Three-dimensional personalized dosimetry for 188Re liver selective internal radiation therapy based on quantitative post-treatment SPECT studies.

We demonstrate that accurate patient-specific distributions of microspheres labeled with 188Re and resulting absorbed doses can be obtained from single-photon emission computed tomography (SPECT) studies performed after 188Re selective internal radiation therapy when accurate correction methods are employed in image reconstruction. Our quantitative image reconstruction algorithm includes corrections for attenuation, resolution degradations and scatter as well as a window-based compensation for contamination. The procedure has been validated using four phantom experiments containing an 18 ml cylindrical source (82-93 MBq of 188Re activity) simulating a liver tumor. In addition, we applied our approach to post-therapy SPECT studies of ten patients with progressive primary or metastatic liver carcinomas. Our quantitative algorithm accurately (within 9%) recovered 188Re activity from four phantom experiments. In addition, for two patients that received three scans, deviations remained consistent between the measured and the reconstructed activities that were determined from studies with differing severity of the dead-time effect. The analysis of absorbed doses for patient studies allowed us to hypothesize that D90 (the minimum dose received by 90% of the tumor volume) may be a reliable metric relating therapy outcomes to the calculated doses. Among several considered metrics, only D90 showed statistically significant correlation with the overall survival.

Different lymphscintigraphic patterns in patients with lymphedema distichiasis.

Mutation of the transcription factor FOXC2 gene has been identified as the cause of lymphedema-distichiasis syndrome (LD). Subjects with LD usually present with lower extremity lymphedema and distichiasis--an additional row of eyelashes. Typically, lymphscintigrams of patients with LD show good transport of the radiotracer from the feet to the inguinal lymph nodes accompanied by reflux of tracer to the skin of the lower extremities ("dermal backflow"). We have examined two patients with LD syndrome and were able to demonstrate two different distinct lymphscintigraphic patterns: lymphatic hyperplasia with reflux and obstructive.

Effect of vitamin E on reperfusion injuries during reconstructive vascular operations on lower limbs.

INTRODUCTION: The challenge against reperfusion injury and tissue oxidative stress, especially in vascular surgical interventions has an essential importance to reach the optimal clinical result. Numerous experimental attempts have proved the positive antioxidant effect of vitamin E in both chronic and acute phase models. In our study we monitored the effect of continuous preoperative treatment with vitamin E, on oxidative stress and tissue inflammation reactions developed after reconstructive operations. PATIENTS AND METHODS: 32 patients have been involved in a randomized, prospective study, all suffering from AFS occlusion proved by angiography, and all undergone supragenual reconstruction. Duration of ischemia and amount of tissues under vascular clamping were almost the same in all patients. In the group treated with E-vitamin, we administered 1 x 200 mg of vitamin E p/o from the preoperative day till the 7th post operative day. Patients of the second group did not receive vitamin E. MATERIALS AND METHODS: Peripheral blood samples were collected immediately before operation and at the end of the second reperfusion hour (early reperfusion period). Late reperfusion period has been monitored by analyzing blood samples taken at 24th hour and 7th day next to the operative ischemia. Among oxidative stress parameters, direct measurement of reactive oxygen intermediator (ROI) and determination of antioxidant state (GSH, Total-SH group, SOD) have been performed. Malondialdehyde was chosen as marker for lipidperoxidation. Inflammation reactions were monitored up on expression of adhesion molecules (CD11a and CD18). We also controlled the oscillation of myeloperoxidase (MPO) activity. RESULTS: Our study has proved that preoperative (from the preoperative day till the 7th post operative day) administration of 200 mg vitamin E could reduce the level of oxidative stress developed after ischemic-reperfusion insult (lipidproxidation, antioxidant enzymes). According to our results, the prooxidant-antioxidant imbalance also diminished in the group with E-vitamin treatment. We proved that elective administration of vitamin E could decrease the WBC activity (MPO activity, free radicals production, expression of adhesion molecules) and its consequential local inflammation process, during early reperfusion.

Ischaemic postconditioning reduces peroxide formation, cytokine expression and leukocyte activation in reperfusion injury after abdominal aortic surgery in rat model.

OBJECTIVE: We studied the protective effects of ischaemic postconditioning (PS) on ischemia-reperfusion injury of the lower extremities in a rat model of abdominal aortic intervention. We aimed to examine the evoked oxidative stress, cytokine expression and leukocyte activation after revascularisation surgery. METHODS: Anesthetized animals (48 Whistar rats) underwent a 60 min infrarenal aorta cross-clamping. After the ischaemic period, an intermittent 4 times 15 s reperfusion--15 seconds ischaemic episodes--were applied (ischaemic postconditioning: group PS). Then we started a 120 min reperfusion in the aorta. In untreated group animals underwent a long ischaemia (60 min) and the following reperfusion (group IR). Peripherial blood samples were collected before operation, and in early (5, 10, 15, 30, 60 and 120 min) reperfusion periods. Serum peroxide level, TNF-alpha concentration, myeloperoxidase (MPO) activity and PMA-induced leukocyte ROS production were measured. RESULTS: In PS group, plasma peroxide level elevation was significantly lower in very early reperfusion (5-30 min) comparing to non-conditioned IR group (10.04+/-1.9 microM/l vs. 16.91+/-3.67 microM/l, p<0.05). PS also reduced serum TNF-alpha concentration (167.41+/-31.26 microg/ml vs. 116.55+/-12.04 microg/ml, p<0.05), MPO activity (1.759+/-0.239 microM/ml vs. 1.22+/-0.126 microM/ml, p<0.05) and leukocyte activation detected by PMA-induced leukocyte ROS production (5.7+/-0.96 AU/10(3) cells vs. 4.63+/-0.69 AU/10(3) cells). CONCLUSIONS: Ischaemic postconditioning could reduce ROI production after IR in early reperfusion period, thus limiting ROI mediated tissue lesion, cytokine-leukocyte activation and inflammatory responses. PS seems to be an effective tool in vascular surgery to reduce reperfusion injuries after revascularization interventions.

Pulmonary pressure- volume relationships after corticotropin (ACTH) and salin injections in fetal rabbits.

ACTH mixed with barium sulfate injected into fetal rabbits on day 24 of a 31-day gestation was associated with increased lung maturity compared with lungs of noninjected controls when assessed by deflation pressure-volume curves and lung weight to body weight ratios measured on day 27. Fetuses injected with saline and barium sulfate also had accelerated (although somewhat less) lung maturation, perhaps from an ACTH-mediated response to stress. The ACTH group LA) maintained the largest lung volumes on deflation, followed by the saline group (B), the ACTH controls (C), and the saline controls (D). Volumes (percentage of total lung capacity) between the two injected groups and their controls (A versus C; B versus D) were significantly different at transthoracic pressures of 15, 10, 7, 4, 0, and -2 cm water (p less than 0.05). Volumes (percentage of total lung capacity) between the ACTH group and the saline group (A versus B) and between the two controls groups (C versus D) were not significantly different. Wet lung weight to body weight ratios were significantly different between the injected groups and their respective controls, between the two injected groups, and between the two control groups.

Pharmacologic regulation of alveolar surfactant in fetal and newborn rabbits: ACTH, heroin, isoxsuprine, and glucocorticoid.

The evidence that pharmacologic doses of glucocorticoids induce lung maturation and diminish risk of respiratory distress syndrome has been reviewed briefly. Studies with heroin corroborate that pharmacologic induction of lung maturation is possible in the human fetus. Endogenous fetal glucocorticoids may serve as a physiologic mechanism that prepares the immature lungs for birth. Catecholamines may induce release of stored surfactant from type 2 cells into alveolar spaces.