IMRT or 3D-CRT in glioblastoma? A dosimetric criterion for patient selection.

Intensity modulated radiation therapy (IMRT) is increasingly employed in glioblastoma (GBM) treatment. The present work aimed to assess which clinical-dosimetric scenario could benefit the most from IMRT application, with respect to three-dimensional conformal radiation therapy (3D-CRT). The number of organs at risk (OARs) overlapping the planning target volume (PTV) was the parameter describing the clinical-dosimetric pattern. Based on the results, a dosimetric decision criterion to select the most appropriate treatment technique is provided. Seventeen previously irradiated patients were retrieved and re-planned with both 3D-CRT and IMRT. The prescribed dose was 60 Gy/30fx. The cases were divided into 4 groups (4 patients in each group). Each group represents the scenario where 0, 1, 2 or 3 OARs overlapped the target volume, respectively. Furthermore, in one case, 4 OARs overlapped the PTV. The techniques were compared also in terms of irradiated healthy brain tissue. The results were evaluated by paired t-test. IMRT always provided better target coverage (V95%) than 3D-CRT, regardless the clinical-dosimetric scenario: difference ranged from 0.82% (p = 0.4) for scenario 0 to 7.8% (p = 0.02) for scenario 3, passing through 2.54% (p = 0.18) and 5.93% (p = 0.08) for scenario 1 and 2, respectively. IMRT and 3D-CRT achieved comparable results in terms of dose homogeneity and conformity. Concerning the irradiation of serial-kind OARs, both techniques provided nearly identical results. A statistically significant dose reduction to the healthy brain in favor of IMRT was scored. IMRT seems a superior technique compared to 3D-CRT when there are multiple overlaps between OAR and PTV. In this scenario, IMRT allows for a better target coverage while maintaining equivalent OARs sparing and reducing healthy brain irradiation. The results from our patients dataset suggests that the overlap of three OARs can be used as a dosimetric criterion to select which patients should receive IMRT treatment.

Clinical target volume delineation in glioblastomas: pre-operative versus post-operative/pre-radiotherapy MRI.

OBJECTIVES: Delineation of clinical target volume (CTV) is still controversial in glioblastomas. In order to assess the differences in volume and shape of the radiotherapy target, the use of pre-operative vs post-operative/pre-radiotherapy T(1) and T(2) weighted MRI was compared. METHODS: 4 CTVs were delineated in 24 patients pre-operatively and post-operatively using T(1) contrast-enhanced (T1(PRE)CTV and T1(POST)CTV) and T(2) weighted images (T2(PRE)CTV and T2(POST)CTV). Pre-operative MRI examinations were performed the day before surgery, whereas post-operative examinations were acquired 1 month after surgery and before chemoradiation. A concordance index (CI) was defined as the ratio between the overlapping and composite volumes. RESULTS: The volumes of T1(PRE)CTV and T1(POST)CTV were not statistically different (248 ± 88 vs 254 ± 101), although volume differences >100 cm(3) were observed in 6 out of 24 patients. A marked increase due to tumour progression was shown in three patients. Three patients showed a decrease because of a reduced mass effect. A significant reduction occurred between pre-operative and post-operative T(2) volumes (139 ± 68 vs 78 ± 59). Lack of concordance was observed between T1(PRE)CTV and T1(POST)CTV (CI = 0.67 ± 0.09), T2(PRE)CTV and T2(POST)CTV (CI = 0.39 ± 0.20) and comparing the portion of the T1(PRE)CTV and T1(POST)CTV not covered by that defined on T2(PRE)CTV images (CI = 0.45 ± 0.16 and 0.44 ± 0.17, respectively). CONCLUSION: Using T(2) MRI, huge variations can be observed in peritumoural oedema, which are probably due to steroid treatment. Using T(1) MRI, brain shifts after surgery and possible progressive enhancing lesions produce substantial differences in CTVs. Our data support the use of post-operative/pre-radiotherapy T(1) weighted MRI for planning purposes.

[Efficacy and securyty of therapeutic hypothermia for hypoxic ischemic encephalopathy: a meta-analysis]. / Meta análisis sobre la eficacia y seguriada de la hipotermia en el tratamiento de la encefalopatía isquémica.

BACKGROUND: Animal and human experimental models suggest that therapeutic hypothermia could reduce neurological disabilities in asphyxiated newborn without adverse events. The objective of this study was review the effectiveness and safety of hypothermia as treatment for hypoxic ischemic encephalophaty. METHODS: MEDLINE, COCHRANE LIBRARY, Academic Google and LILACS databases were searched. Randomized controlled trials with main outcomes of death, neurodevelopmental disability and adverse events were eligible for inclusion in the meta-analysis. RESULTS: Tree studies were included with 751 patients. Combined results of death reduction was not significant (RR 0.83 CI95% 0.67 to 1.04). Severe to moderate neurodevelopmental disability (RR 0.70 CI95% 0.55 to 0.89) and cerebral palsy (RR 0.66 CI95% 0.50 to 0.89) were reduced significantly in newborns receiving hypothermia compared with controls. Cardiac arrhythmias (RR 3.51 CI95% 1.29 to 9.54) and coagulation disorders (RR 1,23 CI95% 1.03 a 1.48) were more common adverse events with hypothermia. CONCLUSIONS: Hypothermia is effective in reducing neurological disability and cerebral palsy. Cardiac arrhythmias and coagulation disorders were more common with hypothermia, however they were clinically benign.

Radiation dose saving through the use of cone-beam CT in hearing-impaired patients.

PURPOSE: Bionic ear implants provide a solution for deafness. Patients treated with these hearing devices are often children who require close follow-up with frequent functional and radiological examinations; in particular, multislice computed tomography (MSCT). Dental volumetric cone-beam CT (CBCT) has been reported as a reliable technique for acquiring images of the temporal bone while delivering low radiation doses and containing costs. The aim of this study was to assess, in terms of radiation dose and image quality, the possibility of using CBCT as an alternative to MSCT in patients with bionic ear implants. MATERIALS AND METHODS: One hundred patients (mean age 26 years, range 7-43) with Vibrant SoundBridge implants on the round window underwent follow-up: 85 with CBCT and 15 with MSCT. We measured the average tissue-absorbed doses during both MSCT and CBCT scans. Each scan was focused on the temporal bone with the smallest field of view and a low-dose protocol. In order to estimate image quality, we obtained data about slice thickness, high- and low-contrast resolution, uniformity and noise by using an AAPM CT performance phantom. RESULTS: Although the CBCT images were qualitatively inferior to those of MSCT, they were sufficiently diagnostic to allow evaluation of the position of the implants. The effective dose of MSCT was almost three times higher than that of CBCT. CONCLUSIONS: Owing to low radiation dose and sufficient image quality, CBCT could be considered an adequate technique for postoperative imaging and follow-up of patients with bionic ear implants.

[The role of intra- and extracellular Ca++ in coronary vessel contraction induced in vitro by noradrenaline following a beta-adrenergic block]. / Ruolo del Ca++ intra ed extracellulare nella contrazione dei vasi coronarici indotta in vitro dalla noradrenalina, dopo blocco beta-adrenergico.

Previous studies reported that norepinephrine (NE) induces contraction of the calf isolated coronary arteries after beta-adrenergic blockade with propranolol (PR), and that the effect disappeared after phentolamine. An higher Ca++ concentration increased the response of preparation to NE, whereas the reduction of the concentration reduced the response. In isolated coronary arteries the baseline tone and contractile response to NE after PR were studied as influenced by DA and nicardipine (NI). NI always induced vessel relaxation and DA induced a contraction followed by relaxation. The NE contraction was not abolished in calcium-free medium but in presence of DA and was reduced by NI in the medium containing Ca++. We conclude that NE induces contractions by facilitating the influx of the extracellular Ca++ and by promoting the liberation of intracellular bound Ca++.

Primary non-Hodgkin lymphomas of the gastrointestinal tract: analysis of 41 cases.

Forty-one patients suffering from primary non-Hodgkin lymphomas of the digestive tract have been observed over a period of 15 years. The primary sites were: the stomach in 27 cases, the small bowel in 8, the ileocecal region in 5, and the mesentery in 1. Patients were staged according to the modified Ann Arbor staging system proposed by Mushoff (20). Four kinds of management were employed: 1) surgery alone; 2) surgery and radiotherapy; 3) surgery, radiotherapy and chemotherapy; 4) surgery and chemotherapy. One patient was treated by chemotherapy alone. Radiotherapy was administered postoperatively and chemotherapy after or during radiotherapy. Generally, 2 opposed fields largely encompassing the tumor area and lomboaortic nodes if necessary, up to 25-30 Gy to the midline, were employed, with a booster dose up to 40-45 Gy to the involved area. Total abdominal irradiation was never employed. No clear difference emerged in survival rate nor in relapse-free survival among the four subgroups, but patients who underwent complete resection fared better than incompletely resected patients. However, these two subgroups were not homogeneous. A clear difference in survival rate did not emerge between patients treated or not with postoperative chemotherapy, whereas patients who relapsed after complete remission or those who never had complete remission had a poor prognosis.

External radiotherapy in the treatment of tonsillar carcinomas. Analysis of 183 cases.

A retrospective analysis of 183 consecutive patients with tonsillar carcinoma observed from 1970 through 1984 and treated by external radiotherapy was carried out. The data were analyzed retrospectively to determine the factors affecting prognosis. Tumor size (T) and lymph node involvement (N) were found to be predominant prognostic factors. The difference in 5 year survival rate between T2 and T3 tumors was significant, and that between N1 and N3 was highly significant, whereas difference in survival could be found between N0 and N1 groups. The primary tumor was controlled by radiotherapy alone in 90% of cases of T1 lesions, 58% of T2, 37% of T3 and 11% of T4, and lymph node metastases was controlled in 70% of N1 cases, 0 of N2 and 15.5% of N3. Twenty-three patients underwent salvage surgery after radiotherapy had failed and the actuarial 5 year survival rate was 75% for stage I, 40% for stage II, 30% for stage III and 13% for stage IV.

Multiple simultaneous bilateral urothelial tumours of the renal pelvis.

Three cases of simultaneous bilateral transitional cell carcinoma of the renal pelvis are reported. In one case the bladder and urethra were also involved. The information provided by radiological studies (particularly renal angiography) and cytology allowed us to define with accuracy not only tumour sites but also the tumour itself and the degree of malignancy. Based on the latter finding, the surgical approach was adapted to each individual case and consisted of papillectomy, partial pyelectomy or heminephrectomy associated with contralateral nephroureterectomy. In one case total cystourethrectomy was performed. Long-term follow-up showed no recurrence in the residual urinary tract 5 to 8 years post-operatively.

Dose evaluation to patients irradiated by 60Co beams, by means of direct measurement on the incident and on the exit surfaces.

A method for direct dose measurements on a patient treated with 60Co beams, is described. A home-made multi-probe dosimeter with silicon diodes as detectors is described. Measurements were performed on the entrance as well as on the exit fields, and a correlation was established with the mid-line dose. The influence of field size, SSD, patient thickness, and inhomogeneities was investigated.

Pathogenesis of persistent infertility in men after varicocelectomy.

With a view to investigating the cause of persistent infertility, the authors studied a group of 27 patients who had, previously, undergone surgical ligation of the spermatic vein for varicocele and infertility. Of these subjects, who failed to father after surgery, 12 presented persisting varicocele at the clinical examination. In 6 cases, the seminal fluid was positive for U. Urealyticum. One patient had orchiepididymitis; in one spermioagglutinating antibodies were found, in one the female partner was found to be infertile. Even preoperatively, three subjects had pathologically high gonadotropin levels, an important sign of testicular parenchyma alteration. In three subjects only there were no pathological findings to explain persistent infertility.

Ureteric substitution with a tapered ileal loop. An experimental study.

The authors present their experience in replacement of the ureter by a tapered ileal loop over a 24-month period, in a group of 10 dogs. With regard to the morphological and functional behaviour of the neo-ureter, the results on the whole were considered satisfactory. However, some problems such as pyelonephritis, associated with obstruction due to mucosal hyperexcretion, remain unsolved at the present time.