Detection of alveolar epithelial injury by<Superscript>99m</Superscript>Tc-DTPA radioaerosol inhalation lung scan following blunt chest trauma

DTPA clearance rate is a reliable index of alveolar epithelial permeability, and is a highly sensitive marker of pulmonary epithelial damage, even of mild degree. In this study, 99mTc-DTPA aerosol inhalation scintigraphy was used to assesss the pulmonary epithelial membrane permeability and to investigate the possible application of this permeability value as an indicator of early alveolar or interstitial changes in patients with blunt chest trauma. A total of 26 patients was chest trauma (4 female, 22 male, 31-80 yrs, mean age; 53+/-13 yrs) who were referred to the emergency department in our hospital participated in this tsudy. Technetium-99m diethylene triamine pentaacetic acid (DTPA) aerosol inhalation scintigraphy was performed on the first and thirtieth days after trauma. Clearance half times (T1/2) were calculated by placing a mono-exponential fit on the curves. Penetration index (PI) was calculated on the first-minute image. On the first day, mean T1/2 value of the whole lung was 63+/-19 minutes (min), and thirtieth day mean T1/2 value was 67+/-21 min. On the first day, mean PI values of the lung and 30th day mean PI value were 0.60+/-0.05, and 0.63+/-0.05, respectively. Significant changes were observed in radioaerosol clearance and penetration indices. Following chest trauma, clearance of 99mTc-DTPA increased owing to breakdown of the alveolar-capillary barrier. This increase in the epithelial permeability of the lung appears to be an early manifestation of lung disease that may lead to efficient therapy in the early phase.     

Impaired lung epithelial permeability in hepatitis C virus antibody positive patients detected by 99mTc-DTPA aerosol scintigraphy

Chronic hepatitis C virus (HCV) infection has been recently identified as an aetiological agent in idiopathic pulmonary fibrosis. The present study was designed to determine the pulmonary clearance rate of 99mTc-diethylenetriaminepentaacetic acid (99mTc-DTPA) in asymptomatic HCV antibody positive (HCV Ab+) patients and the role of 99mTc-DTPA aerosol scintigraphy in the early detection of lung involvement. Twenty-six non-smoker HCV Ab+ and HCV-RNA (+) patients (20 female, six male; aged 43+/-11 years), with no clinical pulmonary symptoms, and normal radiological findings, were studied. Thirty-one healthy non-smoker volunteers (24 female, seven male; aged 40+/-10 years) were taken as a control group. 99mTc-DTPA aerosol inhalation scintigraphy and pulmonary function tests were performed in all patients and in controls. On the basis of the scintigrams the percentage decline in activity per minute (Kep) was evaluated, which represented an accurate parameter of lung membrane permeability. The mean Kep values of healthy controls (0.78+/-0.13 for left lung, 0.79+/-0.14 for right lung) were significantly lower than HCV Ab+ patients (1.10+/-0.31 for left lung, 1.11+/-0.34 for right lung, P<0.001). But no significant change was observed in PFT (P>0.05). We conclude that subclinical alveolitis and/or interstitial lung disease may be present in patients with HCV Ab+, since it is known that an increase in the epithelial permeability of the lung is an early manifestation of interstitial disease.     

Pulmonary clearance of 99mTc-DTPA aerosol in patients with progressive systemic scleroderma]

Alveolar epithelial permeability was assessed in 32 patients with progressive systemic scleroderma (PSS), using 99mTc-DTPA aerosol. Immediately after the inhalation of 99mTc-DTPA aerosol for 3 to 6 minutes under normal tidal breathing, lung was imaged sequentially for 30 minutes from the posterior by a gamma camera and exponential fitting was processed on the time activity curve. T1/2 (min) was used as a parameter for the evaluation of permeability of alveolar epithelium. Patients with collagen disease showed shorter T1/2 (T1/2 = 43.7 +/- 23.8 min) than the normal volunteers (T1/2 = 76.8 +/- 8.7 min). No significant difference was observed between patients with or without interstitial changes on the chest CT. Significant correlation was not observed between T1/2 and %VC or %DLco. In 8 cases, studies were repeated in the interval of 3 to 19 months. Improvement of T1/2 was seen in 4 cases, independent of CT findings. These results suggest that 99mTc-DTPA aerosol clearance study provides information independent from other lung examinations, and may be useful for the assessment of lung interstitial changes in patients with PSS.     

Technetium-99m DTPA inhalation scintigraphy in patients treated with fluoxetine and maprotiline: preliminary results

Drug-metabolising enzymatic activities have been detected in tracheobronchiolar, bronchiolar and alveolar regions in the lungs. Induction of phospholipidosis by amine drugs such as clorphentermine has also been shown. This study aimed to investigate the effect of fluoxetine and maprotiline, which contain amine groups in their structure, on pulmonary epithelial membrane permeability. Twenty-seven patients (mean age 36+/-12 years) with various psychiatric problems, of whom 17 were treated with fluoxetine and 10 with maprotiline, were included in this study. Technetium-99m diethylene triamine penta-acetic acid (DTPA) aerosol inhalation scintigraphy was performed before and after 4-6 weeks of therapy. Following the inhalation of 1480 MBq 99mTc-DTPA for 3 min, lung images in a 64x64 matrix were obtained every minute for 30 min. Regions of interest were drawn around the periphery of the lungs and on the major airways. Clearance half-times (T 1/2) were calculated by placing a mono-exponential fit on the curves. Penetration index (PI) was calculated on the first-minute image. There was no difference between the clearance rates of 99mTc-DTPA before and after therapy for either the fluoxetine or the maprotiline group. After therapy, a significant decrease in PI was found in patients treated with fluoxetine (PI values before and after therapy: 0.53+/-0.03 and 0.49+/-0.05 respectively, P< or =0.05). This finding might have been due to the induction of increased synaptic serotonin (5-HT) by fluoxetine, which acts by inhibiting the re-uptake of 5-HT on presynaptic membranes. Bronchoconstriction of small and medium airways may be caused by direct and indirect effects of 5-HT on smooth muscle contraction.     

Alveolar epithelial permeability in patients with primary spontaneous pneumothorax as determined by Tc-99m DTPA aerosol scintigraphy

PURPOSE: Primary spontaneous pneumothorax (PSP) occurs subsequent to a disruption in the continuity of visceral pleura and escape of air into the pleural space. The cause of PSP is most often the rupture of subpleural blebs or bullae. It is usually difficult to detect evidence of pulmonary pathology. The purposes of the present study were (1) to investigate the changes of pulmonary alveolar epithelial permeability in patients with PSP as determined by Tc-99m DTPA aerosol lung scintigraphy, (2) to assess whether or not some differences exist between apical and basal parts of the lungs, and (3) to determine the relationship between the clearance rate of Tc-99m DTPA and the PFT results, the recurrence rate of PSP, and the percentage of pneumothorax in affected lung. MATERIAL AND METHODS: Thirteen PSP patients (two females, 11 males; mean age 32.5 +/- 11.8 years) with normal chest X-ray were studied. Thirteen healthy non-smoking volunteers (1 female, 12 males; mean age, 35.8 +/- 10 years) were selected as a control group. Tc-99m DTPA aerosol lung scintigraphy and PFT were performed in all patients and controls. Clearance rates (%/min) of Tc-99m DTPA aerosol in right and left lung field, and apical and basal parts of each lung were calculated from dynamic images for 15 min. RESULTS: There was no significant difference (p > 0.05) between patients and controls, or between apical and basal parts of each lung. No correlation was found between the clearance rate of Tc-99m DTPA and PFT results, the recurrence rate of PSP, or the percentage of pneumothorax. CONCLUSION: This study demonstrates that pulmonary epithelial permeability is not altered in PSP patients; the clearance rate of Tc-99m DTPA shows no difference between apical and basal parts of each lung.     

Detection of alveolar epithelial injury by Tc-99m DTPA radioaerosol inhalation lung scan in rheumatoid arthritis patients

Rheumatoid arthritis (RA) is a systemic autoimmune disorder primarily involving the joints. Lung alterations in RA may be primary or secondary to pharmacological treatments and may involve the alveoli, interstitium, airways and/or pleura. Technetium-99m diethylenetriaminepentaacetic acid (Tc-99m DTPA) aerosol inhalation scintigraphy is a sensitive and noninvasive test commonly employed to assess pulmonary epithelial membrane permeability. The purpose of the this study was a) to investigate the changes of pulmonary alveolar epithelial permeability in patients with RA, b) to determine the relationship between the clearance rate of Tc-99m DTPA and pulmonary function test (PFT) results, and c) to determine the relationship between the clearance rete of Tc-99m DTPA and clinical parameters of disease. Twenty-five patients with RA but without lung alterations were included in the study. The patients were 22 females, and 3 males; mean age 53.6 +/- 8.7 years. Technetium-99m DTPA aerosol inhalation scintigraphy was performed on the study and healthy control groups. Clearance half times (T1/2) were calculated by placing a mono-exponential fit on the curves. Penetration index (PI) was calculated on the first-minute image. There were no significant differences in the mean T1/2 or mean PI values between the RA patients and control subjects. No correlation was found between the mean T1/2 values of Tc-99m DTPA clearance and activity of RA, clinical values, or the spirometric measurements except FEV1/FVC and functional status in RA patients (p = 0.02, p = 0.01, respectively). However, a weak correlation was found between duration of disease and T1/2 values of Tc-99m DTPA clearance (p = 0.006). PI values tended to correlate with FEF25-75, although, this was not statistically significant (p = 0.057). This study shows that no changes occur in alveolar-capillary permeability in RA patients without lung alterations.     

Evaluation of the alveolar-capillary membrane permeability using 99mTc-HMPAO aerosols in severe diffuse interstitial fibrosis

Local information on permeability of the alveolar-capillary barrier (PACB) can be ascertained by parametric images, after inhalation of radioarosols and computer processing. Our aim is to compare the results of 99mTc-HMPAO aerosols on PACB studies with those of 99mTc-DTPA aerosols, a standard technique. We compared the two techniques in separate samples: normal controls and patients with severe lung interstitial pathologies. Perfusion studies using 99mTc-MAA have also been performed in all patients. The aerosols were produced using ultrasound and lowered surface tension solution of 99mTc-HMPAO and 99mTc-DTPA. The time-activity curves (TACs) for every pixel on the lung area were used to calculate the half-disappearance times (T1/2). Parametric images were then generated with those times. The comparison of the results obtained with 99mTc-HMPAO and 99mTc-DTPA aerosols suggests that the first ones are more specific for local alterations of the lung epithelial transport in the pathologies studied. This method distinguishes between permeability deficiency due to local perfusion decrease and ACB deterioration.     

Urine excretion of inhaled technetium-99m-DTPA: an alternative method to assess lung epithelial transport

Technetium-99m DTPA clearance (99mTc-DTPA) clearance measured by a gamma camera or a scintillation probe not only reflects epithelial transport, but is also influenced by an unknown amount of mucociliary clearance depending on particle size and aerosol deposition. This is confirmed by factor analysis of dynamic inhalation studies. Assessment of epithelial absorption by urinary excretion of inhaled 99mTc-DTPA is largely independent of aerosol lung deposition. Twenty-four-hour excretion reflects the amount of aerosol cleared by absorption, while two-hour excretion is a quantitative measure of the aerosol absorption rate from the epithelium into blood. Urinary 99mTc-DTPA excretion of two aerosols with different particle size correlated significantly (p less than 0.001) with analysis of lung clearance curves. A very similar regression in the form of a cumulative exponential function was found with both aerosols. Two-hour urine values of nonsmokers differed significantly from those of smokers or patients with active interstitial or infectious lung disease. This alternative procedure is suited as a bedside test and holds promise for patient monitoring and follow-up.     

Dynamic pulmonary scintigraphy with Tc99m radioaerosol for the evaluation of the permeability of the alveolo-capillary barrier

Pulmonary clearance of small droplet 99mTc-DTPA radioaerosol was studied in 100 patients (12 normal subjects, N; 10 asymptomatic healthy smokers, FA; 31 patients with interstitial lung diseases, IP; 47 patients with chronic obstructive lung disease, BPCO). The first seven minutes of clearance were described with the function At = Ao*exp (-K*t) and the time constant K was considered representative of the 99mTc-DTPA clearance rate and hence of the alveolar-capillary barrier permeability. Groups FA, IP and BPCO showed a significant (p less than 0.05) or a highly significant (p less than 0.01) increase in permeability when compared to group N. No correlation was found between permeability and bronchial obstruction tests. The following conclusions were drawn: --99mTc-DTPA dynamic lung scanning is an easy, non-invasive method to assess derangements of alveolar-capillary barrier permeability secondary to epithelial damage; --permeability increase is a very early effect of cigarette smoke damage to the epithelium; --other mechanisms of epithelial injury are present in diffuse lung disease; --while the clinical role of this new pathophysiological test is not yet clear, it is likely that it may become a very early marker of pulmonary epithelial damage in diffuse lung disease.     

Detection of acute inhalation injury in fire victims by means of technetium-99m DTPA radioaerosol inhalation lung scintigraphy

Mortality and morbidity in fire victims are largely a function of injury due to heat and smoke. While the degree and area of burn together constitute a reliable numerical measure of cutaneous injury due to heat, as yet no satisfactory measure of inhalation injury has been developed. In this study, we employed technetium-99m diethylene triamine penta-acetic acid (DTPA) radioaerosol lung scintigraphy (inhalation scan) to evaluate acute inhalation injury in fire victims. Ten normal controls and 17 survivors from a fire accident were enrolled in the study. All patients suffered from respiratory symptoms (dyspnoea and/or cough with sputum).^99mTc-DTPA aerosol inhalation lung scintigraphy was performed in all subjects, using a commercial lung aerosol delivery unit. The degree of lung damage was presented as the clearance rate (k; %/min) calculated from the time-activity curve over the right lungs. In addition, the distribution pattern of the radioactivity in the lungs was evaluated and classified into two groups: homogeneous distribution and inhomogeneous distribution. A plain chest radiograph (CxR) and pulmonary function test (PFT) were performed in the same group of patients. The results showed that 6/17 (35.3%) opatients had inhomogeneous distribution of radioactivity in their inhalation scans, and 11/17 (64,7%) had homogeneous scans. Five of the six patients with inhomogeneous scans were admitted for further management, and all patients with homogeneous scans were discharged from the emergency department and needed no further intensive care. The clearance rates of the right lung were 0.73%±0.13%/min from normal controls and 1.54%±0.58%/min for fire victims. The difference was significant, with aP value of less than 0.01. Using a cut-off value of 0.9%/min (all normal subjects were below 0.9%/min) 14 (82.4%) patients had abnormal clearance rates of^99mTc-DTPA from the lung. In contrast, only three (17.6%) patients had abnormal CxR and three (17.6%) had abnormal PFTs. We conclude that (1) conventional CxR and PFT are not good modalities for evaluating inhalation injury in fire victims because of their low sensitivity, and (2)^99mTc-DTPA radioaerosol inhalation scintigraphy can provide an objective evaluation of inhalation injury during a fire accident and may be useful in therapeutic decision-making and disease monitoring.     

Evaluation of the effects of toluene inhalation on alveolar epithelial permeability by 99mTc-DTPA inhalation scintigraphy in automobile painters

BACKGROUND: The main component of paint thinner used in industry is toluene diisocyanate (TDI) which can cause occupational asthma in 5-10% of exposed workers. AIM: To investigate the effect of TDI on 99mTc clearance rate of alveolar epithelium and on pulmonary function tests (PFT) in automobile painters, and to determine the relationship between 99mTc-DTPA radioaerosol lung scintigraphy and serum levels of antioxidant enzymes and metalloproteinases (MMPs) of automobile painters. METHODS: Twenty-eight automobile painters and 13 control subjects were included in the study. 99mTc-DTPA aerosol inhalation scintigraphy and PFT were administered to all subjects. Clearance half-time (T1/2) and penetration index (PI) on the first-minute image after 99mTc-DTPA scintigraphy were calculated. Blood levels of MDA, antioxidant enzymes and metalloproteinases were measured. RESULTS: The mean T1/2 values of automobile painters were longer in both smoker and non-smoker subjects, but the difference was not significant (P>0.05). Although the PFT values decreased in automobile painters, there was no significant difference between each group. Any correlation between spirometric measurements and T1/2 or PI values in non-smoking automobile painters was not detected. Negative correlation among mean T1/2 value and FVC% and FEV1% in smoking automobile painters, and positive correlation between mean T1/2 value and MMP-9, GSH-Px levels in non-smoking automobile painters were detected. CONCLUSION: Our results suggested that the clearance of 99mTc-DTPA from the lungs of automobile painters was slower than in the control group, but the difference is not statistically significant. This data also supports the observation that TDI occasionally stimulates bronchial changes rather than alveolar changes in automobile painters.     

Pulmonary clearance of technetium 99m diethylene triamine penta-acetic acid aerosol in patients with amiodarone pneumonitis

Amiodarone pneumonitis is a serious complication that may lead to fatal lung fibrosis. In an attempt to diagnose this condition as early as possible, the technetium-99m-labelled diethylene triamine penta-acetic acid (99mTc-DTPA) aerosol washout rates of 10 non-smoking normal volunteers (group 1), 10 non-smoking patients on a long-term amiodarone regimen with dilated cardiomyopathy but no congestive heart failure (group II) and 10 patients with amiodarone pneumonitis (group III) were compared. Spirometric measurements, as percentage predicted, were higher in group I than in group III (P less than 0.05). The global mean effective half-lives of 99mTc-DTPA aerosol for both lungs together in minutes were 65 +/- 14, 55 +/- 16 and 27 +/- 4 for groups I, II and III, respectively. Group III values were significantly lower than those of groups I and II (P less than 0.05). Our results demonstrated that amiodarone pneumonitis alters the alveolar-capillary membrane permeability to hydrophilic molecules. The pulmonary clearance of 99mTc-DTPA aerosol is a useful test in the differentiation of patients on a long-term amiodarone regimen without side effects from patients with amiodarone pneumonitis. The test is rapid, easy to perform and has the potential for playing an important role in deciding which patients should discontinue therapy.     

Determining the influence of biocompatible oxygenators during cardiopulmonary bypass by 99m Tc-DTPA aerosol assessment of pulmonary permeability

Changes in pulmonary permeability provide a partial measure of the clinical impact of biocompatible oxygenator use during cardiopulmonary bypass surgery. Previous research has shown that the clearance rate of 99mTc-labelled diethylene triamine penta-acetic acid (99mTc-DTPA) aerosol from the lungs is increased following cardiopulmonary bypass, resulting from an increase in pulmonary permeability. The aerosol clearance rate has been shown to return to normal after a period of 7 days. A blind trial was set up to assess the clinical impact of a biocompatible, Trillium-coated oxygenator compared with a standard oxygenator. In a group of 25 patients 99mTc-DTPA aerosol studies were carried out prior to cardiopulmonary bypass surgery for mitral valve surgery. Repeat studies were undertaken 3-4 h and 24-28 h after surgery. Analysis of the rates of pulmonary clearance reproduced the trends seen in earlier research. There was however no statistically significant difference in the variation of serial clearance times between the groups of patients undergoing surgery using the Trillium-coated oxygenators and those using the standard oxygenators.     

Pulmonary inhalation scintigraphy using N-isopropyl-p-[123I]iodoamphetamine (123I-IMP) aerosol

N-isopropyl-p-[123I]iodoamphetamine (123I-IMP) is lipophilic substance and permeates through the alveolar epithelium via intracellular transport, whereas 99mTc-DTPA is water-soluble substance and permeates through the alveolar epithelium via paracellular transport. We performed inhalation lung imaging using 123I-IMP and 99mTc-DTPA in order to assess alveolar epithelial permeability in 4 patients with restrictive ventilatory impairment, and 5 volunteers including one smoker. The time-activity (T/A) curves of 123I-IMP were well fitted into two compartments, first and slow, by least-squares fit technique, in contrast to 99mTc-DTPA fitted well with one compartment. In 4 normal volunteers, the T/A curves of the lower pulmonary fields declined faster than those of other pulmonary fields. In 99mTc-DTPA studies, the Kep values of patients with restrictive ventilatory impairment (n = 4) were higher than those of normal volunteers (n = 4) (2.14 +/- 0.30 x 10(-4) vs 1.48 +/- 0.41 x 10(-4), p less than 0.005). On the other hand, in 123I-IMP studies, the Kep values of the patients were much lower than those of normal volunteers (6.79 +/- 0.55 x 10(-5) vs 1.52 +/- 0.45 x 10(-3), p less than 0.005).     

Technetium-99m DTPA inhalation scintigraphy in patients treated with fluoxetine and maprotiline: preliminary results

Drug-metabolising enzymatic activities have been detected in tracheobronchiolar, bronchiolar and alveolar regions in the lungs. Induction of phospholipidosis by amine drugs such as clorphentermine has also been shown. This study aimed to investigate the effect of fluoxetine and maprotiline, which contain amine groups in their structure, on pulmonary epithelial membrane permeability. Twenty-seven patients (mean age 36ᆠ years) with various psychiatric problems, of whom 17 were treated with fluoxetine and 10 with maprotiline, were included in this study. Technetium-99m diethylene triamine penta-acetic acid (DTPA) aerosol inhalation scintigraphy was performed before and after 4-6 weeks of therapy. Following the inhalation of 1480 MBq ^99mTc-DTPA for 3 min, lung images in a 64Ꮘ matrix were obtained every minute for 30 min. Regions of interest were drawn around the periphery of the lungs and on the major airways. Clearance half-times (T_1/2) were calculated by placing a mono-exponential fit on the curves. Penetration index (PI) was calculated on the first-minute image. There was no difference between the clearance rates of ^99mTc-DTPA before and after therapy for either the fluoxetine or the maprotiline group. After therapy, a significant decrease in PI was found in patients treated with fluoxetine (PI values before and after therapy: 0.53ǂ.03 and 0.49ǂ.05 respectively, PА.05). This finding might have been due to the induction of increased synaptic serotonin (5-HT) by fluoxetine, which acts by inhibiting the re-uptake of 5-HT on presynaptic membranes. Bronchoconstriction of small and medium airways may be caused by direct and indirect effects of 5-HT on smooth muscle contraction.     

Evaluation of alveolo-capillary permeability in thyrotoxicosis using Tc-99m DTPA aerosol scintigraphy

Surfactant secreted from type II pneumocytes plays an important role in alveolo-capillary permeability. In thyrotoxicosis, high levels of T3 receptors detected at these cells might affect the alveolo-capillary permeability due to increased serum thyroid hormone levels. The results by CO-diffusion capacity measurement in thyrotoxicosis are conflicting. Changes in alveolo-capillary membrane permeability resulting from thyrotoxicosis are not well established yet. This prompted us to investigate the alveolo-capillary permeability in thyrotoxic patients in comparison with CO-diffusing capacity. For this aim twenty-two non-smoking thyrotoxic patients (before treatment) and fifteen healthy voluntary controls underwent 99mTc-DTPA aerosol scintigraphy. CO-diffusing and pulmonary function tests were performed in all subjects. After ventilation of radiotracer through a nebulizer for 15 minutes, 30 dynamic images (1 frame/minute) were taken from both lungs. ROI's were drawn over both lung areas, and the time-activity curves were generated. Then clearance half time (CT1/2) for radioaerosol was obtained. CT1/2 of thyrotoxic patients did not differ from that of the controls: 77.9 +/- 25.9 min vs. 79.4 +/- 22.3 min; p > 0.05. Similar result was found for CO-diffusion parameters. Also there was no significant correlation between CT1/2 and CO-diffusion parameters. We concluded that in patients with thyrotoxicosis, the alveolo-capillary permeability is unaffected. Further experimental research is needed to establish the possible effects of thyroid hormones on alveolo-capillary membrane.     

99mTc-DTPA and 99mTc-rhenium sulfur aerosol compared as adjuncts to perfusion scintigraphy in patients with suspected pulmonary embolism

Two radiopharmaceuticals, 99mTc-DTPA (D) and 99mTc-rhenium sulfur (R), were evaluated with a nebulizer delivering submicronic particles. Seventy-seven patients were examined (42 D, 35 R). For all patients, the examination began with a ventilation study. Immediately after the last ventilation view, 99mTc MAA was injected. Aerosol performance was assessed in 37 D and 17 R. Nebulization yield was 8.98% for D and 9.31% for R. A lung clearance study was performed in 12 patients for D and in 12 different patients for R. The lung clearance was 0.22%/min for R and 2.35%/min for D. The quality of ventilation and the quantification of bronchial and gastric activity were evaluated; the difference between the two groups was not statistically significant. It may be concluded that radioaerosols allow good quality images to be obtained. The yield of the nebulizer is adequate, so that nebulization of 20 mCi delivers approximately 2 mCi of aerosol activity to the lung. When pulmonary embolism is being investigated, R, due to its slower lung clearance, would appear to be preferable to D for patients suspected of increased bronchoalveolar permeability, especially if the time between nebulization and recording is greater than 10 min.     

Effect of chemotherapy on pulmonary epithelial permeability in lung cancer

The aim of this study is to investigate the effect of one-course chemotherapy on the pulmonary epithelial permeability. Eighteen patients (18 male; mean age: 59+/-10 years) with lung cancer (11 non-small cell, 7 small cell) inhaled 40 mCi (1,480 MBq) (99m)Tc-diethylenetriaminepentaacetic acid (DTPA). Thirty images of 1-min duration were acquired from posterior projection. The first 7 min of the decay-corrected time activity curves were used to calculate lung clearance half-time. Clearance half-times of (99m)Tc-DTPA from the peripheral regions of the lungs were 42+/-19 min before and 56+/-34 min after chemotherapy (p=0.009); from the central regions, clearance half-times were 112+/-94 min before and 160+/-125 min after chemotherapy (p=0.005). This decrease in clearance rate might be related to decreasing mucociliary clearance rate due to the toxic effect of the chemotherapy regimen on cilia movement and/or mucus structure. (99m)Tc-DTPA radioaerosol study can be used to monitor the toxic effects of chemotherapy on the pulmonary epithelium and possibly on mucociliary function.     

131I治疗分化型甲状腺癌肺转移对肺功能的影响

目的探讨131I治疗分化型甲状腺癌肺转移对肺功能的影响.方法甲状腺癌肺转移患者58例,131I累积治疗剂量3.7～92.5 GBq,131I末次治疗后3个月行X线胸片、肺功能[肺活量(VC)、时间肺活量(FVC)、第1 s最大呼气量(FEV1)、最大通气量(MVV)]检测和99Tcm-DTPA气溶胶半清除时间测定.结果① 肺功能各指标在各累积剂量组之间差异无显著性(P>0.05);在性别组之间VC、FVC、FEV1差异无显著性(P>0.05),但MVV差异非常显著(P<0.01).②99Tcm-DTPA气溶胶半清除时间正常对照组(n=8)参考值为53.2±8.6.各组间比较差异均未见显著性(P>0.05).③1例43岁女性患者肺功能低下(其VC、FVC、FEV1和MVV分别为58.1%、58.1%、43.6%和37.2%),99Tcm-DTPA气溶胶半清除时间缩短(26.4 min),X线胸片示双肺纹多或粗,131I显像未见异常浓聚灶.该患者甲状腺乳头状癌肺转移12年,131I治疗8次,累积剂量51.8 GBq,不能排除肺纤维化.结论 131I治疗累积剂量对肺功能无显著影响.131I累积剂量>37 GBq者需警惕发生肺纤维化.结合X线胸片、肺功能和99Tcm-DTPA测定可综合评估甲状腺癌肺转移131I治疗后的肺损伤情况.     

Pulmonary clearance of 99mTc-HMPAO aerosol

The clearance rate of inhaled aerosols of a lipophilic substance, 99mTc-HMPAO (Hexamethyl propylene amine oxime) was studied and compared to that of hydrophilic substances in 6 normal volunteers and 18 patients with lung diseases. The subject in sitting position inhaled a single deep breath of 99mTc-HMPAO aerosols, and held his breath about 30 sec. Then he continued to breath aerosols again for about 3 min. Radioactivity rapidly falls down during breath holding, to about 60% of the peak value (fast phase), with T 1/2 of 3.75 +/- 2.22 sec in 6 normal volunteers. This rapid phase was not appeared in hydrophilic aerosols with 99mTc-DTPA and 99mTc-pertechnetate and in lipophilic aerosol with 123I-IMP aerosol. The clearance of residual activity of 99mTc-HMPAO was slow with T 1/2 of 17.4 +/- 4.0 min. The T 1/2 of 99mTc-DTPA, 99mTc-pertechnetate and 123I-IMP were 50.2 +/- 20.9 min, 11.4 +/- 4.3, and 62.5 +/- 20.8 min respectively. 99mTc-HMPAO may cross transcellularly using the whole alveolar surface. The clearance of aerosols in the fast phase is rapid and depend on the regional perfusion. On the other hand, hydrophilic aerosol pass by an intercellular pathway and the clearance will be diffusion limited. As conclusion, inhalation study of 99mTc-HMPAO might be a new method to evaluate perfusion following ventilation study.