Sleep disturbances and changes in urinary 6-sulphatoxymelatonin levels in patients with breast cancer undergoing lumpectomy.

BACKGROUND: Sleep disturbances and changes in self-reported discomfort and melatonin secretion are common in the post-operative period. We aimed to study the distribution of sleep stages in the perioperative period and evaluate changes in secretion of the melatonin metabolite aMT6s and subjective parameters of sleepiness, pain, general well-being and fatigue in patients undergoing surgery for breast cancer. METHODS: Twelve patients, 30-70 years, undergoing lumpectomy were included. Polysomnography was performed the night before surgery (PREOP), the night after (PO1) and 14 days after (PO14). Recordings were scored as awake, light-sleep, slow-wave sleep and rapid-eye-movement (REM) sleep. Sleep stages were analysed as % of total sleep time (TST). Self-reported discomfort was assessed using questions about the level of fatigue, well-being, pain and sleepiness. Urinary aMT6s was measured by radioimmunoassay. RESULTS: There was significantly decreased REM sleep on PO1 (5.9% of TST) compared with PREOP (18.7% of TST) (P < 0.005). An increase in light sleep was observed on PO1 (68.4% of TST) compared with PREOP (55.0% of TST) (P < 0.05). No significant changes in TST, sleep latency, sleep period or total time awake were found. The observed sleep changes were normalised after 2 weeks. No significant changes were found in pain, well-being, fatigue or sleepiness. Night secretion of aMT6s showed a trend towards a decrease from PREOP to PO1 (P = 0.09) and normalisation on PO14 (P = 0.27 between PREOP and PO14). CONCLUSION: Patients with breast cancer undergoing lumpectomy had significantly disturbed sleep architecture the night after surgery, and these changes were normalised after 2 weeks.

Impact of oral preoperative and perioperative immunonutrition on postoperative infection and mortality in patients undergoing cancer surgery: systematic review and meta-analysis with trial sequential analysis.

BACKGROUND: Infectious complications occur in 4-22 per cent of patients undergoing surgical resection of malignant solid tumours. Improving the patient's immune system in relation to oncological surgery with immunonutrition may play an important role in reducing postoperative infections. A meta-analysis was undertaken to evaluate the potential clinical benefits of immunonutrition on postoperative infections and 30-day mortality in patients undergoing oncological surgery. METHODS: PubMed, Embase and Cochrane Library databases were searched to identify eligible studies. Eligible studies had to include patients undergoing elective curative surgery for a solid malignant tumour and receiving immunonutrition orally before surgery, including patients who continued immunonutrition into the postoperative period. The main outcome was overall infectious complications; secondary outcomes were surgical-site infection (SSI) and 30-day mortality, described by relative risk (RR) with trial sequential analysis (TSA). Risk of bias was assessed according to Cochrane methodology. RESULTS: Some 22 RCTs with 2159 participants were eligible for meta-analysis. Compared with the control group, immunonutrition reduced overall infectious complications (RR 0·58, 95 per cent c.i. 0·48 to 0·70; I2 = 7 per cent; TSA-adjusted 95 per cent c.i. 0·28 to 1·21) and SSI (RR 0·65, 95 per cent c.i. 0·50 to 0·85; I2 = 0 per cent; TSA-adjusted 95 per cent c.i. 0·21 to 2·04). Thirty-day mortality was not altered by immunonutrition (RR 0·69, 0·33 to 1·40; I2 = 0 per cent). CONCLUSION: Immunonutrition reduced overall infectious complications, even after controlling for random error, and also reduced SSI. The quality of evidence was moderate, and mortality was not affected by immunonutrition (low quality). Oral immunonutrition merits consideration as a means of reducing overall infectious complications after cancer surgery.

ANTECEDENTES: Entre un 4-22% de los pacientes a los que se realiza una resección quirúrgica de tumores sólidos malignos presentan complicaciones infecciosas. Mejorar el sistema inmunitario del paciente quirúrgico oncológico mediante inmunonutrición puede tener un papel relevante en la reducción de las infecciones postoperatorias. Se realizó un metaanálisis para evaluar los posibles beneficios clínicos de la inmunonutrición en las infecciones postoperatorias y la mortalidad a los 30 días en pacientes sometidos a cirugía oncológica. MÉTODOS: Se realizó una búsqueda en las bases de datos de Pubmed, Embase y Cochrane para identificar los estudios clave. Se consideraron aquellos estudios que incluyeron pacientes con cirugía curativa electiva de un tumor maligno sólido que recibieron inmunonutrición por vía oral antes de la cirugía, así como también los que siguieron con inmunonutrición en el postoperatorio. La variable principal fueron las complicaciones infecciosas generales y las secundarias fueron la infección de la herida quirúrgica y la mortalidad a los 30 días, presentadas como el riesgo relativo (RR) obtenido a partir en un análisis secuencial de experimentos (trial sequential analysis, TSA). El riesgo de sesgo se evaluó según la metodología Cochrane. RESULTADOS: Para el metaanálisis se identificaron 22 ensayos clínicos con 2.075 participantes. En comparación con el grupo de control, la inmunonutrición redujo las complicaciones infecciosas generales (RR 0,58, i.c. del 95% 0,48-0,70, I2 = 7%, TSA ajustado i.c. del 95% 0,28-1,21) y las infecciones de la herida quirúrgica (RR 0,65, i.c. del 95% 0,50-0,85, I2 = 0%, TSA ajustado, i.c. del 95% 0,21-2,04). No hubo diferencias en la mortalidad a los 30 días (RR 0,69, i.c. del 95% 0,32-1,4, I2 = 0%). CONCLUSIÓN: la inmunonutrición redujo las complicaciones infecciosas generales, incluso después de controlar el error aleatorio. La inmunonutrición también redujo la infección de la herida quirúrgica. La calidad de la evidencia fue moderada y la mortalidad no se vio afectada por la inmunonutrición (baja calidad). La inmunonutrición oral debería ser tenida en cuenta como una forma de reducir las complicaciones infecciosas generales después de la cirugía del cáncer.

Factors regulating ovarian function in pigs.

The hormonal interactions of the hypothalamic-pituitary-ovarian-uterine axis are accountable for a normal reproduction in female pigs. It is of importance to have knowledge of estrous symptoms and hormonal profiles around ovulation. The introduction of the transrectal ultrasonography in sows has given us the possibility to study ovarian activity in conscious animals and relate the timing of estrus to ovulation. Combining this technique with measuring of several hormones like luteinizing hormone (LH), follicle-stimulating hormone (FSH), inhibin, estradiol, progesterone, insulin-like growth hormone I (IGF-I), prostaglandin F2alpha (PGF2alpha) metabolite, oxytocin, facilitate our knowledge about the sequence of ovarian events. Evidence suggests that activation of the hypothalamic-pituitary-adrenal axis may hamper the normal gonadotropin secretion and in consequence, the ovarian function. The metabolic status during lactation, weaning of piglets and social stress might affect onset of ovarian activity and the related estrous behavior. The role of seminal plasma, artificial insemination and presence of the boar might also be included as factors regulating the temporal kinetics of ovulation, corpus luteum development, uterine function and steroid production in the ovary. Studies using a simulated stress by means of adrenocorticotrophic hormone (ACTH) administration or food deprivation are tools in understanding how the ovary is susceptible to impairment. The intention of this paper is to review current knowledge concerning the endocrine aspects of normal and stress-influenced ovarian function in pigs.

The primary structure and enzymic properties of porcine prochymosin and chymosin.

Preliminary investigations by N-terminal sequence analysis showed that pig and calf chymosin possessed 80% amino acid sequence identity but showed considerable differences in their enzymatic properties. A comparison of their structures may therefore contribute to an understanding of the significance of the amino acid residues responsible for the differences in these properties. Pig chymosis was extracted from the stomachs of pigs of less than 3 weeks of age, and was purified by ion exchange chromatography. Half of the primary structure was determined by amino acid sequencing and the complete structure was deduced from a cloned chymosin cDNA. Results showed that the zymogen showed 81% sequence identity with calf prochymosin and 57% identity with pig pepsinogen A. The size of the propart and location of the residue which becomes the N-terminus in the active molecule were the same in the prochymosins. The maximum general proteolytic activity at pH 3.5 of pig chymosin was 2-3% of that of the activity of pig pepsin A at pH 2, whereas the milk clotting activity relative to the general proteolytic activity of pig chymosin was much higher than that of calf chymosin. Agar gel electrophoresis at pH 5.3 of stomach extracts of individual pigs showed the existence of two predominant genetic variants of zymogen and enzyme. The two variants could not be distinguished by amino acid composition or N-terminal sequencing, and no differences in the enzymatic properties of the genetic variants were observed. It was concluded that of the residues that participate in the substrate binding, calf and pig chymosin differ in the following positions (pig pepsin numbering, subsites in parentheses): Ser 12 Thr (S4), Leu 30 Val (S1/S3), His 74 Gln (S'2), Val 111 Ile (S1/S3), Lys 220 Met (S4). With regard to the low general proteolytic activity of pig chymosin, the substitution Asp 303 Val relative to calf chymosin may contribute to an explanation of this.

Enhancement of SPECT images by Fourier filtering the projection image set.

Tomographic images from rotating gamma camera systems are often difficult to interpret because of poor contrast and high noise levels. A method is presented for improving the quality of these images by Fourier filtering the projection image set prior to reconstruction. A two-dimensional circularly symmetric Gaussian function is used as the spatial frequency filter. This filter can be optimized to enhance contrast and suppress noise in the projection image set in a straightforward and simple manner from the power spectra of representative projections. Preprocessing of the projections makes it possible to use a ramp reconstruction filter. The resulting tomographic sections show a dramatic improvement in image quality.

Dosimetry of iodine-131 ethiodol in the treatment of hepatoma.

The in vivo distribution and kinetics of [131I]Ethiodol injected through the hepatic artery have been measured on a group of four patients with hepatocellular carcinoma. The [131I]Ethiodol was distributed predominantly in the liver (70-90%) and lungs (10-20%) and was selectively concentrated and retained in the patients with massive and multinodular hepatomas with approximately 10% of the administered activity localizing in tumor. The radioactivity in the blood 2 hr postinjection was less than 0.1% and was never higher than 0.9% of the administered activity. The radioactivity cleared from normal liver tissue with an effective half-life of approximately 4 days while the clearance time from the tumor was 20-25% longer. Activity in the lungs initially increased and then cleared with a 5-day effective half-life. Based on these measurements, the estimated dose per mCi of [131I]Ethiodol administered is 31 rad to the liver, 22 rad to the lungs, 1.9 rad to the total body and 239 rad to a 4-cm diameter tumor. These results suggest that [131I]Ethiodol has the potential to deliver curative radiation doses to hepatomas with acceptable radiation burdens to normal tissues.

An improved method for the quantification of left-to-right cardiac shunts.

We have investigated a technique for quantifying QP/QS in left-to-right cardiac shunts. In this method, the gamma variate, which is fitted to the first-pass portion of the lung curve, is used to generate a curve, which simulates the response of a normal lung curve with systemic recirculation. The difference between this curve and the observed lung curve is then used to calculate QP/QS. This method was evaluated on a set of simulated lung time-activity curves with precisely known QP/QS values on a group of 11 patients with no clinical suspicion of cardiac shunt and on a group of 30 patients referred for cardiac shunt studies. The QP/QS in each of these studies was determined by three individuals using both the Maltz-Treves method and the new method. This method yielded QP/QS values that were more accurate on the simulated lung data and had less interobserver variation on all the studies than those obtained from the Maltz-Treves method.

Sensitivity, resolution and image quality with a multi-head SPECT camera.

This investigation sought to determine which collimation factors were most important in providing superior image quality with a three-headed SPECT device. The relationship between sensitivity, resolution and SPECT image quality was studied. Two different sets of parallel-hole collimators were used. The ultrahigh-resolution collimators have higher spatial resolution (8.9 versus 11.0 mm), but only 55% of the sensitivity of the high-resolution collimators. A phantom with hot rods was imaged with both collimator sets. Observers compared images with the ultrahigh-resolution collimators to images of varying counts with the high-resolution collimators and determined which high-resolution images matched the ultrahigh-resolution images in image quality. Eleven patient studies were acquired with both collimator sets for equal time, and observers chose which image set they preferred. Transverse images of brain and liver studies were simulated with varying resolution and counts and subjectively compared. The phantom study indicated that the improvement in resolution led to image quality comparable to increasing the number of counts by a factor of 2.5 to 3.4. The clinical studies showed that the ultrahigh-resolution collimators were preferred in a large majority of the cases. These trends were also seen in the simulation study. These results confirm that higher resolution collimators should be used with multihead SPECT devices. The improvement in resolution more than compensates for the loss in sensitivity, leading to an overall improvement in image quality.

Abnormal thallium-201 scans in patients with chest pain and angiographically normal coronary arteries.

We reviewed the exercise thallium-201 (TI-201) scans and clinical data of 41 patients with chest pain and normal coronary arteries to identify clinical factors associated with "false-positive" studies. Exercise TI-201 studies were performed before angiography and often precipitated referral. Sex, beta-blocker therapy, anginal pattern, and results of exercise electrocardiography were evaluated and compared with TI-201 imaging. A negative TI-201 study was the most common finding (p less than 0.005). Of the 41 patients, 11 (27%) had abnormal exercise TI-201 scans. No clinical factor was significantly associated with a false-positive TI-201 scans. Of the 11 patients with abnormal scans, 9 had greater than or equal to 1 cardiac abnormality: right bundle branch block in 2, mitral valve prolapse in 3, paroxysmal atrial fibrillation in 2, abnormal left ventricular diastolic pressure in 3, and left bundle branch block in 1. Thus, (1) when results of exercise TI-201 imaging are used to refer patients for angiography, "false-positive" TI-201 studies are common; (2) sex, beta blockade, anginal pattern, and results of exercise electrocardiogram are not useful predictors of a false-positive TI-201 study; and (3) patients with chest pain, normal coronary arteries, and abnormal TI-201 scans frequently have other cardiac abnormalities.

Neutrophil labeling: problems and pitfalls.

The use of neutrophils labeled with gamma-emitting radionuclides has been shown to be acceptable for in vivo kinetic studies as well as for imaging inflammatory foci. Among the gamma-emitting radionuclides, indium-111 appears to be the agent of choice. Labeling neutrophils with 111In, however, is a relatively new technique. Although simple to perform, it involves several stages, none of which could be carried out without problems. These are discussed and the current research aimed at eliminating the problems is outlined. The knowledge of specific chemotactic receptors and surface antigens has stimulated investigations into selective neutrophil labeling that will continue to be challenging and exciting.

Radioiodinated fatty acid esters in the management of hepatocellular carcinoma: preliminary findings.

Radioiodinated fatty acid esters, such as lipiodol or ethiodol, are localized in the hypervascular hepatocellular carcinoma (HCC) for a long time following intra-arterial hepatic injection, enabling delivery of high internal radiation to the tumor. The desired radiation can easily be delivered to small HCC, less than 5 cm in diameter, in single or multiple procedures with an 8-week interval. For larger tumors, [131I]lipiodol or [131I]ethiodol in conjunction with chemotherapy emulsion, Ivalon embolization or all three combinations should be considered for maximal clinical results. A strong beta emitter with shorter physical half-life, i.e. 90Y will be more effective in the management of HCC if one can label lipiodol with 90Y.

A method for obtaining an approximate Wiener filter.

The Wiener restoration filter yields the minimum mean-square error between the restored image and the true object function. However, it has found limited use because, in its usual formulation, it requires information about the object power spectrum which is generally unknown. In this paper, it is shown that the Wiener filter can be derived from the noise-free image power spectrum, and a method is presented for estimating this from the observed data. From this estimate an approximate Wiener filter was calculated. The method was tested on three sets of simulated data which included a constant background, rectangular defects, and Gaussian defects at varying contrast and noise levels. The performance of the approximate Wiener filter was compared both to the true Wiener filter and to the standard 1-2-1 three-point smooth. The results confirmed that the approximate Wiener filter adapted to the information content of the observed data and closely matched the performance of the true Wiener filter. The approximate Wiener filter outperformed the three-point smooth in all cases, especially at low contrast and high noise levels. The approximate Wiener filter can be calculated without operator intervention and requires little additional computation time over conventional Wiener filter techniques.

A method for quantifying SPECT uniformity.

Field uniformity is an important parameter for monitoring the performance of SPECT imaging systems. However, it is difficult to apply objective measures of uniformity because of the large variance associated with reconstructed images. In the proposed method, annular sampling of the SPECT uniformity image is used to reduce the noise level without decreasing the magnitude of uniformity artifacts. The reconstructed uniformity image is sectioned into annular rings centered on the center of rotation to match the expected distribution of uniformity artifacts. Statistical fluctuations are reduced by averaging the counts within the annular rings, allowing the use of objective measures of field uniformity such as integral uniformity. Application of the annular sampling technique on simulated and phantom uniformity images showed that the technique could reliably quantify SPECT uniformity artifacts at acceptable count levels. As a result this method can be used to objectively evaluate SPECT field uniformity in systems which utilize parallel collimation and circular orbits.

A precise method for correcting count-rate losses in scintillation cameras.

Quantitative studies performed with scintillation detectors often require corrections for lost data because of the finite resolving time of the detector. Methods that monitor losses by means of a reference source or pulser have unacceptably large statistical fluctuations associated with their correction factors. Analytic methods that model the detector as a paralyzable system require an accurate estimate of the system resolving time. Because the apparent resolving time depends on many variables, including the window setting, source distribution, and the amount of scattering material, significant errors can be introduced by relying on a resolving time obtained from phantom measurements. These problems can be overcome by curve-fitting the data from a reference source to a paralyzable model in which the true total count rate in the selected window is estimated from the observed total rate. The resolving time becomes a free parameter in this method which is optimized to provide the best fit to the observed reference data. The fitted curve has the inherent accuracy of the reference source method with the precision associated with the observed total image count rate. Correction factors can be simply calculated from the ratio of the true reference source rate and the fitted curve. As a result, the statistical uncertainty of the data corrected by this method is not significantly increased.

Quantitation of SPECT performance: Report of Task Group 4, Nuclear Medicine Committee.

A comprehensive performance testing program is an essential ingredient of high-quality single-photon emission computed tomography (SPECT). Many of the procedures previously published are complicated, time consuming, or require a special testing environment. This Task Group developed a protocol for evaluating SPECT imaging systems that was simple, practical, required minimal test equipment, and could be performed in a few hours using processing software available on all nuclear medicine computers. It was designed to test rotational stability of uniformity and sensitivity, tomographic spatial resolution, uniformity and contrast, and the accuracy of attenuation correction. It can be performed in less than three hours and requires only a Co-57 flood source, a line source, and a tomographic cylindrical phantom. The protocol was used 51 times on 42 different cameras (seven vendors) by four different individuals. The results were used to establish acceptable ranges for the measured parameters. The variation between vendors was relatively small and appeared to reflect slight differences in basic camera performance, collimation, and reconstruction software. Individuals can use the tabulated values to evaluate the performance of individual systems.

The safety and pharmacokinetics in adult subjects of an intravenously administered 99mTc-labeled 17 amino acid peptide (CYT-379).

A phase I study was designed to evaluate the safety and pharmacokinetics of a novel platelet reactive peptide, peptide acetyl-SYGRGDVRGDFKCTCCA-amide (CYT-379), which binds to the fibrinogen receptor of activated platelets and also binds to 99mTc. Eleven subjects with suspected deep venous thrombosis had 0.1, 0.5 or 1.0 mg of the peptide infused intravenously. Pharmacokinetics were determined by assaying blood samples in 6 of the 11 subjects and by urine sampling in 5 of these 6 subjects. Plasma and whole blood time-activity curves demonstrated an initial fast component with half-time clearance of 0.2 +/- 0.01 and 0.2 +/- 0.02 h and a slow component with half-time clearance of 2.8 +/- 0.3 and 2.7 +/- 0.2 h (mean +/- SEM for plasma and whole blood, respectively). Urine clearance was 22.6 +/- 3.3 and 10.8 +/- 1.6 mL/min when normalized to body surface area. The cumulative excretion of 99mTc-CYT-379 in the urine was 16.6 +/- 3.6, 45.6 +/- 16.9 and 45.6 +/- 1.8% of the administered dose over 0-2, 0-12 and 0-24 h after radiopharmaceutical injection, respectively. Images obtained in 11 subjects immediately, at 1-2, and 4-6 h after injection were evaluated for abnormalities and were compared with duplex Doppler ultrasonography. 99mTc-CYT-379 images were positive in only 3 of 7 subjects who had a positive duplex Doppler examination in at least one lower extremity. One subject with negative duplex Doppler had also negative 99mTc-CYT-379 scintigraphy. One subject with negative scintigraphy and two other subjects with positive scintigraphy had no other imaging studies of the deep venous system performed. No adverse reactions were observed during or after the infusion of 99mTc-CYT-379. 99mTc-CYT-379 appears to be a safe radiopharmaceutical and demonstrates rapid clearance from plasma in human subjects.

Spatial resolution and count density requirements in brain SPECT imaging.

A set of simulations has been performed to investigate the spatial resolution and count density requirements for brain SPECT imaging. Projections were drawn from a matrix representation of the Hoffman brain phantom. These projections were convolved with realistic point spread functions and Poisson noise was added to simulate a wide range of imaging situations normalized to a fixed imaging time. The projections were optimally smoothed with a Wiener filter and were reconstructed with a ramp filter. The quality of the reconstructed images was determined objectively from the normalized mean square between the simulated data and the true distribution. This ranking was validated against the preferences of a group of trained observers. The results from this study indicate that the optimal choice of spatial resolution (collimation) depends on the available count density. As the count density (normalized to 10 mm resolution) increases by a factor of 2.7, results from the simulations indicate that the optimal spatial resolution improves by 1 mm. For brain studies in which the administered activity is limited (such as 123I IMP), the optimal spatial resolution is approximately 8 to 9 mm. With 99Tcm labelled brain agents the amount of administered radioactivity can be increased six-fold and the optimal spatial resolution is predicted to fall to about 6 to 7 mm. If sensitivity is further increased by the use of a dedicated SPECT unit with multiple detectors, the optimal spatial resolution will be on the order of 4 to 5 mm.

An investigation of 11C-methane, 13N-nitrous oxide and 11C-acetylene as regional cerebral blood flow agents.

Radioisotopes of xenon or krypton are generally used as the inert diffusible indicators in regional cerebral blood flow (rCBF) studies. These gases have disadvantages when introduced into the body inhalation because of their low solubility in body tissues. The use of 11C-methane, 13N-nitrous oxide and 11C-acetylene as inhalation rCBF agents has been investigated. These gases span a wide range of solubilities: methane is four times less soluble than xenon in body tissues while nitrous oxide and acetylene are respectively 3 and 6 times more soluble. Cerebral blood flow measurements were performed on normal volunteers using the three labelled gases as well as 133Xe. All tracers were administered by inhalation and the cerebral clearance of the gases was monitored by coincidence detection. Uptake in the body was found to be dependent on solubility. The computed blood flow values found using the various indicators were in excellent agreement and were within the normal cerebral blood flow range. The high solubilities of acetylene and nitrous oxide result in a more efficient transfer of tracer from lung to brain than the conventionally used agents. The positron emission is also advantageous for tomographic rCBF measurements.

Blocking of tissue factor pathway inhibitor (TFPI) shortens the bleeding time in rabbits with antibody induced haemophilia A.

Tissue factor (TF)/FVIIa initiates coagulation by activating factor IX (FIX) and factor X (FX). Tissue factor pathway inhibitor (TFPI)-FXa complexes form and inhibit TF/FVIIa. Blocking of TFPI may facilitate haemostasis initiated by FVIIa/TF thereby compensating for impaired FIX/FVIII-dependent coagulation. This hypothesis was tested in a study using rabbits made temporarily haemophilic by the injection of antibodies against FVIII. These rabbits were given i.v. injections of anti-TFPI IgG antibodies and 40 min later bleeding was initiated by cutting the nail including the apex of the cuticle. Injection of anti-TFPI IgG shortened the bleeding time significantly from 26 min to 11 min (normal mean bleeding time in non-haemophilia rabbits: 5 min). Treatment with anti-TFPI IgG also resulted in a shortening of the haemophilic aPTT to a level slightly longer than the normal aPTT. In addition, the prolonged dilute TF clotting time was shortened by the anti-TFPI IgG treatment. Thus, both bleeding and coagulation parameters indicated that blocking of TFPI may be potentially haemostatic in haemophilia.

Pulmonary CT image classification with evolutionary programming.

RATIONALE AND OBJECTIVES: It is often difficult to classify information in medical images from derived features. The purpose of this research was to investigate the use of evolutionary programming as a tool for selecting important features and generating algorithms to classify computed tomographic (CT) images of the lung. MATERIALS AND METHODS: Training and test sets consisting of 11 features derived from multiple lung CT images were generated, along with an indicator of the target area from which features originated. The images included five parameters based on histogram analysis, 11 parameters based on run length and co-occurrence matrix measures, and the fractal dimension. Two classification experiments were performed. In the first, the classification task was to distinguish between the subtle but known differences between anterior and posterior portions of transverse lung CT sections. The second classification task was to distinguish normal lung CT images from emphysematous images. The performance of the evolutionary programming approach was compared with that of three statistical classifiers that used the same training and test sets. RESULTS: Evolutionary programming produced solutions that compared favorably with those of the statistical classifiers. In separating the anterior from the posterior lung sections, the evolutionary programming results were better than two of the three statistical approaches. The evolutionary programming approach correctly identified all the normal and abnormal lung images and accomplished this by using less features than the best statistical method. CONCLUSION: The results of this study demonstrate the utility of evolutionary programming as a tool for developing classification algorithms.