RESUMO
Solving the problem of heat focusing and standardization of the clinical application of hyperthermia requires a mathematical prediction model. The model should include the medium constitutive parameter, and be able to predict positioning of the microwave applicators to optimize treatment planning and provide for reproducible treatment set-up. We present a configuration of 3 applicators subtended by an equilateral triangle in order to target and relocate a 'hot spot' for improved treatment of deep tumors. A simple geometric analysis is illustrated. The microwave beam absorption profile, from the three power sources, was obtained from phantom studies depicting the radiative heat pattern for the triapplicator system (TRIPAS). A complex mathematical model was developed to demonstrate interaction of the beams in the medium. It was observed empirically that under coherent propagation in the near field electromagnetic (EM) waves tend to add at the center, while varying the propagation axial focal length caused a relocation of the summing focal points. Mathematical prediction correlated very well with the phantom studies. SAR values above 100 W/kg were achieved at 12.5 cm phantom depth, creating a relocatable 'hot spot' at the concentric foci of the 3 air cooled horn microwave applicators operating at 300 MHz.
Assuntos
Hipertermia Induzida/instrumentação , Simulação por Computador , Fenômenos Eletromagnéticos , Desenho de Equipamento , Temperatura Alta , Humanos , Hipertermia Induzida/métodos , Modelos Biológicos , Modelos Estruturais , Músculos/fisiologia , Radiação , TermômetrosAssuntos
Hipertermia Induzida , Neoplasias/terapia , Adulto , Idoso , Neoplasias da Mama/radioterapia , Neoplasias da Mama/terapia , Terapia Combinada , Feminino , Neoplasias de Cabeça e Pescoço/radioterapia , Neoplasias de Cabeça e Pescoço/terapia , Humanos , Hipertermia Induzida/métodos , Masculino , Micro-Ondas/uso terapêutico , Pessoa de Meia-Idade , Neoplasias/patologia , Neoplasias/radioterapia , Dosagem Radioterapêutica , Indução de Remissão , Taxa de Sobrevida , Fatores de TempoAssuntos
Hipertermia Induzida , Neoplasias/terapia , Neoplasias Abdominais/terapia , Queimaduras/etiologia , Terapia Combinada , Humanos , Hipertermia Induzida/efeitos adversos , Hipertermia Induzida/métodos , Neoplasias Pulmonares/radioterapia , Neoplasias Pulmonares/terapia , Neoplasias/tratamento farmacológico , Neoplasias/radioterapia , Neoplasias Pélvicas/terapia , Indução de Remissão , Taxa de Sobrevida , Terapia Assistida por Computador , Fatores de TempoRESUMO
Results in 256 cases of malignant disease treated by multifraction combination hyperthermia-radiation therapy under the supervision of one physician are presented. The overall response rate was 94% including a 62% complete response. Complications specifically ascribed to hyperthermia were minor, and most side effects of combined treatment were radiation dose related. Tumor response was somewhat better for chest wall recurrence (72% CR) and for adenocarcinoma in general (64% CR), but no significant dependence on tumor site or type was found. Most patients were treated with low dose external radiation with hyperthermia given by air cooled microwave applicators or intracavitary antennae operating at 915 or 300 MHz, and some by interstitial microwave antennae plus 192 Ir. Results appeared to be independent of the microwave source employed. Response did depend on radiation dose: complete response rate with 4000 rad was 65%, and with 2000 rad was 42%.
Assuntos
Diatermia , Neoplasias/radioterapia , Braquiterapia/efeitos adversos , Neoplasias da Mama/radioterapia , Terapia Combinada , Diatermia/efeitos adversos , Feminino , Humanos , PrognósticoRESUMO
This paper compares the clinical and parametric performance, at 140 keV, of three different large-field cameras in a single institution. The instruments tested were the Ohio Nuclear 410, Picker 4/15, and Searle LFOV. There were differences noted in both qualitative and quantitative measurements of physical performance, but these differences could not be demonstrated in clinical studies.
Assuntos
Tomografia Computadorizada de Emissão/instrumentação , Aumento da Imagem , Tomografia Computadorizada de Emissão/normasRESUMO
Both early and delayed Tc-99m glucoheptonate brain images were evaluated in 859 patients in order to determine whether the early imaging with this agent is clinically useful. The results suggest that the early brain images are inferior to the delayed ones in detecting CNS lesions. Use of both, however, may help to differentiate skull or scalp abnormalities from true lesions of the brain.
Assuntos
Encéfalo/diagnóstico por imagem , Compostos de Organotecnécio , Açúcares Ácidos , Tecnécio , Adulto , Idoso , Encefalopatias/diagnóstico por imagem , Pré-Escolar , Diagnóstico Diferencial , Feminino , Humanos , Masculino , Cintilografia , Fatores de TempoRESUMO
99mTc glucoheptonate was used as a brain imaging agent in a consecutive series of 859 patients. Sensitivity was 94% in patients with proved CNS tumors. Static imaging of patients with infarction showed a sensitivity of 62%. When the perfusion study was included, this valve increased to 90%. Overall sensitivity was 83%, specificity 99%, and accuracy 95% without inclusion of perfusion results. When these results were included, overall sensitivity was 93%, specificity 99%, and accuracy 98%.
Assuntos
Encefalopatias/diagnóstico por imagem , Neoplasias Encefálicas/diagnóstico por imagem , Encéfalo/diagnóstico por imagem , Açúcares Ácidos , Tecnécio , Erros de Diagnóstico , Avaliação de Medicamentos , Feminino , Heptoses , Humanos , Pessoa de Meia-Idade , CintilografiaRESUMO
Delayed 99mTc-glucoheptonate and pertechnetate scans were evaluated in a paired study for their ability to detect brain lesions. Glucoheptonate was found to be superior in eight of 17 cases of brain tumor and in two of ten patients with cerebral infarction. In addition, early (30 min) 99mTc-glucoheptonate brain scans were compared with delayed studies: the former were inferior in 48% of the cases. We conclude that 99mTc-glucoheptonate is a promising agent for delayed brain scanning, offering better lesion detection than pertechnetate.
Assuntos
Encefalopatias/diagnóstico , Cintilografia , Açúcares Ácidos , Tecnécio , Adulto , Encéfalo/irrigação sanguínea , Neoplasias Encefálicas/diagnóstico , Neoplasias da Mama/diagnóstico , Carcinoma Broncogênico/diagnóstico , Feminino , Humanos , Infarto/diagnóstico , Neoplasias Pulmonares/diagnóstico , Melanoma/diagnóstico , Metástase Neoplásica , Neoplasias Cranianas/diagnóstico , Fatores de Tempo , Neoplasias do Colo do Útero/diagnósticoRESUMO
Two patients on chronic renal hemodialysis developed acute neurologic symptoms and unusual brain scan findings, including very prominent cranial sinuses. Symptoms and scan abnormalities reverted to normal within a few days. The possible mechanisms are discussed.
Assuntos
Encefalopatias/diagnóstico , Cintilografia , Diálise Renal/efeitos adversos , Adolescente , Adulto , Encefalopatias/etiologia , Cavidades Cranianas , Feminino , Humanos , Masculino , Ácido Pentético , TecnécioRESUMO
Twenty-eight patients with cerebral tumors were evaluated after craniotomy with combined radionuclide techniques in order to assess presence or absence of tumor recurrence. The combination of a positive pertechnetate or Tc-phosphate scan with a positive gallium scan strongly indicates the presence of recurrent or residual tumor. Infection may also cause uptake but was easily distinguished by the distribution. Negative gallium scans with positive technetium scans were indicative of non-recurrence in this series.
Assuntos
Neoplasias Encefálicas/diagnóstico , Craniotomia , Recidiva Local de Neoplasia/diagnóstico , Cintilografia , Neoplasias Encefálicas/cirurgia , Craniotomia/métodos , Radioisótopos de Gálio , Humanos , Osteomielite/diagnóstico , Cintilografia/métodos , Crânio , TecnécioRESUMO
The hemangiopericytoma is an invasive tumor of vascular origin. No matter how benign the course and how circumscribed the mass, it must be considered a lesion with high malignant potential. In the case report here, a hemangiopericytoma of the pancreas with metastasis to the liver was associated with microangiopathic hemolytic anemia in a 78-year old woman. The anemia may have been present before the onset of metastasis. If so, it could have been a major factor in the breakdown of host response and could have initiated the malignant dissemination. Under these circumstances it could be an indicator of metastasis in patients with previously diagnosed tumors. However, there are many cases of metastatic malignancy associated with this anemia in which the opposite situation holds. The anemia is usually of extracorpuscular origin. Apparently intravascular coagula1ion caused by injury from tumor-cell aggregates in small vessels induces erythrocyte fragmentation in fibrin strands. A vicious cycle of cell fragmentation, vascular injury and fibrin strand formation completes the course. Analysis of the findings should be based upon more than a strictly pathologic approach; it should also be related to the new discoveries in cancer research.
Assuntos
Anemia Hemolítica/etiologia , Hemangiopericitoma/complicações , Neoplasias Hepáticas/complicações , Microcirculação/patologia , Neoplasias Pancreáticas/complicações , Idoso , Animais , Eritrócitos/patologia , Feminino , Hemangiopericitoma/diagnóstico , Hemangiopericitoma/patologia , Humanos , Neoplasias Hepáticas/diagnóstico , Neoplasias Hepáticas/patologia , Metástase Neoplásica , Neoplasias Pancreáticas/diagnóstico , Neoplasias Pancreáticas/patologia , CintilografiaRESUMO
Both 99mTc-pertechnetate and 67Ga-citrate brain scans were performed in 93 patients with cerebral neoplasms and in 70 others with cerebral infarction or hemorrhage. Tumor detection was clearly better with 67Ga(96%) than with 99mTc(85%). Cerebral infarctions consistently either failed to concentrate 67Ga(67%) of revealed a much lower concentration than the 99mTc study (27%). In 6% of the infarction patients, gallium and technetium scans were equivalent.
Assuntos
Encefalopatias/diagnóstico , Radioisótopos de Gálio , Cintilografia , Arteriopatias Oclusivas/diagnóstico , Neoplasias Encefálicas/diagnóstico , Artérias Cerebrais , Cromatografia , Humanos , Infarto/diagnóstico , Meningioma/diagnóstico , Metástase Neoplásica , Tecnécio , Doenças Vasculares/diagnósticoRESUMO
Thirty-one patients with carcinoma of the thyroid were evaluated using 131-I scan of the torso including the area of the liver. Focal areas of 131I uptake were found in the liver in two patients with follicular thyroid carcinoma. Both patients showed associated abnormalities on 99m-Tc-sulfur colloid liver scans. The remaining 29 patients showed either no uptake or a normal diffuse pattern of 131-I uptake in liver. Careful evaluation of the liver is recommended on the radioiodine body scan for metastases in patients with thyroid carcinoma.