A unified design algorithm of two-dimensional digital filters for radioisotope image processing

A unified design algorithm of two-dimensional digital filters for radioisotope image processing based on the Fourier-Bessel transform and the weighted least-squares method is described. The algorithm presented here can treat the various kinds of two-dimensional digital filters in a unified approach. Design examples are presented and several graphs are included to show the relationships between the design parameters as an aid in practical applications. The application of the method in radioisotope image processing is also presented. Several low-pass, Wiener and band-pass filters were designed using the method and applied to some clinical data in nuclear medicine including SPECT images. The digital filter design technique proposed here is considered to provide a powerful tool for extraction of additional qualitative information and improvement of the quality of nuclear medicine images both in research and in routine clinical work.

[Single photon emission computed tomography (SPECT) with N-isopropyl-p-(123I) iodoamphetamine in partial epilepsy--evaluation of delayed image]

Thirty eight patients with partial seizures in the interictal phase were studied using single photon emission computed tomography performed 30 min. (early image) and 4-4.5 hrs. (delayed image) after an injection of 111 MBq (3 mCi) N-isopropyl-p(123I) iodoamphetamine (IMP). Five types of distribution changes were observed on IMP-SPECT between the early and delayed images. Eight patients, Type 1, exhibited an unchanged distribution of IMP between the early and delayed images. Fifteen patients, Type 2, showed a smaller area of low uptake on the IMP-SPECT (delayed image) compared to that on the IMP-SPECT (early image)-redistribution. The Type 3 patients exhibited an initial uptake area on the IMP-SPECT (early image) which later became a lower uptake area on the IMP-SPECT (delayed image)-reversed redistribution. This type was further classified into three categories according to the initial uptake pattern including (a) Type 3A, 3 patients with increased uptake area, (b) Type 3B, 6 patients with normal uptake area, and (c) Type 3C, 6 patients with decreased uptake area. With Type 2, the epileptic findings on the present interictal electroencephalography (EEG) were shown in 11 of 15 patients. However, we could not find any other remarkable correlation among these 5 types and the clinical factors (the types of seizures, the X-CT findings, the present interictal EEG data, the present frequency of seizures, and the intervals from the last seizure). In 2 patients with Type 3B who suffered from simple partial seizures, a region of the normal distribution on the IMP-SPECT (early image) became a lower uptake area on the IMP-SPECT (delayed image), corresponding topologically to the ictal symptoms. In this experience, we determined that the IMP-SPECT (delayed image) could be useful in patients with the epileptic lesions unable to be detected on the IMP-SPECT (early image).

A unified computer program for assessment of attenuation correction and data acquisition methods in single photon emission computed tomography (SPECT)

A computer based simulation program was developed to assess the usefulness of various attenuation correction algorithms and data acquisition methods in single photon emission computed tomography (SPECT) in a unified approach. The program analytically calculated projection ray sums from a mathematical model with various distributions of activities and either uniform or non uniform attenuation coefficients by using the line integrals including the effect of attenuation. Data acquisition starting at arbitrary angles, various acquisition angles, including a 180 degree scan and a non circular orbit of a gamma camera, including an elliptical orbit can readily be taken into consideration in our simulation program. To simulate non circular orbit data acquisition, the resolution dependence on the object distance from the collimator surface was incorporated into the simulation. This computer based simulation program allows various combinations of attenuation correction algorithms such as hybrid methods, and data acquisition methods can be evaluated under a large number of study conditions. The usefulness of this computer based simulation program is shown with several representative examples.

Tachykinins modulate multiple ionic conductances in voltage-clamped rat spinal dorsal horn neurons

1. The membrane actions of substance P (SP) and a related tachykinin, neurokinin A (NKA), have been investigated by means of a single-electrode, voltage-clamp technique in the immature rat dorsal horn neurons using an in vitro spinal cord slice preparation. 2. When the membrane potential was held at the resting level of between -75 and -55 mV, bath application of SP or NKA (10(-7) to 10(-5) M, for 1-3 min) induced an inward shift in the holding current lasting several minutes. The magnitude of this effect varied between 10 and 400 pA depending on the concentration of the peptides and the holding potential. 3. When a dorsal horn neuron was held at the resting level and subjected to 1-s depolarizing commands to membrane potentials between -60 and -35 mV, slow inward relaxations and inward tail currents, the latter on repolarization to the holding potential, were recorded. During the tachykinin-induced inward shift in the holding current, the inward relaxation and the tail current were augmented in a dose-related manner. 4. The SP-induced augmentation of the slow inward relaxation and the inward tail current is likely to be due to the enhancement of the activation of the Ca2+ current, because the effect was present, and even augmented in a zero-Ca2+, Ba2+-containing solution, it was reduced or completely abolished by zero-Ca2+, Co2+-, or Mg2+-containing solutions and is largely independent of the changes in external Na+, K+, or Cl- ions. Moreover, in the presence of the K+-channel blocker, tetraethylammonium (TEA), the effect is increased. 5. Depolarizing voltage commands to potentials positive to -35 mV evoked a large, outward K+ current response in the dorsal horn neurons, which was in part Ca2+-sensitive. The outward current response was augmented by SP. The SP effect persists, although being reduced in a zero-Ca2+, Ba2+- or Co2+-containing solutions. 6. In a zero-Ca2+ solution containing Co2+ and TEA, the augmentation of the Ca2+ current and the outward K+ current by SP was abolished. However, the SP-induced increase in a Ca2+-sensitive, voltage-insensitive conductance remained, although being reduced, and the response showed a reversal at about -28 mV. This current may be a result of a tachykinin-activated nonspecific increase in cationic permeability of the membrane of dorsal horn neurons, because the current is reduced by more than one-half when Na+ or Ca2+ is removed from the bathing medium.(ABSTRACT TRUNCATED AT 400 WORDS)

[Visualization of epileptic lesions using single photon emission computed tomography (SPECT) with N-isopropyl-p-(123I) iodoamphetamine after intravenous loading of bemegride--report of a case]

Single photon emission computed tomography (SPECT) was performed 30 minutes and 4 hours after injection of 111 MBq (3 mCi) N-isopropyl-p-(123I) iodoamphetamine (IMP) which was injected 5 minutes after the completion of intravenous bemegride loading. A 31-year-old female with simple partial seizures evolving to complex partial seizures evolving to generalized tonic-clonic convulsive seizures with a history of hospitalization, suffering from low-grade fever, generalized convulsive seizures, and impaired consciousness at the age of 27 years was studied. Angiographic examinations, X-CT, MRI, CSF examinations, and interictal neurological examinations were normal. She suffered from clonic convulsions in her right shoulder and arm, and hallucinations and dysmnesia which were characteristic of temporal lobe epilepsy. More recently she suffered from impaired consciousness once or twice a month. While the controlled IMP-SPECT study was normal, the IMP-SPECT study examined after the activation by intravenous bemegride loading showed the pattern of a regional increased uptake of IMP in the epileptic lesions corresponding with the epileptic symptoms, and a surrounding border of decreased uptake which might be the inhibition of surrounding neuronal activity and metabolism. In conclusion, the bemegride loading IMP-SPECT study could be a potential diagnostic method in patients with seizures whose epileptic lesions were not determined by the conventional methods or in whom the surgical interventions were considered, by reason of its capability to demonstrate positively the epileptic lesions.

[Diagnostic value of the reflux sign in cholescintigraphy after administration of a gallbladder contracting agent--a comparison with X-ray cholangiography]

This study reviewed 25 patients with the reflux sign in cholescintigraphy to assess its diagnostic value in evaluating biliary passage. After at least 4-hour fasting 5 mCi of 99mTcPMT or p-butyl IDA was injected intravenously and serial images were recorded before and after intramuscular injection of 10 micrograms of ceruletide diethylamine (caerulein). The reflux sign was determined positive when increased radioactivities in the left hepatic duct (minor reflux; MIR) or more peripheral intrahepatic ducts (major reflux; MAR) were recognized after injection of caerulein. The reflux sign was found in 28 of 237 (12%) studies. Direct and/or indirect X-ray cholangiograms were available in 25 (MIR; 15, MAR; 10). They included common bile duct (CBD) stone in 4, dilated CBD in 4, biliary dyskinesia (BD) in 4, chronic pancreatitis (CP) in 4, gallbladder (GB) stone in 3, duodenal ulcer (DU) in 2, CBD adenoma, pancreatic pseudocyst (PP), duodenal diverticle (DD), and acute cholangitis (AC) in 1 each. Their serum bilirubin levels were within normal limit in all but 2 at the time of cholescintigraphy. Transit time of radionuclides to the duodenum was found prolonged more than 60 min in 17 (68%) patients and persistent pooling in the CBD was found in 8 (28%) patients on scintigrams. The diameter of the CBD on X-ray cholangiogram was ranged 4 to 17 mm. Dilated CBD of more than 10 mm was found in 13 (52%) patients and apparent stenosis of the CBD in 6 (24%) patients. MAR seemed to correspond to increased diameter of the common hepatic more than 2 mm after caerulein injection in DIC. No abnormal findings in X-ray cholangiography was found in 10 (40%) patients including 3 with BD, 2 with GB stone, 2 with DU, 1 each with CP, PP, and AC. All those patients demonstrated MIR. We concluded that major reflux (MAR) sign was helpful in detecting an incomplete obstruction of the CBD, especially in patients with slightly to mildly dilated CBD.

Pilot study of recombinant human alpha-interferon for chronic non-A, non-B hepatitis

Recombinant human alpha-interferon was administered to 15 patients with chronic non-A, non-B hepatitis as a part of a pilot study. Patients received injections of 2 million units per day of interferon three times weekly for 16 wk. The treatment schedule was completed in all but one, whose serum aminotransferase levels were continuously elevated during treatment. In seven of the 15 patients, elevated serum aminotransferase levels decreased rapidly during therapy and eventually fell into the normal or nearly normal range. However, once the therapy was stopped, a prompt return of aminotransferase levels to pretreatment values usually was observed. After 3 months of follow-up, aminotransferase activities remained normal in only two patients in whom liver histology showed marked improvement in intralobular degeneration and focal necrosis of hepatocytes. Anti-interferon antibody was detected in four patients at the end of therapy, and decreased 2',5'-oligoadenylate synthetase activity occurred in two patients and in another with relapsed aminotransferase level. Whether alpha-interferon therapy could control the disease activity in patients with chronic non-A, non-B hepatitis deserves further evaluation in a prospective controlled trial.

Pharmacological properties of YM-11124, a selective immunosuppressive agent for cell-mediated immunity

Effect of YM-11124 on cell-mediated immune responses, type I to type III allergic reactions and inflammatory reaction was determined in mice, rats and guinea pigs. YM-11124 inhibited picryl chloride- and methylated bovine serum albumin-induced delayed-type hypersensitivity reactions by the treatment during both the sensitization and the elicitation phases in mice. Bilateral adrenalectomy did not prevent the suppression of DTH response by YM-11124. YM-11124 significantly prolonged the survival time of allogenic skin grafts in mice. Furthermore, YM-11124 inhibited the passive Arthus reaction in guinea pigs and the reversed passive Arthus reaction in rats. However, YM-11124 did not affect the passive cutaneous anaphylaxis reaction in rats, Forssman shock in guinea pigs and paw edema in rats. These results indicate that YM-11124 suppresses not only cell-mediated immune responses (type IV allergic reactions) but also type III allergic reactions without influence on types I and II allergic reactions as well as acute inflammation.

SPECT volume measurement using an automatic threshold selection method combined with a V filter

The volume measurement of various organs by single photon emission computed tomography (SPECT) has generally been performed by summing up the voxels lying within the outer edge of the organ determined by thresholding as a function of the maximum reconstructed counts within a volume of interest. The optimum threshold level, however, is influenced by various factors. To eliminate this problem, Mortelmans et al. (1986) proposed to use an automatic threshold selection method (ATSM) based on discriminant criteria and to correct the errors induced by the imperfect system response using the method based on linear regression analysis, which has some problems in practical application. We tried to use ATSM combined with a V filter. The correlation coefficient (r) and the regression equation between the true (x) and the calculated volume (y) obtained by experimentation using 22 phantoms with a volume ranging between 26 ml and 380 ml were as follows: r = 0.994 and y(ml) = 1.015 x +1.09 using ATSM combined with a V filter, while r = 0.993 and y(ml) = 1.110 x +30.55 using only ATSM. The relative error between the true and the calculated volumes decreased significantly (P less than 0.01) from 37.7% +/- 26.9% to 5.5% +/- 4.2%. The results suggest that ATSM combined with a V filter is useful for correcting the errors caused by an imperfect system response, and is available and reliable for SPECT volume determination even when the organ volume is small.

Ultrastructural study of a perineurioma

A case of soft tissue tumor in the left brachialis muscle of a 49-year-old Japanese female patient was studied by electron microscopy. The tumor was diagnosed as intramuscular myxoma by light microscopy, but electron microscopic observation revealed that the tumor almost entirely consisted of cells similar to normal perineurial cells. The tumor cells possessed long, slender cytoplasmic processes covered by well-developed but discontinuous basal laminae, clusters of pinocytotic vesicles, and infrequent intercellular junctions. Perineurial cells have also been observed in other peripheral nerve lesions: neurofibromas, nerve sheath myxomas, and localized hypertrophic neuropathies. However, the term "perineurioma" or "perineurial cell tumor" should be reserved for discrete tumorous masses that are almost entirely composed of perineurial cells without evidence of residual axons, Schwann cells, fibroblasts, or tactile corpusclelike structures. Perineurioma may represent a third category of peripheral nerve sheath tumors, ultrastructurally distinct from schwannomas and neurofibromas.

[Left ventricular volume curve analysis using gated blood pool emission computed tomography]

Analysis of the left ventricular volume curve was performed using gated blood pool emission computed tomography (SPECT) in six patients with old myocardial infarction (MI), five with hypertrophic cardiomyopathy (HCM), three with dilated cardiomyopathy (DCM), and five normal controls (N). Image collection was synchronized with the QRS complex, and each cardiac cycle was divided into nine to 10 frames. In each frame, left ventricular volume was determined based on the number of voxels above the threshold level (50% cut-off level), and the volume curve was fitted to the third harmonics of Fourier analysis. From the fitted curve, the peak ejection rate (PER), the peak filling rate (PFR), end-diastolic volume (EDV), end-systolic volume (ESV) and ejection fraction (EF) were calculated. 1. There were good correlations between SPECT and the conventional gated blood pool (MUGA) for PER (r = 0.694, p less than 0.005), PFR (r = 0.527, p less than 0.025) and EF (r = 0.682, p less than 0.005). 2. PER in MI (2.21 +/- 0.55, mean +/- SD) was lower than in N (3.68 +/- 0.80, p less than 0.05) and HCM (4.85 +/- 2.39, p less than 0.05), and EF in MI (36.6 +/- 6.4) was lower than in HCM (68.7 +/- 23.7, p less than 0.05). 3. There were good correlations between EDVs (y = 1.11x + 5.71, r = 0.877, p less than 0.01), and ESVs (y = 1.05x - 3.88, r = 0.876, p less than 0.01) estimated by MUGA and SPECT.(ABSTRACT TRUNCATED AT 250 WORDS)

Determination of alcohols in alcoholic beverages by micro high-performance liquid chromatography with indirect photometric detection

Aliphatic alcohols in alcoholic beverages were determined by micro high-performance liquid chromatography with indirect photometric detection. Theophylline was added to the mobile phase as the visualization agent. Ethanol, propanols and butanols could be determined by this method.

Calcitonin gene-related peptide enhances calcium current of rat dorsal root ganglion neurons and spinal excitatory synaptic transmission

The actions of calcitonin gene-related peptide (CGRP) were examined on Ca2+-dependent action potentials and voltage-dependent Ca2+ currents in rat dorsal root ganglion (DRG) neurons in vitro. In addition, we tested the effect of CGRP on excitatory synaptic transmission in the rat spinal dorsal horn. CGRP produced a reversible increase in the amplitude and the duration of the Ca2+ spike of DRG neurons and directly increased the voltage-dependent Ca2+ current by enhancing both the transient and the sustained components of the current. The increase in the Ca2+ current is likely to be responsible for the increase in the Ca2+ spike and facilitation of excitatory synaptic transmission.

Quantitative aspect of two-factor analysis applied to radionuclide gated cardiac studies

The quantitative aspect of two factor analysis (TFA) applied to radionuclide gated cardiac studies was investigated using clinical data and a computer based simulation method. In the clinical investigation, the ejection fraction (EF) calculated from the extracted ventricular pattern (EVP) significantly correlated with the left ventricular EF(LVEF) determined from multiple gated cardiac blood pool scans (MUGA), while the regression line deviated considerably from the line of identity. The contribution of the EVP(CEVP) to the total information inversely correlated significantly with the LVEF. In the computer simulation, a model simulating the atrial, ventricular, and background regions was studied. In the case with no statistical noise and constant background, the EF calculated from the EVP was nearly equal to the true EF, and the CEVP decreased as the EF increased. The statistical noise increased the EF and decreased the CEVP, this tendency was most marked when the true EF was less than about 50%. When background varied largely with time, the quantitative aspect deteriorated considerably. In conclusion, the clinical investigation results suggest that TFA has some possible use in quantitative analysis, however, the stimulation results suggest that it should be used carefully because its quantitative aspect is affected by various factors.

[A study involving early carcinomas of the gall bladder]

In recent years, with the development of diagnostic procedures, the number of cases of early carcinoma of the gall bladder has been seen to gradually increase. In this paper, 8 cases of early gall bladder carcinoma have been evaluated, using a diagnostic approach. Cholecystolithiasis was the complication in 6 cases, and abdominal pain was seen as the most common symptom. Findings by various image diagnoses, such as ultrasonography, DIC, ERCP, and CT scan are described and discussed with a review of literature. Ultrasonography was considered to be the most useful tool for the detection and diagnosis of an early carcinoma of the gall bladder. A survey is thought to be required, involving the cases that have accumulated throughout the entire nation.

Pilot study of recombinant human interleukin 2 for chronic type B hepatitis

Recombinant human interleukin 2 was administered to 10 patients with chronic type B hepatitis as a part of a pilot study to evaluate its antiviral activity. Patients received 1 to 3 x 10(5) units per day of interleukin 2 for 21 to 28 days, and all completed the treatment schedule. During therapy, serum values of DNA polymerase decreased in 6 and became negative in four patients. However, when therapy was discontinued, DNA polymerase levels increased to pretreatment levels in most cases. Serum HBeAg levels did not change during treatment. Serum aminotransferase levels transiently increased in 6 of the 10 patients during therapy; but once therapy was stopped, levels fell markedly. Side effects of interleukin 2 therapy included fever, chills, anorexia and fatigue. After 1 year of follow-up, three treated patients had lost HBeAg and had marked improvement in aminotransferase levels. These serologic and biochemical improvements occurred 1.5 to 11 months after therapy was stopped. Whether a 3- to 4-week course of interleukin 2 therapy leads to an increased rate of seroconversion from HBeAg to antibody in chronic type B hepatitis deserves further evaluation in prospectively randomized, controlled trials.

Pharmacological properties of the orally active leukotriene antagonist [[5-[[3-(4-acetyl-3-hydroxy-2-propylphenoxy)-propyl]thio]-1,3,4- thiadiazol-2-yl]thio]acetic acid

The anti-leukotriene effect of [[5-[[3-(4-acetyl-3-hydroxy -2- propylphenoxy)propyl] thio]-1,3,4-thiadiazol-2-yl] thio] acetic acid (YM-16638) was examined. In isolated guinea-pig ileum, YM-16638 antagonized the contractions induced by slow reacting substance of anaphylaxis (SRS-A) and leukotriene D4 (LTD4) with IC50 values of 6.0 x 10(-8) and 1.1 x 10(-7) mol/l, respectively. However, the compound at 10(-5) mol/l did not affect the contractions induced by histamine, acetylcholine, 5-hydroxytryptamine, prostaglandin (PG)E2 and PGF2 alpha. In isolated guinea-pig trachea, YM-16638 inhibited the contractions elicited by LTC4, LTD4 and LTE4 and its IC50 values were 5.7 x 10(-8), 1.6 x 10(-7) and 9.6 x 10(-8) mol/l, respectively. In isolated human bronchi, YM-16638 also antagonized the contractions induced by LTC4, LTD4 and LTE4 and its IC50 values were 6.0 x 10(-8), 1.2 x 10(-7) and 2.1 x 10(-8) mol/l, respectively. YM-16638 at the doses of 3 to 100 mg/kg p.o. inhibited the skin reaction induced by LTD4 in conscious guinea-pigs and its ED50 value was 17.9 mg/kg p.o. Successive oral administration of YM-16638 (50 mg/kg/d) for 10 days did not develop tolerance in its inhibitory effect against LTD4-induced skin reaction. Furthermore, the compound at the doses of 10 and 30 mg/kg p.o. significantly inhibited the antigen-induced bronchoconstriction in conscious guinea-pigs pretreated with mepyramine, propranolol and indomethacin. These results indicate that YM-16638 is a selective, potent and orally active leukotriene antagonist.

Actions of calcitonin gene-related peptide on rat spinal dorsal horn neurons

The membrane actions of calcitonin gene-related peptide (CGRP) and the effect on the Ca-dependent action potential of dorsal horn neurons have been investigated by means of an intracellular recording technique in the immature rat in vitro spinal cord slice-dorsal root ganglion preparation. Bath application of CGRP (10(-8)-10(-6) M for 1-10 min) produced a slow reversible depolarization in about one-third of the cells examined. Biphasic membrane response consisting of an initial hyperpolarization followed by a late prolonged depolarization was seen in a smaller proportion of tested cells. Both membrane responses were present, and even enhanced, when synaptic transmission and Na spikes were blocked by perfusing the slice with a TTX-containing Krebs solution. The CGRP-induced membrane changes were also present in media containing TTX and TEA. The CGRP-evoked depolarization was associated with an increase in the input resistance, and enhanced excitability in a majority of neurons tested. In addition, CGRP modified the duration of Ca-dependent action potentials of dorsal horn neurons, the most consistent change being a prolonged increase in the spike duration. Our results are consistent with a neurotransmitter or neuromodulator role for CGRP in the rat spinal dorsal horn.

Isolated tissue and binding studies of YM-17690, a novel and non-analogous leukotriene agonist

YM-17690, 3-[4-carboxymethoxy-3-[p-(4-phenylbutoxy) benzamido]phenyl]propionic acid, produced a dose-dependent contraction of guinea-pig ileum and its EC50 value was 1.6 X 10(-8) M. The response was not affected by pretreatment with atropine, mepyramine, indomethacin, dazoxiben and AA-861 (a 5-lipoxygenase inhibitor), but was inhibited by FPL-55712 (an LTD4 and LTE4 antagonist). YM-17690 induced dose-dependent contractions of guinea-pig lung parenchyma and trachea with EC50 values of 3.9 X 10(-9) and 2.2 X 10(-8) M, respectively. Pretreatment of these tissues with FPL-55712 resulted in a parallel shift of the YM-17690 dose-response curves to the right. The pA2 values for FPL-55712 in lung parenchyma and trachea were 7.41 and 8.21, respectively, and the slopes of the regression lines of Schild plots were 1.00 and 1.02, respectively. YM-17690 produced a dose-dependent inhibition of [3H]LTD4 binding to guinea-pig lung membranes and its pKi value was 9.28. However, the compound showed only 25% inhibition of [3H]TLC4 binding to guinea-pig hippocampus membranes, even at 10(-5) M. These results suggest that YM-17690 is a selective leukotriene (LTD4 and LTE4) agonist and that it will therefore be a valuable tool in the study of actions of leukotrienes and for the characterization of their receptors.

Simulation and experimental study of respiratory motion effect on image quality of single photon emission computed tomography (SPECT)

The effect of respiratory motion on the image quality of single photon emission computed tomography (SPECT) was investigated by computer simulation and experimentation. In the computer simulation, the phantom was assumed to be cylindrical with a uniform background and a spherical cold or hot spot. To simulate respiratory motion, a cyclic linear motion parallel to the axis of rotation of a gamma camera was assumed. The contrast in the transaxial images was calculated for various respiratory amplitudes and its dependence on lesion size and object contrast was investigated. In the experiments, a moving phantom was used to simulate respiratory motion. The simulation and the experimental results were in good agreement within the range of statistical error. The effect on the lesion detectability was investigated using receiver operating characteristics (ROC) analysis, and a method for correcting respiratory motion was devised.

Monte Carlo estimates of absorbed dose rate in various tissues and organs

A computer program based on the Monte Carlo technique was developed for calculation of absorbed dose rate in various tissues and organs. The accuracy of the program was tested by reproducing Berger's values of the specific absorbed fractions for point isotropic sources in water, and a good agreement with those obtained by the moments method was found within an error of several percent. In comparing with experiment and other Monte Carlo results, good agreement was also obtained within the range of statistical error. The absorbed dose rate for an 123I, 124I, 125I, 126I and 99mTc point source and their specific dose constants in various tissues and organs were calculated using this program. This computer program has the mass energy absorption and attenuation coefficients for 69 tissues and organs as a database file, and can be extended to various radionuclides used in nuclear medicine by adding their nuclear data to the program.