A multicenter validation of regional cerebral blood flow quantitation using [123I]iodoamphetamine and single photon emission computed tomography.

Recently, two methods have been proposed for regional cerebral blood flow (rCBF) quantitation using [123I]iodoamphetamine (IMP) and single-photon emission computed tomography (SPECT). The table look-up (TLU) method has been shown to provide both rCBF and volume of distribution, Vd, images from two SPECT scans, while a single-scan autoradiographic (ARG) technique provided rCBF using a fixed and assumed Vd. In both methods, a single blood sample was referred to calibrate the previously determined standard input function. The present multicenter project was designed to evaluate the accuracy of both methods for use as clinical investigative tools. Ten independent institutions performed [123I]IMP-SPECT studies according to both methods in 76 subjects (10 normal volunteers, 32 patients with cerebrovascular disease, and 34 patients with other diseases). Calculated rCBF values were compared with those obtained by the following reference methods available in the participating institutions; [15O] H2O positron emission tomography (PET) (five institutions), [133Xe]SPECT (four institutions), and the [123I]IMP microsphere method (three institutions). Both ARG and TLU methods provided rCBF values that were significantly correlated with those measured by the [15O] H2O PET technique (p < 0.001 for all subjects; overall regression equation, y = 15.14 + 0.54x) and those measured by the [123I]IMP-microsphere method (p < 0.001 for all subjects: y = 2.0 + 0.80x). Significant correlation (p < 0.05) was observed in 18 of 24 subjects studied with the [133Xe] SPECT reference technique (overall regression equation, y = 15.0 + 0.55x). Mean cortical gray matter rCBF in a group of normal subject was 43.9 +/- 3.3 and 43.4 +/- 2.0 ml/min/100 g for the ARG and TLU methods, respectively. Regional Vd of [123I]IMP estimated by the TLU method was 45 ml/ml +/- 20% in the normal cortical region. Close agreement between ARG and TLU rCBF values was observed (y = -3.21 + 1.07x, r = 0.97), confirming the validity of assuming a fixed Vd in the ARG method. Results of this study demonstrate that both the ARG and TLU methods accurately and reliably estimate rCBF in a variety of clinical settings.

Response to percutaneous transhepatic portal embolization: new proposed parameters by 99mTc-GSA SPECT and their usefulness in prognostic estimation after hepatectomy.

UNLABELLED: Accumulation of 99mTc-galactosyl human serum albumin (GSA) in the liver correlates well with the parameters of hepatic function tests. We performed 99mTC-GSA SPECT before and after percutaneous transhepatic portal embolization (PTPE) to induce compensatory hypertrophy of the remnant lobe before extensive hepatic resection and analyzed the responses of new proposed parameters in the future remnant lobe that showed hypertrophy. The aim of this study was to evaluate the usefulness of these parameters in prognostic estimation after hepatectomy. METHODS: We studied 10 patients with cholangiocarcinoma and 1 patient with metastatic liver tumor from sigmoid colon cancer. 99mTc-GSA SPECT was performed immediately before and 2 wk after PTPE. We analyzed the responses of the liver uptake ratio (LUR), functional volume (FV), and liver uptake density (LUD) in the future remnant lobe and evaluated their relationship with the prognosis after subsequent hepatic resection. RESULTS: LUR and FV increased slightly but were not associated with the prognosis after hepatic resection. LUD increased significantly after PTPE in the group showing a good outcome after hepatic resection but decreased after PTPE in the group showing a poor outcome (post-PTPE LUD, 0.064+/-0.017%/cm3 versus 0.035+/-0.006%/ cm3, P<0.05; response rate, 22.2%+/-11.9% versus -8.9%+/-17.6%, P<0.01). CONCLUSION: Responses of LUD to PTPE before hepatic resection in the future remnant lobe represent changes in asialoglycoprotein receptor activity per hepatocyte and predict responses to subsequent hepatic resection. LUD may be an important parameter for determining the outcome after hepatic resection.

Assessment of demented patients by dynamic SPECT of inhaled xenon-133.

We studied the potential for using dynamic single photon emission computed tomography of inhaled xenon-133 (133Xe) gas in the assessment of demented patients. An advanced ring-type single photon emission computed tomography (SPECT) "HEADTOME" with improved spatial resolution [15 mm in full width at half maximum (FWHM)] was used for tomographic measurement of regional cerebral blood flow (rCBF). All 34 patients underwent a detailed psychiatric examination and x-ray computed tomography scan, and matched research criteria for Alzheimer's disease (n = 13), senile dementia of the Alzheimer type (n = 9), or multi-infarct dementia (n = 12). In comparison with a senile control group (n = 7), mean CBF of both the whole brain and the temporo-parietal region was significantly less in the Alzheimer's disease and senile dementia Alzheimer type groups, but no significant difference was seen between the senile control group and multi-infarct dementia group. The correlation was 0.72 (p less than 0.004) between the mean CBF of the whole brain and the score of Hasegawa's Dementia Scale, and 0.94 (p less than 0.0001) between rCBF of the temporo-parietal region and the scale in Alzheimer's disease. In the senile dementia Alzheimer type group, the correlations were 0.77 (p less than 0.01) and 0.83 (p less than 0.004) respectively. No significant correlations were found in the multi-infarct dementia group. A temporo-parietal reduction in the distribution of the rCBF characteristic in the Alzheimer's disease group and a patchy whole brain reduction characteristic in the multi-infarct dementia group was detected. The ability of our improved SPECT to provide both quantitative measurement of rCBF and characteristic rCBF distribution patterns, makes it a promising tool for research or routine examination of demented patients.

Correlation of regional cerebral blood flow with performance on neuropsychological tests in schizophrenic patients.

Regional cerebral blood flow (rCBF) was determined by the 133Xe inhalation technique (Headtome II: ring detection SPECT) in 53 DSM-III schizophrenic patients. The rCBF values were corrected by using end-tidal carbon dioxide concentration values (PECO2). After rCBF measurement, neuropsychological tests--Word Fluency Test, Maze Test and Wisconsin Card Sorting Test--were performed. There were significant correlations between frontal rCBF and scores on each neuropsychological test. In particular, a moderate correlations between the frontal rCBF and the performance on the Wisconsin Card Sorting Test was noted. It seems likely that decrease of rCBF in prefrontal regions at rest reflects a disturbance of frontal lobe function in schizophrenic patients.

Possible association between delusional disorder, somatic type and reduced regional cerebral blood flow.

1. A 78-year-old female with DDST and pain disorder was treated by clomipramine 20-100 mg/day. The hypochondriacal delusion was completely resolved, while the pains were partially resolved. 2. The SPECT using Xe-133 taken at the early stage of clomipramine treatment, when she still had hypochondriacal delusions, showed markedly reduced rCBF in the temporal and parietal lobes, with predominance on the left hemisphere. Meanwhile, the SPECT taken after resolution of the hypochondriacal delusions showed a marked improvement in the reduced rCBF. 3. This report suggests that DDST has some association with reduced rCBF in the temporal and parietal lobes.

Analysis of the early blood kinetics of 99mTc-GSA and its verification: new one-compartment model and regression equation.

Technetium-99m-galactosyl human serum albumin (99mTc-GSA) is a radiopharmaceutical that binds to asialoglycoprotein receptors in the hepatocyte membrane; the level of 99mTc-GSA accumulation in the liver correlates well with the parameters of hepatic function tests. We hypothesized that the early blood kinetics of 99mTc-GSA could be described by a simple one-compartment model expressed as an offset + a monoexponential function (y=y0 +Ae(-alpha)t). The aims of this study were to assess the validity of this hypothesis using sequentially measured blood levels of 99mTc-GSA, which were approximated by a regression expression, and to analyse the regression equation. 99mTc-GSA levels were measured in blood samples collected from 30 patients with liver disease. From sequential changes in radioactivity up to 30 min after injection, a regression equation expressed as an offset+ a monoexponential function was calculated and evaluated by multiple correlation coefficients and absolute deviations (% error). The liver uptake rate 15 min after injection of 99mTc-GSA (liver uptake rate 15, UTR 15) was calculated from the regression equation in each case. The respective relationships of this parameter to the coefficient [A] and gradient [alpha] were evaluated. In all cases, the measured values of radioactivity in blood samples could be fitted to an offset + a monoexponential function. The validity of our hypothesis was supported by examining regression equations calculated from blood 99mTc-GSA levels. Analysis of the regression equations suggested a potential for a new index of hepatic functional reserve.

Prolonged lung retention of 123I-IMP in pulmonary fibrosis.

We compared radiographic findings and the retention of N-isopropyl- p[123I]-iodoamphetamine (123I-IMP) in 23 patients with pulmonary fibrosis. During the 30 minutes following a rapid injection of 55.5 MBq of 123I-IMP into the antecubital vein, the image of regional activity was stored. After this, 185 MBq of 99mTc-MAA was injected and its image was stored to determine the region of interest. The half time (T1/2) of 123I-IMP release from the lung was calculated in each pixel between 10 and 25 minutes after the injection. Chest roentgenograms were taken, and the lung field was divided into 6 portions (right upper, middle and lower, and left upper, middle and lower). A quantitative score was assigned to the radiographic finding (X-ray score). The T1/2 values in the above patients were longer than the T1/2 values in normal subjects. Prolonged T1/2 values were observed in the lung fields which had high X-ray scores. The X-ray scores and the T1/2 values in corresponding areas had a positive relation.

Noninvasive identification of left main and three-vessel coronary artery disease by thallium-201 single photon emission computed tomography during adenosine infusion.

Advanced coronary artery disease, defined as left main or three-vessel coronary disease, was identifiable noninvasively by means of adenosine Tl-201 single photon emission tomography. Among 75 consecutive patients with angiographically documented coronary artery disease, there were 11 patients with the presence (group 1) and 64 patients with the absence (group 2) of advanced coronary artery disease. The lung-to-heart ratio (L/H ratio) of Tl-201 uptake was calculated as the fraction of average Tl-201 counts per pixel in the lung divided by those in the myocardium. The left ventricular dilation ratio (LVDR) was determined as a ratio of left ventricular cavity size in the early image to that in the delayed image. The patients in group 1 had more defects (2.3 +/- 0.6 seg. vs. 0.9 +/- 0.7 seg., p < 0.001), a higher L/H ratio (35 +/- 4% vs. 28 +/- 5%, p < 0.001) and a higher LVDR (1.13 +/- 0.04 vs. 1.06 +/- 0.04, p < 0.001) than those in group 2. The diagnostic accuracy of the identification of advanced coronary artery disease was 89% by perfusion defects, 68% by L/H ratio and 81% by LVDR. Stepwise discriminant analysis revealed that LVDR (F = 36.2, p < 0.0001) and perfusion defects (F = 8.9, p < 0.004) were the significant and independent discriminators of advanced coronary disease. Identification of patients with left main or three-vessel coronary disease was enhanced by additional analysis of cavity dilation of the left ventricle and increased Tl-201 activity in the lung.

Fundamental dose distribution for interstitial irradiation with Au grains.

A principle of radiation therapy is to determine a proper dose distribution for tumor localization. In this paper we present several models of arranging Au grains for interstitial irradiation and discuss characteristics of their dose distributions. Au grains were arranged in a lattice of three by three for evaluation of isodose curves on a source plane and several planes parallel to it. Intersource distances were varied to determine adequate distances for ideal dose distributions for tumor control. Through this study, we concluded that the most favorable intersource distance for effective dose distribution was 1.0-1.25 cm. We also found that interstitial irradiation with Au grains was hard to apply to deeply spreading tumors.

Modification of measurement of effective renal plasma flow from blood pool clearance curve of I-123-orthoiodohippurate using single blood sampling.

The methods of measuring effective renal plasma flow (ERPF) based on the two-compartment analysis of plasma clearance of I-123-orthoiodohippurate (OIH) disregard the distribution of I-123-OIH to erythrocytes, resulting in over-estimation of ERPF. In this study, a new simple modification was established to obtain accurate ERPF. Intercompartmental clearance rates among plasma, erythrocytes, and extracellular fluid were determined through in vitro and in vivo experiments to enable the three-compartment analysis of plasma clearance curves of I-123-OIH using multiple blood samplings in comparison with the two-compartment analysis. Multiplying renal blood flow derived from two-compartment analysis of the whole blood clearance curve by (1-hematocrit/100) was a new modification for measuring ERPF to reduce the complexity of three-compartment analysis and to supplement the distribution of I-123-OIH to erythrocytes. Comparing ERPF derived from the modified two-compartment analysis with that from three-compartment analysis demonstrated good agreement (r = 0.883, p = 0.001) between the two methods. ERPF derived by this new method was also compared with the clearance of paraaminohippurate (PAH), resulting in a regression line which was much closer to unity and a better correlation between them (r = 0.926) than that between PAH clearance and ERPF (r = 0.909) derived from conventional two-compartment analysis.

[A phase III multi-center clinical trial on 123I-orthoiodohippurate (123I-OIH)].

A multi-center clinical trial was performed to evaluate the clinical usefulness of 123I-orthoiodohippurate (123I-OIH) in patients with renal and urinary disorders. 123I-OIH was evaluated to be "safe" in all 259 cases it was injected. 123I-OIH was useful in all 248 cases analyzed for the overall clinical usefulness evaluated by the investigators. The clinical significance of the drug was also evaluated in terms of renal blood flow function, renal parenchymal function, urinary function and the ability to differentiate between renal and urinary disorders. In the comparison with 123I-OIH (90 cases), 123I-OIH was superior as evaluated by the investigators and the Committee both. In the comparison with 99mTc-DTPA (113 cases), 123I-OIH was evaluated as superior by the investigators, but no significant difference was found by the Committee. In image qualities, 123I-OIH was evaluated as superior to 131I-OIH and equal to 99mTc-DTPA by the Committee. In overall efficiency, 123I-OIH was evaluated as being more valuable than 131I-OIH in 92% of the 90 cases and more valuable than 99mTc-DTPA in 50% of the 113 cases. 123I-OIH was evaluated as being less valuable than 131I-OIH in no cases and less valuable than 99mTc-DTPA in 7% of the 113 cases. These results suggest that 123I-OIH is superior to 131I-OIH and equal or superior to 99mTc-DTPA as a radiopharmaceutical for gamma camera-renography.

[Effect of scattering and spatial resolution on SPECT quantification values: experimental study using phantoms and clinical application].

The relative SPECT values are often inaccurate by the scattering and limited spatial resolution of single photon emission CT (SPECT). These effects were studied using phantoms and some attentions on clinical application were investigated. Using cylindrical phantom divided into six compartments filled with various radioactivities, the linear correlation between SPECT value and radioactivity, and also correlation with partial reduction of radioactivity were identified. But the SPECT value was relatively increased in proportion to the reduction of radioactivity due to the increase of scattering contribution. The SPECT value represented lower radioactivity when the cortical thickness was smaller than two times of FWHM and represented half radioactivity when the cortical thickness was equal to FWHM. Excellent correlation between SPECT value and radioactive partial volume averaging of brain with CSF was recognized using our hand made phantom simulating various degree of atrophic brain. It is very important to compare SPECT image with X-CT or MR image to avoid misreading taking the above mentioned effects due to scattering and limited spatial resolution.

[Xenon-133 rCBF SPECT by newly designed bolus inhalation method].

Single photon emission computed tomography (SPECT) with 133Xe gas inhalation method enables measurement of regional cerebral blood flow (rCBF) quantitatively. But this method is inferior to the method with 99mTc-HMPAO or 123I-IMP in the quality of images. Efficient administration of 133Xe gas more than usual is supposed to improve quality of SPECT images. In this study we designed bolus inhalation method, a new method to efficiently administer 133Xe gas of usual dose (1,850 MBq), and examined its fundamental aspects and clinical feasibility. The method was initiated by bolus administration of 133Xe gas synchronously in inspiration phase via a small tube connected to a mouthpiece and was followed by steady breathing of the gas in a closed circuit with a spiro-bag. Introduction of this method provided almost twofold increase in count ratio at the head in comparison with a conventional inhalation method. Consequently, considerable improvement in the quality of rCBF images was achieved by optimization of a reconstruction filter of SPECT.

[The most suitable parameter to distinguish brain tumor using 201Tl-chloride and SPECT].

We performed 201Tl single photon emission CT (SPECT) studies on 62 patients with brain tumors prior to any therapy for the tumor. Ten lesions of open-scar and 17 patients without brain tumor were also studied. The SPECT imaging were initiated 5 min (early image) and 4 hours (delayed image) after injection with 74 MBq of 201Tl-chloride. For a semi-quantitative analysis, we used the ratio of delayed count density to the early count density of the tumor (Td/Te), the ratio of tumor to normal brain tissue (Te/B(e)) on the early SPECT and the index of T/B ((Td/Te)/(Bd/B(e))). Delay to early ratio of 34 normal brain tissue (Bd/B(e)) was 1.22 +/- 0.15 and tended to decrease with the age. The Td/Te ratio of meningioma and region of operation scar was about 0.75 which was less than that of normal brain tissue. In 31 patients with astrocytic tumor, Td/Te ratio was clearly higher in poorly differentiated tumor than in well differentiated one. The index of Td/Te ratio was superior to Te/B(e) or T/B ratio for differentiating brain tumor and grading astrocytic tumor.

[Cerebral blood flow and brain size in healthy subjects--sensitivity to age and gender].

Cerebral blood flow was measured in 56 healthy subjects who ranged in age from 1.3 to 80 years. The Xe-133 inhalation method with ring type single photon emission computed tomography (SPECT); HEADTOME was used. The cerebral blood flow were calculated by the method of Kanno & Lassen. Then the value were corrected for end-tidal CO2 concentration that had an excellent correlation with PaCO2 and was one of the most sensitive factors to change cerebral blood flow. The brain-size index was obtained by measuring the lateral and antero-posterior diameters from the SPECT images. The mean cerebral blood flow in children less than five years of age was 90-100 ml/100 g/min that was approximately twice that found in adults. The mean cerebral blood flow decreased rapidly with age until 24.0 years of age in male and 21.7 in female. Thereafter, there was a slow decrease and a negative correlation with age was found. In adults, the mean value of the cerebral blood flow of females was slightly higher than that of males (p less than 0.01). In contrast, the brain-size index of females was significantly smaller than that in males (p less than 0.01). There was a significant negative correlation to an inverse proportionality of cerebral blood flow and brain-size index (p less than 0.002). But, there was no significant correlation between total flow index that obtained to multiplied mean flow by brain-size index and brain-size index or gender.

[Investigation of discrepancy between 99mTc-HMPAO and 133Xe rCBF SPECT; a comparative study with X-ray CT findings].

To investigate the discrepancy between 99mTc-hexamethylpropyleneamine oxime (HMPAO) and 133Xe rCBF SPECT, the findings of thirty patients with reasonable rCBF reduction on 133Xe SPECT were compared with HMPAO SPECT and X-ray CT. The subjects did not include the cases of acute and subacute CVD. Both SPECT were performed within two weeks by ring-type dynamic SPECT (HEADTOME, Simadzu, Japan). In comparison between the SPECT findings by 133Xe and 99mTc-HMPAO, the subjects were classified into three groups as follow. Group A: Similar findings in the both SPECT were noted in 6 cases (20%). Group B: Smaller findings on HMPAO SPECT than that by 133Xe were in 11 cases (37%). Group C: No findings of rCBF reduction on HMPAO SPECT were in 13 cases (43%). The rCBF of the lesion measured by 133Xe SPECT in the group C was 24-35 ml/100 g/min. The density of HMPAO in the lesion did not correlate with the rCBF value. Only the severity of CT findings tend to correlate with the density of HMPAO. These results suggest that the reduction of HMPAO density depends directly on some kind of neural injury rather than the rCBF value. The injury may be caused by the flow reduction under the threshold of each neural cell. So the correlation between HMPAO density and actual rCBF might show like sigmoid curve. Then the HMPAO SPECT might directly reflect the regional extraction and fixation ratio, and the reduction of blood flow cause the minute neural-injury in the lesion of moderately reduced rCBF.

[Relation between uptake of 67Ga-citrate in salivary glands and irradiation doses].

A retrospective study is performed 67Ga-citrate uptake by scintigraphy to evaluate the relation between gallium uptake of salivary glands and radiotherapy with special reference to radiation dose and period after initial irradiation. Sixteen patients with radiotherapy to their head and neck regions were studied, undergone 67Ga scintigraphy for four times or more were investigated. The following results were obtained: 1. About half of the total number of salivary glands increased the uptake of 67Ga-citrate during radiotherapy. 2. The number of salivary glands which increased uptake in a group which received more than 30 Gy was greater than that in a group less than 30 Gy, and many of them remained with increased activity for one year after radiotherapy. 3. Uptake in glands that received dose less than 30 Gy showed rapid increasement initially, and showed decrease of uptake in six months after the irradiation. We concluded that there was different tendency of gallium uptake between a group of patient with irradiation of less than 30 Gy and that with irradiation of more than 30 Gy. It is suggested that we must always consider gallium uptake of salivary glands for long term after the radiotherapy, when we discuss the recurrence or metastases of neck lymph nodes of patients, who have performed radiotherapy to their head and neck regions, especially high dose irradiation.

[Improved the accuracy of 99mTc-MAG3 plasma clearance method: the problem of the calculated plasma volume and its modification].

The 99mTc-MAG3 plasma clearance method (MPC method), reported by Oriuchi et al., is a simple and useful count-based gamma camera method for calculating the 99mTc-MAG3 plasma clearance (CLMAG). However, a discrepancy of CLMAG calculated by MPC method (MPC-CLMAG) from the tubular extraction rate (TER) calculated by Russell's single-sample clearance determination (Russell-TER) was noted. The calculated plasma volume is assumed to be the cause. Since the plasma volume is reported to have a linear correlation with body surface area, Dissmann's formula was applied to calculate the plasma volume. Then Dissmann's formula was replaced by Ogawa's formula in the MPC method, and the procedure was then called the modified MPC method. The CLMAG were obtained using MPC method, modified MPC method and the TER was obtained Russell's method in 95 patients with urological disorders. Then the MPC-CLMAG and modified MPC-CLMAG were compared with Russell-TER. Comparison of the MPC-CLMAG with the Russell-TER demonstrated a coefficient of correlation of 0.82, but dissociation of the slope of regression lines was found between males and females. The modified MPC-CLMAG improved the coefficient of correlation to 0.92, and diminished the dissociation of the slope of regression lines between males and females. We verified that the dissociation was due to the plasma volume calculated by Ogawa's formula. Ogawa's formula included hematocrit, body weight, body height and different coefficients for gender. The plasma volume calculated by Ogawa's formula were lower in males and higher in females than that calculated by Dissmann's formula. And marked discrepancy in the plasma volume in patients with a body surface area below 0.5 m2 was observed. So the MPC method might become more accurate by substituting Dissmann's formula for Ogawa's formula resolting in a method that is applicable to both males and females, children and adults in clinical use.

[Estimation of malignancy using SPECT with 201Tl chloride in astrocytic tumors].

This study was designated to estimate the usefulness of SPECT with 201Tl chloride (Tl-SPECT) for the determination of the malignancy in astrocytic tumors. The subjects consisted of 39 astrocytic tumors in supra-tentorial regions. Tl-SPECT undertaken ten minutes to obtain an early image and four hours to obtain a delayed image, after intravenous injection of 74MBq 201Tl chloride (Tl). Tl index (L/N) was defined as the RI count ratio in the tumor lesion (L) to that in the normal parenchyma (N). Histological classification was determined by the WHO grading, and the results showed one case at Grade I, 11 cases at Grade II, 23 cases at Grade III and 4 cases at Grade IV. The proliferating activity was determined by the labeling index using the monoclonal antibody of proliferating cell nuclear antigen (PCNA). In both of the early and delayed images, Tl index was significantly higher (p < 0.01) in high grade astrocytomas compared with low grade tumors. There was a close correlation between the Tl index and the proliferating activity. The relationship between the Tl index and prognosis indicated that the high Tl index was corresponded to the poor prognosis. These results showed that the Tl index is useful to determine the malignancy of astrocytic tumors.

[Immunochemiluminometric assay (Automated Chemiluminescence System ACS: 180) for CEA].

We examined Automated Chemiluminescence System ACS: 180 for CEA assay, especially about confidence of the functional sensitivity. Serum CEA levels of normal subjects and patients were measured not only with ACS: 180 but also with immunoradiometric assay (CEA kit [Daiichi] II). Using ACS: 180 assay for CEA, intra-assay coefficients of variation (C.V.s) were 4.06% at 1.97 ng/ml, 1.62% at 17.3 ng/ml, and 2.28% at 81.3 ng/ml. Interassay C.V.s were 4.02% at 1.99 ng/ml, 1.21% at 16.5 ng/ml, and 3.44% at 79.4 ng/ml. The detection limit (functional sensitivity) of ACS: 180 assay for CEA was 0.4 ng/ml by the precision profile. The coefficient of correlation of 164 sera, which CEA values were among 0.4-100 ng/ml (working range of ACS: 180), between with ACS: 180 and with CEA kit [Daiichi] II was R = 0.942, y = 1.07 x +0.09 (p < 0.05). Seven (13.2%) normal subjects (n = 53) and 45 (34.1%) patients with malignant diseases (n = 132) had higher serum CEA levels than the cut off value (2.5 ng/ml). The sera of 82 malignant patients who had both pre- and post-operation sample were determined. Sixty-five patients of them were decrease after operation. These results of ACS: 180 resembled to that of CEA kit [Daiichi] II. We conclude that ACS: 180 for CEA assay was precise enough to measure below the cut off value, and had good performance of its speed (short incubation) and convenience.