In situ long-term monitoring system for radioactive contaminants.

A long-term in situ subsurface instrument for monitoring radioactive contaminant plumes, as an alternative to soil analysis, is described. A portable, laser-based reader optically stimulates luminescence from sensors, each containing an Al2O3:C dosemeter. The sensors, designed for placement at various subsurface locations around a waste site, are allowed to accumulate dose for a predetermined time that is based on the instrument's minimum detectable dose (MDD). The reader is then attached to the sensor by fibre optic cable to read the accumulated dose; an increase above natural background levels indicating the presence of leaked radioactivity. Based on an MDD of 5 microGy, it is shown that the sensor can measure soil concentrations of 1.85 Bq cm(-3) after an exposure time of 50 h for 137Cs and 67 h for 90Sr/90Y. Discrimination between beta and gamma radiation is possible using an end cap placed over one of the two paired sensors, allowing simultaneous measurement of 137Cs and 90Sr/90Y in a mixed field. The monitor system represents a substantial improvement over quarterly soil sampling because of a greatly increased measurement frequency and the ability to perform measurements reproducibly.

Design of a finger ring extremity dosemeter based on OSL readout of alpha-Al2O3:C.

A finger-ring dosemeter and reader has been designed that uses OSL readout of alpha-Al2O3:C (aluminium oxide). The use of aluminium oxide is important because it allows the sensitive element of the dosemeter to be a very thin layer that reduces the beta and gamma energy dependence to acceptable levels without compromising the required sensitivity for dose measurement. OSL readout allows the ring dosemeter to be interrogated with minimal disassembly. The ring dosemeter consists of three components: aluminium oxide powder for measurement of dose, an aluminium substrate that gives structure to the ring, and an aluminised Mylar cover to prevent the aluminium oxide from exposure to light. The thicknesses of the three components have been optimised for beta response using the Monte Carlo computer code FLUKA. A reader was also designed and developed that allows the dosemeter to be read after removing the Mylar. Future efforts are discussed.

Management of the neck in N0 squamous cell carcinoma of the oral cavity.

Mortality in treated squamous cell carcinoma of the oral cavity is most often owing to locoregional failure. In an attempt to improve survival, an aggressive approach to surgical management is often favoured. Although it is generally accepted that the N0 neck should be treated if the risk of micrometastatic disease exceeds 20%, there is little direct support in the literature for this position. A retrospective review of all patients presenting with T1-2, N0 squamous cell carcinoma of the oral cavity treated at the Cancer Control Agency of British Columbia from 1985 to 1994 was conducted. Patients were followed for a minimum of 5 years with documentation of patterns of recurrence and disease-specific survival relative to initial management. The decision regarding management of the neck was frequently made to accommodate treatment of the primary site or reconstructive strategies. Thirteen percent of patients with T1, N0 disease underwent prophylactic neck dissection. No significant difference in outcome was noted in this group. Thirty-three percent of patients with T2, N0 disease underwent prophylactic neck dissection. There was a trend toward improved 5-year survival and lower recurrence rates in the group whose necks were treated, but the difference was not found to be statistically significant. In conclusion, this review showed a trend toward increased survival with prophylactic treatment of the neck in T2, N0 squamous cell carcinoma of the oral cavity, but a larger study would be needed to show a statistically significant benefit.

A randomised trial of accelerated versus conventional radiotherapy in head and neck cancer.

BACKGROUND AND PURPOSE: To study the effect of accelerated radiation treatment in locally advanced head and neck cancer, a prospective randomised trial was conducted comparing two fractionation schemes which differed only in the overall treatment time; fraction size and total dose were the same in both arms. MATERIALS AND METHODS: Eighty-two patients with stage 3 or 4 squamous cell cancer of the oral cavity, oropharynx, hypopharynx or larynx considered suitable for radical radiotherapy as primary treatment were stratified by site and stage and randomised to receive 66 Gy in 33 2 Gy daily fractions in 45-48 days (o.d.) or 66 Gy in 33 2 Gy twice daily fractions in 22-25 days (b.i.d.). RESULTS: An initial improved clinical response in tumour control in the b.i.d. arm was not sustained and the 3 year recurrence free survival and overall survival rates were similar and not significantly different. The actuarial recurrence free survival was 49.1% in the b.i.d. arm and 44.3% in the o.d. arm. The disease free 3 year survival was 59.4% and 56.8%, respectively. The acute and late normal tissue effects were scored using the RTOG scale. As expected the acute effects were much greater in the b.i.d. arm. The combined grade 3 and 4 late effects were similar but the proportion of grade 4 reactions was significantly higher in the b.i.d. arm. The increase in grade 4 toxicity caused the trial to be discontinued after 82 of the planned 226 patients had been randomised. CONCLUSIONS: The severity of the normal tissue effects and a failure to demonstrate sustained local control does not support this fractionation scheme in patients with such extensive head and neck cancer.

Functional results in oral cavity reconstruction using reinnervated versus nonreinnervated free fasciocutaneous grafts.

Recent advances in free-tissue transfer have given the otolaryngologist--head and neck surgeon a number of reliable options for reconstruction of the oral cavity following ablative procedures. One recent modification has been the transfer of free reinnervated fasciocutaneous grafts in the hope of enhancing oral rehabilitation following surgery. To assess the efficacy of this modification, a protocol was established to retrospectively evaluate patients that received either reinnervated or non-reinnervated free-tissue transfers. Factors including site, surgical resection, type of tissue transfer, and follow-up period were controlled. Evaluation of free-graft sensory return and quality of life was carried out through physical examination and patient interview. Speech assessment was carried out using standardized tests of intelligibility administered by a speech pathologist. Swallowing assessment was carried out with videocinefluoroscopic and scintigraphic techniques, and the oropharyngeal swallow efficiency was calculated. Sensory return in the reinnervate free grafts was superior; however, there was not statistical difference between groups in the speech and swallowing tests. Quality of life was judged to be good in both groups. Sensory return and functional outcome in intraoral reconstruction after tumour ablation was reviewed and discussed

Radiation-absorbed dose estimates to normal organs following intraperitoneal 186Re-labeled monoclonal antibody: methods and results.

The radiation-absorbed dose was estimated following i.p. administration of a 186Re-labeled murine antibody, NR-LU-10, in 27 patients with advanced ovarian cancer. Data for the dosimetry estimation were obtained from quantitative gamma camera imaging and gamma counting of serum and i.p. fluid radioactivity. A peritoneal cavity model was used to estimate the dose to normal organs from radioactivity within the peritoneal cavity. Estimates of radiation-absorbed dose to normal organs in rad/mCi administered (mean + SD) were: whole body, 0.7 + 0.3; marrow, 0.4 + 0.1; liver, 1.9 + 0.9; kidneys, 0.2 + 0.2, and intestine, 0.2 + 0.2. The radiation-absorbed dose estimates to the normal peritoneal surface varied depending on the volume of fluid infused and whether the activity was measured by the gamma camera or from the peritoneal fluid samples. Using gamma camera data, the peritoneal surface dose ranged from 7 to 36 rads/mCi; when using the peritoneal fluid sample data, the dose ranged from 2 to 25 rads/mCi. Myelosuppression, observed in several patients, correlated best with marrow dose estimates based on the serum radioactivity, and significant toxicity was observed at marrow doses greater than 100 rads. The noninvasive methods of dose estimation for i.p. administration of radioimmunoconjugates provided reasonable absorbed dose estimates when compared with previously described, more invasive methods.

Multiple oncocytic laryngeal cysts presenting as acute airway obstruction.

Solitary oncocytic cyst of the larynx is a recognized clinical and pathologic entity. Multiple oncocytic cysts have only rarely been described. A 67-year-old female presented with rapidly progressive airway obstruction requiring emergency tracheotomy. The obstruction was caused by multiple cystic lesions throughout the supraglottic region. Microscopic examination of laryngeal biopsies showed cysts within the lamina propria, lined by oncocytic epithelium. The differential diagnosis and pathogenesis of oncocytic cysts is discussed with a review of other laryngeal cystic lesions.

Pharmacokinetics and normal organ dosimetry following intraperitoneal rhenium-186-labeled monoclonal antibody.

UNLABELLED: Pharmacokinetics, biodistribution and radiation dose estimates following intraperitoneal administration of a 186Re-labeled murine antibody, NR-LU-10, were assessed in 27 patients with advanced ovarian cancer. METHODS: Quantitative gamma camera imaging and gamma counting of serum and intraperitoneal fluid radioactivity were used to obtain data for dosimetry estimation. The MIRD intraperitoneal model was used to estimate dose to normal organs from radioactivity within the peritoneal cavity. The absorbed dose to normal peritoneum was estimated in two ways: from the gamma camera activity and peritoneal fluid samples. RESULTS: Serum activity peaked at 44 hr and depended on the concentration of radioactivity in the peritoneal fluid. Mean cumulative urinary excretion of 186Re was 50% by 140 hr. Estimates of radiation absorbed dose to normal organs in rad/mCi administered (mean +/- s.d.) were whole body 0.7 +/- 0.3; marrow 0.4 +/- 0.1; liver 1.9 +/- 0.9; lungs 1.3 +/- 0.7; kidneys 0.2 +/- 0.2; intestine 0.2 +/- 0.2. Peritoneal surface dose estimates varied depending on the volume of fluid infused and the method of dose determination. Using gamma camera data, the peritoneal dose ranged from 7 to 36 rad/mCi. Using peritoneal fluid sample data, the dose ranged from 2 to 25 rad/mCi. Significant myelosuppression was observed at marrow doses above 100 rad. CONCLUSION: Noninvasive methods of dose estimation for intraperitoneal administration of radioimmunoconjugates provide reasonable estimates when compared with previously described methods.

Dosimetry of rhenium-186-labeled monoclonal antibodies: methods, prediction from technetium-99m-labeled antibodies and results of phase I trials.

Rhenium-186 is a beta-emitting radionuclide that has been studied for applications in radioimmunotherapy. Its 137 keV gamma photon is ideal for imaging the biodistribution of the immunoconjugates and for obtaining gamma camera data for estimation of dosimetry. Methods used for determining radiation absorbed dose are described. We have estimated absorbed dose to normal organs and tumors following administration of two different 186Re-labeled immunoconjugates, intact NR-LU-10 antibody and the F(ab')2 fragment of NR-CO-02. Tumor dose estimates in 46 patients varied over a wide range, 0.4-18.6 rads/mCi, but were similar in both studies. Accuracy of activity estimates in superficial tumors was confirmed by biopsy. Prediction of 186Re dosimetry from a prior 99mTc imaging study using a tracer dose of antibody was attempted in the NR-CO-02 (Fab')2 study. Although 99mTc was an accurate predictor of tumor localization and the mean predicted and observed radiation absorbed doses to normal organs compared favorably, 186Re dosimetry could not be reliably predicted in individual patients. The methods described nevertheless provide adequate estimates of 186Re dosimetry to tumor and normal organs.

Epistaxis: efficacy of arterial ligation and long-term outcome.

Epistaxis is the most common otolaryngologic emergency requiring hospital admission. Patients with this disorder are usually managed conservatively beginning with the simplest mode of treatment with surgical arterial ligation being reserved for cases of failed nasal packing. The purpose of this retrospective review was to evaluate the efficacy of arterial ligation and document all of the complications secondary to these procedures, especially the minor complications secondary to transantral internal maxillary artery (IMAX) ligation. A total of 402 patients admitted to the Vancouver General Hospital between 1980-1990 with a primary diagnosis of epistaxis were the basis for this review. The hospital charts of those patients who underwent arterial ligation were reviewed. A phone questionnaire was directed to this group. External carotid artery (ECA) ligation was associated with a high rate of rebleeding (9/20-45%) during the 10 year follow-up period. IMAX ligation was an effective procedure for controlling epistaxis with a small number of rebleeds (3/29-10%). Although few major complications were noted in the IMAX ligation group, frequent minor complications were noted on prolonged follow-up. Despite this, patient satisfaction was very good in the IMAX ligation group.

Design and evaluation of a subclassification system for supraglottic laryngeal cancer.

The management of supraglottic laryngeal cancer is predicted upon tumor staging as determined by the American Joint Committee Classification (AJCC). Because of changes in both radiotherapy and surgical treatment, the current AJCC may lack the detail and specificity required for accurate selection of treatment. An expanded classification system should provide predictive information that would aid in clinical decision making. Using the AJCC as a foundation, a subclassification system based upon existing knowledge of laryngeal anatomy, embryology and pattern of tumor spread was developed. This system identifies those cancers that involve subsites deemed to represent regions of increased risk for spread. The validity of this subclassification system and its clinical application was assessed by reviewing 139 cases of supraglottic laryngeal cancer and performing a statistical analysis with respect to treatment outcome. The results of this study support the conclusion that two subpopulations of laryngeal tumors, those with a subsite designation of infrahyoid epiglottis, and those demonstrating fixation of the vocal cord, may benefit from a more aggressive treatment protocol.

Obtaining S values for rectangular-solid tumors inside rectangular-solid host organs.

A method is described for obtaining S values between a tumor and its host organ for use with the MIRD formalism. It applies the point-source specific absorbed fractions for an infinite water medium, tabulated by Berger, to a rectangular solid of arbitrary dimensions which contains a rectangular tumor of arbitrary dimensions. Contributions from pairs of source and target volume elements are summed for the S values between the tumor and itself, between the remaining healthy host organ and itself, and between the tumor and the remaining healthy host organ, with the reciprocity theorem assumed for the last. This method labeled MTUMOR, is interfaced with the widely used MIRDOSE program which incorporates the MIRD formalism. An example is calculated.

Anaplastic carcinoma presenting with cervical lymphadenopathy.

We describe 50 patients with anaplastic carcinoma presenting with a mass in the neck. The diagnosis of anaplastic carcinoma was confirmed by immunocytochemistry to exclude very poorly differentiated squamous carcinomas, amelanotic melanoma, and non-Hodgkin's lymphoma. The primary site was established immediately in 26 patients (25 in the head and neck; 1 in the lung); a further 4 had radiological evidence of a primary tumour in the lung. The primary site was established later in 1 patient, in the ethmoid sinuses. In 20 patients the primary site was never established. The commonest primary site was the nasopharynx. The basic treatment policy was radiotherapy, although 20% of patients with a known primary tumour, and 50% of those without, were untreated. The 2-year survival was about 30% in both groups, and did not differ significantly. Prognostic factors for survival were age, performance status, and T status of the primary tumour. Sex, node status, node level, and laterality of nodes, were not.

Clinical manifestations of otological syphilis.

One patient with early otological syphilis and five patients with late otological syphilis are described including audiological and serological findings. In patients with late syphilis poorer than expected speech discrimination scores relative to the pure tone audiograms were noted. Profound hypo-activity of vestibular responses to caloric stimulation was present in the cases of late otological syphilis. Routine non-treponemal serological tests were not sensitive enough to establish the diagnosis. It is recommended that more sensitive treponemal serological tests such as the FTA-ABS should be employed.

Active and passive control of hepatic blood volume responses to hemorrhage at normal and raised hepatic venous pressure in cats.

Hepatic blood volume decreases in response to a rapid hemorrhage (15.3 mL/min) were measured in cats anesthetized with pentobarbital or ketamine-chloralose, by use of in vivo plethysmography alone or in combination with various surgical procedures and vascular circuits. The hepatic blood volume contracts during hemorrhage to compensate for a constant proportion (26 +/- 6%) of the blood loss regardless of the extent of the actual blood loss. Following denervation of the liver and alpha adrenoreceptor blockade (3 mg phentolamine, intraportal) the liver compensation was unaltered. After denervation, nephrectomy, hypophysectomy, and adrenalectomy the liver was still able to compensate for 20 +/- 7.4% of the hemorrhage. Decreases in liver volume were linearly related to decreases in total hepatic blood flow that ensued whether the decreased blood flow was induced by hemorrhage or by clamping of the arteries supplying the splanchnic organs (superior mesenteric artery, celiac artery). The hepatic volume response to hemorrhage could be predicted accurately (97 +/- 6.6%) simply from the linear passive relationship between flow and volume for a particular animal. However when hepatic venous pressure was experimentally elevated, the volume response to passive flow decrease was markedly reduced whereas the response to hemorrhage and noradrenaline infusion was unimpaired suggesting that active control factors were required to produce normal hepatic volume responses to hemorrhage at raised venous pressure. Phentolamine reduced the response at raised venous pressure but was without effect at normal venous pressure in the same animal, indicating that the hepatic nerves and (or) adrenal catecholamines are of paramount importance in control of the response at raised venous pressure when the passive flow influence is much reduced.

An intracaval cannulation for obtaining pure, mixed hepatic venous blood samples.

A method for obtaining pure, mixed hepatic venous blood is described and evaluated in anesthetized cats. Hepatic vascular congestion does not occur with this "intracaval cannulation", however small elevations in central venous blood pressure were noted. Although these changes persisted they did not result in systemic vascular congestion, judging from the normal arterial and portal pressures and from the lack of progressive decrease in arterial blood pressure. Blood samples obtained using the intracaval cannulation were shown to contain identical levels of oxygen as those obtained using a more complex surgical preparation. Reflux of blood from the vena cava does not occur during sampling. The responsiveness of this sampling method to rapid changes in venous content was evaluated by following the changes in glucose balance caused by direct stimulation of the hepatic nerves. The responses measured were similar to those measured in a separate set of experiments obtained using blood samples from a surgically isolated hepatic venous supply.

Effect of di-n-propylacetate and γ-acetylenic GABA on hyperbaric oxygen-induced seizures and GABA metabolism.

The administration of γ-acetylenic GABA or di-n-propylacetate to mice delayed the onset of hyperbaric oxygen-induced seizures in the animals. The former compound caused large increases in brain GABA content and strong inhibition of glutamate decarboxylase activity, whereas the latter compound brough about only moderate increases in brain GABA level and had little or no effect on the enzyme activity. It is suggested that the GABA system is not involved in the anticonvulsant mechanism of γ-acetylenic GABA but may play a role in the action of di-n-propylacetate.