EFFECT OF WETNESS LEVEL ON THE SUITABILITY OF WET GAUZE AS A SUBSTITUTE FOR SUPERFLAB® AS A BOLUS MATERIAL FOR USE WITH 6 MV PHOTONS

Despite the availability of commercial tissue equivalent bolus material, wet gauze has an application in radiation therapy to provide superior conformance to irregular contours. Wet gauze bolus has the potential to reduce air gaps between the bolus and surface, which could decrease surface dose if sufficiently large to disrupt electronic equilibrium. Wet gauze bolus is often fabricated and wetness judged qualitatively. We assessed the effect of specific gauze wetness levels, quantified in terms of physical density, at various field sizes with respect to their effectiveness as bolus material compared with Superflab^®. For large fields, >7 × 7 cm² in this study, wet gauze sponges with a physical density of 1.02 g/cm³ performed essentially identical to Superflab^®; at a smaller field size the wet gauze was slightly less effective, likely due to the heterogeneity of the gauze-water matrix. Gauze that was wetter, with a physical density of 1.2 g/cm³, or less wet, with a physical density of 0.75 g/cm³ was not as effective either due to enhanced photon absorption in the wetter sponges, or less effective establishment of electronic equilibrium in the less wet sponges. The presence of an air gap under Superflab^® led to reduced surface dose, especially for small fields and large air gaps. Thus, if Superflab^® use leads to poor contact with the skin, wet gauze having a physical density of 1.02 g/cm³ can be used as a substitute. Judging the water content of wet gauze subjectively is not acceptable as over- or under wetness can lead to decreased effectiveness of the bolus material.     

EVALUATION OF HEPATOBILIARY SCINTIGRAPHY AS AN INDICATOR OF HEPATIC FUNCTION IN DOMESTIC PIGEONS (COLUMBA LIVIA) BEFORE AND AFTER EXPOSURE TO ETHYLENE GLYCOL

This study investigated the use of quantitative hepatobiliary scintigraphy to assess liver function in 14 white Carneaux pigeons (Columba livia). Liver scintigraphy using 99mTc-mebrofenin was performed and liver function was quantified using deconvolutional analysis and the area under the normalized heart time-activity curve as previously described in the dog and horse. Liver biopsies were performed in all birds before and after toxin-induced liver damage with ethylene glycol. Before the induction of liver disease, all biopsy specimens showed varying degrees of granulomatous inflammation. After ethylene glycol administration, hepatic lesions were scored and compared with scintigraphic findings. Scintigraphic results showed a significant decrease (P = 0.04) in hepatic function using the area under the normalized time-activity curve. There was good correlation between the overall histologic score posttoxin exposure and scintigraphic measures of liver function (P < 0.03). Based upon these preliminary results, the area under the heart time-activity curve can determine hepatic extraction as a measure of hepatic parenchymal cell function. The results also showed that worsening hepatic cellular function correlated with increased histologic damage to the liver. The use of hepatobiliary scintigraphy using 99mTc-mebrofenin to determine liver function in pigeons has not been previously reported. Additional studies are warranted to evaluate the application of this technique in clinical patients and to establish the sensitivity of this technique.     

THE USE OF COMPUTED TOMOGRAPHY FOR ASSESSMENT OF THE SWIM BLADDER IN KOI CARP (CYPRINUS CARPIO)

Seven normal koi (Cyprinus carpio) and seven koi with negative buoyancy were examined using computed tomography (CT) to assess the swim bladder. The volume of the swim bladder was calculated in all animals. In the healthy koi there was a statistical correlation (r=0.996) between body mass and swim bladder volume with volume (ml) being related to body mass according to the formula 4.9+0.054 × BM (g). In all koi with buoyancy problems, the gas volume of the swim bladder was reduced. Additionally, fluid was found within the swim bladder in three of the abnormal koi. CT proved to be a quick noninvasive technique for the examination of the swim bladder in koi.     

THE TOXICITY OF JUTE (CORCHORUS OLITORIUS) SEED TO PIGS

SUMMARY Finely ground Corchorus olitorius seed was administered as a daily drench to 1 pig at 100mg/kg body weight and as a single drench to 2 pigs at 500 mg/kg body weight. The latter 2 died within 48 hours, and the former was killed on the 7th day as it approached a moribund state. Clinical signs observed were anorexia, vomiting and dysentery. Autopsy revealed severe haemorrhagic enteritis. The seed was also fed to pigs at levels of 0.05%, 0.1% and 0.5% by weight of the ration for 4 weeks. Levels of 0.05% or greater caused reductions in voluntary feed intake and weight gain.