Gallium-67 citrate imaging studies of the lung

Pre-feasibility Study for Establishing Radioisotope and Radiopharmaceutical Production Facilities in Developing Countries

BACKGROUND

A significant number of developing countries have no facilities to produce medical radioisotopes and radiopharmaceuticals.

OBJECTIVE

In this paper we show that access to life-saving radioisotopes and radiopharmaceuticals and the geographical distribution of corresponding infrastructure is highly unbalanced worldwide.

METHODS

We discuss the main issues which need to be addressed in order to establish the production of radioisotopes and radiopharmaceuticals, which are especially important for developing countries as newcomers in the field. The data was gathered from several sources, including databases maintained by the International Atomic Energy Agency (IAEA), World Health Organization (WHO), and other international organizations; personal interactions with representatives in the nuclear medicine field from different regions of the world; and relevant literature.

RESULTS

Developing radioisotope and radiopharmaceutical production program and installing corresponding infrastructure requires significant investments, both man-power and financial. Support already exists to help developing countries establish their medical radioisotope production installations from several organizations, such as IAEA.

CONCLUSION

This work clearly shows that access to life-saving radioisotopes and the geographical distribution of corresponding infrastructure is highly unbalanced. Technology transfer is important as it not only immediately benefits patients, but also provides employment, economic activity and general prosperity in the region to where the technology transfer is implemented.

Monitoring treatment responses in patients with pulmonary TB using serial lung gallium-67 scintigraphy

OBJECTIVE

Gallium-67 scintigraphy is more sensitive than chest radiography in a single concurrent detection of pulmonary tuberculosis (TB). As for inflammation, the intensity of pulmonary uptake of 67Ga citrate theoretically is a function of the inflammation level in the lung. To maximize clinical applicability of 67Ga scintigraphy in the evaluation of pulmonary TB, we prospectively assessed serial qualitative associations between intensity of the uptake of 67Ga citrate and the severity of lung inflammation, reflected by the burden of Mycobacterium tuberculosis in the sputum of patients undergoing anti-TB chemotherapy.

SUBJECTS AND METHODS

Each enrolled patient had chest radiographic, microbiologic, 67Ga imaging, and semiquantitation of sputum acid-fast bacillus (AFB) assessments before and at the third and sixth months after receiving anti-TB chemotherapy. The burden of pulmonary M. tuberculosis (presumably, in proportion to the semiquantitation of AFB in sputum) and the intensity of 67Ga citrate uptake in the lung at each synchronized assessment were regarded as a paired variable. Odds ratios were obtained from odds (derived using generalized estimating equations) in favor of higher pulmonary 67Ga uptake in differing scores of semiquantitation of sputum AFB. Linear trend for pulmonary 67Ga citrate uptake corresponding to varied pulmonary M. tuberculosis burdens was assessed using contrast analysis of their odds ratios.

RESULTS

Thirty patients (24 men and six women) with pulmonary TB were enrolled. Eighty-six paired semiquantitations of sputum AFB-67Ga-scintigraphic studies were collected. Twenty-six patients were cured of their pulmonary TB. The pulmonary 67Ga uptake increased in proportion to the higher score of semiquantitation of sputum AFB (p = 0.009, for trend).

CONCLUSION

In patients with pulmonary TB, the higher the burden of M. tuberculosis in the lung, the higher the intensity of pulmonary 67Ga citrate uptake. Serial 67Ga-scintigraphy examinations are helpful in evaluations of the effectiveness of anti-TB therapy when assessments based on chest radiography are difficult.

Gallium and other agents in diseases of the lung

The use of gallium for pulmonary diseases is hampered by its relative lack of specificity, typical 1- to 3-day delay between injection and imaging time, and suboptimal imaging characteristics. Other nuclear and nonnuclear imaging modalities, such as (18)F-fluorodeoxyglucose positron emission tomography (PET) and high-resolution chest computed tomography, have replaced gallium in many clinical algorithms. Yet gallium and other radiotracers, such as thallium, sestamibi, and labeled white blood cells, are useful in many specific clinical situations involving lymphoma and other neoplasias, inflammatory processes such as sarcoid and interstitial pneumonia, tuberculosis and other infections, and the acquired immune deficiency syndrome. Gallium and some of the other single-photon agents still have value in establishing a diagnosis, assessing the location and extent of disease, differentiating active disease from chronic scarring, guiding potential biopsy, and determining recurrence and response to therapy in patients with certain lung diseases, particularly when access to PET imaging is not available.

Differential uptake of TI-201 by small-cell lung cancer in a patient with pneumoconiosis-related pulmonary nodules

A 68-year-old man with pneumoconiosis was thought to have small-cell lung cancer based on the results of a biopsy of a bone tumor. Three pulmonary nodules were observed on a chest radiograph. Compared with a chest radiograph taken 4 months earlier, one of the nodules had grown. It was difficult to differentiate this nodule from pneumoconiosis-related benign pulmonary nodules from the appearance on the chest radiograph and CT. Ga-67 scintigraphy and TI-201 lung SPECT were performed to characterize these nodules. TI-201 SPECT showed differential high uptake in the enlarged nodule, whereas Ga-67 scintigraphy showed equally intense uptake in all these nodules. Transbronchial biopsy of the nodule that showed high TI-201 uptake revealed cancer cell nests against a background of interstitial fibrosis. The pathologic diagnosis was small-cell lung cancer that had developed in lung scar tissue. This case suggests the utility of TI-201 in scintigraphic assessments of pneumoconiosis-related pulmonary nodules when lung cancer is suspected.

Comparison of thallium-201 and gallium-67 citrate scintigraphy in the diagnosis of pulmonary disease

Gallium is presently used in the diagnosis of inflammatory, granulomatous, and neoplastic lung disease despite its many logistical problems. In contrast, thallium-201 scintigraphy, which was initially developed for myocardial imaging, offers the principal advantage of immediate imaging and diagnosis although it had not been investigated previously for use in pulmonary disease. In this study, thallium and gallium were prospectively compared with each other for the diagnosis of a variety of lung diseases. The overall concordance rate was 75%. Thallium was found to be significantly more sensitive than gallium for the entire group studied (N = 51, p < 0.006). In a subset of patients in whom a firm diagnosis was established, thallium was also found to be more sensitive, 86% vs 64%. The greater sensitivity of thallium-201 and its several inherent advantages suggest that thallium-201 should replace gallium-67 citrate as the radioisotope of choice for nuclear imaging of the chest.

Radioimmunodetection of lung cancer with IMACIS-1, I-131 labeled monoclonal antibodies to CEA and CA19-9. Comparison of accumulations in irradiated and non-irradiated site

IMACIS-1 is a radiopharmaceutical containing a mixture of Iodine-131 labeled monoclonal antibodies to CEA and CA19-9. IMACIS-1 immunoscintigraphy was evaluated for tumor detection in 7 primary lung cancer and 2 metastatic lung cancer patients who received radiotherapy. No adverse side effects due to IMACIS-1 were observed in this study. Positive detection was achieved in 5 of 9 patients (55.6%). It was less, but nearly the same as the detection rate obtained with Gallium-67 citrate (67Ga-citrate) in these patients. There was no clear correlation between IMACIS-1 accumulation and the CEA or CA19-9 serum levels. The IMACIS-1 positive detection rate decreased in many of the irradiated lesions. We considered that the decreased number of tumor cells and changes in blood perfusion are some of the factors controlling accumulation in tumors.

Pneumocystis carinii infections in HIV-infected children

Since 1981, 1200 children with acquired immunodeficiency syndrome have been reported to the Centers for Disease Control. Among these children, Pneumocystis carinii has been the leading cause of serious morbidity and mortality. This review discusses the epidemiology, diagnosis, and treatment of P. carinii.

Pulmonary uptake in 67-gallium citrate scintigraphy-the 'negative heart' sign

Diffuse pulmonary uptake in 67-gallium citrate (67-Ga) scintigraphy occurs in a large number of neoplastic and inflammatory conditions. Discrimination between normal and abnormal 67-Ga uptake over the chest can be difficult and a simple visual method for identifying abnormal studies is described. A series of 39 gallium scintigrams was retrospectively reviewed by the authors and reported without knowledge of the patients' clinical condition. Subsequent clinical follow up was obtained to establish the accuracy of the scintigram interpretation. Comparison of pulmonary uptake with that over the cardiac area is recommended as a simple and reliable method of confirming that the level of pulmonary activity is abnormal. In highly abnormal cases the cardiac area is seen as a 'negative heart' image due to the considerably increased activity in the lungs. This sign is best seen with abnormal diffuse uptake but is also seen with abnormal focal uptake. Care must be taken, as the sign may be masked, if uptake over the cardiac area itself is increased.

Gallium-67 citrate imaging for the assessment of radiation pneumonitis

In order to evaluate its usefulness in the assessment of radiation pneumonitis, gallium-67 citrate (67Ga) imaging was performed before and after radiation therapy (RT) on 103 patients with lung cancer. In 23 patients with radiation pneumonitis detected radiographically, abnormal 67Ga uptake in sites other than tumors was found in all post-RT 67Ga lung images. Three patterns of uptake were found: (A), focal uptake corresponding to the RT field (n = 10); (B), diffuse uptake including the RT field (n = 4), and (C), diffuse uptake outside the RT field (n = 9). The area of 67Ga uptake was consistent with that of interstitial pneumonitis as revealed histopathologically in 7 cases. 67Ga uptake in pattern (C) was an indicator of poor prognosis for the patients with radiation pneumonitis. 67Ga uptake in the patients with reversible pneumonitis disappeared with steroid therapy. Sixteen (20%) of 80 asymptomatic patients, in whose chest radiographs there was no finding of radiation pneumonitis, showed transient 67Ga uptake. These were considered to occur in the subclinical radiation pneumonitis. These data suggest that 67Ga imaging is more sensitive than chest radiography in the detection of radiation pneumonitis and is useful in the assessment of the extent and clinical course of radiation pneumonitis.

Gallium-67 scanning in the clinical evaluation of human immunodeficiency virus infection: indications and limitations

This review, examines the indications for and limitations of gallium-67 (67Ga) scanning in the evaluation of patients infected with human immunodeficiency virus (HIV). The imaging protocol, as well as the normal biodistribution of 67Ga and its normal variants are discussed. The diagnostic significance of the different scintigraphic patterns that are found in acquired immune deficiency syndrome (AIDS) or AIDS-related complex (ARC) patients is reviewed. The use of 67Ga scintigraphy for measurement of the effectiveness of treatment in this patient population is also discussed, as is the likelihood that this examination could be used as a prognostic indicator in the future.

Thoracic imaging with gallium-67

In the past, gallium-67 imaging has undergone several ups and downs related to its clinical importance. After a period of initial enthusiasm, its role and indications are now established. At present, there are two fields of clinical interest for ⁶⁷Ga-imaging: (1) mediastinal staging in bronchogenic carcinoma and the staging of malignant lymphoma; (2) assessment of activity in interstitial lung diseases, especially sarcoidosis and inflammatory lung disorders. The advantage of ⁶⁷Ga-imaging is that it is highly sensitive for the detection of neoplastic and inflammatory processes, independent of anatomical barriers. Particularly with the challenge of AIDS, ⁶⁷Ga-imaging will gain increasing importance in the future. The low specificity of gallium for detecting underlying disorders precludes its use as a primary diagnostic tool. Therefore, and because of the cost and radiation load, the indications for application will have to be selected very carefully.

The role of nuclear medicine in pulmonary neoplastic processes

It has been demonstrated that the single most important factor in determining survival in patients with bronchogenic carcinoma is the extent of spread of metastasis from the primary lesion. This explains the extensive efforts in developing accurate staging tests for pulmonary tumors, both primary and metastatic, with special emphasis on the determination of pulmonary hilar and mediastinal spread of disease. Continued improvements in nuclear medicine instrumentation along with the development of tumor specific radiopharmaceuticals, as well as agents that have the capability of tracking tumor viability, have changed the orientation of scintigraphic techniques in the evaluation of pulmonary neoplastic processes. Gallium scintigraphy is no longer considered as a primary imaging modality in the staging of pulmonary tumors, and in most institutions has been replaced by computed tomography (CT) for this purpose. It has been demonstrated that gallium, relative to other imaging modalities, is a sensitive indicator of hilar spread of tumor. However, because of the normally high background activity within the sternum and spine, mediastinal abnormalities are poorly detected. Since most pulmonary tumors metastasize via regional nodes to the pulmonary hilum and then to the mediastinum, the high sensitivity for the detection of pulmonary hilar abnormalities and the high specificity for mediastinal lesion detection suggest that gallium scintigraphy is a valuable adjunctive test when used appropriately. Thallium 201 as a tumor agent is being studied by several institutions. Preliminary results indicate a high degree of sensitivity for the detection of pulmonary hilar and mediastinal lesions and there are early indications that thallium is a promising agent to evaluate tumor viability. With the development of new generation monoclonal antibodies, the prospects for highly sensitive and specific agents for detecting hilar and mediastinal spread of tumor is extremely encouraging. CT and NMR have made major contributions to the noninvasive workup of patients with bronchogenic carcinoma. Neither modality has been demonstrated to be accurate enough to adequately evaluate this patient population. Thus, there is a critical need for new noninvasive tests that will accurately assess the status of the patient so that appropriate therapy can be instituted.

Radiologic evaluation of the mediastinum

New imaging techniques have had a major impact on radiologic evaluation of the mediastinum. Computed tomography has led the way in defining internal anatomy noninvasively. Ultrasound plays a small but well-defined role in the evaluation of certain mediastinal masses. Digital vascular imaging has, in certain instances, replaced conventional angiography, though it seems unlikely to render conventional angiography obsolete. Other modalities such as magnetic resonance imaging are being applied and promise to become even more important in the near future. Finally, mediastinal sampling by needle biopsy under radiologic guidance has been shown to be a reliable technique when appropriately utilized.

Contribution of radionuclide imaging to radiation oncology

Radionuclide imaging has been helpful to oncologists in the initial evaluation and follow-up of patients with primary and metastatic disease. With the introduction of ultrasound and computed tomography, there has been some reduction in the number of radionuclide imaging procedures. These imaging modalities should be used to complement one another. With the introduction of single-photon emission computed tomography in clinical nuclear medicine, there will be a significant improvement in the sensitivity, accuracy, and quantitative ability to detect abnormal lesions. There are intensive efforts in the development of tumor imaging using new agents. Specific antibodies for surface tumor antigens can be labeled with radioisotopes and used as tools for screening primary tumors and metastatic lesions. Therefore, for the present, radionuclide imaging will continue to contribute to clinical oncology.

Pre-operative mediastinal evaluation in primary bronchial carcinoma--a review of staging investigations

A review of staging investigations in the preoperative evaluation of mediastinal involvement in primary bronchial carcinoma is presented. The following conclusions are offered as guidelines for the use of mediastinal staging procedures in clinical practice: Surgical staging methods have the over-riding advantage of superior specificity over indirect imaging techniques. Where 67Ga-imaging or CT scanning are not available, routine pre-operative mediastinoscopy or, when appropriate, mediastinotomy will identify most patients with non-resectable disease but this approach entails a high proportion of true negative examinations. Radioisotope ventilation and perfusion lung imaging has no place in the pre-operative staging of lung cancer. Where the techniques are available, 67Ga-imaging and CT scanning have a use in selecting patients for mediastinal exploration. A negative mediastinal 67Ga scan or a negative CT examination suggest that mediastinal exploration will be unrewarding in the vast majority of cases and may be omitted prior to thoracotomy. A positive mediastinal 67Ga scan or the demonstration of abnormal mediastinal nodes by CT is an indication for mediastinal exploration which, if negative should be followed by thoracotomy.

Gallium-67 in the evaluation of sarcoidosis: correlations with serum angiotensin-converting enzyme and bronchoalveolar lavage

Gallium-67 (67Ga) scanning was assessed for its usefulness in the evaluation and follow-up of 54 patients with sarcoidosis, both treated and untreated. Scans were repeated in 23 subjects. Serum levels of angiotensin-converting enzyme (ACE) were determined concurrently in all 54 patients and bronchoalveolar lavage was performed in 29 patients. Gallium-67 scan was effective in the detection and assessment of lesions not revealed by traditional methods of investigation, particularly those affecting the mediastinum, spleen, and salivary glands. The scan also enabled fibrotic lesions, which do not show uptake, to be distinguished from granulomatous lesions, which do--an advantage of prognostic interest particularly in patients with pulmonary lesions. Another merit of 67Ga scanning was that it offered a means of following disease progression in each site. In patients showing spontaneous clearing of disease or receiving treatment the scintigraphic method was more sensitive than serum ACE determination. Scan findings showed a rough correlation with serum ACE but not with bronchoalveolar lavage findings. This suggests that the three markers probably reflect different stages of the granulomatous process. On the strength of this study the indications for gallium scanning in sarcoid patients can be defined more clearly than has previously been possible.