Determination of the energy dependence of the BC-408 plastic scintillation detector in medium energy x-ray beams.

The energy dependence of the response of BC-408 plastic scintillator (PS), an approximately water-equivalent material, has been investigated by employing standardized x-ray beams. IEC RQA and ISO N series x-ray beam qualities, in the range of 40-100 kVp, were calibrated using a PTW-type ionization chamber. The energy response of a thick BC-408 PS detector was measured using the multichannel pulse height analysis method. The response of BC-408 PS increased gradually with increasing energy in the energy range of 40-80 kVp and then showed a flat behavior at about 80 to 120 kVp. This might be due to the self-attenuation of scintillation light by the scintillator itself and may also be partly due to the ionization quenching, leading to a reduction in the intensity of the light output from the scintillator. The results indicated that the sensitivity drop in BC-408 PS material at lower photon energies may be overcome by adding some high-Z elements to its polyvinyltoluene (PVT) base. The material modification may compensate for the drop in the response at lower photon energies. Thus plastic scintillation dosimetry is potentially suitable for applications in diagnostic radiology.

Prognostic significance of estrogen receptor, progesterone receptor, HER2/neu, Ki-67, and nm23 expression in patients with invasive breast cancer.

PURPOSE: To determine the prognostic significance of estrogen receptor (ER), progesterone receptor (PR), HER2/neu, Ki-67, and nm23 immunohistochemical expression with respect to progression free survival (PFS) and overall survival (OS) in Turkish patients with invasive breast cancer (IBC). METHODS: Patients with IBC (n = 81; mean age = 51.9 ± 11.1 years) were prospectively enrolled at the Department of Oncology, Uludag University Medical Center, Bursa, Turkey. Immunohistochemistry was performed on formalin- fixed, paraffin-embedded tissue sections. RESULTS: We did not find any significant association between immunohistochemical expression of ER, PR, HER2/ neu, Ki-67, and nm23 and the baseline characteristics of IBC patients. The median patient PFS was 30 months (range 22-45), and the median OS was 32 months (range 23-46). Stratification of the patient population according to nm23 immunohistochemical expression revealed a statistically significant difference in terms of both OS (p < 0.05) and DFS (p < 0.05). Multivariate Cox regression analysis indicated that tumor grade, axillary lymph node status, and nm23 immunohistochemical expression were the 3 main independent prognostic factors for PFS and OS in IBC patients. CONCLUSION: Reduced nm23 immunohistochemical expression is an independent negative prognostic factor for OS and PFS. Patients with negative nm23 expression may require a more intensive follow-up.

Parenchyma-saving surgical treatment of giant pulmonary hydatid cysts.

OBJECTIVE: The purpose of this study was to review 97 patients with giant pulmonary hydatid cysts and assess the clinical features and results of different operative techniques over a 27-year period. MATERIAL AND METHODS: Between January 1981 and December 2007, 590 patients were operated on for pulmonary hydatidosis and 97 (17 %) of these patients had giant pulmonary hydatid cyst. We retrospectively reviewed the medical records of these 97 patients. The diameter of the hydatid cysts were measured using radiological methods and intraoperatively. RESULTS: Seventy-eight patients were male (80 %) and 19 were female (20 %). The median age was 23.4 years (range: 15-63 years). The most common symptoms were chest pain (54 %), cough (43 %) and dyspnea (41 %). Fourteen patients were asymptomatic (14 %). The diameters of the cyst ranged between 10 and 25 cm (mean 13.8 cm). The cysts were located in the right hemithorax in 52 (54 %) patients, in the left hemithorax in 44 (45 %) patients and bilaterally in one patient (1 %). Five patients had more than one cyst. The procedures consisted of cystotomy and capitonnage in 53 patients, enucleation and capitonnage in 27 patients and simple cystotomy or enucleation in 8 patients. Anatomical resection was performed in 9 patients. Prolonged air leakage of more than 7 days occurred in five patients; one patient underwent an operation and a Heimlich valve was placed in two patients. There was no postoperative mortality. Recurrence was not detected at follow-up after 6 months and 27 months. CONCLUSION: The higher lung tissue elasticity and delayed symptoms due to localizations of the cyst are the reasons for the occurrence of giant hydatid cysts in the lung. A parenchyma-saving operation should be performed instead of anatomical resection because of the low complication rates and because most complications can be treated conservatively.

Relationship between bone mineral density of the proximal femur and strength of hip muscles in postmenopausal women.

The relationship between muscle strength and bone density is well known, but only a limited number of studies relating muscle strength to bone mineral density of a site-specific limb have been performed. The main purposes of this study were as follows: (1) to assess the relationship between the strength of hip muscles and bone mineral density of the proximal femur in 100 postmenopausal women; (2) to compare strength values of three subgroups, which were formed on the basis of the femoral neck Z-scores. By using an isokinetic dynamometer (Cybex 350), muscle strength tests were performed for hip muscles and bone mineral density measurements were obtained by dual energy x-ray absorptiometry. Statistical analysis demonstrated a moderately positive correlation between bone mineral density of the femoral neck and hip muscle strength (with abductors: r = 0.267, P = 0.008; with adductors: r = 0.276, P = 0.007). A moderate correlation was also found between bone mineral density of Ward's triangle and hip adductors (r = 0.327; P = 0.001). When muscle strength mean values of subgroups were compared with each other, there was no statistically significant differences. These data may suggest that the isokinetic strength of hip muscles may not contribute to the bone mineral density of the proximal femur.