Laser hyperthermia using Nd-YAG laser was studied experimentally and clinically to treat deep-seated brain tumors. Histological changes, temperature profile, and modification of the blood-brain barrier were studied using cat and rat brains. In a clinical study 5 patients with brain tumors were treated with laser hyperthermia using this computed tomography-stereotactic technique. All tumors of these patients disap-peared on computed tomography, and 3 of the 5 patients are still alive without reccur-rence. It was possible to make optimal lesion and to have accurate peripheral temperature control by using the combination of the Komai stereotactic method and the SLT Nd-YAG laser system. Interstitial laser hyperthermia using this method is easy and safe to use, and it is beneficial to treat deep-seated brain tumors.
Hospital average length of stay varies considerably between countries. However, there is limited patient-level research identifying or discounting possible reasons for these differences. This study compares the length of stay of patients in Japan, where it is the longest in the OECD, and Canada, where length of stay is closer to the OECD mean. Administrative patient-level data, including age, gender, co-morbidities, intervention, discharge plan, outcome and length of stay were collected from two Japanese and two Ontario, Canada hospitals for two diagnoses: colorectal cancer surgery and acute myocardial infarction. Analyses examined linkages between patient characteristics, hospitals and countries and length of stay. When controlling for patient demographic characteristics, the incidence of co-morbidities and discharge plan practices, Japanese length of stay tended to be significantly longer than that in Canada for both diagnoses. Mortality rates were not significantly different; however, the readmission rate (28 days or less) for acute myocardial infarction was higher in the Canadian hospitals. The findings indicate that non-clinical factors contribute to sustained international differences in length of stay. These factors may include professional or cultural norms, differing payment schemes and access to long-term care facilities. The study also introduces a protocol that can be used for international patient-level comparisons that can enable effective policy and management learning.
Deep-seated brain tumor is difficult to treat surgically. Hyperthermia using various energy sources has been tried, but has failed to gain wide use because of equipment problems and poor temperature control. It is possible now to use Nd:YAG laser with a stable low-energy supply as an energy source for laser hyperthermia (laserthermia). Animal study and clinical study were done using SLT CL50, Computer-control Laserthermia System to treat deep-seated brain tumors. Experimental study revealed that laserthermia produced minimal edema, temperature control was satisfactory, and blood-brain barrier opened up for 6 days following laserthermia. Five patients with brain tumors were treated with laserthermia. Follow-up CT scan revealed disappearance of tumor in 4 patients and decrease in volume in 1 patient. Long-term neurological follow up revealed no deterioration. Laserthermia using Nd:YAG laser is safe and easy to use and it is beneficial to treat deep-seated brain tumors.
The authors describe a new photodynamic therapy (PDT) method for malignant brain tumors. Pheophorbide a (Ph-a), the photosensitizer, has low toxicity, causes no skin sensitization and is activated with an acoustic Q switched neodymium yttrium-argon-garnet (Nd:YAG) laser which achieves deep tissue penetration. The Ph-a distribution in Fisher 344 (F344) rats bearing rat T9 glioma at 24 hours after intravenous injection was very low in the normal brain tissue, but significantly higher in the T9 glioma giving a tumor to normal brain tissue concentration ratio of 7.5:1. The in vitro survival rate of T9 glioma cells pretreated with Ph-a was 68.8 +/- 5.4% after laser irradiation for 20 minutes, significantly lower than in the control groups. This indicates that Ph-a was activated with the acoustic Q switched Nd:YAG laser causing the photodynamic effect. The survival rate after Ph-a pretreatment and laser irradiation in a waterbath at 44.0 degrees C was further reduced to 15.8 +/- 3.3%. In vivo PDT studies using T9 glioma cells inoculated into the dorsal region of F344 rats showed tumor eradication in four of six rats. The combination of PDT and laser hyperthermia produced tumor eradication in all six rats. The combination of PDT and hyperthermia is a promising method for tumor treatment.
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