[en] Six patients with a typical Mac Leod syndrom have been studied. The local pulmonary ventilation was measured by means of xenon-133 and the local pulmonary circulation by means of albumin microspheres labelled with technetium-99m. The matrix of ventilation indexes, which measured the local respiratory flow during the first inspiration, demonstrated a severe decrease of ventilation in the whole diseased lung. At the end of the 'wash in' period, the scintigraphic image was almost normal; this fact demonstrated the existence of a normal alveolar volume. During the 'wash out' period, a gas trapping was noted, corresponding to the decrease of aerial flow observed during the first breath. The circulation scintigraphies showed in all cases a dramatic hypovascularisation of the diseased lung. These findings pictured the syndrom of the 'well aerated and poorly ventilated lung' with partial suppression of the circulation secundary to multiple distal bronchial stenosis. Identical scintigraphic findings were found in four cases of bronchial carcinoma with a partial stenosis of the stem bronchus

[en] Gallium-67 citrate is known to localize within inflammatory sites. Gallium-67 scanning is used for the evaluation of lung inflammation (i.e. alveolitis) during interstitial lung diseases. We investigated 27 patients with cryptogenetic fibrosing alveolitis (n=17) and hypersensitivity pneumonitis (n=10) using gallium-67 lung scanning and lung function tests (forced vital capacity, diffusing capacity, resting and exercise blood gases). Investigations were performed before and after one year of methylprednisolone treatment. None of eight healthy volunteers had any abnormal gallium-67 uptake. In all patients with cryptogenetic fibrosing alveolitis and initial abnormal gallium-67 uptake was observed (mean fixation index: 163±18). In addition, analysis of lung function tests a year after initial evaluation showed that unchanged or improving patients presented initially with a lower gallium-67 index than patients with evidence of deterioration (163.9±23.7 vs 251.0±23.3.; p<0.01). Similarly, among patients with hypersensitivity pneumonitis the index was lower in unchanged or improving patients than in those with deterioration (74.0±22 vs 226.7±4.9; p<0.05). Thus gallium-67 scanning is useful in the management of cryptogenetic fibrosing alveolitis and hypersensitivity pneumonitis. (author)

[en] A first approach to the medical use of oxygen 15 in the form of O₂, then CO and CO₂, was to measure the diffusion capacity of oxygen. The production of oxygen 15 from nitrogen 14 is described first. Where its use in vivo is concerned, two experimental techniques were adopted: the single breath method and that of the single breath after breathing for 30 seconds in a closed circuit. The first results are reported

[en] Abnormalities of pulmonary diffusion mainly affect the oxygen diffusion which is 20 times less soluble than CO₂. In practice, however, O₂ diffusion cannot be measured and diffusion is measured by determining the diffusion capacity of CO (DLCO). The use of ¹⁵O for directly measuring the pulmonary diffusion of oxygen is described. Oxygen 15 is produced by the ¹⁴N(d,n)¹⁵O reaction, using a gaseous target 95.5% N₂ and 4.5% O₂. The gas is then passed over platinum foil and copper at 850⁰ to remove any O₃ or oxides of nitrogen. The technique used to determine ¹⁵O diffusion capacity is similar to that used to determine DLCO. ¹⁵O is administered in a single breath, followed by 10 seconds of breath holding. Before the administration of ¹⁵O, the subject is connected to a closed circuit spirometer containing only 4.5% O₂, and takes ten normal breaths in order to lower the alveolar PO₂ to values approximating the pulmonary arterial PO₂. In each subject, the DLCO is also determined and alveolar volume is measured using the helium dilution technique. The results are given per unit of alveolar volume (DLO₂/Vsub(A)). The values of DLCO/Vsub(A) in control subjects are compared

[en] Short communication

[en] Radiation is often necessary after pneumonectomy, either immediately or due to local cancer recurrence. High radiation doses represent a challenge due to the limited tolerance of the necessity of preserving and protecting the remaining lung parenchyma. The use of CT scan based-treatment planning allows delivery of high radiation doses. To evaluate the radiation tolerance of the lung after high radiation dose, we compared pulmonary function tests performed before surgery and after radiation therapy. Ten male patients (mean age, 56 years old; age range, 45-73) were irradiated after pneumonectomy for lung cancer. All patients had a CT scan-based treatment planning. The mean radiation dose was 56 Gy (45-66 Gy) delivered with a linear accelerator and multiple complex fields. Two or more sets of pulmonary function tests were available (before surgery and 2 to 6 months after radiation). No patient developed clinical radiation pneumonitis and most of the patients had a minimal para-mediastinal fibrosis at CT scan. Postirradiation pulmonary lung tests were compared to the theoretical values of the estimated defect observed after pneumonectomy. No significant decrease in forced expiratory volume in 1s/inspiratory vital capacity (FEV1/IVC) was observed in ten evaluable patients; the observed values were comparable to those expected after pneumonectomy without irradiation (FEV1/IVC: 61 to 100%), showing that irradiation did not alter pulmonary function. Computerized tomography-based treatment planning and the use of complex beam positioning allowed optimal lung parenchymal preservation. Through this procedure, high doses of radiation can be delivered to the mediastinum and bed tumor. Comparison of pulmonary function tests performed before surgery and after radiation showed no alteration of lung function, even after high doses. Optimal tools required for the evaluation of radiation on lung parenchyma are still to be defined. (authors)