Interstitial hyperthermia in combination with brachytherapy

Flexible coaxial cables were modified to serve as microwave antennas operating at a frequency of 915 MHz. These antennas were inserted into nylon afterloading tubes that had been implanted in tumors using conventional interstitial implantation techniques for iridium-192 seed brachytherapy. The tumor volume was heated to 42-45 degrees C within 15 minutes and heating was continued for a total of 1 hour per treatment. Immediately following a conventional brachytherapy dose and removal of the iridium seeds the tumors were heated again in a second treatment. This interstitial technique for delivering local hyperthermia should be compatible with most brachytherapy methods. The technique has proved so far to be practical and without complications. Temperature distributions obtained in tissue phantoms and a patient are described.     

Clinical outcome after percutaneous transhepatic obliteration of esophageal varices

A 4.5-yr experience with percutaneous transhepatic obliteration of gastroesophageal varices in 49 patients is reviewed with respect to technical success, control of active hemorrhage, rebleeding frequency, survival, and complications to better define clinical guidelines regarding its application. The procedure was successfully completed in 94% (46 of 49) of patients, and complete obliteration of all variceal feeder vessels was achieved in approximately one-half (52%). Variceal hemorrhage was controlled in three-quarters (76%) of actively bleeding patients, and recurrent hemorrhage occurred in 65% of patients at mean follow-up of 33 wk. Complete obliteration of all variceal feeder vessels was found not to be necessary from a technical standpoint, because the frequency of control of active hemorrhage and rebleeding were not significantly different in those patients having partial as compared with complete obliteration. In comparison with the reported outcome following standard medical therapy of bleeding varices, survival after variceal obliteration appears similar, but death from hemorrhage may be reduced. The interval to rebleeding is longer in patients having elective variceal obliteration after medical control of hemorrhage than in actively bleeding patients undergoing urgent obliteration of varices. The complication rate of obliteration was acceptable, but Child's class C patients with uncontrolled hemorrhage were a subgroup that experienced high mortality and derived little benefit from obliteration. Variceal obliteration is most appropriate in the bleeding but medically stabilized patient or the inoperable patient with recurrent bleeding. Active bleeding is most often controlled and recurrent bleeding may be prevented for several months, thus allowing consideration of elective shunt surgery.     

The Effect of Hemorrhage on Plasma Iron Turnover

The plasma iron turnover rate in rats following a single hemorrhage reachesa maximum in about 48 hours and returns to normal between the seventh andtenth day. There is considerable variation in individual rats in both the maximum rate attained and the time required for recovery. No significant difference in response was observed due to the severity of hemorrhage uponremoval of 2.7 to 18 per cent of total red cells.

Submitted on June 20, 1960 Accepted on November 20, 1960     

Improved surface coil imaging in MR: decoupling of the excitation and receiver coils

We obtained magnetic resonance images with good sensitivity and radio frequency (RF) uniformity using separate transmitter and receiver coils. The excitation, namely, the rotation of the magnetization vector into a plane perpendicular to the magnetic field, was done by applying a homogeneous RF magnetic field produced by a large saddle-shaped coil. Surface coils were used for detection only. Because two coils that operated on the same resonance frequency were used, a coupling problem developed. This problem, which involved inhomogeneity of the RF magnetic field caused by the large current induced in the surface coil during excitation, could only be solved by minimizing the mutual inductance or maximizing the impedance of the surface coil resonance circuit during excitation. We were able to solve this problem using an electronic detuning method.     

The economic impact and cost of visual impairment in Australia

AIMS: To quantify the total economic costs of vision loss in Australia. METHODS: Prevalence data of visual impairment, unpublished data on indirect costs, and national healthcare cost databases were used. RESULTS: Vision disorders cost Australia an estimated A$9.85 billion in 2004. A$4.8 billion is the loss of wellbeing (years of life lost as a result of disability and premature mortality). Vision disorders rank seventh and account for 2.7% of the national loss of wellbeing. Direct health system costs total A$1.8 billion. They have increased by A$1 billion over the last 10 years and will increase a further A$1-2 billion in the next 10 years. Cataract, the largest direct cost, takes 18% of expenditure. The health system costs place vision disorders seventh, ahead of coronary heart disease, diabetes, depression, and stroke. Indirect costs, A$3.2 billion, include carers' costs, low vision aids, lost earnings, and other welfare payments and taxes. CONCLUSIONS: Even a developed economy such as Australia's cannot afford avoidable vision loss. Priority needs to be given to prevent preventable vision loss; to treat treatable eye diseases; and to increase research into vision loss that can be neither prevented nor treated.