ABSTRACT
Objective To evaluate the dosimetric difference between carbon ion radiotherapy and photon radiotherapy for treating tumors at lacrimal system. Methods Using the CT images of 10 patients with tumors at lacrimal system, the carbon ion plan, the photon volume intensity modulation plan ( VMAT) and the fixed wild photon intensity modulation radiotherapy ( IMRT) plan were generated. The prescription was 54 Gy(RBE) in 18 fractions for clinical target volume (CTV) and 63 Gy(RBE) in 18 fractions for CTV-boost. Dosimetric differences of organ at risks were compared based on the same planning target volumes ( PTVs) with similar dose coverages. Results There was no statistically significant difference in the PTV coverage among three plans ( P>0. 05) . Compared to VMAT and IMRT plans, carbon ion plans reduced the mean doses of eyeballs, mean doses and near-maximum doses of optical nerves of both ipsilateral ( t=7. 35, 3. 79, 4. 66, 8. 48, 2. 52, 2. 76, P<0. 05 ) and contralateral eyes ( t=3. 87, 10. 49, 9. 16, 4. 43, 6. 53, 5. 12, P<0. 05), while the mean dose of brain was decreased from(5. 65± 3. 58) and ( 5. 76 ± 2. 09 ) Gy ( RBE ) to ( 0. 81 ± 0. 90 ) Gy ( RBE ) ( t= 6. 76, 17. 33, P<0. 05 ) . Conclusions Compared to photon VMAT or IMRT, carbon ion could reduce the doses to optical critical organs around tumors. Thus, carbon ion radiotherapy has potential to reduce patients' radiation related side-effects.
ABSTRACT
Objective@#To evaluate the dosimetric difference between carbon ion radiotherapy and photon radiotherapy for treating tumors at lacrimal system.@*Methods@#Using the CT images of 10 patients with tumors at lacrimal system, the carbon ion plan, the photon volume intensity modulation plan (VMAT) and the fixed wild photon intensity modulation radiotherapy (IMRT) plan were generated. The prescription was 54 Gy(RBE) in 18 fractions for clinical target volume (CTV) and 63 Gy(RBE) in 18 fractions for CTV-boost. Dosimetric differences of organ at risks were compared based on the same planning target volumes (PTVs) with similar dose coverages.@*Results@#There was no statistically significant difference in the PTV coverage among three plans (P>0.05). Compared to VMAT and IMRT plans, carbon ion plans reduced the mean doses of eyeballs, mean doses and near-maximum doses of optical nerves of both ipsilateral ( t=7.35, 3.79, 4.66, 8.48, 2.52, 2.76, P<0.05) and contralateral eyes (t=3.87, 10.49, 9.16, 4.43, 6.53, 5.12, P<0.05), while the mean dose of brain was decreased from(5.65±3.58) and (5.76±2.09)Gy(RBE) to (0.81±0.90)Gy(RBE) (t=6.76, 17.33, P<0.05).@*Conclusions@#Compared to photon VMAT or IMRT, carbon ion could reduce the doses to optical critical organs around tumors. Thus, carbon ion radiotherapy has potential to reduce patients′ radiation related side-effects.
ABSTRACT
La presente revisión de tema ojo seco está orientada a médicos no oftalmólogos. Se realiza un repaso de la anatomía del sistema lagrimal y fisiología básica de la película lagrimal. Se define el concepto de ojo seco, su importancia epidemiológica y su sintomatología. Se realiza un detallado análisis de la clasificación etiológica definiendo las diferencias entre hipolacrimea asociada o no a síndrome de Sjõgren y ojo seco evaporativo de causa intrínseca y extrínseca, con énfasis en los mecanismos fisiopatológicos subyacentes. Se entrega una visión que da cuenta de la complejidad, envergadura y condición multifactorial de este problema de salud visual y se hace énfasis en la necesidad de identificar de manera integral el tipo de ojo seco para poder instalar un tratamiento basado en la corrección del mecanismo subyacente y no a través de aproximación sintomática de la terapia.
The current review of dry eye disease is directed to non ophthalmologist physicians. We perform an assessment of the anatomy of the lacrimal system and basic physiology of the tear film. The definition of dry eye, its epidemiologic importance and symptoms are explained. A detailed analysis of the etiologic classification is described defining the difference between reduction in tear secretion associated or not to Sjõgren's syndrome and evaporative dry eye of intrinsic or extrinsic origin. We highlight the underlying pathophysiologic mechanisms, conveying the complexity, broadness and multi-factorial conditions related to this visual health problem. We stress the need for identifying in a comprehensive manner the type of dry eye in order to install a treatment based on the underlying mechanism and not through a symptomatic approach to therapy.
Subject(s)
Humans , Dry Eye Syndromes/classification , Dry Eye Syndromes/etiology , Dry Eye Syndromes/physiopathology , Dry Eye Syndromes/epidemiology , Lacrimal Apparatus/anatomy & histology , Lacrimal Apparatus/physiologyABSTRACT
Os autores relatam o caso de um paciente com lacrimejamento bilateral, que à dacriocistografia apresentou acentuada dilatação do sistema lacrimal, sem sinais de obstrução. Na prática clínica, é comum o encontro de dilatação de vias lacrimais, geralmente em associação a obstrução distal destas. A ausência de fator obstrutivo no caso descrito suscitou a hipótese de tratar-se de variação anatômica. O objeto do presente estudo é a análise desta hipótese por meio de revisão da literatura sobre a anatomia normal e variações das vias lacrimais. Também é descrita a técnica de realização da dacriocistografia com subtração digital em nossa instituição e sua correlação com os achados tomográficos.
The authors report the case of a patient with tear discharge in both eyes. A dacryocystography was obtained and showed marked dilation of the lacrimal system without signs of obstruction. In clinical practice it is common to find distal obstruction of the lacrimal system causing enlargement. The absence of an obstructive factor in our case was considered an anatomical variation. The purpose of this study is to analyze, by reviewing the literature, the normal anatomy and variations of the lacrimal system. It is also described a digital subtraction dacryocystography's technique performed in our institution and the correlation with tomographyfindings.
Subject(s)
Humans , Male , Adult , Lacrimal Apparatus/anatomy & histology , Lacrimal Apparatus/physiology , Lacrimal Apparatus , Dilatation, Pathologic , Tomography, X-Ray ComputedABSTRACT
Os autores realizam um estudo revisional e iconográfico das vias lacrimais através dos métodos radiológicos, sendo eles a radiografia convencional, a tomografia linear, a tomografia computadorizada e a ressonância magnética. Os métodos de imagem são fundamentais para definir diagnóstico e terapia, pois, além de demonstrarem as alterações das vias lacrimais, sugerem quais os pacientes que terão melhor prognóstico com a abordagem cirúrgica. Pelo seu custo mais baixo, menor dose de radiação, baixo índice de complicações e pela informação que pode ser obtida, recomenda-se que a dacriocistografia por tomografia linear seja o método inicial de investigação.
The authors perform a revisional and iconographic study of the lacrimal system by means of radiological methods, namely, conventional radiography, linear tomography, computed tomography and magnetic resonance imaging. Image methods are essential to define diagnosis and therapy, considering that besides demonstrating alterations of the lacrimal system, they may indicate the patients with better prognosis associated with the surgical approach. Considering the lower cost, lower radiation dose, low rate of complications, and level of information that can be obtained dacryocystography by means of linear tomography is recommended as the initial investigation method.
Subject(s)
Humans , Lacrimal Apparatus/physiopathology , Lacrimal Duct Obstruction/diagnosis , Dacryocystorhinostomy , Diagnostic ImagingABSTRACT
Neste artigo são descritos três casos de pacientes que apresentavam epífora, os quais foram submetidos à realização de estudo dacriocistográfico e se tornaram assintomáticos, sem a necessidade de qualquer outro procedimento ou medicamento. Ressalta-se o potencial terapêutico do método, pois a literatura sobre este assunto é escassa em crianças e nenhuma em adultos.
We describe three cases of patients that presented epiphora having been submitted the accomplishment of dacryocystographic study, which ones turned asymptomatic after the accomplishment of the exam, without any other procedure or medicine. The therapeutic potential of the method is stood out, once the literature onthis subject is scarce in children and none in adults.
Subject(s)
Humans , Male , Female , Middle Aged , Dacryocystorhinostomy , Lacrimal Duct Obstruction/therapyABSTRACT
Dacryocystography has been widely used in the assessment of the lacrimal passage system, particularly in patients with epiphora. The site of obstruction and presence of fistulas, tumors, diverticula, or calculi can be evaluated, so that therapy can be accurately planned. It has been reported by other authors about the results of dacryocystography in Korea, but there were not enough subjects to study. A retrospective study has been carried out on 171 patients(194 eyes) who have undergone dacryocystography for epiphora at Kangbuk Samsung hospital from December 1992 to June 1993, to assess age, sex, duration of epiphora, previous treatments, incidence rate of obstruction site of the lacrimal system, causes of lacrimal obstruction. The incidence rate of lacrimal system obstruction on dacryocystography was 172 eyes(88.7%). The most common site of obstruction was nasolacrimal duct(107 eyes, 55.2%) and then inferior canaliculus(30 eye, 15.5%), lacrimal sac(18 eyes, 9.3%) and common canaliculus(17 eyes, 8.8%). The most common cause of obstruction was unknown(89 eyes, 51.7%), and then chronic dacryocystitis (45 eyes, 26.2%), congenital(14 eyes, 8.1 %).