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To study dose-effect relations of prostate implants with I-125 seeds, accurate knowledge of the dose distribution in the prostate is essential. Commonly, a post-implant computed tomography (CT) scan is used to determine the geometry of the implant and to delineate the contours of the prostate. However, the delineation of the prostate on CT slices is very cumbersome due to poor contrast between the prostate capsule and surrounding tissues. Transrectal Ultrasound (TRUS) on the other hand offers good visualization of the prostate but poor visualization of the implanted seeds. The purpose of this study was to investigate the applicability of combining CT with 3D TRUS by means of image fusion. The advantage of fused TRUS-CT imaging is that both prostate contours and implanted seeds will be well visible. In our clinic, post-implant imaging was realized by simultaneously acquiring a TRUS scan and a CT scan. The TRUS transducer was inserted while the patient was on the CT couch and the CT scan was made directly after the TRUS scan, with the probe still in situ. With the TRUS transducer being visible on both TRUS and CT images, the geometrical relationship between both image sets could be defined by registration on the transducer. Having proven the applicability of simultaneous imaging, the accuracy of this registration method was investigated by additional registration on visible seeds, after preregistration on the transducer. In 4 out of 23 investigated cases an automatic grey value registration on seeds failed for each of the investigated cost functions, and in 2 cases for both cost functions, due to poor visibility of the seeds on the TRUS scan. The average deviations of the seed registration with respect to the transducer registration were negligible. However, in a few individual cases the deviations were significant and probably due to movement of the patient between TRUS and CT scan. In case of a registration on the transducer it is important to avoid patient movement in-between the TRUS and CT scan and to keep the time in-between the scans as short as possible. It can be concluded that fusion of a CT scan and a simultaneously made TRUS scan by means of a three-dimensional (3D) transducer is feasible and accurate when performing a registration on the transducer, if necessary, fine-tuned by a registration on seeds. These fused images are likely to be of great value for post-implant dose distribution evaluations.

OBJECTIVE To evaluate the long-term results of salvage cystectomy after interstitial radiotherapy (IRT) and external beam radiotherapy (EBRT) for transitional cell carcinoma, and to assess the morbidity and functional results of the different urinary diversions used. PATIENTS AND METHODS The records of 27 patients treated with salvage cystectomy in one institution between 1988 and 2003 were retrospectively analysed. RESULTS Salvage cystectomy was used after failure of IRT in 14 or EBRT in 13 patients, with a 3- and 5-year survival probability of 46% (95% confidence interval 26–65) and 33 (11–54)%. The 5-year overall survival after cystectomy was 54% after IRT and 14% after EBRT (P = 0.12). Tumour category, response to radiation, American Society of Anesthesiology score, and complete tumour resection had a significant influence on survival. Five of seven patients with incomplete resection died because of local disease, with a median survival of 5 months. There was clinical understaging after radiotherapy in 41% of patients. Nine patients had an orthotopic neobladder, with complete day- and night-time continence in eight and four, respectively. All patients but one had good voiding function. There were early complications in two and late complications in six patients (for Bricker, seven of 14 and none; for Indiana, none of four and two of four). The duration of hospitalization was not influenced by the type of diversion. Erectile function was maintained in four of six patients after a sexuality-preserving cystectomy and neobladder. CONCLUSIONS Salvage cystectomy can be performed with acceptable morbidity using any type of urinary diversion. Understaging after radiotherapy is common, but preoperative selection needs improving. A very significant factor for an adverse outcome and death from local tumour recurrence was incomplete resection, suggesting that salvage cystectomy should only be attempted if complete resection is probable.

The purpose of this study is to develop a model that quantifies in three dimensions changes in bladder shape due to changes in bladder and/or rectal volume. The new technique enables us to predict changes in bladder shape over a short period of time, based on known urinary inflow. Shortly prior to the treatment, the patient will be scanned using a cone beam CT scanner (x-ray volume imager) that is integrated with the linear accelerator. After (automated) delineation of the bladder, the model will be used to predict the short-term shape changes of the bladder for the time interval between image acquisition and dose delivery. The model was developed using multiple daily CT scans of the pelvic area of 19 patients. For each patient, the rigid bony structure in follow-up scans was matched to that of the planning CT scan, and the outer bladder and rectal wall were delineated. Each bladder wall was subdivided in 2500 domains. A fixed reference point inside the bladder was used to calculate for each bladder structure a "Mercator-like" 2D scalar map (similar to a height map of the globe), containing the distances from this reference point to each domain on the bladder wall. Subsequently, for all bladder shapes of a patient and for all domains on the wall individually, the distance to the reference point was fitted by a linear function of both bladder and rectal volume. The model uses an existing bladder structure to create a new structure via expansion (or contraction), until the expressed volume is reached. To evaluate the predictive power of the model, the jack-knife method was used. The errors in the fitting procedure depended on the part of the bladder and range from 0 to 0.5 cm (0.2 cm on average). It was found that a volume increase of 150 cc can lead to a displacement up to about 2.5 cm of the cranial part of the bladder. With the model, the uncertainty in the position of the bladder wall can be reduced down to a maximum value of about 0.5 cm in case the bladder volume increase is known. Furthermore, it was found that a change in rectal filling causes a shift of the bladder, while its shape is hardly influenced. In conclusion, we developed a model that describes the bladder shape and position as a function of the bladder volume and the rectal filling. The model accurately describes the complex shape of the bladder as it works on each domain of the bladder separately.

Eleven patients, ranging in age from 58 to 79 years and referred for 125I implantation because of localised prostatic carcinoma, were subjected to iliopelvic lymphoscintigraphy (IPL) prior to lymph node dissection. Scintigraphy was performed by perianal injection into the ischiorectal fossa of 0.2 ml 99mTc radio-labelled antimony sulphide colloid. The sensitivity of IPL was 100% and the specificity 13%, with a prevalence of positive nodes of 27%. It was concluded that IPL is not useful as a non-surgical method of detecting lymph node invasion in localised prostatic carcinoma because of the low specificity.