Radiobiology of stereotactic body radiation therapy (SBRT).

Recent advances in the technology of radiotherapy have enabled the development of new therapeutic modalities that deliver radiation with very high accuracy, reduced margins and high dose conformation, allowing the reduction of healthy tissue irradiated and therefore minimizing the risk of toxicity. The next step was to increase the total tumor dose using conventional fractionation (which remains the best way to relatively radioprotect healthy tissues when large volumes are treated) or to use new fractionation schemes with greater biological effectiveness. Based on the experience gained in radiosurgery, the latter way was chosen for small and well-defined tumors in the body. Stereotactic body radiotherapy delivers high doses of radiation to small and well-defined targets in an extreme hypofractionated (and accelerated) scheme with a very high biological effectiveness obtaining very good initial clinical results in terms of local tumor control and acceptable rate of late complications. In fact, we realize a posteriori that it was not feasible to administer such biologically equivalent dose in a conventional fractionation because the treatment could last several months. So far, these new therapeutic modalities have been developed due to technologic advances in image guidance and treatment delivery but without a solid biological basis. It is the role of traditional radiobiology (and molecular radiobiology) to explain the effects of high doses of ionizing radiation on tumor and normal tissues. Only through a better understanding of how high doses of ionizing radiation act, clinicians will know exactly what we do, allowing us in the future to refine our treatments. This article attempts to describe through simple and understandable concepts the known aspects of the biological action of high doses of radiation on tumor and normal tissues, but it is clear that we need much more basic research to better understand the biology of high doses of radiation.

Detection of type II endoleaks in abdominal aortic aneurysms after endovascular repair.

Abdominal aortic aneurysm (AAA) is a condition where the weakening of the aortic wall leads to its widening and the generation of a thrombus. To prevent a possible rupture of the aortic wall, AAA can be treated non-invasively by means of the endovascular aneurysm repair technique (EVAR), consisting of placing a stent-graft inside the aorta by a cateter to exclude the aneurysm sac from the blood circulation. A major complication is the presence of liquid blood turbulences, called endoleaks, in the thrombus formed in the space between the aortic wall and the stent-graft. In this paper we propose an automatic method for the detection of type II endoleaks in computer tomography angiography (CTA) images. The lumen and thrombus in the aneurysm area are first segmented using a radial model approach. Then, these regions are split into Thrombus Connected Components (TCCs) using a watershed-based segmentation and geometric and image content-based characteristics are obtained for each TCC. Finally, TCCs are classified into endoleaks and non-endoleaks using a multilayer Perceptron (MLP) trained on manual labeled sample TCCs provided by experts.

Radiobiology of the acute radiation syndrome.

ACUTE RADIATION SYNDROME OR ACUTE RADIATION SICKNESS IS CLASSICALLY SUBDIVIDED INTO THREE SUBSYNDROMES: the hematopoietic, gastrointestinal and neurovascular syndrome but many other tissues can be damaged. The time course and severity of clinical signs and symptoms are a function of the overall body volume irradiated, the inhomogeneity of dose exposure, the particle type, the absorbed dose and the dose rate. Classical pathophysiology explain the failure of each of these organs and the timing of appearance of their signs and symptoms due to radiation-induced cytocidal effects of a great number of parenchymal cells of hierarchically organized tissues. Contemporaneously, many other radiation-induced effects has been described and all of them may lead to tissue injury with their corresponding signs and symptoms that can be expressed after short or long period of time. Radiation-induced multi-organ involvement is thought to be due to radiation-induced systemic inflammatory response mediated by released pro-inflammatory cytokines.

Treatment of primary spontaneous pneumothorax by videothoracoscopic talc pleurodesis under local anesthesia: a review of 133 procedures.

AIM: To review our experience of treatment of primary spontaneous pneumothorax by videothoracoscopic talc pleurodesis. METHODS: From 2000 to 2008, 124 consecutive patients with primary spontaneous pneumothorax were operated; 105 were men (84.7%) and 19 were women (15.3%) with a mean age of 26.6 years (range 17-46 years). RESULTS: No mortality was recorded. Staging according to Vanderschueren's classification was as follows: stage I, 61 patients (45.9%); stage II, 39 patients (29.3%); stage III, 31 patients (23.3%); stage IV, two patients (1.5%). The overall rate of complications was 9% (12/133), corresponding to prolonged air leak in 9(6.7%) patients and hemothorax in 3(2.2%) patients. Four patients (3%) had recurrence requiring reoperation. There were no episodes of acute respiratory failure, pneumonia or subcutaneous emphysema following talc pleurodesis. CONCLUSIONS: Thoracoscopic pleural talc pleurodesis as a treatment for recurrent pneumothorax is easy, safe, and rapid, and causes minimal morbidity and mortality.

Compliance to the prescribed overall treatment time (OTT) of curative radiotherapy in normal clinical practice and impact on treatment duration of counteracting short interruptions by treating patients on Saturdays.

BACKGROUND AND PURPOSE: To evaluate the compliance of the prescribed OTT in a normal clinical practice and to establish the incidence, duration and causes of unplanned interruptions of radiation therapy. To quantify the impact of an institutional policy to maintain the OTT counteracting some short interruptions by treating patients on Saturday morning. MATERIAL AND METHODS: The treatment charts of all new patients treated with curative intent in a period of one year were reviewed retrospectively. All treatments started on Monday or Tuesday and split-course was not used. The difference between the actual realized and the planned OTT was calculated as a measure of compliance. Recalculations of OTT were made to quantify the impact of compensating short gaps by treating patients on Saturday. The cause of interruption was also recorded and classified. RESULTS: The charts of 478 consecutive patients treated with curative intent were reviewed. The overall incidence of unplanned interruptions was 76.6%. Public holidays and machine maintenance caused most of interruptions, and machine breakdown caused 13%. 17.9% of the interruptions were greater than 5 days and 5.6% greater than 10 days. Only 23.4% of patients finished their radiotherapy in the planned OTT (12.6% if no compensation on Saturday). 48.9% of head and neck cancer patients finished their treatment in the planned OTT (19.5% if no compensation on Saturday). The time in excess ranged up to 44 days, and the average time in excess was 3.3 days for the entire group (4.2 days if no compensation on Saturday). For head and neck cancer patients, the time in excess was 1.9 days (3.9 days if no compensation on Saturday). CONCLUSIONS: This study has documented that the incidence and duration of unplanned interruptions of standard treatment schedules is a major problem in normal clinical practice. Most interruptions are short and due mainly to public holidays and machine maintenance and for these reasons they can be planned. In spite of the extra costs, counteracting some short interruptions by treating patients on Saturday is a good way to maintain the OTT without loss of local control.

Compliance to the prescribed overall treatment time (OTT) of curative radiotherapy in normal clinical practice and impact on treatment duration of counteracting short interruptions by treating patients on Saturdays

BACKGROUND AND PURPOSE: To evaluate the compliance of the prescribed OTT in a normal clinical practice and to establish the incidence, duration and causes of unplanned interruptions of radiation therapy. To quantify the impact of an institutional policy to maintain the OTT counteracting some short interruptions by treating patients on Saturday morning. MATERIAL AND METHODS: The treatment charts of all new patients treated with curative intent in a period of one year were reviewed retrospectively. All treatments started on Monday or Tuesday and split-course was not used. The difference between the actual realized and the planned OTT was calculated as a measure of compliance. Recalculations of OTT were made to quantify the impact of compensating short gaps by treating patients on Saturday. The cause of interruption was also recorded and classified. RESULTS: The charts of 478 consecutive patients treated with curative intent were reviewed. The overall incidence of unplanned interruptions was 76.6%. Public holidays and machine maintenance caused most of interruptions, and machine breakdown caused 13%. 17.9% of the interruptions were greater than 5 days and 5.6% greater than 10 days. Only 23.4% of patients finished their radiotherapy in the planned OTT (12.6% if no compensation on Saturday). 48.9% of head and neck cancer patients finished their treatment in the planned OTT (19.5% if no compensation on Saturday). The time in excess ranged up to 44 days, and the average time in excess was 3.3 days for the entire group (4.2 days if no compensation on Saturday). For head and neck cancer patients, the time in excess was 1.9 days (3.9 days if no compensation on Saturday). CONCLUSIONS: This study has documented that the incidence and duration of unplanned interruptions of standard treatment schedules is a major problem in normal clinical practice. Most interruptions are short and due mainly to public holidays and machine maintenance and for these reasons they can be planned. In spite of the extra costs, counteracting some short interruptions by treating patients on Saturday is a good way to maintain the OTT without loss of local control (AU)

Anatomical redistribution of sweating after T2-T3 thoracoscopic sympathicolysis: a study of 210 patients.

BACKGROUND: The cutaneous influence areas of the different sympathetic ganglia have not been fully established to date. The aim of this study was to define the cutaneous influence area of sympathetic ganglia T2-T3. METHODS: A total of 210 patients with primary hyperhidrosis (PH) underwent 420 thoracoscopic sympathicolysis procedures of ganglia T2-T3 in a prospective study. All completed a preoperative questionnaire and a second questionnaire 12 months after the operation. The questionnaires evaluated perspiration in the different body areas. Only the zones of anhidrosis were considered in delimiting the cutaneous expression of sympathetic ganglia T2-T3. RESULTS: Redistribution of perspiration as reported by the patients comprised significant reduction in the palms, axillas, and soles, and an increase in the abdomen, back, and gluteal and popliteal regions. Regarding the incidence of anhidrosis by anatomical location, statistically significant changes were recorded in the head, hands, axillas, and soles (p < 0.001). CONCLUSIONS: Bilateral upper thoracic sympathicolysis is followed by redistribution of body perspiration, with a clear decrease in the zones regulated by mental or emotional stimuli, and an increase in the areas regulated by environmental stimuli, though we are unable to establish the etiology of this redistribution.

[Results of high bilateral endoscopic thoracic sympathectomy and sympatholysis in the treatment of primary hyperhidrosis: a study of 1016 procedures]. / Resultados de la simpaticólisis y la simpatectomía torácica superior bilateral endoscópica en el tratamiento de la hiperhidrosis primaria. Estudio de 1.016 procedimientos.

OBJECTIVE: Thoracic sympatholysis and sympathectomy are the current standard treatments for primary hyperhidrosis. In this study, we evaluated the incidence of peri- and postoperative complications associated with these procedures. PATIENTS AND METHODS: From 1996 to 2004, 520 consecutive patients (364 women), with a mean age of 26.8 years, were treated for primary hyperhidrosis at our hospital. The procedure was bilateral in all but 24 cases. The 484 patients in the sympatholysis group underwent a single intervention while the 36 patients in the sympathectomy group underwent 2 separate interventions. RESULTS: No deaths occurred. Anhidrosis of the target area was achieved in 97.6% of patients while 2.2% experienced hypohidrosis. In 0.2% of the cases, the procedure was initially unsuccessful and a second intervention was required. The mean duration of hospital stay was 72 hours for patients in the sympathectomy group and 17 hours for the sympatholysis group. Serious intraoperative complications requiring conversion to thoracotomy were recorded in 0.2% of patients. Postoperative complications--of which pneumothorax was the most common--occurred in 5.2% of the cases (in 22.5% of the sympathectomy group and 3.55% of the sympatholysis group). Compensatory hyperhidrosis occurred in 48.4% of the patients, excessive dryness of the hands and palpebral ptosis in 0.38%, and gustatory sweating in 0.9%. The degree of patient satisfaction was quite high (88.5%) and only 2.3% were very unsatisfied. CONCLUSIONS: Given the results obtained, we can conclude that both sympatholysis and sympathectomy are appropriate treatments for hyperhidrosis. Nonetheless, because sympatholysis is both easier to perform and less aggressive, we consider it the treatment of choice for primary hyperhidrosis.

Resultados de la simpaticólisis y la simpatectomía torácica superior bilateral endoscópica en el tratamiento de la hiperhidrosis primaria. Estudio de 1.016 procedimientos / Results of high bilateral endoscopic thoracic sympathectomy and sympatholysis in the treatment of primary hyperhidrosis: a study of 1016 procedures

Objetivo: La simpaticolisis y la simpatectomía torácica son actualmente los tratamientos habituales de la hiperhidrosis primaria. En este estudio evaluamos la incidencia cuantitativa y cualitativa de las complicaciones peri y postoperatorias. Pacientes y métodos: Desde 1996 a 2004 se intervino consecutivamente a 520 pacientes (364 mujeres) con hiperhidrosis primaria, con una edad media de 26,8 años. En todos, excepto en 24 casos, el procedimiento fue bilateral. La intervención se realizó en un tiempo en 484 pacientes (simpaticólisis) y en 2 tiempos en 36 (simpatectomía). Resultados: No hubo mortalidad. La anhidrosis del territorio deseado fue del 97,6%, se apreció hipohidrosis en el 2,2% y hubo un 0,2% de fallos que requirieron reintervención. La estancia media fue de 72 h en el grupo de simpatectomía y de 17 h en el de simpaticólisis. Se registró un 0,2% de complicaciones intraoperatorias mayores con reconversión a toracotomía. Se produjo un 5,2% de complicaciones postoperatorias (un 22,5% en las simpatectomías y un 3,55% en la simpaticólisis), de las cuales el neumotórax fue la más frecuente. Se observó hiperhidrosis compensadora en un 48,4% de los casos, sequedad excesiva de manos y ptosis palpebral en el 0,38%, e hiperhidrosis gustativa en un 0,9% de casos. El grado de satisfacción fue muy elevado (88,5%) y sólo un 2,3% de los pacientes se manifestaron muy insatisfechos. Conclusiones: De los resultados obtenidos se deduce que tanto la simpaticolisis como la simpatectomía son tratamientos adecuados de la hiperhidrosis, si bien la mayor sencillez y menor agresividad de la primera nos llevan a considerarla el tratamiento de elección en la hiperhidrosis primaria

Objective: Thoracic sympatholysis and sympathectomy are the current standard treatments for primary hyperhidrosis. In this study, we evaluated the incidence of peri- and postoperative complications associated with these procedures. Patients and methods: From 1996 to 2004, 520 consecutive patients (364 women), with a mean age of 26.8 years, were treated for primary hyperhidrosis at our hospital. The procedure was bilateral in all but 24 cases. The 484 patients in the sympatholysis group underwent a single intervention while the 36 patients in the sympathectomy group underwent 2 separate interventions. Results: No deaths occurred. Anhidrosis of the target area was achieved in 97.6% of patients while 2.2% experienced hypohidrosis. In 0.2% of the cases, the procedure was initially unsuccessful and a second intervention was required. The mean duration of hospital stay was 72 hours for patients in the sympathectomy group and 17 hours for the sympatholysis group. Serious intraoperative complications requiring conversion to thoracotomy were recorded in 0.2% of patients. Postoperative complications--of which pneumothorax was the most common--occurred in 5.2% of the cases (in 22.5% of the sympathectomy group and 3.55% of the sympatholysis group). Compensatory hyperhidrosis occurred in 48.4% of the patients, excessive dryness of the hands and palpebral ptosis in 0.38%, and gustatory sweating in 0.9%. The degree of patient satisfaction was quite high (88.5%) and only 2.3% were very unsatisfied. Conclusions: Given the results obtained, we can conclude that both sympatholysis and sympathectomy are appropriate treatments for hyperhidrosis. Nonetheless, because sympatholysis is both easier to perform and less aggressive, we consider it the treatment of choice for primary hyperhidrosis

Thoracic sympathicolysis for primary hyperhidrosis: a review of 918 procedures.

BACKGROUND: Bilateral upper thoracic sympathectomy or sympathicolysis, currently the standard treatment for palmar or axillary hyperhidrosis, is regarded as a safe procedure. This study evaluates the quantitative and qualitative incidence of intraoperative and postoperative complications resulting from bilateral thoracic sympathicolysis. METHODS: From 1996 to 2004, 458 consecutive patients with primary hyperhidrosis underwent surgery. These patients comprised 143 men (31.2%) and 315 women (68.7%) with a mean age of 26 years (range, 14-52 years). In all but seven cases, the procedure was bilaterally synchronous. RESULTS: No mortality was recorded. The anhydrosis rate was 97.4%, with a hypohidrosis rate of 2.4% and a failure rate of 0.2%. The latter was resolved with reintervention. The mean hospital stay was 17 h. The rate of major perioperative complications with conversion to thoracotomy was 0.4%. The overall rate of postoperative complications was 3.6%. The complications and rates observed were as follows: pneumothorax (2.06%), subcutaneous emphysema (1.08%), pleural bleeding (0.2%), hemothorax (0.1%), and atelectasis (0.1%). Compensatory hyperhidrosis was observed in 48.4% of the patients, but the sensation of compensatory hyperhidrosis was reported in 85.6% of the cases. Excessive dryness of the hands was reported in 0.38%, Horner's syndrome in 0.32%, and gustatory hyperhidrosis in 1.1% of the cases. The overall satisfaction rate was 88.5%. CONCLUSIONS: The results suggest that endoscopic bilateral thoracic sympathicolysis is an effective method for managing primary hyperhidrosis, especially severe palmar hyperhidrosis, but it is necessary to inform patients fully concerning the undesirable effects.