Feasibility study of patient positioning verification in electron beam radiotherapy with an electronic portal imaging device (EPID).

The purpose of this study is to demonstrate the feasibility of verification and documentation in electron beam radiotherapy using the photon contamination detected with an electronic portal imaging device. For investigation of electron beam verification with an EPID, the portal images are acquired irradiating two different tissue equivalent phantoms at different electron energies. Measurements were performed on an Elekta SL 25 linear accelerator with an amorphous-Si electronic portal imaging device (EPID: iViewGT, Elekta Oncology Systems, Crawley, UK). As a measure of EPID image quality contrast (CR) and signal-to-noise ratio (SNR) are determined. For characterisation of the imaging of the EPID RW3 slabs and a Gammex 467 phantom with different material inserts are used. With increasing electron energy the intensity of photon contamination increases, yielding an increasing signal-to-noise ratio, but images are showing a decreasing contrast. As the signal-to-noise ratio saturates with increasing dose a minimum of 50 MUs is recommended. Even image quality depends on electron energy and diameter of the patient, the acquired results are mostly sufficient to assess the accuracy of beam positioning. In general, the online EPID acquisition has been demonstrated to be an effective electron beam verification and documentation method. The results are showing that this procedure can be recommended to be routinely and reliably done in patient treatment with electron beams.

[Endonasal and endocanalicular dacryocystorhinostomy by diode laser. Preliminary results]. / Dacriocistorrinostomía endonasal y endocanalicular con láser diodo. Resultados preliminares.

AIM OF THE STUDY: To describe the surgical technique and to evaluate the clinical results after having performed the transcanalicular and endocanalicular dacryocystorhinostomies by diode laser, including the advantages and limits of this technique. METHODS: 34 were performed by diode laser in patients with clinical history of epiphora, with or without mucopurulent secretion, for nasolacrimal duct obstruction. The study was prospective, interventional, non randomized and non comparative. Diode laser was used to realize vaporization of lacrimal sac, osteotomy and vaporization with coagulation of nasal mucosa. The mean of surgical time was 15 minutes (range 7 to 29 minutes). Bicanalicular intubation was performed with a silicone tube and prolene filament for two months in all cases. Postsurgical follow-up was between 4 and 11 months. The degree of epiphora was evaluated by the Munk scale and lacrimal permeability was evaluated by endoscopic functional staining test in all cases. RESULTS: Out of the 34 DCR-EDN+ENC that were performed, 32 cases (94.11%) remain asymptomatic. Two of them (5.88%) required endonasal dacryocystorhinostomies by drilling, because the bony perforation was impossible to achieve by laser fiber. Two cases (5.88%) presented fibrosis and lacrimal and lower canaliculi obstruction, without epiphora because the superior canaliculi was permeable. CONCLUSION: Endonasal and endocanalicular dacryocystorhinostomy technique performed by diode laser is a valid method. It does not cause cutaneous scarring, it decreases thermic canalicular damage, it respects the lacrimal pump, it minimizes pain and bleeding, it needs less surgical time and it has turned into an out-patient procedure with a minimal surgical and postsurgical morbility.

Dacriocistorrinostomía endonasal y endocanalicular con láser diodo. Resultados preliminares / Endonasal and endocanalicular dacryocystorhinostomy by diode laser. Preliminary results

Objetivo: Detallar las maniobras quirúrgicas y valorar los resultados tras la realización de dacriocistorrinostomías endonasales y endocanaliculares con láser diodo, incluyéndolas ventajas y restricciones de esta cirugía. Método: Se practican 34 dacriocistorrinostomías endonasales y endocanaliculares con láser diodo bajo anestesia tópica y local en pacientes con clínica de epífora, con o sin secreción mucopurulenta, por obstrucción a nivel del conducto nasolagrimal. El estudio es prospectivo, intervencional, no randomizado y no comparativo. Se realiza vaporización de saco lagrimal, la osteotomía y la vaporización y coagulación de mucosa nasal con el láser diodo. El tiempo quirúrgico medio fue de 15 minutos (rango 9 - 25 minutos). En todos los procesos se efectúa intubación bicanalicular con tubos de silicona e hilo de prolene durante dos meses. El periodo observacional postquirúrgico fue entre 4 y 11 meses. En todos los pacientes se valoró el grado de epífora mediante la escala de Munk y la permeabilidad lagrimal con el test de tinción funcional endoscópica. Resultados: De las 34 dacriocistorrinostomías endonasales y endocanaliculares; permanecen asintomáticos 32 casos (94,11 por ciento). Dos (5,88 por ciento) pacientes precisaron de dacriocistorrinostomía endonasal con fresado por imposibilidad de perforación ósea con la fibra del láser. Dos casos (5,88 por ciento) presentaron fibrosis y obstrucción del punto lagrimal y canalículo inferior, estando sin epífora por permeabilidad del trayecto superior. Conclusiones: La dacriocistorrinostomía endonasal y endocanalicular con láser diodo es un procedimiento válido que no origina cicatriz en piel, disminuye el daño térmico canalicular, respeta el bombeo lagrimal excretor, minimiza el dolor y sangrado, y reduce el tiempo quirúrgico, siendo una cirugía ambulatoria con morbilidad operatoria y postquirúrgica mínima (AU)

AIM OF THE STUDY: To describe the surgical technique and to evaluate the clinical results after having performed the transcanalicular and endocanalicular dacryocystorhinostomies by diode laser, including the advantages and limits of this technique. METHODS: 34 were performed by diode laser in patients with clinical history of epiphora, with or without mucopurulent secretion, for nasolacrimal duct obstruction. The study was prospective, interventional, non randomized and non comparative. Diode laser was used to realize vaporization of lacrimal sac, osteotomy and vaporization with coagulation of nasal mucosa. The mean of surgical time was 15 minutes (range 7 to 29 minutes). Bicanalicular intubation was performed with a silicone tube and prolene filament for two months in all cases. Postsurgical follow-up was between 4 and 11 months. The degree of epiphora was evaluated by the Munk scale and lacrimal permeability was evaluated by endoscopic functional staining test in all cases. RESULTS: Out of the 34 DCR-EDN+ENC that were performed, 32 cases (94.11%) remain asymptomatic. Two of them (5.88%) required endonasal dacryocystorhinostomies by drilling, because the bony perforation was impossible to achieve by laser fiber. Two cases (5.88%) presented fibrosis and lacrimal and lower canaliculi obstruction, without epiphora because the superior canaliculi was permeable. CONCLUSION: Endonasal and endocanalicular dacryocystorhinostomy technique performed by diode laser is a valid method. It does not cause cutaneous scarring, it decreases thermic canalicular damage, it respects the lacrimal pump, it minimizes pain and bleeding, it needs less surgical time and it has turned into an out-patient procedure with a minimal surgical and postsurgical morbility (AU)