The use of a gas chromatograph coupled to a metal oxide sensor for rapid assessment of stool samples from irritable bowel syndrome and inflammatory bowel disease patients.

There is much clinical interest in the development of a low-cost and reliable test for diagnosing inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS), two very distinct diseases that can present with similar symptoms. The assessment of stool samples for the diagnosis of gastro-intestinal diseases is in principle an ideal non-invasive testing method. This paper presents an approach to stool analysis using headspace gas chromatography and a single metal oxide sensor coupled to artificial neural network software. Currently, the system is able to distinguish samples from patients with IBS from patients with IBD with a sensitivity and specificity of 76% and 88% respectively, with an overall mean predictive accuracy of 76%.

Optimization of stereotactically-guided conformal treatment planning of sellar and parasellar tumors, based on normal brain dose volume histograms.

PURPOSE: To investigate the optimal treatment plan for stereotactically-guided conformal radiotherapy (SCRT) of sellar and parasellar lesions, with respect to sparing normal brain tissue, in the context of routine treatment delivery, based on dose volume histogram analysis. METHODS AND MATERIALS: Computed tomography (CT) data sets for 8 patients with sellar- and parasellar-based tumors (6 pituitary adenomas and 2 meningiomas) have been used in this study. Treatment plans were prepared for 3-coplanar and 3-, 4-, 6-, and 30-noncoplanar-field arrangements to obtain 95% isodose coverage of the planning target volume (PTV) for each plan. Conformal shaping was achieved by customized blocks generated with the beams eye view (BEV) facility. Dose volume histograms (DVH) were calculated for the normal brain (excluding the PTV), and comparisons made for normal tissue sparing for all treatment plans at > or =80%, > or =60%, and > or =40% of the prescribed dose. RESULTS: The mean volume of normal brain receiving > or =80% and > or =60% of the prescribed dose decreased by 22.3% (range 14.8-35.1%, standard deviation sigma = 7.5%) and 47.6% (range 25.8-69.1%, sigma = 13.2%), respectively, with a 4-field noncoplanar technique when compared with a conventional 3-field coplanar technique. Adding 2 further fields, from 4-noncoplanar to 6-noncoplanar fields reduced the mean normal brain volume receiving > or =80% of the prescribed dose by a further 4.1% (range -6.5-11.8%, sigma = 6.4%), and the volume receiving > or =60% by 3.3% (range -5.5-12.2%, sigma = 5.4%), neither of which were statistically significant. Each case must be considered individually however, as a wide range is seen in the volume spared when increasing the number of fields from 4 to 6. Comparing the 4- and 6-field noncoplanar techniques to a 30-field conformal field approach (simulating a dynamic arc plan) revealed near-equivalent normal tissue sparing. CONCLUSION: Four to six widely spaced, fixed-conformal fields provide the optimum class solution for the treatment of sellar and parasellar lesions, both in terms of normal brain tissue sparing and providing a relatively straightforward patient setup. Increasing the number of fields did not result in further significant sparing, with no clear benefit from techniques approaching dynamic conformal radiotherapy in the cases examined.

Comparison of a multi-leaf collimator with conformal blocks for the delivery of stereotactically guided conformal radiotherapy.

Stereotactically-guided conformal radiotherapy is a practical technique for irradiating irregular lesions in the brain. The shaping of the conformal fields may be achieved using lead alloy blocks, a conventional multi-leaf collimator (MLC) or a mini/micro-MLC. Although the former gives more precise shaping, it is labour intensive. The latter methods are more practical as both mould room and treatment room times are reduced, but the shaping is limited by the finite leaf-width. This study compares treatment plans, in terms of normal tissue doses and tumour coverage, for fields shaped using conformal blocks and a conventional MLC in two series of geometrical shapes and nine patient tumours. For the range of tumour sizes considered (volumes 14-264 cm3, minimum dimension 30 mm, maximum 102 mm), the MLC treats, on average, 14% (range 3-34%) and 17% (range 0-36%) more normal brain tissue than conformal blocks to >50% and >80% of the prescription dose, respectively. The large variability is due to strong dependence on tumour shape and the presence of partial leaf-widths in the MLC fit. It is therefore important to consider both of these effects when deciding whether the MLC is appropriate for a particular target volume.

Whole body doses from linear accelerator-based stereotactic radiotherapy.

PURPOSE: The objective of this work was to measure whole body radiation doses in a humanoid phantom from linear accelerator-based cranial stereotactic radiosurgery/therapy (SRS/T), using different beam arrangements. METHODS AND MATERIALS: A standard noncoplanar five-arc beam arrangement and a four-arc technique without a sagittal arc were used to deliver 20 Gy in a single fraction to a midline spherical target volume in the corpus callosum region of an Alderson-Rando anthropomorphic phantom using (i) a 20-mm and (ii) a 40-mm circular collimator. Whole body dose measurements were made using lithium fluoride thermoluminescent dosimetry. Whole body isodose plots in the sagittal and coronal planes and organ doses were compared for the two arcing beam arrangements. An ionization chamber was used to record the exit dose at intervals along the length of the phantom at midline and 4.5 cm off-axis for (i) a single fixed field and (ii) a solitary 90 degrees sagittal arc using a 40-mm circular collimator. RESULTS: The sagittal arc was the major contributor to neck and trunk doses when the five- and four-arc arrangements were compared, with fourfold greater thyroid dose. The gonad dose was increased by the sagittal arc, but was largely due to leakage radiation. The dose from a fixed field exiting down the long axis of the phantom was tenfold greater than that from a solitary 90 degrees sagittal arc. When the fixed field or arc traversed the lung or exited through the pharynx and major upper airways, the dose measurements below the diaphragm were 30-40% higher than those along the exit path of maximum soft tissue density. CONCLUSION: When SRS/T is used in nonmalignant conditions such as cranial arteriovenous malformations or benign tumors the exit paths of arcing beams or fixed fields should be taken into account when deciding upon the final treatment plan. Such consideration should minimize the risk of radiation-induced malignancy, notably in the thyroid gland of younger patients.

Hypofractionated stereotactic radiotherapy in the management of recurrent glioma.

PURPOSE: This study aimed to assess the efficacy and toxicity of hypofractionated stereotactic radiotherapy (SRT) in the management of patients with recurrent glioma. METHODS AND MATERIALS: From January 1989 to July 1994, 36 patients with glioma were treated at the time of recurrence. Twenty-nine had recurrent high-grade astrocytoma, 3 high-grade oligodendroglioma, 1 high-grade ependymoma, and 3 pilocytic astrocytoma. Hypofractionated stereotactic radiotherapy was given using either three noncoplanar arcs or four to six noncoplanar fixed beams at 5 Gy/fraction, to doses ranging from 20 to 50 Gy initially on a dose escalation program. Two patients received 20 Gy, 8 received 30 Gy, 10 received 35 Gy, 10 received 40 Gy, 5 received 45 Gy, and 1 received 50 Gy, treating 5 days/week. RESULTS: The median survival of 29 patients with recurrent high-grade astrocytoma was 11 months from the time of SRT. This compared to a median survival of 7 months for a cohort matched for age, performance status, and initial histologic grade who received nitrosourea-based chemotherapy at recurrence (p < 0.05). Initial low-grade astrocytoma histology was the only favorable prognostic factor for survival on univariate analysis. Three patients with recurrent oligodendroglioma remain alive 11, 23, and 34 months after SRT. Three children treated for recurrent pilocytic astrocytoma remain alive 14, 41, and 55 months following SRT. Presumed radiation damage, defined as reversible steroid-dependent toxicity, was observed in 13 patients (36%) and required reoperation in 2 (6%). A total dose of >40 Gy was a major predictor of radiation damage (p < 0.005). CONCLUSION: Hypofractionated SRT is a noninvasive, well-tolerated, outpatient-based method of delivering palliative, high-dose, focal irradiation.

Long-term outcome after percutaneous treatment of transitional cell carcinoma of the renal pelvis.

PURPOSE: The application of conservative surgery has been established in the treatment of transitional cell tumors of the renal pelvis. We reviewed retrospectively the long-term outcome after percutaneous treatment of select patients referred to a tertiary center with transitional cell tumors of the renal pelvis. MATERIALS AND METHODS: We studied 28 patients referred with a presumptive diagnosis of transitional cell carcinoma of the renal pelvis based on filling defects noted on excretory urograms. At percutaneous endoscopy tumor was resected in 26 patients, while no tumor was found in 2. All 19 men and 7 women smoked, and mean age at presentation was 65 years. Of the patients 18 presented with hematuria and 6 had bilateral upper tract tumors. After percutaneous resection, the access tract was irradiated either with iridium wire in 12 patients or a commercial high dose rate radiation delivery system in 12. Thiotepa was instilled into the nephrostomy tube without brachytherapy in 1 patient and 1 received no adjuvant treatment in all. All patients were followed by excretory urography and urine cytology. Cystoscopy and retrograde pyelography were performed when technically possible. RESULTS: After percutaneous tumor resection 6 patients (23%) had local recurrence in the treated renal pelvis, including 3 at 44, 55 and 60 months, respectively. Further conservative treatment was initially possible in 4 of these patients but ultimately only 2 (both of whom had late recurrences) retained the treated kidney. Of the 11 patients with recurrence elsewhere in the urinary tract the bladder was invariably involved (11), while synchronous or metachronous ureteral recurrence was less common (3). Nine patients remained free of any urothelial recurrence in the upper or lower tract. No patient had recurrent tumor in the nephrostomy tract. Of the patients 7 suffered from procedure-related complications, including 1 who had a persistent urinary fistula that failed to heal after brachytherapy and required nephroureterectomy. There have been 6 deaths during followup, of which 2 were disease related. The 3-year estimated local recurrence-free survival rate was 86% (95% confidence interval 63 to 95%), cause-specific survival rate 91% (95% confidence interval 67 to 98%) and overall survival rate 78% (95% confidence interval 55 to 90%). Differences in recurrence-free survival, comparing those with recurrence in the treated renal pelvis or elsewhere in the urothelium and those remaining disease-free, did not translate to a significant overall survival difference (p < 0.5) between these groups. CONCLUSIONS: Our results suggest that the combination of percutaneous local resection and tract irradiation offers an effective long-term alternative to radical extirpation in the management of select patients with superficial transitional cell carcinoma confined to the renal pelvis. When the postoperative nephrostogram demonstrates a leaking renal pelvis, tract irradiation should not be given.

Childhood T-cell lymphoblastic lymphoma--does early resolution of mediastinal mass predict for final outcome? The United Kingdom Children's Cancer Study Group (UKCCSG).

This study presents a retrospective review of chest radiography in children with Murphy stage III T-cell lymphoblastic lymphoma. All received a standard leukaemia-based protocol with intensive induction, consolidation and continuing chemotherapy. Neither initial thoracic disease bulk nor the presence of a pleural effusion predicted outcome. However a significant difference was found when the 50 patients in whom the chest radiograph returned to normal within 60 days of commencing treatment were compared with the 18 patients with persistent mediastinal abnormalities, for both event-free [hazard ratio < or = 60 days to > 60 days (HR) 3.55 (95% CI 1.33-9.48); P = 0.007] and overall survival [HR 2.95 (95% CI 1.07-8.18); P = 0.03]. It appears that this relatively simple estimate of chemosensitivity may identify a group of particularly good-risk patients in whom drugs associated with late morbidity such as anthracyclines may be reduced and conversely a higher risk group in whom further intensification of treatment would be justified.

Computerized axial tomographic scan measurements as prognostic indicators in patients with cervical carcinoma.

This retrospective study of 56 patients with carcinoma of the uterine cervix treated with radical radiotherapy at the Royal Marsden Hospital, London, examined whether simple measurements of maximum tumour dimension from computerized axial tomographic (CT) scans have any prognostic significance. Our results indicate that tumour depth (i.e. maximum antero-posterior dimension) of 4 cm or more is associated with a statistically significant increased relative risk of death of 2.4 (95% CI 1.1-5.5; p = 0.045), as compared with tumours with a depth of less than 4 cm. In addition, there was a clear correlation between tumour depth and lymph node involvement (r = 0.36; p < 0.01), and tumour depth and width (r = 0.70; p < 0.005). We suggest that a measurement of maximum tumour depth from the staging CT scan in these patients provides valuable additional information about likely occult lymph node metastases and prognosis, over and above that suggested by the FIGO staging system alone.

Nephrostomy track brachytherapy following percutaneous resection of transitional cell carcinoma of the renal pelvis.

Percutaneous nephrostomy can be used to resect transitional cell carcinoma (TCC) from the renal pelvis, to avoid nephrectomy in selected patients. This procedure carries a potential risk of tumour seeding along the nephrostomy track, which it is our policy to irradiate prophylactically. A total of 25 procedures on 23 patients have been carried out since 1982. The 18 males and five females had a median age of 64 years (range 46-81) at the time of treatment. Of the ten patients with only one functioning kidney, nine had undergone contralateral nephroureterectomy, seven for TCC, one for a non-functioning kidney, and one for renal tuberculosis; one patient had received radical radiotherapy for an inoperable contralateral renal tumour. The other 13 patients had asked for a conservative treatment approach to be adopted. From 1982-1989, low dose rate 192Ir wire was used in 13 patients to deliver a median dose of 45 Gy (range 40-50) to the full length of the track at the surface of nephrostomy tube. Since 1989, we have used a high dose rate (HDR) 192Ir microSelectron to treat 12 patients with a single fraction of 10-12 Gy, including two who had undergone previously 192Ir wire track irradiation of the same kidney. One patient required a nephroureterectomy after developing a non-healing renal pelvis leak following combined modality treatment. Otherwise, no early or late radiation-related morbidity has been seen, and no nephrostomy track recurrences have occurred during a median follow-up of 5 years (range 1-9). The HDR microSelection has enabled us to deliver this treatment quickly and simply during the standard postoperative stay in hospital following percutaneous nephrostomy.