimated by the two methods agreed well (r=1.00, m=0.98). In conclusion, accurate rMBF values can be efficiently quantified by the refined method incorporating myocardium geometric information into the two-compartment model using N-13 ammonia and PET.