SyncMRT: a solution to image-guided synchrotron radiotherapy for quality assurance and pre-clinical trials.

In this work, a new image guidance system and protocols for delivering image-guided radiotherapy (IGRT) on the Imaging and Medical Beamline (IMBL) at the ANSTO Australian Synchrotron are introduced. The image guidance methods used and the resulting accuracy of tumour alignment in in vivo experiments are often under-reported. Image guidance tasks are often complex, time-consuming and prone to errors. If unchecked, they may result in potential mis-treatments. We introduce SyncMRT, a software package that provides a simple, image guidance tool-kit for aligning samples to the synchrotron beam. We have demonstrated sub-millimetre alignment using SyncMRT and the small-animal irradiation platform (the DynamicMRT system) on the IMBL. SyncMRT has become the standard for carrying out IGRT treatments on the IMBL and has been used in all pre-clinical radiotherapy experiments since 2017. Further, we introduce two quality assurance (QA) protocols to synchrotron radiotherapy on the IMBL: the Winston-Lutz test and hidden target test. It is shown that the presented QA tests are appropriate for picking up geometrical setup errors and assessing the end-to-end accuracy of the image guidance process. Together, these tools make image guidance easier and provide a mechanism for reporting the geometric accuracy of synchrotron-based IGRT treatments. Importantly, this work is scalable to other delivery systems, and is in continual development to support the upcoming veterinary radiotherapy trials on the IMBL.

A commercial treatment planning system with a hybrid dose calculation algorithm for synchrotron radiotherapy trials.

Synchrotron Radiotherapy (SyncRT) is a preclinical radiation treatment which delivers synchrotron x-rays to cancer targets. SyncRT allows for novel treatments such as Microbeam Radiotherapy, which has been shown to have exceptional healthy tissue sparing capabilities while maintaining good tumour control. Veterinary trials in SyncRT are anticipated to take place in the near future at the Australian Synchrotron's Imaging and Medical Beamline (IMBL). However, before veterinary trials can commence, a computerised treatment planning system (TPS) is required, which can quickly and accurately calculate the synchrotron x-ray dose through patient CT images. Furthermore, SyncRT TPS's must be familiar and intuitive to radiotherapy planners in order to alleviate necessary training and reduce user error. We have paired an accurate and fast Monte Carlo (MC) based SyncRT dose calculation algorithm with EclipseTM, the most widely implemented commercial TPS in the clinic. Using EclipseTM, we have performed preliminary SyncRT trials on dog cadavers at the IMBL, and verified calculated doses against dosimetric measurement to within 5% for heterogeneous tissue-equivalent phantoms. We have also performed a validation of the TPS against a full MC simulation for constructed heterogeneous phantoms in EclipseTM, and showed good agreement for a range of water-like tissues to within 5%-8%. Our custom EclipseTM TPS for SyncRT is ready to perform live veterinary trials at the IMBL.

A Monte Carlo model of synchrotron radiotherapy shows good agreement with experimental dosimetry measurements: Data from the imaging and medical beamline at the Australian Synchrotron.

Experimental measurement of Synchrotron Radiotherapy (SyncRT) doses is challenging, especially for Microbeam Radiotherapy (MRT), which is characterised by very high dynamic ranges with spatial resolutions on the micrometer scale. Monte Carlo (MC) simulation is considered a gold standard for accurate dose calculation in radiotherapy, and is therefore routinely relied upon to produce verification data. We present a MC model for Australian Synchrotron's Imaging and Medical Beamline (IMBL), which is capable of generating accurate dosimetry data to inform and/or verify SyncRT experiments. Our MC model showed excellent agreement with dosimetric measurement for Synchrotron Broadbeam Radiotherapy (SBBR). Our MC model is also the first to achieve validation for MRT, using two methods of dosimetry, to within clinical tolerances of 5% for a 20×20 mm2 field size, except for surface measurements at 5 mm depth, which remained to within good agreement of 7.5%. Our experimental methodology has allowed us to control measurement uncertainties for MRT doses to within 5-6%, which has also not been previously achieved, and provides a confidence which until now has been lacking in MRT validation studies. The MC model is suitable for SyncRT dose calculation of clinically relevant field sizes at the IMBL, and can be extended to include medical beamlines at other Synchrotron facilities as well. The presented MC model will be used as a validation tool for treatment planning dose calculation algorithms, and is an important step towards veterinary SyncRT trials at the Australian Synchrotron.

Characterization of Diffuse Intrinsic Pontine Glioma Radiosensitivity using Synchrotron Microbeam Radiotherapy and Conventional Radiation Therapy In Vitro.

Synchrotron microbeam radiation therapy is a promising preclinical radiotherapy modality that has been proposed as an alternative to conventional radiation therapy for diseases such as diffuse intrinsic pontine glioma (DIPG), a devastating pediatric tumor of the brainstem. The primary goal of this study was to characterize and compare the radiosensitivity of two DIPG cell lines (SF7761 and JHH-DIPG-1) to microbeam and conventional radiation. We hypothesized that these DIPG cell lines would exhibit differential responses to each radiation modality. Single cell suspensions were exposed to microbeam (112, 250, 560, 1,180 Gy peak dose) or conventional (2, 4, 6 and 8 Gy) radiation to produce clonogenic cell-survival curves. Apoptosis induction and the cell cycle were also analyzed five days postirradiation using flow cytometry. JHH-DIPG-1 cells displayed greater radioresistance than SF7761 to both microbeam and conventional radiation, with higher colony formation and increased accumulation of G2/M-phase cells. Apoptosis was significantly increased in SF7761 cells compared to JHH-DIPG-1 after microbeam irradiation, demonstrating cell-line specific differential radiosensitivity to microbeam radiation. Additionally, biologically equivalent doses to microbeam and conventional radiation were calculated based on clonogenic survival, furthering our understanding of the response of cancer cells to these two radiotherapy modalities.

Characterization of Diffuse Intrinsic Pontine Glioma Radiosensitivity using Synchrotron Microbeam Radiotherapy and Conventional Radiation Therapy In Vitro.

Synchrotron microbeam radiation therapy is a promising preclinical radiotherapy modality that has been proposed as an alternative to conventional radiation therapy for diseases such as diffuse intrinsic pontine glioma (DIPG), a devastating pediatric tumor of the brainstem. The primary goal of this study was to characterize and compare the radiosensitivity of two DIPG cell lines (SF7761 and JHH-DIPG-1) to microbeam and conventional radiation. We hypothesized that these DIPG cell lines would exhibit differential responses to each radiation modality. Single cell suspensions were exposed to microbeam (112, 250, 560, 1,180 Gy peak dose) or conventional (2, 4, 6 and 8 Gy) radiation to produce clonogenic cell-survival curves. Apoptosis induction and the cell cycle were also analyzed five days postirradiation using flow cytometry. JHH-DIPG-1 cells displayed greater radioresistance than SF7761 to both microbeam and conventional radiation, with higher colony formation and increased accumulation of G2/M-phase cells. Apoptosis was significantly increased in SF7761 cells compared to JHH-DIPG-1 after microbeam irradiation, demonstrating cell-line specific differential radiosensitivity to microbeam radiation. Additionally, biologically equivalent doses to microbeam and conventional radiation were calculated based on clonogenic survival, furthering our understanding of the response of cancer cells to these two radiotherapy modalities.

Absorbed dose determination in kilovoltage X-ray synchrotron radiation using alanine dosimeters.

Alanine dosimeters from the National Physical Laboratory (NPL) in the UK were irradiated using kilovoltage synchrotron radiation at the imaging and medical beam line (IMBL) at the Australian Synchrotron. A 20 × 20 mm2 area was irradiated by scanning the phantom containing the alanine through the 1 mm × 20 mm beam at a constant velocity. The polychromatic beam had an average energy of 95 keV and nominal absorbed dose to water rate of 250 Gy/s. The absorbed dose to water in the solid water phantom was first determined using a PTW Model 31014 PinPoint ionization chamber traceable to a graphite calorimeter. The alanine was read out at NPL using correction factors determined for 60Co, traceable to NPL standards, and a published energy correction was applied to correct for the effect of the synchrotron beam quality. The ratio of the doses determined by alanine at NPL and those determined at the synchrotron was 0.975 (standard uncertainty 0.042) when alanine energy correction factors published by Waldeland et al. (Waldeland E, Hole E O, Sagstuen E and Malinen E, Med. Phys. 2010, 37, 3569) were used, and 0.996 (standard uncertainty 0.031) when factors by Anton et al. (Anton M, Büermann L., Phys Med Biol. 2015 60 6113-29) were used. The results provide additional verification of the IMBL dosimetry.

Absorbed dose-to-water protocol applied to synchrotron-generated x-rays at very high dose rates.

Microbeam radiation therapy (MRT) is a new radiation treatment modality in the pre-clinical stage of development at the ID17 Biomedical Beamline of the European synchrotron radiation facility (ESRF) in Grenoble, France. MRT exploits the dose volume effect that is made possible through the spatial fractionation of the high dose rate synchrotron-generated x-ray beam into an array of microbeams. As an important step towards the development of a dosimetry protocol for MRT, we have applied the International Atomic Energy Agency's TRS 398 absorbed dose-to-water protocol to the synchrotron x-ray beam in the case of the broad beam irradiation geometry (i.e. prior to spatial fractionation into microbeams). The very high dose rates observed here mean the ion recombination correction factor, k s , is the most challenging to quantify of all the necessary corrections to apply for ionization chamber based absolute dosimetry. In the course of this study, we have developed a new method, the so called 'current ramping' method, to determine k s for the specific irradiation and filtering conditions typically utilized throughout the development of MRT. Using the new approach we deduced an ion recombination correction factor of 1.047 for the maximum ESRF storage ring current (200 mA) under typical beam spectral filtering conditions in MRT. MRT trials are currently underway with veterinary patients at the ESRF that require additional filtering, and we have estimated a correction factor of 1.025 for these filtration conditions for the same ESRF storage ring current. The protocol described herein provides reference dosimetry data for the associated Treatment Planning System utilized in the current veterinary trials and anticipated future human clinical trials.

Absolute dosimetry on a dynamically scanned sample for synchrotron radiotherapy using graphite calorimetry and ionization chambers.

The absolute dose delivered to a dynamically scanned sample in the Imaging and Medical Beamline (IMBL) on the Australian Synchrotron was measured with a graphite calorimeter anticipated to be established as a primary standard for synchrotron dosimetry. The calorimetry was compared to measurements using a free-air chamber (FAC), a PTW 31 014 Pinpoint ionization chamber, and a PTW 34 001 Roos ionization chamber. The IMBL beam height is limited to approximately 2 mm. To produce clinically useful beams of a few centimetres the beam must be scanned in the vertical direction. In practice it is the patient/detector that is scanned and the scanning velocity defines the dose that is delivered. The calorimeter, FAC, and Roos chamber measure the dose area product which is then converted to central axis dose with the scanned beam area derived from Monte Carlo (MC) simulations and film measurements. The Pinpoint chamber measures the central axis dose directly and does not require beam area measurements. The calorimeter and FAC measure dose from first principles. The calorimetry requires conversion of the measured absorbed dose to graphite to absorbed dose to water using MC calculations with the EGSnrc code. Air kerma measurements from the free air chamber were converted to absorbed dose to water using the AAPM TG-61 protocol. The two ionization chambers are secondary standards requiring calibration with kilovoltage x-ray tubes. The Roos and Pinpoint chambers were calibrated against the Australian primary standard for air kerma at the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA). Agreement of order 2% or better was obtained between the calorimetry and ionization chambers. The FAC measured a dose 3-5% higher than the calorimetry, within the stated uncertainties.

Eosinophil-Associated Gene Pathways but not Eosinophil Numbers are Differentially Regulated between Synchrotron Microbeam Radiation Treatment and Synchrotron Broad-Beam Treatment by 48 Hours Postirradiation.

Synchrotron microbeam radiation treatment (MRT) is a preclinical radiotherapy technique with considerable clinical promise, although some of the underlying radiobiology of MRT is still not well understood. In recently reported studies, it has been suggested that MRT elicits a different tumor immune profile compared to broad-beam treatment (BB). The aim of this study was to investigate the effects of synchrotron MRT and BB on eosinophil-associated gene pathways and eosinophil numbers within and around the tumor in the acute stage, 48 h postirradiation. Balb/C mice were inoculated with EMT6.5 mouse mammary tumors and irradiated with microbeam radiation (112 and 560 Gy) and broad-beam radiation (5 and 9 Gy) at equivalent doses determined from a previous in vitro study. After tumors were collected 24 and 48 h postirradiation, RNA was extracted and quantitative PCR performed to assess eosinophil-associated gene expression. Immunohistochemistry was performed to detect two known markers of eosinophils: eosinophil-associated ribonucleases (EARs) and eosinophil major basic protein (MBP). We identified five genes associated with eosinophil function and recruitment (Ear11, Ccl24, Ccl6, Ccl9 and Ccl11) and all of them, except Ccl11, were differentially regulated in synchrotron microbeam-irradiated tumors compared to broad-beam-irradiated tumors. However, immunohistochemical localization demonstrated no significant differences in the number of EAR- and MBP-positive eosinophils infiltrating the primary tumor after MRT compared to BB. In conclusion, our work demonstrates that the effects of MRT on eosinophil-related gene pathways are different from broad-beam radiation treatment at doses previously demonstrated to be equivalent in an in vitro study. However, a comparison of the microenvironments of tumors, which received MRT and BB, 48 h after exposure showed no difference between them with respect to eosinophil accumulation. These findings contribute to our understanding of the role of differential effects of MRT on the tumor immune response.

High spatial resolution dosimetric response maps for radiotherapy ionization chambers measured using kilovoltage synchrotron radiation.

Small circular beams of synchrotron radiation (0.1 mm and 0.4 mm in diameter) were used to irradiate ionization chambers of the types commonly used in radiotherapy. By scanning the chamber through the beam and measuring the ionization current, a spatial map of the dosimetric response of the chamber was recorded. The technique is able to distinguish contributions to the large-field ionization current from the chamber walls, central electrode and chamber stem. Scans were recorded for the NE 2571 Farmer chamber, the PTW 30013, IBA FC65-G Farmer-type chambers, the NE 2611A and IBA CC13 thimble chambers, the PTW 31006 and 31014 pinpoint chambers, the PTW Roos and Advanced Markus plane-parallel chambers, and the PTW 23342 thin-window soft x-ray chamber. In all cases, large contributions to the response arise from areas where the incident beam grazes the cavity surfaces. Quantitative as well as qualitative information about the relative chamber response was extracted from the maps, including the relative contribution of the central electrode. Line scans using monochromatic beams show the effect of the photon energy on the chamber response. For Farmer-type chambers, a simple Monte Carlo model was in good agreement with the measured response.

Biodosimetric quantification of short-term synchrotron microbeam versus broad-beam radiation damage to mouse skin using a dermatopathological scoring system.

OBJECTIVES: Microbeam radiotherapy (MRT) with wafers of microscopically narrow, synchrotron generated X-rays is being used for pre-clinical cancer trials in animal models. It has been shown that high dose MRT can be effective at destroying tumours in animal models, while causing unexpectedly little damage to normal tissue. The aim of this study was to use a dermatopathological scoring system to quantify and compare the acute biological response of normal mouse skin with microplanar and broad-beam (BB) radiation as a basis for biological dosimetry. METHOD: The skin flaps of three groups of mice were irradiated with high entrance doses (200 Gy, 400 Gy and 800 Gy) of MRT and BB and low dose BB (11 Gy, 22 Gy and 44 Gy). The mice were culled at different time-points post-irradiation. Skin sections were evaluated histologically using the following parameters: epidermal cell death, nuclear enlargement, spongiosis, hair follicle damage and dermal inflammation. The fields of irradiation were identified by γH2AX-positive immunostaining. RESULTS: The acute radiation damage in skin from high dose MRT was significantly lower than from high dose BB and, importantly, similar to low dose BB. CONCLUSION: The integrated MRT dose was more relevant than the peak or valley dose when comparing with BB fields. In MRT-treated skin, the apoptotic cells of epidermis and hair follicles were not confined to the microbeam paths.

Intra-cavitary dosimetry for IMRT head and neck treatment using thermoluminescent dosimeters in a naso-oesophageal tube.

Complex intensity-modulated radiation therapy (IMRT) treatment plans require rigorous quality assurance tests. The aim of this study was to independently verify the delivered dose inside the patient in the region of the treatment site. A flexible naso-gastric tube containing thermoluminescent dosimeters (TLDs) was inserted into the oesophagus via the sinus cavity before the patient's first treatment. Lead markers were also inserted into the tube in order that the TLD positions could be accurately determined from the lateral and anterior-posterior electronic portal images taken prior to treatment. The measured dose was corrected for both daily linac output variations and the estimated dose received from the portal images. The predicted dose for each TLD was determined from the treatment planning system and compared to the measured TLD doses. The results comprise 431 TLD measurements on 43 patients. The mean measured-to-predicted dose ratio was 0.988 +/- 0.011 (95% confidence interval) for measured doses above 0.2 Gy. There was a variation in this ratio when the measurements were separated into low dose (0.2-1.0 Gy), medium dose (1.0-1.8 Gy) and high dose (>1.8 Gy) measurements. The TLD-loaded, naso-oesophageal tube for in vivo dose verification is straightforward to implement, and well tolerated by patients. It provides independent reassurance of the delivered dose for head and neck IMRT.

A method of dosimetry for synchrotron microbeam radiation therapy using radiochromic films of different sensitivity.

This paper describes a method of film dosimetry used to measure the peak-to-valley dose ratios for synchrotron microbeam radiation therapy (MRT). Two types of radiochromic film (manufactured by International Specialty Products, NJ, USA) were irradiated in a phantom and also flush against a microbeam collimator (beam width 25 microm, centre-to-centre spacing 200 microm) on beamline BL28 B2 at the SPring-8 synchrotron. Four experiments are reported: (1) the HD-810 and EBT varieties of radiochromic film were used to record 'peak' dose and 'valley' (regions in between peaks) dose, respectively; (2) a stack of HD-810 film sheets was microbeam-irradiated and analysed to investigate a possible dose build-up effect; (3) a very high MRT dose was delivered to HD-810 film to elicit a measurable valley dose to compare with the result obtained using broad beam radiation; (4) the half value layer of the beam with and without the microbeam collimator was measured to investigate the effect of the collimator on the beam quality. The valley dose obtained for films placed flush against the collimator was approximately 0.2% of the peak dose. Within the water phantom, the valley dose had increased to between 0.7 and 1.8% of the peak dose, depending on the depth in the phantom. We also demonstrated, experimentally and by Monte Carlo simulation, that the dose is not maximal on the surface and that there is a dose build-up effect. The microbeam collimator did not make an appreciable difference to the beam quality. The values of the peak-to-valley ratio reported in this paper are higher than those predicted by previously published Monte Carlo simulation papers.

In-vivo dosimetry from total body irradiation patients (2000-2006): results and analysis.

In-vivo dosimetry is an important technique to ensure accuracy of delivered dose during total body irradiation (TBI). We present an analysis of semiconductor diode dosimetry, constituting seven years of dosimetry data from eighty-six patients who underwent total body irradiation. For lateral field irradiation, the mean exit dose, averaged over five anatomical sites (head, sternal notch, chest, abdomen and pelvis) and as a percentage of the planned dose was 95.7% (SD 7.8%). For AP/PA irradiation, the mean exit dose averaged over five anatomical sites and as a percentage of the planned dose was 95.5% (SD 9.8%). We propose a number of possible reasons for these differences, including patient setup variations, movement of the patient and diodes during treatment, imprecise placement of planned bolus material, inaccurate inhomogeneity corrections and modelling by the treatment planning system.

Cirugía de control de daños: análisis fisiopatológico e implicancias / Demage control surgery: phisio-pathologic analysis and involves

Antecedentes: La cirugía "por etapas" o "de control de daños" ha cambiado conceptualmente el manejo de pacientes en estado "in tremis". estos pueden tener una patología de base traumática, ginecoobstétrica o bien de cualquier otro origen que descompese su sistema cardiovascular o metabólico. Si bien es un concepto fisiopatológico moderno, el origen se remonta a los primeros años del siglo XX. Objetivos: Evaluar la experiencia de nuestro hospital en el manejo de pacientes sometidos a la táctica del "control de daño". Diseño: Estudio de evaluación retrospectiva. Población: pacientes que ingresaron con traumatismos en abdomen y que fueron declarados "in extremis" ante el estado metabólico y/o cardiovascular. Método: Se evaluaron 41 pacientes de los cuales veinte eran traumatismos hepáticos, siete traumatismos pelvianos, cinco traumatismos de hipocondrio izquierdo, otros cinco con traumatismos retroperitoneales en zona ll y otros cuatro con traumatismo duodenopancreático. Resultados: Con una mortalidad global de 18 casos (43,9 por ciento), los que presentaron mayor mortalidad grupal fueron los de hipocondrio izquierdo (60 por ciento) y los retroperitoneales (60 por ciento), finalmente los pelvianos con 57,1 por ciento y los duodenopancreáticos con 50 por ciento. Los traumatismos hepáticos presentaron una mortalidad del 30 por ciento. Conclusiones: Es una táctica clinicoquirúrgica para un grupo reducido de pacientes cuyo estado hemodinámico y/o metabólico presenta alta mortalidad. La indicación de la incorporación del paciente a la sistemática del control del daño es del cirujano. Los resultados obtenidos dependen además de la calidad profesional y técnica de los Servicios de Terapia Intensiva, Anestesia y Hemoterapia. El control del daño mantiene elevada aún la mortalidad. El hecho está relacionado con la condición de extrema gravedad de cada uno de los pacientes. Debe tenerse presente que sólo entre un 5 y un 9 por ciento de los traumatizados graves reúne criterios de aplicación de esta terapéutica (AU)

Cirugía de control de daños: análisis fisiopatológico e implicancias / Demage control surgery: phisio-pathologic analysis and involves

Antecedentes: La cirugía "por etapas" o "de control de daños" ha cambiado conceptualmente el manejo de pacientes en estado "in tremis". estos pueden tener una patología de base traumática, ginecoobstétrica o bien de cualquier otro origen que descompese su sistema cardiovascular o metabólico. Si bien es un concepto fisiopatológico moderno, el origen se remonta a los primeros años del siglo XX. Objetivos: Evaluar la experiencia de nuestro hospital en el manejo de pacientes sometidos a la táctica del "control de daño". Diseño: Estudio de evaluación retrospectiva. Población: pacientes que ingresaron con traumatismos en abdomen y que fueron declarados "in extremis" ante el estado metabólico y/o cardiovascular. Método: Se evaluaron 41 pacientes de los cuales veinte eran traumatismos hepáticos, siete traumatismos pelvianos, cinco traumatismos de hipocondrio izquierdo, otros cinco con traumatismos retroperitoneales en zona ll y otros cuatro con traumatismo duodenopancreático. Resultados: Con una mortalidad global de 18 casos (43,9 por ciento), los que presentaron mayor mortalidad grupal fueron los de hipocondrio izquierdo (60 por ciento) y los retroperitoneales (60 por ciento), finalmente los pelvianos con 57,1 por ciento y los duodenopancreáticos con 50 por ciento. Los traumatismos hepáticos presentaron una mortalidad del 30 por ciento. Conclusiones: Es una táctica clinicoquirúrgica para un grupo reducido de pacientes cuyo estado hemodinámico y/o metabólico presenta alta mortalidad. La indicación de la incorporación del paciente a la sistemática del control del daño es del cirujano. Los resultados obtenidos dependen además de la calidad profesional y técnica de los Servicios de Terapia Intensiva, Anestesia y Hemoterapia. El control del daño mantiene elevada aún la mortalidad. El hecho está relacionado con la condición de extrema gravedad de cada uno de los pacientes. Debe tenerse presente que sólo entre un 5 y un 9 por ciento de los traumatizados graves reúne criterios de aplicación de esta terapéutica

Tratamiento no operatorio en el traumatismo abdominal cerrado: análisis preliminar / Non operative management for blunt solid organ abdominal trauma

Antecedentes: Es controvertido el tratamiento no operatorio en el traumatismo abdominal cerrado. Establecida la causa mecánica, los cirujanos tuvieron históricamente tendencia a la exploración quirúrgica en los traumatismos moderados y graves. Objetivo: Analizar una secuencia de tratamiento no operatorio en el traumatismo abdominal cerrado tipos I, II y III (de acuerdo a la clasificación AAST). Lugar de aplicación: Departamento de Cirugía General, Complejo Médico-Hospitalario de Fuerzas de Seguridad. Diseño: Estudio prospectivo observacional. Material y métodos: 39 pacientes con traumatismo abdominal cerrado con criterios de inclusión para análisis secuencial de tratamiento no operatorio: 12 hepáticos, 15 renales y 12 esplénicos. Resultados: Se encontró 0 por ciento de mortalidad con 4 fallas terapéuticos (10,2 por ciento) una hepática y 3 esplénicas. No hubo fallas con trauma renal. Internación hospitalaria prolongada en lesiones esplénicas. Conclusiones: Sólo en centros asistenciales con dedicación al trauma con disponibilidad de diagnósticos imagenológicos las 24 hs del día con protocolos de inclusión y exclusión de pacientes pueden realizar tratamiento no operatorio. Deben involucrarse en ésto autoridades y cirujanos actuantes debido al costo de internaciones prolongadas. Desventajas incluyen el retardo en la decisión quirúrgica. La principal ventaja es la disminución de laparotomías innecesarias

Tratamiento no operatorio en el traumatismo abdominal cerrado: análisis preliminar / Non operative management for blunt solid organ abdominal trauma

Antecedentes: Es controvertido el tratamiento no operatorio en el traumatismo abdominal cerrado. Establecida la causa mecánica, los cirujanos tuvieron históricamente tendencia a la exploración quirúrgica en los traumatismos moderados y graves. Objetivo: Analizar una secuencia de tratamiento no operatorio en el traumatismo abdominal cerrado tipos I, II y III (de acuerdo a la clasificación AAST). Lugar de aplicación: Departamento de Cirugía General, Complejo Médico-Hospitalario de Fuerzas de Seguridad. Diseño: Estudio prospectivo observacional. Material y métodos: 39 pacientes con traumatismo abdominal cerrado con criterios de inclusión para análisis secuencial de tratamiento no operatorio: 12 hepáticos, 15 renales y 12 esplénicos. Resultados: Se encontró 0 por ciento de mortalidad con 4 fallas terapéuticos (10,2 por ciento) una hepática y 3 esplénicas. No hubo fallas con trauma renal. Internación hospitalaria prolongada en lesiones esplénicas. Conclusiones: Sólo en centros asistenciales con dedicación al trauma con disponibilidad de diagnósticos imagenológicos las 24 hs del día con protocolos de inclusión y exclusión de pacientes pueden realizar tratamiento no operatorio. Deben involucrarse en ésto autoridades y cirujanos actuantes debido al costo de internaciones prolongadas. Desventajas incluyen el retardo en la decisión quirúrgica. La principal ventaja es la disminución de laparotomías innecesarias (AU)