Radionuclide angiography and ventilation/perfusion studies in two patients with systemic arterial supply to the basal segment of the left lung.

The findings of radionuclide studies in two adult men with systemic arterial supply to the basal segment of the left lung without sequestration are reported. Radionuclide angiography with Tc-99m human serum albumin-diethylenetriamine showed that the lung was perfused by the systemic circulation rather than by the pulmonary artery. Ventilation and perfusion scans with Xe-133 and Tc-99m MAA showed a V/Q mismatch in this area, suggesting the presence of normal bronchial communication without a pulmonary arterial supply. These results also suggest the presence of a left-to-left shunt in the well-ventilated lung in this area. MRI and conventional angiography showed an aberrant artery arising from the descending thoracic aorta, supplying the basal segment of the left lung without a pulmonary artery. In both patients, left lower lobectomy showed normal alveobronchial structures without sequestration. Radionuclide angiography and ventilation/perfusion imaging appear to be reliable noninvasive methods for diagnosing this rare anomaly with a left-to-left shunt.

[Characteristics and problems of flow cytometric nuclear DNA content analysis in lung cancer using bronchoscopically-obtained specimens].

Flow cytometric nuclear DNA content analysis was performed on 106 bronchoscopically-obtained specimens from 67 patients with primary lung cancer. Brushing, curettage and biopsy samples in which tumor cells were identified by microscopic examination were considered suitable for analysis. The incidence of DNA aneuploidy in small cell carcinoma (77.8%) was higher than that in any other histological type of lung cancer. Intratumoral heterogeneity was found to affect the detectability of DNA aneuploidy, suggesting that care must be taken to obtain adequate samples of tumor cells and to consider intratumoral heterogeneity. These results indicate that this method can be used for nuclear DNA content analysis not only in cases of resectable lung cancer but also for unresectable lung cancers and may provide useful biological information in the clinical management of all types of lung cancer.

Altered regional clearance of 99Tcm-DTPA in radiation pneumonitis.

99Tcm-diethylene triaminepenta-acetic acid (99Tcm-DTPA) lung scintigrams were investigated in 11 patients with radiation pneumonitis to assess the alteration of clearance of this small solute. Thirty minutes after the injection of 99Tcm-DTPA, all 11 patients showed abnormal accumulation. This uptake was seen in the areas with reduced 99Tcm-macroaggregated albumin activity. The curves of the lung/heart ratios obtained after 1 min after injection of 99Tcm-DTPA in areas showing abnormal accumulation were of three types. Comparison of the slope for the initial 5 min of the lung/heart curves between the abnormal accumulation sites and the contralateral non-irradiated lung revealed a significant difference. The uptake ratio (the mean counts of the last frame divided by initial peak count) was related to the degree of abnormal accumulation in the radiation pneumonitis. Moreover, study of rabbits with radiation pneumonitis revealed similar behaviour by 99Tcm-DTPA as observed clinically. This simple and rapid method may be useful in detecting and monitoring the altered regional kinetics of 99Tcm-DTPA in radiation pneumonitis.

Altered kinetics of 123I-IMP in irradiated rabbit lungs.

Radiation-induced alteration of intrapulmonary kinetics of 123I-IMP was investigated in 11 rabbits receiving a 50 Gy dose of radiation to one lung. In all 13 examinations of these rabbits, 3-17 weeks following radiation, the delayed images of 123I-IMP lung scintigrams showed abnormal accumulation in the irradiated lungs. The time-activity curves of the irradiated lung following injection of 123I-IMP had shallower downslopes of both the initial fast phase and the following slow phase than those of the non-irradiated lung. Finally the radioactivity of the irradiated lung exceeded that of the normal lung. The altered intrapulmonary kinetics of 123I-IMP in the irradiated lung was clearly confirmed. 99Tcm-MAA lung perfusion scintigrams showed reduced uptake in the irradiated lungs; the uptake decreased with time following radiation. Pulmonary arterial perfusion was considered to influence the distribution and kinetics of 123I-IMP, however, those of 123I-IMP did not reflect only the pulmonary arterial perfusion observed by 99Tcm-MAA scintigrams. Chest radiography and histological studies revealed a relatively slight change or injury of the irradiated lung in these rabbits. These results indicate that this agent could be useful in detecting and assessing early lung injury induced by radiation, and will give us pathological information in addition to lung perfusion in the peripheral area where the large 99Tcm-MAA molecule cannot reach.

[Experimental study on 123I-IMP kinetics in irradiated lung of rabbit].

Radiation-induced alteration of intra-pulmonary kinetics of 123I-IMP was investigated in 11 rabbits received a 50 Gy dose of radiation to the hemithorax. In all of these rabbits examined during 3-17 weeks following the irradiation, an abnormal accumulation was seen in the irradiated lung on the delayed image obtained 60 minutes after the injection of 123I-IMP. The time-activity curves in the irradiated lung following the injection had shallower downslopes of both the initial fast phase and the following slow phase than those of non-irradiated lung, and finally 123I-IMP uptake of the irradiated lung exceeded that of the normal lung. Chest radiographies all of 11 rabbits showed no abnormal shadow and histological studies in 6 of them revealed a relatively slight change or injury of the irradiated lung during 3-17 weeks. These results indicate that this agent may be useful for detecting and assessing relatively early and slight lung injury induced by irradiation.

Clinical and experimental studies on the mechanism of abnormal accumulation in lung scanning with 123I-IMP.

To investigate the intrapulmonary kinetics of N-isopropyl-p-I-123-iodoamphetamine (123I-IMP), lung scanning with 123I-IMP was performed in patients with various lung disorders. Compared with the normal lung field, abnormal accumulation of 123I-IMP was detected in all patients in delayed imaging performed 24 h after 123I-IMP injection. These sites were within areas of absent or reduced perfusion observed by pulmonary perfusion scanning using 99Tcm-macroaggregated albumin (99Tcm-MAA). A similar phenomenon was seen in additional experiments in rabbits with regional pulmonary arterial hypoperfusion resulting from a balloon catheter-induced bronchial occlusion. 123I-IMP accumulation in areas where 99Tcm-MAA images are absent or decreased may be explained by the ability of 123I-IMP to penetrate significantly narrowed microvascular beds with reduced perfusion. Our clinical and experimental results indicate that pulmonary arterial perfusion, particularly hypoperfusion, influence the pulmonary kinetics of 123I-IMP. This compound is a potentially useful non-particulate agent for the assessment of pulmonary arterial perfusion.

[The assessment of 99mTc-HMPAO tumor scintigraphy using VX-2 tumors in rabbits].

Tumor scintigraphy using 99mTc-hexamethyl-propyleneamine oxime (99mTc-HMPAO) was performed in VX-2 tumors implanted in the muscles of the lower limbs of rabbits to evaluate the possibility that this agent could be used to estimate the blood perfusion of the tumor. The distribution of 99mTc-HMPAO in the tumor immediately after the intravenous injection of this radiopharmaceutical exhibited almost the same distribution on the static image 1 hour after administration. Tumor time-activity curve for 99mTc-HMPAO revealed initial peak after the injection followed by fading of 99mTc-HMPAO activity and subsequent gradual decrease in activity over the next 1 hour. The ratio of 99mTc-HMPAO activity in the tumor to that in normal muscle tissue during this next 1 hour was high and independent of time. These findings indicate that static 99mTc-HMPAO scintigraphy can provide qualitative but not quantitative data useful in the estimation of tumor blood perfusion. Moreover, comparison of distribution of 99mTc-HMPAO on the static images and angiographic, histological findings also suggest that static 99mTc-HMPAO images accurately reflect tumor blood perfusion.

[Experimental study on the mechanism of the intrapulmonary kinetics of 123I-IMP in a balloon occluded bronchus in rabbits].

To investigate the mechanism of intrapulmonary kinetics of N-isopropyl-p-123I-iodoamphetamine (123I-IMP), we performed lung scanning with 123I-IMP in 13 rabbits in which a unilateral bronchus was occluded by a balloon catheter. In 9 rabbits, on the delayed distribution images, an abnormal accumulation of 123I-IMP was detected in the hypoperfusion area of the peripheral lung field of the occluded bronchus, which was detected on lung perfusion images with 99mTc-MAA. Comparison of early (a summation image during 20 seconds immediately after injection) and delayed (a summation image from 70 to 90 minutes after injection) distribution images confirmed that during this period, 123I-IMP accumulated in the area of reduced distribution of 123I-IMP. Moreover, at the site of abnormal accumulation, washout of 123I-IMP from the lung was delayed compared with that in the normal lung field. We find this experimental study is similar to the results in 63 clinical cases, which we have reported previously, and confirm that pulmonary arterial perfusion, especially hypoperfusion, influences the intrapulmonary kinetics of 123I-IMP.

Assessment of 99Tcm-HMPAO tumour scintigraphy using VX-2 tumours implanted in a lower limb muscle of rabbits.

Tumour scintigraphy using 99Tcm-hexamethylpropyleneamine oxime (99Tcm-HMPAO) was investigated in VX-2 tumours implanted in the muscles of the lower legs of rabbits to assess the feasibility of using this agent clinically for this procedure. On the time-activity curves for 99Tcm-HMPAO in the tumour, an initial peak and a subsequent decrease of radioactivity immediately after the initial peak were observed, while there was a slow, gradual decrease of activity over the next hour. The tumour/normal muscle ratio of HMPAO activity during this period was high and constant, and was independent of time. Comparison of the static images of 99Tcm-HMPAO with angiography and histological findings suggests that the tumour image of 99Tcm-HMPAO reflects tumour blood perfusion. These findings indicate that the distribution of 99Tcm-HMPAO on static images can provide a qualitative assessment of the perfusion of the tumour, despite the limitations of this tracer for quantifying tumour blood flow due to its early efflux from the tumour.

Clinical study of varicocele by sequential scrotal scintigraphy.

Sequential scrotal scintigraphy was used to study testicular blood flow in 122 patients with clinically diagnosed varicocele. The sensitivity of scrotal scintigraphy was 91.7% on the whole sequential images. The late-phase image was superior in sensitivity to that of the early-phase images. The difference in time between the arrival of radioactivity in the iliac artery and in the pampiniform plexus grew shorter with increasing grade of varicocele. Time-activity curves were classified into four patterns. One type (Type 3), which was more frequently observed in grade II and grade III varicocele than grade I varicocele, showed a decreased arterial perfusion of the left side lesion. It is concluded that scintigraphic analysis using both sequential images and time-activity curves is not only highly representative of the grade of clinically palpable varicocele, but also provides a better understanding of local hemodynamics in the scrotum.

[Intracavitary and interstitial hyperthermia with the 2 mm diameter microwave applicator].

Experimental and clinical studies were done on intracavitary and interstitial hyperthermia with a 2 mm diameter applicator with a 7 cm tip (Aloka, Co., Ltd.). Microwave energy at 2450 MHz was used to heat tumors. An outer cannula of 16G Medicut was implanted in the tumor. When a rabbit VX-2 tumor was heated, the temperature reached over 40 degrees C at 15 watts. We applied the same method to two patients, one with recurrent oropharyngeal tumor and the other with recurrent pelvic tumor. This applicator looks promising.