Management Of Small Pulmonary Nodules Research Articles

The use of diagnostic complex robotic-assisted segmentectomy in the management of incidental and screen-detected pulmonary nodules.

Robotic-assisted thoracoscopic surgery (RATS) facilitates complex pulmonary segmentectomy which offers one-stage diagnostic and therapeutic management of small pulmonary nodules. We aimed to explore the potential advantages of a faster, simplified pathway and earlier diagnosis against the disadvantages of unnecessary morbidity in benign cases. In an observational study, patients with small, solitary pulmonary nodules deemed suspicious of malignancy by a multidisciplinary team were offered surgery without a pre or intraoperative biopsy. We report our initial experience with RATS complex segmentectomy (using >1 parenchymal staple line) to preserve as much functioning lung tissue as possible. Over a 4-year period, 245 RATS complex segmentectomies were performed; 140 right: 105 left. A median of 2 (1-4) segments was removed. There was no in-hospital mortality and no requirement for postoperative ventilation. Complications were reported in 63 (25.7%) cases, of which 36 (57.1%) were hospital-acquired pneumonia. A malignant diagnosis was found in 198 (81%) patients and a benign diagnosis in 47 (19%). The malignant diagnoses included: adenocarcinoma in 136, squamous carcinoma in 31 and carcinoid tumour in 15. The most frequent benign diagnosis was granulomatous inflammation in 18 cases. RATS complex segmentectomy offers a precise, safe and effective one-stop therapeutic biopsy in incidental and screen-detected pulmonary nodules.

Early detection of lung cancer through programmatic management of pulmonary nodules in the Mississippi Delta.

126 Background: Lung cancer (LC) causes the most cancer deaths in the US, but early detection improves outcomes. Uptake of Low-Dose CT screening (LDCT) has been low, contributing to race-based disparities. Programmatic management of incidentally detected pulmonary nodules (PN) provides a complementary avenue for early detection which could address disparities. In our PN cohort, Detecting Early LC in the Mississippi Delta (DELUGE), we provide broad access to early detection across a region fraught with geographic, socioeconomic, and race-based disparities. However, many detected PN will not result in LC. After successful implementation at the program level, we seek to evaluate individual-level factors important for early-detection. We evaluated how individuals with small PN identified in DELUGE differ between those who were and were not diagnosed with LC. Methods: DELUGE is a prospective cohort study where we systematically manage incidentally detected PN with trained navigators and evidence-based risk stratification. We constructed DELUGE in a community-based healthcare system across the mid-south with some of the highest per-capita LC incidence and mortality rates in the US. We evaluated all PN ≤30mm in DELUGE from 2015-2022. We compared clinical and demographic characteristics between individuals who were or were not diagnosed with LC within 24 months. Primary analysis used logistic regression, reporting odds ratios (OR) with 95% confidence intervals. Results: From 2015-2022, 17,945 individuals with PN ≤30 mm (71% of the total cohort of 25,339) were identified and enrolled in DELUGE. They had median age of 65 years, were 56% female, and 27% Black / 69% White. 853 (4.8%) patients were diagnosed with LC within two years. PN size significantly predicted LC diagnosis. For every 1 mm increase in nodule size the odds of LC increased by 15% (OR: 1.15 [1.14-1.16]); PN in an upper lobe (OR: 2.0 [1.7-2.2]) and those with cavitation also increased the odds of LC (OR: 2.9[1.9-4.2]). Sex, rural/urban residence, and number of PN were not associated with LC. The most predictive individual level characteristics were age, prior cancer history (OR: 1.3 [1.1-1.5], family cancer history (OR: 1.7 [1.5-2.0], COPD (OR: 3.3 [2.9-3.8]), and smoking history (OR: 6.6 [5.3-8.4]). In the multiple variable model, the most significant associations with LC diagnosis included PN size, age, insurance, family cancer history, COPD, and smoking history (all p<0.0001). This model could provide estimated sensitivity 0.81 and specificity 0.81 for predicting LC (AUC= 0.88). Conclusions: Factors measurable at baseline have predictive ability, and predictive modeling may be useful in management of small PN. More focused follow-up could improve programmatic efficiency, targeting the alleviation of geographic, socioeconomic, and race-based health disparities in this high poverty region of the US.

Implementation of Individualized Low-Dose Computed Tomography-Guided Hook Wire Localization of Pulmonary Nodules: Feasibility and Safety in the Clinical Setting.

Background: CT-guided hook-wire localization is an essential step in the management of small pulmonary nodules. Few studies, however, have focused on reducing radiation exposure during the procedure. Purpose: This study aims to explore the feasibility of implementing a low-dose computed tomography (CT)-guided hook wire localization using tailored kVp based on patients' body size. Materials and Methods: A total of 151 patients with small pulmonary nodules were prospectively enrolled for CT-guided hook wire localization using individualized low-dose CT (LDCT) vs. standard-dose CT (SDCT) protocols. Radiation dose, image quality, characteristics of target nodules and procedure-related variables were compared. All variables were analyzed using Chi-Square and Student's t-test. Results: The mean CTDIvol was significantly reduced for LDCT (for BMI ≤ 21 kg/m2, 0.56 ± 0.00 mGy and for BMI > 21 kg/m2, 1.48 ± 0.00 mGy) when compared with SDCT (for BMI ≤ 21 kg/m2, 5.24 ± 0.95 mGy and for BMI > 21 kg/m2, 6.69 ± 1.47 mGy). Accordingly, the DLP of LDCT was significantly reduced as compared with that of SDCT (for BMI ≤ 21 kg/m2, 56.86 ± 4.73 vs. 533.58 ± 122.06 mGy.cm, and for BMI > 21 kg/m2, 167.02 ± 38.76 vs. 746.01 ± 230.91 mGy.cm). In comparison with SDCT, the effective dose (ED) of LDCT decreased by an average of 89.42% (for BMI ≤ 21 kg/m2) and 77.68% (for BMI > 21 kg/m2), respectively. Although the images acquired with the LDCT protocol yielded inferior quality to those acquired with the SDCT protocol, they were clinically acceptable for hook wire localization. Conclusions: LDCT-guided localization can provide safety and nodule detection performance comparable to SDCT-guided localization, benefiting radiation dose reduction dramatically, especially for patients with small body mass indexes.

The development and validation of a radiomic nomogram for the preoperative prediction of lung adenocarcinoma

BackgroundAccurate diagnosis of early lung cancer from small pulmonary nodules (SPN) is challenging in clinical setting. We aimed to develop a radiomic nomogram to differentiate lung adenocarcinoma from benign SPN.MethodsThis retrospective study included a total of 210 pathologically confirmed SPN (≤ 10 mm) from 197 patients, which were randomly divided into a training dataset (n = 147; malignant nodules, n = 94) and a validation dataset (n = 63; malignant nodules, n = 39). Radiomic features were extracted from the cancerous volumes of interest on contrast-enhanced CT images. The least absolute shrinkage and selection operator (LASSO) regression was used for data dimension reduction, feature selection, and radiomic signature building. Using multivariable logistic regression analysis, a radiomic nomogram was developed incorporating the radiomic signature and the conventional CT signs observed by radiologists. Discrimination and calibration of the radiomic nomogram were evaluated.ResultsThe radiomic signature consisting of five radiomic features achieved an AUC of 0.853 (95% confidence interval [CI]: 0.735–0.970), accuracy of 81.0%, sensitivity of 82.9%, and specificity of 77.3%. The two conventional CT signs achieved an AUC of 0.833 (95% CI: 0.707–0.958), accuracy of 65.1%, sensitivity of 53.7%, and specificity of 86.4%. The radiomic nomogram incorporating the radiomic signature and conventional CT signs showed an improved AUC of 0.857 (95% CI: 0.723–0.991), accuracy of 84.1%, sensitivity of 85.4%, and specificity of 81.8%. The radiomic nomogram had good calibration power.ConclusionThe radiomic nomogram might has the potential to be used as a non-invasive tool for individual prediction of SPN preoperatively. It might facilitate decision-making and improve the management of SPN in the clinical setting.

Management of incidental lung nodules

Due to the increase of incidentally detected pulmonary nodules and the information obtained from several screening programs, updated guidelines with new recommendations for the management of small pulmonary nodules have been proposed. These international guidelines coincide in proposing periodic follow-up for small nodules, less than 8 mm of diameter. Fleischner and British Thoracic Society guidelines are the most recent and popular guidelines for incidental pulmonary nodules management. They have specific recommendations according to nodule characteristics (density and size) and cancer risk of the patient. Both guidelines separate recommendations for solid and subsolid nodules. Predictive risk models have been developed to improve the nodule management. In certain cases follow up may not be the best option. We discuss the scenarios and options to achieve a histologic diagnosis of these tiny pulmonary nodules.

P1.03-052 The Effect of Rounding on Rate of Positive Results on CT Screening for Lung Cancer

Effective management of small pulmonary nodules to reduce frequency of false positives has been one of the most challenging issues to implementation of screening. Measurement of size is important as it determines whether a nodule is positive result and also whether growth has occurred. Lung-RADS v.1 guideline requires nodule measurement to be rounded to the nearest whole number, it is not specified whether individual length and width measures should also be rounded prior to rounding the diameter. An alternative approach is the one used in I-ELCAP where measurements were recorded to one decimal place. This study explored how rounding would affect the frequency of positive results both for baseline and annual rounds. Using data collected from CT screenings of 21,136 I-ELCAP participants, we evaluated four different approaches for calculating the nodule diameter (D) based on measurements of the length (L) and width (W) listed below: 1) Measurement of L and W to one decimal place (x.x) and calculation of D without rounding; 2) rounding D to the nearest integer; 3) rounding the L and W measurements to the nearest integer before calculating D with no further rounding; and 4) rounding the calculated D determined by method 3 to the nearest integer. Threshold of positive results was 6.0 mm for baseline round and 4.0 mm for annual repeat rounds of screening. Frequency of positive results in the baseline and annual repeat rounds were compared. For baseline screening using the current I-ELCAP definition (Method 1), the rate of positive results was 10.2%. Using method 2, 3 and 4, positive rates were 12.8%, 10.5% and 13.2%, respectively. Use of rounding would have increased the frequency of positive results by 25.7%, 3.0%, and 28.9%, respectively. Of 85,877 repeat screenings, the rate of positive results was 8.0% using method 1. Using method 2, 3 and 4, positive rates were 9.7%, 8.3% and 9.8%, respectively. Use of rounding would have increased the frequency of positive results on repeat screenings by 20.5%, 3.2%, and 22.3%, respectively. Regardless of where the rounding occurred, it results in more nodules designated as positive. This effect is most pronounced when the rounding occurs in average diameter, and since frequency of nodules increases as size decreases, small nodules are therefore the most frequent cause for positive results and rounding can lead to large increases in positive rates.

Lung cancer screening and management of small pulmonary nodules

Worldwide lung cancer is the leading cause of death from cancer. Most lung cancers are diagnosed at an advanced stage, so survival after lung cancer is generally poor. Diagnosis of lung cancer at earlier stages may be associated with an increased survival rate. This indicates that the implementation of lung cancer screening programs at the population level by means of low dose computed tomography might helpful to improve the outcome and mortality of lung cancer patients. By means of rapid advances in imaging technologies over the last decades it became possible to detect small lung nodules as small as a couple of millimeters. This recent developments require management algorithms to guide the clinical management of suspicious and indeterminate lung nodules found in computer tomography during lung cancer screening or by incidental finding.This review will focus on both, the recent advances in lung cancer screening and the guidelines for the management of small pulmonary nodules.

Management of solid and sub-solid lung nodules

Pulmonary nodules present a unique challenge for radiologists which includes the detection of malignancy and identification of benign disease, recommending the appropriate procedures to avoid unnecessary thoracotomy, and ensuring that excessive radiation from follow-up computed tomography (CT) examinations is kept to a minimum. Although seasoned radiologists can use an approach based on their extensive experience, in this era of evidence-based medicine, guidelines have been established that include both radiologic and clinical factors in an integrated fashion. Such guidelines have been developed by the Fleischner Society, first in 2005, for the management of small pulmonary nodules detected on CT scans, and then, in 2013, for the management of sub-solid nodules [1]. For incidentally detected solitary nodules, these guidelines integrate elements as individual risk factors (via pre-test probability), with lesion size, growth rate, and morphology, based on imaging characteristics. Relevant risk factors to consider in the evaluation of pulmonary nodules are smoking history and patient age. Patients with a substantial smoking history and over 40 years of age are defined as high-risk patients, whereas low-risk patients are those with a negligible smoking history and no other known risk factors, and who are below 40 years of age. Based on the Fleischner Society recommendation [1], lesions less than 4 mm do not require any further invasive or non-invasive measures or evaluations. However, lesions with a diameter of more than 8mm should be evaluated with either follow-up CT scans, including dynamic, contrast-enhanced scans, positron emission tomography (PET)-CT, and biopsy. For lesions that fall between the 4 mm and 8 mm size, CT follow-up with a limited number of scans is recommended. Sub-solid nodules are often found during screening studies or incidentally on CT scans. They are characterized by their appearance as rounded areas of increased attenuation, and a homogeneous or heterogeneous texture. Sub-solid nodules can be subdivided according to their composition: non-solid lesions that consist of ground-glass opacity only; and part solid lesions that contain both ground-glass and soft tissue elements. Sub-solid nodules can regress, persist, or grow. Small persistent non-solid nodules are often atypical adenomatous hypoplasia (AAH) and focal fibrosis, whereas non-solid and part-solid nodules that increase in size typically indicate malignancy, which can include adenocarcinoma in situ (AIS), minimally invasive adenocarcinoma (MIA), and invasive adenocarcinoma, as well as lympho-proliferative disease. How these lesions develop has not been entirely elucidated as yet, but it seems that a small percentage of ground-glass opacities (AAH) develop into larger lesions that can eventually comprise solid components due to invasion and alveolar collapse [2]. In any case, radiologically, an increase in lesion density, growth, or the development of solid portions are all indicative of malignancy. CT analysis and surveillance of sub-solid nodules is the modality of choice for the identification of malignant lesions. The primary factor is nodule size. While lesions less than 5 mm in diameter are usually AAHs, lesions greater than 15 mm is size are malignant, and are typically MIAs and invasive adenocarcinomas. Generally, a diameter of more than 8 mm is indicative of malignancy. Another important indicator of malignancy is lesion growth. The growth of the lesion may affect either the ground-glass or the solid components, or both. Volume doubling times of AIS and MIAs are much longer, compared to invasive adenocarcinomas and squamous cell lesions. Morphologically, the presence of lobulated borders, air bronchograms and bubble-like lucencies, and the development of solid portions in pure ground-glass abnormalities are all indicative of malignancy. Lesion morphology is closely related to prognosis. Nodules with an increasing percentage of solid components represent a poorer prognosis, but, for patients with pure ground-glass abnormalities or those with only a small area of a solid component, the survival rate after lesion resection is 100%. The Fleischner Society management guidelines [2] for sub-solid lesions recommend that part solid nodules, especially those that persist or grow in size, mandate further evaluation and monitoring, and typically, require surgical resection. Smaller lesions, with a negligible area of solid components, can be managed with follow-up CT scans.

An Update on the Evaluation and Management of Small Pulmonary Nodules

The widespread utilization of chest CT scans has increased the importance of the proper evaluation of incidentally found lung nodules. The primary goal in the evaluation of these nodules is to determine whether they are malignant or benign. Clinical factors such as older age, tobacco smoking, and current or remote history of malignancy increase the pretest likelihood of malignancy. Radiological features of these nodules are important in differentiating benign from malignant lesions. However, the etiology of the lung nodules frequently remains indeterminate and requires further evaluation. The approach to the management of indeterminate lung nodules ranges between observation with repeat chest CT scan, further diagnostic studies such as PET scan or invasive procedures to obtain tissue diagnosis. This article reviews the importance of the different radiological features of lung nodules. This is followed by an update on the approach to the management of the different types of small lung nodules.

Management of small pulmonary nodules in patients with sarcoma

Small pulmonary nodules in patients with sarcoma are problematic, because it is difficult to distinguish such small metastatic nodules from benign. The purpose of this study was to establish management guidelines for such small pulmonary nodules in patients with sarcoma. Pulmonary nodules were detected in 70 of 206 patients with sarcoma. About 55 patients were classified as having pulmonary metastasis. Seventeen of these 55 patients with pulmonary metastases were excluded from the imaging review because they did not undergo the required imaging examination. This study reviewed 38 patients with metastatic nodules and 15 patients with benign nodules. A statistically significant relationship was observed between the size of the nodules and final clinical decision. The patients with pulmonary nodules which did not exceed 5 mm in size showed significantly better cumulative overall survival rate after the detection of pulmonary nodules than those with larger nodules (5-years: 58.4 vs. 20.4%). There was no significant difference in the overall survival rate between the patients with smaller pulmonary benign lesions which did not exceed 5 mm in size and those with a normal chest CT (5-years: 92.3 vs. 85.3%). The only factor to diagnose in a metastatic pulmonary lesion is the size of the nodules. If the nodule remains < or = 5 mm in size for more than 6 months, the nodule will be a benign lesion. On the contrary, if the nodule becomes larger than 5 mm within 6 months, a surgical excision of the nodules is recommended.

CT-guided percutaneous fine-needle aspiration biopsy of pulmonary nodules measuring 10 mm or less

To determine the value of computed tomography (CT)-guided fine-needle aspiration biopsy (FNAB) of small pulmonary nodules measuring 10 mm or less. CT-guided FNABs of 55 nodules, measuring 10mm or less, were performed between January 2003 and February 2006. A coaxial technique was used, with an outer 19 G Bard Truguide needle and inner 22 G disposable Greene biopsy needle. Adequacy of specimens was assessed on-site by a cytotechnologist. The sizes of the nodules, distance from pleura, number of pleural punctures and aspirates, complications encountered, cytological diagnosis, and outcome were recorded. The mean nodule diameter was 9 mm (range 5-10 mm). The average distance from the costal pleura was 31 mm (range 0-88 mm). In 50 of the 55 FNABs, the pleura was crossed once. An average of four aspirates was performed per case. Twenty-five FNABs (45.5%) were adequate for diagnosis (24 malignant and one tuberculosis). In 11 cases, where no definite diagnosis was made following FNAB, the outcome was not affected. In 10 cases, samples were insufficient for diagnosis and the nodules were subsequently diagnosed as malignant. Eight cases were excluded in the final analysis as follow-up details were unavailable. The sensitivity for malignancy and overall accuracy were 67.7 and 78.8%, respectively. Pneumothorax occurred in 29 (52.7%) patients, with five (9.1%) requiring thoracostomy tubes. CT-guided FNAB is a useful tool in the diagnosis and management of small pulmonary nodules, despite the lower diagnostic accuracy and higher complication rate than those of larger pulmonary lesions.

PET in Management of Small Pulmonary Nodules

PET in Management of Small Pulmonary Nodules

Callback and Follow-up Guidelines for Whole-Body CT Screening

HomeRadiologyVol. 241, No. 2 PreviousNext CommunicationsLetters to the EditorCallback and Follow-up Guidelines for Whole-Body CT ScreeningFerris M. HallFerris M. HallAuthor AffiliationsDepartment of Radiology, Beth Israel Deaconess Medical Center, 330 Brookline Avenue, Boston, MA 02215 e-mail: [email protected]Ferris M. HallPublished Online:Nov 1 2006https://doi.org/10.1148/radiol.2412051871MoreSectionsFull textPDF ToolsImage ViewerAdd to favoritesCiteTrack CitationsPermissionsReprints ShareShare onFacebookTwitterLinked In References1 Furtado CD, Aguirre DA, Sirlin CB, et al. Whole-body CT screening: spectrum of findings and recommendations in 1192 patients. Radiology 2005;237:385–394. Link, Google Scholar2 MacMahon H, Austin JHM, Gamsu G, et al. Guidelines for management of small pulmonary nodules detected on CT scans: a statement from the Fleischner Society. Radiology 2005;237:395–400. Link, Google ScholarArticle HistoryPublished in print: 2006 FiguresReferencesRelatedDetailsCited ByBMC Surgery, Vol. 10, No. 1The Use of CT for Screening: A National Survey of Radiologists' Activities and Attitudes1Ingrid M. Burger, , Nancy E. Kass, , Jonathan H. Sunshine, , and Stanley S. Siegelman, 1 July 2008 | Radiology, Vol. 248, No. 1Simplified Imaging Approach for Evaluation of the Solid Renal Mass in Adults1Ray Dyer, , David J. DiSantis, , and Bruce L. McClennan, 1 May 2008 | Radiology, Vol. 247, No. 2College of Radiology, Academy of Medicine of Malaysia position on whole body screening CT scans in healthy asymptomatic individuals (2008)1 October 2008 | Biomedical Imaging and Intervention Journal, Vol. 4, No. 4Academic Radiology, Vol. 14, No. 6Recommended Articles Top Publications in Radiology, 2021Radiology2022Volume: 303Issue: 1pp. 1-2Test Sets and Real-Life Performance: Can One Predict the Other?Radiology: Imaging Cancer2020Volume: 2Issue: 5The Impact of Acquisition Dose on Quantitative Breast Density Estimation with Digital Mammography: Results from ACRIN PA 4006Radiology2016Volume: 280Issue: 3pp. 693-700Contemporary Risk Management for RadiologistsRadioGraphics2018Volume: 38Issue: 6pp. 1717-1728Supplemental MRI in Extremely Dense Breasts: Sharp Reduction in False-Positive Rate in the Second Screening Round of the DENSE TrialRadiology2021Volume: 299Issue: 2pp. 287-289See More RSNA Education Exhibits Contrast-Enhanced Mammography: Current Indications and Future Directions  Digital Posters2019Contrast-Enhanced Mammography: Current Applications and Future DirectionDigital Posters2018Breast Density Included in the Modern Rules of Mammographic ScreeningDigital Posters2019 RSNA Case Collection Hyperplastic Residual Breast TissueRSNA Case Collection2022 Post vaccination axillary adenopathyRSNA Case Collection2021Miliary Pulmonary TuberculosisRSNA Case Collection2021 Vol. 241, No. 2 Metrics Altmetric Score PDF download

Management of Patients with Small Pulmonary Nodules: A Survey of Radiologists, Pulmonologists, and Thoracic Surgeons

The objective of our study was to survey recommendations for the management of small pulmonary nodules found on helical CT from radiologists, pulmonologists, and thoracic surgeons. We surveyed 774 radiologists, 623 pulmonologists, and 101 thoracic surgeons. All are members of an associated Austrian scientific society and were asked for their recommendations in 13 hypothetical cases. Statistical analysis was focused on possible differences between medical specialities, residents and fellows, and male and female doctors and on a possible influence of the number of years in training or in medical practice. Complete surveys were returned from 91 radiologists, 74 pulmonologists, and 12 thoracic surgeons. The most frequent recommendation from radiologists was follow-up, whereas the most frequent recommendation from pulmonologists and surgeons was biopsy. The most frequently advised CT follow-up period was 3 months. Whereas thoracic surgeons preferred video-assisted thoracoscopy, radiologists and pulmonologists recommended less invasive procedures (bronchoscopy, CT-guided biopsy) to gain a specific diagnosis. There are significant differences in the management of small pulmonary nodules among radiologists, pulmonologists, and thoracic surgeons. Whereas radiologists tend to recommend short-term follow-up, pulmonologists and thoracic surgeons prefer a more aggressive approach, especially in patients with a higher likelihood of malignancy.

Guidelines for Management of Small Pulmonary Nodules Detected on CT Scans: A Statement from the Fleischner Society

Lung nodules are detected very commonly on computed tomographic (CT) scans of the chest, and the ability to detect very small nodules improves with each new generation of CT scanner. In reported studies, up to 51% of smokers aged 50 years or older have pulmonary nodules on CT scans. However, the existing guidelines for follow-up and management of noncalcified nodules detected on nonscreening CT scans were developed before widespread use of multi-detector row CT and still indicate that every indeterminate nodule should be followed with serial CT for a minimum of 2 years. This policy, which requires large numbers of studies to be performed at considerable expense and with substantial radiation exposure for the affected population, has not proved to be beneficial or cost-effective. During the past 5 years, new information regarding prevalence, biologic characteristics, and growth rates of small lung cancers has become available; thus, the authors believe that the time-honored requirement to follow every small indeterminate nodule with serial CT should be revised. In this statement, which has been approved by the Fleischner Society, the pertinent data are reviewed, the authors' conclusions are summarized, and new guidelines are proposed for follow-up and management of small pulmonary nodules detected on CT scans.

A novel technique for localization and excisional biopsy of small or Ill-defined pulmonary lesions

Background The purpose of this study was to develop and evaluate radiotracer-guided localization of small or ill-defined pulmonary nodules for thoracoscopic excisional biopsy. Methods This study consisted of two parts: a laboratory study in rats to determine the most suitable radiotracer, and a pilot study in humans to determine the feasibility of radiotracer lung nodule localization. The right lung of 12 rats was injected with a technetium 99m (Tc 99m) based radiotracer solution: 4 each with macroaggregated albumin (MAA), unfiltered sulfur colloid (SC), and pertechnetate (TcO 4). Serial imaging was performed using a small animal gamma camera for 4 hours following injection. In 13 patients, computed tomographic (CT) guided injection of Tc 99m MAA solution was made into or adjacent to a pulmonary nodule suspicious for primary lung cancer. Gamma probe localization of the nodule was performed during subsequent thoracoscopic surgery. Results In the animal model, MAA provided more precise localization than SC or TcO 4 and was selected for the human study. In the human series, all 13 patients had successful gamma probe localization of their lesion. There were no radiologic or surgical complications. Seven of 13 nodules were malignant, and five of these nodules were stage IA primary lung carcinomas. Conclusions Computed tomographic-guided radiotracer localization of small or ill-defined pulmonary nodules using Tc 99 m MAA before thoracoscopic excisional biopsy is feasible and may make excisional biopsy the preferred management strategy for the management of small pulmonary nodules in patients at high risk for malignancy.