RESUMEN

The aims of the present study were to identify and describe the occurrence of nematode parasites in the gonads of bluefish Pomatomus saltatrix from off the coast of the state of Rio de Janeiro, Brazil. Only females were found to be parasitized by the nematodes, which were identified as P. saltatrix using morphological, morphometric and molecular data. Infection of female bluefish by this nematode had the following values: prevalence, 48.7%; mean intensity, 2.6; mean abundance, 1.3; and range of infection, 1-10 specimens. Histopathological examination of transverse and longitudinal sections of the parasitized ovaries showed nematodes at different stages of development among oocytes, but no indication of any associated inflammatory reaction. The presence of nematodes in the ovaries of bluefish is an important indication of fish hygiene, and parasitized fish are usually rejected by consumers because of their repugnant appearance.

Asunto(s)

RESUMEN

Fish consumption plays an important role in the human diet. Hoplias malabaricus, trahira, is a freshwater fish widely appreciated in several Brazilian states and it is frequently infected by Contracaecum multipapillatum third-instar larvae (L3). The aim of the present study was to evaluate the allergenic potential of the C. multipapillatum L3 crude extract (CECM). BALB/c mice were immunized intraperitoneally (ip) with 10 or 50 µg CECM associated with 2 mg of aluminium hydroxide on days 0, 14 and 48. The determination of specific IgG and IgE antibody levels was done after immunization, and the late immunity was evaluated by the intradermal reaction in the ear pavilion. Epicutaneous sensitization was performed in the dorsal region, with antigenic exposure via a Finn-type chamber, containing 100 µg of chicken ovum albumin (OVA) or 100 µg CECM. After the exposures, the specific antibody levels were determined. In the ip immunization, there was a gradual increase in IgG antibody levels, independent of CECM concentration. In relation to IgE production, it was transitory, and immunization with 10 µg was more efficient than that of 50 µg. The same result was observed in the cellular hypersensitivity reaction. In the case of antigen exposure by the epicutaneous route, it was verified that only CECM was able to induce detectable levels of specific IgG and IgE antibodies. In the present study it was demonstrated that both intraperitoneal immunization and epicutaneous contact with C. multipapillatum larval antigens are potentially capable of inducing allergic sensitization in mice.

Asunto(s)

RESUMEN

This study investigated the occurrence, prevalence, mean abundance and mean intensity of monogenoidean parasites in Piaractus mesopotamicus farmed in cages in the reservoir of the Itaipu Hydroelectric Power Station, Paraná River, Brazil. The parasite distribution pattern and the correlation of prevalence and abundance with the total length of hosts were also investigated. Four monogenoidean species were collected: Anacanthorus penilabiatus, A. toledoensis, Mymarothecium ianwhitingtoni and M. viatorum. All the parasites collected in P. mesopotamicus showed the typical aggregated distribution pattern, and the abundance and the prevalence did not shown any correlation with the total length of hosts.(AU)

Neste estudo foi investigada a ocorrência, prevalência, abundância média e intensidade média de Monogenoidea parasitos de Piaractus mesopotamicus, cultivados em tanques-rede no reservatório da Usina Hidrelétrica de Itaipu, rio Paraná, Brasil. Foram investigados ainda o padrão de distribuição parasitária e a correlação entre a prevalência e abundância com o comprimento total dos hospedeiros. Quatro espécies de Monogenoidea foram coletadas: Anacanthorus penilabiatus, A. toledoensis, Mymarothecium ianwhitingtoni e M. viatorum. Todos os parasitos coletados em P. mesopotamicus apresentaram típico padrão de distribuição agregada e não foi observada correlação entre a abundância e a prevalência e o comprimento total dos hospedeiros.(AU)

Asunto(s)

RESUMEN

Abstract This study investigated the occurrence, prevalence, mean abundance and mean intensity of monogenoidean parasites in Piaractus mesopotamicus farmed in cages in the reservoir of the Itaipu Hydroelectric Power Station, Paraná River, Brazil. The parasite distribution pattern and the correlation of prevalence and abundance with the total length of hosts were also investigated. Four monogenoidean species were collected: Anacanthorus penilabiatus, A. toledoensis, Mymarothecium ianwhitingtoni and M. viatorum. All the parasites collected in P. mesopotamicus showed the typical aggregated distribution pattern, and the abundance and the prevalence did not shown any correlation with the total length of hosts.

Resumo Neste estudo foi investigada a ocorrência, prevalência, abundância média e intensidade média de Monogenoidea parasitos de Piaractus mesopotamicus, cultivados em tanques-rede no reservatório da Usina Hidrelétrica de Itaipu, rio Paraná, Brasil. Foram investigados ainda o padrão de distribuição parasitária e a correlação entre a prevalência e abundância com o comprimento total dos hospedeiros. Quatro espécies de Monogenoidea foram coletadas: Anacanthorus penilabiatus, A. toledoensis, Mymarothecium ianwhitingtoni e M. viatorum. Todos os parasitos coletados em P. mesopotamicus apresentaram típico padrão de distribuição agregada e não foi observada correlação entre a abundância e a prevalência e o comprimento total dos hospedeiros.

Asunto(s)

RESUMEN

This study investigated the occurrence, prevalence, mean abundance and mean intensity of monogenoidean parasites in Piaractus mesopotamicus farmed in cages in the reservoir of the Itaipu Hydroelectric Power Station, Paraná River, Brazil. The parasite distribution pattern and the correlation of prevalence and abundance with the total length of hosts were also investigated. Four monogenoidean species were collected: Anacanthorus penilabiatus, A. toledoensis, Mymarothecium ianwhitingtoni and M. viatorum. All the parasites collected in P. mesopotamicus showed the typical aggregated distribution pattern, and the abundance and the prevalence did not shown any correlation with the total length of hosts.

Asunto(s)

RESUMEN

Anisaquidose é uma doença provocada por parasitos da família Anisakidae e se caracteriza por manifestações gastrointestinais e alérgicas. O Anisakis simplex é o parasito mais patogênico ao homem e altamente alergênico. Porém, outros anisaquídeos também são danosos aos humanos, mas é desconhecida a imunogenicidade dessas larvas. O objetivo deste trabalho foi avaliar o potencial imunogênico do parasito Hysterothylacium deardorffoverestreetorum (HD) em modelo murino. Camundongos da linhagem BALB/c foram divididos em três grupos experimentais e receberam as preparações antigênicas obtidas de larvas de HD: extrato bruto de larvas (EBH), extrato secretado/ excretado de larvas (ESH) e extrato bruto de larvas após excreção/secreção (EEH). Amostras séricas foram obtidas em diferentes dias após imunização para determinação dos níveis de anticorpos específicos pelo ensaio imunoenzimático (ELISA). Os resultados demonstram aumento na produção de imunoglobulina (Ig) G após a segunda imunização, com aumento progressivo após a terceira imunização. Já em relação à IgE, a reatividade foi mais tardia, demonstrando aumento progressivo após a terceira imunização. Foi avaliada a imunidade celular por meio da intradermorreação, como resultado estatisticamente significativo em relação ao controle utilizado. Este experimento é a primeira descrição da potencialidade patogênica desse parasito em mamíferos e representa um avanço no diagnóstico da anisaquidose humana.(AU)

Anisaquidosis is a disease caused by parasites of Anisakidae family and is characterized by gastrointestinal and allergic reactions. The Anisakis simplex is a more pathogenic Anisakidae to humans and is highly allergenic. However, other species of this family also have characteristics that are harmful to humans, but little is known about the immunogenicity this parasites. The objective of this study was to experimentally assess the immunogenic potential of the parasite Hysterothylacium deardorffoverestreetorum (H.D) in mice. Mice of inbred BALB/c strain were divided into three groups and received three immunizations of the following antigenic preparations obtained from L3 larvae H.D: Crude larval extract of H.D (CEH) Extract secreted / excreted larvae H.D. (ESH) and crude extract of larvae after excretion / secretion (EEH). Serum samples were obtained on different days after immunization to determine the levels of circulating specific antibodies by enzyme-linked immunosorbent assay (ELISA). The results show increased production of immunoglobulin (Ig) G after the second immunization with a gradual increase after the third immunization. Regarding IgE reactivity, this occurred later, demonstrating a progressive increase only after the third immunization. Cellular immunity was evaluated by intradermal, and showed statistically significant result compared to the control used. This experiment is the first description of the pathogenic potential of this parasite in mammals and represents a breakthrough in the diagnosis of human Anisakidosis.(AU)

Asunto(s)

RESUMEN

Anisaquidose é uma doença provocada por parasitos da família Anisakidae e se caracteriza por manifestações gastrointestinais e alérgicas. O Anisakis simplex é o parasito mais patogênico ao homem e altamente alergênico. Porém, outros anisaquídeos também são danosos aos humanos, mas é desconhecida a imunogenicidade dessas larvas. O objetivo deste trabalho foi avaliar o potencial imunogênico do parasito Hysterothylacium deardorffoverestreetorum (HD) em modelo murino. Camundongos da linhagem BALB/c foram divididos em três grupos experimentais e receberam as preparações antigênicas obtidas de larvas de HD: extrato bruto de larvas (EBH), extrato secretado/ excretado de larvas (ESH) e extrato bruto de larvas após excreção/secreção (EEH). Amostras séricas foram obtidas em diferentes dias após imunização para determinação dos níveis de anticorpos específicos pelo ensaio imunoenzimático (ELISA). Os resultados demonstram aumento na produção de imunoglobulina (Ig) G após a segunda imunização, com aumento progressivo após a terceira imunização. Já em relação à IgE, a reatividade foi mais tardia, demonstrando aumento progressivo após a terceira imunização. Foi avaliada a imunidade celular por meio da intradermorreação, como resultado estatisticamente significativo em relação ao controle utilizado. Este experimento é a primeira descrição da potencialidade patogênica desse parasito em mamíferos e representa um avanço no diagnóstico da anisaquidose humana.(AU)

Anisaquidosis is a disease caused by parasites of Anisakidae family and is characterized by gastrointestinal and allergic reactions. The Anisakis simplex is a more pathogenic Anisakidae to humans and is highly allergenic. However, other species of this family also have characteristics that are harmful to humans, but little is known about the immunogenicity this parasites. The objective of this study was to experimentally assess the immunogenic potential of the parasite Hysterothylacium deardorffoverestreetorum (H.D) in mice. Mice of inbred BALB/c strain were divided into three groups and received three immunizations of the following antigenic preparations obtained from L3 larvae H.D: Crude larval extract of H.D (CEH) Extract secreted / excreted larvae H.D. (ESH) and crude extract of larvae after excretion / secretion (EEH). Serum samples were obtained on different days after immunization to determine the levels of circulating specific antibodies by enzyme-linked immunosorbent assay (ELISA). The results show increased production of immunoglobulin (Ig) G after the second immunization with a gradual increase after the third immunization. Regarding IgE reactivity, this occurred later, demonstrating a progressive increase only after the third immunization. Cellular immunity was evaluated by intradermal, and showed statistically significant result compared to the control used. This experiment is the first description of the pathogenic potential of this parasite in mammals and represents a breakthrough in the diagnosis of human Anisakidosis.(AU)

Asunto(s)

RESUMEN

O objetivo do presente estudo foi registrar a ocorrência de larva de nematoide da família Raphidascarididae, Hysterothylacium deardorffoverstreetorum, em bijupirá Rachycentron canadum (Linnaeus, 1766), criado e alimentado com ração e "trashfish" em fazendas marinhas localizadas no Rio de Janeiro, Brasil, alertando para possíveis riscos zoonóticos ao se usar esse tipo de alimentação para criação de peixes. Foram necropsiados 15 animais. Os parasitas encontrados foram coletados, fixados e, posteriormente, conservados em álcool a 70°GL, clarificados e identificados. Em todos os animais necropsiados, apenas um espécime estava parasitado com uma larva de Hysterothylacium deardorffoverstreetorum na serosa do fígado do peixe e conclui-se que a presença desse parasita em bijupirá de criação alimentado por "trashfish pode estar associada à alimentação, indicando, assim, um potencial risco zoonótico.(AU)

The aim of this study was to record the occurrence of nematode larvae of the Raphidascarididae family, Hysterothylacium deardorffoverstreetorum in cobia Rachycentron canadum (Linnaeus, 1766) grown and fed with trashfish in marine farms located in Rio de Janeiro, Brazil, warning regarding possible zoonotic risk using this type of food for fish. Fifteen animals were necropsied. Parasites found were collected, fixed and later preserved in alcohol 70°GL, clarified and identified. In all animals necropsied, only one specimen was infested with a Hysterothylacium deardorffoverstreetorum larvae in the serosa of fish liver. It is concluded that the presence of the parasite in cobia culture fed with trashfish may be associated with a potential zoonotic risk.(AU)

Asunto(s)

RESUMEN

O objetivo do presente estudo foi registrar a ocorrência de larva de nematoide da família Raphidascarididae, Hysterothylacium deardorffoverstreetorum, em bijupirá Rachycentron canadum (Linnaeus, 1766), criado e alimentado com ração e "trashfish" em fazendas marinhas localizadas no Rio de Janeiro, Brasil, alertando para possíveis riscos zoonóticos ao se usar esse tipo de alimentação para criação de peixes. Foram necropsiados 15 animais. Os parasitas encontrados foram coletados, fixados e, posteriormente, conservados em álcool a 70°GL, clarificados e identificados. Em todos os animais necropsiados, apenas um espécime estava parasitado com uma larva de Hysterothylacium deardorffoverstreetorum na serosa do fígado do peixe e conclui-se que a presença desse parasita em bijupirá de criação alimentado por "trashfish pode estar associada à alimentação, indicando, assim, um potencial risco zoonótico.(AU)

The aim of this study was to record the occurrence of nematode larvae of the Raphidascarididae family, Hysterothylacium deardorffoverstreetorum in cobia Rachycentron canadum (Linnaeus, 1766) grown and fed with trashfish in marine farms located in Rio de Janeiro, Brazil, warning regarding possible zoonotic risk using this type of food for fish. Fifteen animals were necropsied. Parasites found were collected, fixed and later preserved in alcohol 70°GL, clarified and identified. In all animals necropsied, only one specimen was infested with a Hysterothylacium deardorffoverstreetorum larvae in the serosa of fish liver. It is concluded that the presence of the parasite in cobia culture fed with trashfish may be associated with a potential zoonotic risk.(AU)

Asunto(s)

RESUMEN

Este trabalho registra a ocorrência espontânea de ameloblastoma em P. scalare. O tumor foi obtido a partir de um exemplar de Acará Bandeira, sendo fixado, seccionado, e os fragmentos processados para microscopia de luz e microscopia eletrônica de varredura (MEV). O exame macroscópico evidenciou uma massa tumoral que se estendia do rebordo alveolar do maxilar superior à face externa labial. À MEV, a neoplasia apresentou uma série de espículas. Microscopicamente, percebia-se um processo neoplásico constituído por tecido conjuntivo de característica mixoide, ricamente vascularizado, onde eram observados fragmentos de tecido osteoide. A amostra revelou proliferação neoplásica do epitélio odontogênico, onde as células neoplásicas se organizavam na forma de paliçada. Alterações histopatológicas em peixes têm sido úteis biomarcadores do efeito à exposição a substâncias tóxicas, sendo as neoplasias lesões específicas, comumente encontradas em peixes de áreas poluídas, revelando uma associação entre as lesões e a exposição a irritantes.(AU)

Asunto(s)

RESUMEN

Este trabalho registra a ocorrência espontânea de ameloblastoma em P. scalare. O tumor foi obtido a partir de um exemplar de Acará Bandeira, sendo fixado, seccionado, e os fragmentos processados para microscopia de luz e microscopia eletrônica de varredura (MEV). O exame macroscópico evidenciou uma massa tumoral que se estendia do rebordo alveolar do maxilar superior à face externa labial. À MEV, a neoplasia apresentou uma série de espículas. Microscopicamente, percebia-se um processo neoplásico constituído por tecido conjuntivo de característica mixoide, ricamente vascularizado, onde eram observados fragmentos de tecido osteoide. A amostra revelou proliferação neoplásica do epitélio odontogênico, onde as células neoplásicas se organizavam na forma de paliçada. Alterações histopatológicas em peixes têm sido úteis biomarcadores do efeito à exposição a substâncias tóxicas, sendo as neoplasias lesões específicas, comumente encontradas em peixes de áreas poluídas, revelando uma associação entre as lesões e a exposição a irritantes.(AU)

Asunto(s)

RESUMEN

Total mercury concentrations were determined by atomic absorption spectrometry in muscle tissue of two commercially important species of carnivorous fishes croaker (Micropogonias furnieri) and cutlassfish (Trichiurus lepturus) caught in Itaipu estuary, Rio de Janeiro. In this study, whitemouth croaker presented more mercury than Atlantic cutlassfish. Bioaccumulation differences can be explained by the biological behavior of juveniles whitemouth croaker, that remain in the estuary up to maturity, which makes them good indicators of local environmental impacts (0.110 mg Kg(-1) HgT). It also can be explained by differences in nutritional requirements between the different life stages of two species. The analysis showed the presence of low levels of the metal. However, our results suggest a possible risk to human health, depending on the level of fish consumption.

Asunto(s)

RESUMEN

The aim of this study was to verify the immunogenicity of Pterobothrium heteracanthum (Cestoda: Trypanorhyncha) crude protein extract (PH-CPE) in BALB/c mice. The parasites were obtained from Micropogonias furnieri (Osteichthyes: Sciaenidae). Groups of six mice were each immunized with 10, 50 or 100 µg of PH-CPE, on days 0 and 35. Both specific IgG and IgE responses were developed after immunization. The immunoblot assay revealed that specific IgG recognizes PH-CPE proteins with two molecular weight ranges, 60-75 and 30-40 kDa, and that IgE recognizes larger proteins over 120 kDa. This appears to be the first report on the immunogenicity of metacestodes within the Pterobothriidae and that PH-CPE is a potential inducer of a specific IgE response.

Asunto(s)

RESUMEN

Anisakidosis is a human parasitic disease caused by infections with members of the Anisakidae family. Accidental infection after fish intake affects the gastrointestinal tract as a consequence of mechanical damage caused by migrating larvae. Infections can also trigger allergies, hives, severe asthma or anaphylaxis with angioedema. Although mouse models of intraperitoneal antigenic stimulation exist, enabling immunological studies, few models using gastric introduction of live larvae are available for the study of immunological and gastrointestinal damage in mice. This study was designed to characterize serum reactivity against Anisakis spp. and Contracaecum spp. in Balb/c mice following orogastric inoculation and to assess gastrointestinal damage. These anisakid species were classified at the Universidade Federal Fluminense (UFF) School of Veterinary Medicine and materials for live larval inoculation were developed at the UFF Immunobiology laboratory. Live larvae were inoculated following injection with a NaCl solution. Blood samples were collected and sera screened for immunoglobulin (Ig)E and IgG anti-larva responses to both nematodes, specific for somatic and excretory/secretory antigens, by enzyme-linked immunosorbent assay (ELISA). The means of the optical densities were analysed using analysis of variance (ANOVA) with Tukey's post-hoc test and the general linear model. This analysis identified the presence of anti-IgG seroreactivity to both somatic and excretory/secretory Anisakis antigens in inoculated animals compared with controls (P< 0.001), and no gastric or intestinal damage was observed. These experiments demonstrated that introduction of live Contracaecum spp. into the gastrointestinal tract did not elicit serum sensitization in animals.

Asunto(s)

RESUMEN

PURPOSE: To evaluate the impact of different machines on plan quality using both intensity modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) techniques. MATERIALS AND METHODS: Eight patients with squamous cell carcinoma of the oropharynx were selected at random. Plans were computed for IMRT and VMAT Smart Arc, using Pinnacle TPS for an Elekta (IMRT-E, VMAT-E) and Varian linac (IMRT-V, VMAT-V). A three-dose level prescription was used to deliver 70, 63 and 58.1 Gy to regions of macroscopic, microscopic high- and low-risk disease, respectively. All doses were given in 35 fractions. Comparisons were performed on dose-volume histogram data, monitor units (MU), and delivery time. RESULTS: VMAT-E plans resulted slightly MU efficient (-24 % p < 0.05) compared to VMAT-V while IMRT-V shortened delivery time (-19 % p < 0.05) compared to IMRT-E. All the delivery techniques resulted in equivalent target coverage in terms of D(98) % and D(2) %. For VMAT technique, a significant improvement of 7 % in homogeneity index (HI) for PTV58.1 was observed for Varian machine. A slight improvement in OARs sparing was observed with Elekta machine both for IMRT and VMAT techniques. CONCLUSION: Similar plan quality was observed for Elekta and Varian linacs, significant differences were observed in delivery efficiency, as MU number and delivery times, in favor of Elekta and Varian, respectively.

Asunto(s)

RESUMEN

Polonium-210 ((210)Po) concentration was quantified in the muscle tissue and organs of two predatory marine fishes (Genypterus brasiliensis and Cynoscion microlepidotus) from Cabo Frio, Rio de Janeiro, Brazil. The species C. microlepidotus, a benthic carnivore, registered higher (210)Po in its tissue. The organs associated with digestion displayed the maximum radionuclide compared with other organs. The average activity was 2 mBq kg(-1) for G. brasiliensis and it was 6 mBq kg(-1) for C. microlepidotus. The activity concentrations varied significantly between the species and among organs.

Asunto(s)

RESUMEN

INTRODUCTION: To evaluate the delivery accuracy of dynamic (DMLC) and static (SMLC) intensity modulated radiation therapy (IMRT) techniques using portal dosimetry (PD) in Varian Eclipse Treatment Planning System. MATERIALS AND METHODS: Seven DMLC IMRT Head and Neck plans were retrospectively generated for the study using SMLC mode at 20, 10 and 5 levels of intensity (SMLC20, SMLC10, SMLC5). Dosimetric verifications performed by PD on a total of 107 fields were evaluated using the gamma index (maximum (γmax), average (γavg), percentage of points with (γ%) ≤ 1). The images were acquired at a source-detector distance of 100 cm at gantry zero degree and also at clinically planned gantry angles. RESULTS: For both modes, measurements are within acceptable criteria. (γ%) ≤ 1 improves by increasing SMLC levels (+3.4 % from SMLC5 to SMLC20, p < 0.001) and using DMLC (+3.9 % and +0.6 % compared to SMLC5 and SMLC20, respectively, p < 0.001). Also (γmax) parameter improves significantly by increasing SMLC levels (+22 % from SMLC5 to SMLC20) and using DMLC (+34 % and +16 % compared to SMLC5 and SMLC20, respectively). The effect of the gantry rotation influences the delivery accuracy by up to -7 % (p < 0.05). The effect of leaves travelling direction was almost negligible (1 %). CONCLUSIONS: A good agreement between calculated and measured fluences was obtained for DMLC and SMLC techniques at higher intensity levels; however, DMLC delivery ensures the best reproduction of computed fluence maps. The gantry rotation influences the delivery accuracy in particular for SMLC modes at lower intensity levels.

Asunto(s)

RESUMEN

The present study focuses on the anatomopathological alterations provoked by parasitism by Calyptospora sp. in 40 specimens of Aequidens plagiozonatus collected in Pará, Brazil. Examinations of the fresh material by compression of the hepatopancreas and histological sections showed immature forms and oocysts characteristic of the genus Calyptospora, in addition to a large quantity of melanomacrophagic centers spread throughout the organ. No significant inflammation of the hepatic tissue was observed. The melanomacrophagic centers and the compression of the hepatocytes are part of the response of the host to the parasite. This study represents the first record of parasitism by Calyptospora in A. plagiozonatus.

Descreveram-se as alterações anatomopatológicas provocadas pelo parasitismo por Calyptospora sp. em 40 espécimes de Aequidens plagiozonatus, provenientes do município de Peixe-boi, Pará, Brasil. Foram encontradas formas imaturas e oocistos característicos do gênero Calyptospora, nos exames frescos por compressão e cortes histológicos, além de um grande número de centros melanomacrofágicos dispersos por todo o órgão. Digna de nota foi a ausência de inflamação significativa no tecido hepático. Centros melanomacrofágicos e compressão dos hepatócitos estão envolvidos na resposta do hospedeiro ao parasito. Este é o primeiro registro de ocorrência de parasitismo por Calyptospora sp. na espécie estudada.

Asunto(s)

RESUMEN

PURPOSE: The major uncertainties in treating lung cancer are the repositioning errors and respiratory lung tumor motion. Typically, margins are added to the clinical target volume (CTV) to obtain a planning target volume (PTV) allowing the accommodation of such uncertainties. We want to test a new technique to assess the adequacy of the chosen PTV using an aSi electronic portal imaging device (EPID). METHODS: Four patients affected by lung cancer and treated by radical 3D conformal radiotherapy (3DRT) were studied. During treatment the EPID was used in cine mode acquisition: acquired images were used to the aim. RESULTS AND CONCLUSIONS: Treatment monitoring with an EPID in cine mode is shown to be a clinically feasible and useful tool.

Asunto(s)

RESUMEN

PURPOSE: To evaluate the dosimetric changes of parotid glands (PG) during a course of intensity-modulated radiotherapy (IMRT) in head and neck (H&N) cancer patients. METHODS: Ten patients with H&N cancer treated by IMRT were analyzed. The original treatment plan (CT(plan)) was transferred to cone-beam computed tomography (CBCT) acquired at the 15th and 20th treatment day (CBCT(plan) I and II, respectively). The PG mean dose (D(mean)), the dose to 50 % of the volume, and the percent of volume receiving 30 and 50 Gy were measured by the dose volume histogram. RESULTS: 30 IMRT plans were evaluated (3 plans/patient). All dosimetric end points increased significantly for both PG only when CT(plan) was compared to CBCT(plan) I. The D(mean) increased significantly only for ipsilateral PG (p = 0.02) at week 3. CONCLUSION: During a course of IMRT, CBCT is a feasible method to check the PG dosimetric variations. Perhaps, the 3rd week of radiotherapy could be considered as the time-check-point.

Asunto(s)