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Background and purpose To analyse the clinical use of needles and examine the feasibility to meet the planning criteria in three fractions of cervical cancer brachytherapy. Furthermore, to investigate whether the needles with the largest discrepancy between application and loading are essential to treatment planning. Materials and methods For 22 patients we analysed the applied and loaded needle patterns, and examined the dosimetric results for small ( Results On average 5.8 needles were applied and 4.8 loaded per fraction, with average intensity 22% (17% for small, 29% for large CTVHR). Mid-lateral needles were applied and loaded most frequently and intensely. The average CTVHR D90% prescribed dose was 88.8 Gy (SD 4.2) EQD210, the average OAR D 2 cm 3 limit was respected. Omitting the mid-ventral needles, minimal statistically significant differences were found in dose distributions between RP and CP. Conclusions Applying on average 5.8 needles per fraction it was possible to meet the planning criteria for targets and OARs in three BT fractions for both small and large CTVHR. The mid-ventral needles were not essential in treatment planning, unless situated in the vicinity of the GTVres.

Purpose There is an increasing interest for dose differentiation in prostate radiotherapy. The purpose of our study was to analyze the spatial distribution of tumor satellites inside the prostate. Methods and materials 61 prostatectomy specimens were stained with H&E. Tumor regions were delineated by the uro-pathologist. Volumes, distances and cell densities of all delineated tumor regions were measured and further analyzed. Results Multifocal disease was seen in 84% of the patients. The median number of tumor foci was 3. The median distance between the index lesion and the satellites was 1.0cm, with a maximum of 4.4cm. The index lesions accounted for 88% of the total tumor volume. The contribution of tumor foci 3 to the total tumor volume was 2%. The median cell density of the index lesion and all satellites, regardless of size, were significantly higher than that of the prostate. Conclusions Satellites do not appear in a limited margin around the index lesion (GTV). Consequently, a fixed CTV margin would not effectively cover all satellites. Thus if the aim is to treat all tumor foci, the entire prostate gland should be considered CTV.

Purpose: To evaluate the safety and efficacy of an absorbable hydrogel when injected between the rectum and prostate to reduce rectal radiation toxicity in adult men undergoing Intensity Modulated Radiotherapy (IMRT) for treatment of low and intermediate risk prostate cancer. Methods: This prospective, non-randomized, multi-center, single arm, open-label study included 52 men with a confirmed diagnosis of prostate cancer. They received transperineal injection of the hydrogel and 3–5 days after injection the simulation scans. All patients received IMRT (78 Gy delivered, 2 Gy per fraction). Space stability was evaluated by using MRI or CT. Gastrointestinal (GI) and genitourinary (GU) toxicity was assessed using RTOG/EORTC scoring system and proctoscopy after 12 months. The median follow up time was 12 months. Results: Hydrogel application was straight forward using brachytherapy equipment and techniques, with minimal patient discomfort. Six patients (12%) experienced acute GI Grade 2 toxicity, with no patients experiencing Grade 3 or 4 toxicity. In addition, no patients had early late GI toxicity P Grade 2 after 12 months. The gel was stable during the course of radiotherapy and was not detectable in MRI after 9–12 months due to absorption in 42 of 43 patients. Conclusion: These data demonstrated that the hydrogel is a safe method to displace the rectal wall away from the prostate therefore substantially reducing toxicity to the rectum.