This study investigates the dose escalation to dominant intra-prostatic lesions (DILs) that is achievable using single-source-strength (SSS) and dual-source-strength (DSS) low-dose-rate (LDR) prostate brachytherapy and a sector-based plan approach.

Twenty patients were retrospectively analysed. Image registration and planning were undertaken using VariSeed v9·0. SSS and DSS boost plans were produced and compared to clinical plans. Dosimetric robustness to seed displacement for SSS and DSS plans was compared to clinical plans using Monte Carlo simulations.

Fourteen out of 20 patients had DIL identifiable on magnetic resonance imaging. Median increase in sector D90 of 27% (p < 0·0001) and sector V150 of 31% (p < 0·0001) was achieved with SSS planning without exceeding local rectum and urethra dose constraints. DSS plans achieved dose distributions not statistically significantly different from the SSS plans with a median of eight fewer seeds and two fewer needles. SSS and DSS plan sensitivity to random seed displacement was similar to the clinical plans.

Treatment planning using VariSeed to produce SSS and DSS focal boost plans is feasible for LDR prostate brachytherapy to achieve a median escalation in sector D90 of 27% without exceeding local urethral and rectal constraints. SSS and DSS plan dosimetric robustness was similar to clinical plan dosimetric robustness.

To demonstrate the importance of fluid management in the perioperative period by presenting a case of hyponatraemic seizures following prostate brachytherapy.

A 61-year-old gentleman, who had prostate cancer but was otherwise well, developed confusion and word-finding difficulties the day after prostate brachytherapy. This was followed by tonic–clonic seizures that necessitated treatment, intubation and ventilation, and admission to the intensive care unit. Investigations revealed serum sodium of 116 mmol/L. Fluid balance was inadequately recorded, but the patient had drank more than 3 L of water before he developed hyponatraemia.

Postoperative severe hyponatraemia and hyponatraemic encephalopathy develop because of anti-diuretic hormone release and hypotonic fluid administration. These are medical emergencies and should be managed in an intensive care unit. Symptoms range from headache, nausea and confusion to seizures, respiratory arrest and death, and are related to cerebral oedema. Treatment is done using hypertonic sodium chloride to increase the serum sodium to safe levels. Care should be taken to avoid overly rapid correction of serum sodium. Complete documentation of fluid balance is essential to allow proper assessment of fluid status. Patients should be advised on appropriate oral fluids in the postoperative period.

To assess the reliability of post-implant CT (PICT) dosimetry for I-125 prostate seed brachytherapy by investigating the variation between centres in performing PICT through a multi-centre audit.

Computerised tomography data sets from four I-125 prostate brachytherapy patients were circulated to nine participating centres. Centres followed local protocol for PICT outlining and seed identification, dosimetry for D90, V100 and V150 for the prostate was reported. Outlines were compared to determine the variation in: quality parameters (D90, V100 and V150), dose-volume histograms and approach to PICT dosimetry between the centres.

There was significant variation in the prostate outlines drawn by the nine centres; for a prostate with mean volume 43 cm3, the range was 39–57 cm3 which led to variations of D90 of 119–154 Gy (mean 140 Gy) and V100 of 80–93% (mean of 88%). Using automatic seedfinder software reduced discrepancies between centres identifying seeds; overall consistency in seed location was good.

There was a significant uncertainty in the outlining of the prostate volume for PICT dosimetry with an uncertainty value of around ± 20 Gy on D90. PICT is a valuable technique but its accuracy and consistency limitations must be appreciated.