Real-time brachytherapy for prostate cancer – implant analysis

SummaryBackgroundIn HDR brachytherapy precision of catheter implantation is crucial for conformal treatment planning as a starting point for better optimization process.AimThe aim was to investigate differences between virtual and real needle position and the effect of needle displacement on dosimetric parameters as a function of prostate volume for better evaluation of “real” implant with respect to final dose distribution.Materials/MethodsThirty treatment plans calculated by Nucletron SWIFT™ were randomly selected. Dosimetric data including V100 for prostate gland and D10 for urethra were analyzed as a function of prostate volume and needle displacement.Needle displacement was determined by measuring the distance between virtual and real positions of respective needles in three sectional images: at the base, apex of the prostate gland and reference image. Dosimetric parameters were determined for consecutive computer plans: virtual (before implantation), live (after implantation and renewed optimization). For the purpose of this study a new parameter, VD (Volume-Dose), was created.ResultsVD indicates the quality of “real” dose distribution with respect to “virtual” treatment plan. In order to realize the assumption of virtual plan (VD<1) for a given prostate volume, mean values of needle displacement r should not exceed racceptable according to the formula: racceptable (Vp) ∝ Vp2. For larger glands (above 30cc) final dose distribution is less dependent on needle displacement than smaller ones.ConclusionsThe experiment determined maximum values of needle displacement for a given Vp parameter, allowing one to take advantage of optimization algorithms and to improve the final dose distribution

Estimation of the α/β ratio for lower lip cancer treated with interstitial HDR brachytherapy

BackgroundA standard linear-quadratic (LQ) model is now routinely used for clinical data analysis and the prediction of the clinical effect of radiotherapy. The typical α/β values suggested in the literature range from 10 to 20Gy for most tumours and early responding normal tissues, and from 2 to 5Gy for late responding tissues.AimThe estimation of α/β ratio values for planoepithelial lower lip cancer.Materials/MethodsThe clinical material is based on the records of 25 patients undergoing radical treatment with interstitial brachytherapy: 19 patients were administered brachytherapy exclusively and 6 patients were treated postoperatively. The following stage arrangement was applied: T1 in 15 pts, T2 in 9 pts, N0 in 24 pts and N1 only in one T2 patient. Radiotherapy was based on HDR brachytherapy using the interstitial technique. Patients with positive margins after surgery were qualified for postoperative brachytherapy. The dose was either specified at the reference 80% isodose according to the Paris System or points calculated 3-5 mm from the macroscopic tumour. The average total dose was 38.3Gy, the number of fractions being 7 and the fraction dose 5.3Gy. The overall treatment time was 12 days. The average follow-up period was 30 months. A standard probit regression in conjunction with a linear-quadratic model was used.ResultsThe estimated value of the α/β ratio for lip cancer was 12Gy (±3.72*10−10 95% CI).ConclusionsThe estimated α/β ratio is consistent with α/β ratios published for squamous cell head and neck cancers

Real-time brachytherapy for prostate cancer – implant analysis

BackgroundIn HDR brachytherapy precision of catheter implantation is crucial for conformal treatment planning as a starting point for better optimization process.AimThe aim was to investigate differences between virtual and real needle position and the effect of needle displacement on dosimetric parameters as a function of prostate volume for better evaluation of “real” implant with respect to final dose distribution.Materials/MethodsThirty treatment plans calculated by Nucletron SWIFT™ were randomly selected. Dosimetric data including V100 for prostate gland and D10 for urethra were analyzed as a function of prostate volume and needle displacement.Needle displacement was determined by measuring the distance between virtual and real positions of respective needles in three sectional images: at the base, apex of the prostate gland and reference image. Dosimetric parameters were determined for consecutive computer plans: virtual (before implantation), live (after implantation and renewed optimization). For the purpose of this study a new parameter, VD (Volume-Dose), was created.ResultsVD indicates the quality of “real” dose distribution with respect to “virtual” treatment plan. In order to realize the assumption of virtual plan (V

gec estro acrop recommendations in skin brachytherapy

Abstract Purpose The aim of this publication is to compile available literature data and expert experience regarding skin brachytherapy (BT) in order to produce general recommendations on behalf of the GEC-ESTRO Group. Methods We have done an exhaustive review of published articles to look for general recommendations. Results Randomized controlled trials, systemic reviews and meta-analysis are lacking in literature and there is wide variety of prescription techniques successfully used across the radiotherapy centers. BT can be delivered as superficial application (also called contact BT or plesiotherapy) or as interstitial for tumours thicker than 5 mm within any surface, including very irregular. In selected cases, particularly in tumours located within curved surfaces, BT can be advantageous modality from dosimetric and planning point of view when compared to external beam radiotherapy. The general rule in skin BT is that the smaller the target volume, the highest dose per fraction and the shortest overall length of treatment can be used. Conclusion Skin cancer incidence is rising worldwide. BT offers an effective non-invasive or minimally invasive and relative short treatment that particularly appeals to elder and frail population

Non-melanoma skin cancer treated with high-dose-rate brachytherapy: a review of literature

Purpose: The incidence of non-melanoma skin cancer (NMSC) has been increasing over the past 30 years. There are different treatment options and surgical excision is the most frequent treatment due to its low rates of recurrence. Radiotherapy is an effective alternative of surgery, and brachytherapy (BT) might be a better therapeutic option due to high radiation dose concentration to the tumor with rapid dose fall-off resulting in normal tissues sparing. The aim of this review was to evaluate the local control, toxicity, and cosmetic outcomes in NMSC treated with high-dose-rate BT (HDR-BT). Material and methods: In May 2016, a systematic search of bibliographic database of PubMed, Web of Science, Scopus, and Cochrane Library with a combination of key words of “skin cancer”, “high dose rate brachytherapy”,“squamous cell carcinoma”, “basal cell carcinoma”, and “non melanoma skin cancer“ was performed. In this systematic review, we included randomized trials, non-randomized trials, prospective and retrospective studies in patients affected by NMSC treated with HDR-BT. Results: Our searches generated a total of 85 results, and through a process of screening, 10 publications were selected for the review. Brachytherapy was well tolerated with acceptable toxicity and high local control rates (median: 97%). Cosmetic outcome was reported in seven study and consisted in an excellent and good cosmetic results in 94.8% of cases. Conclusions: Based on the review data, we can conclude that the treatment of NMSC with HDR-BT is effective with excellent and good cosmetics results, even in elderly patients. The hypofractionated course appears effective with very good local disease control. More data with large-scale randomized controlled trials are needed to assess the efficacy and safety of brachytherapy

The first ever satellite radiotherapy centre in the UK

The Christie Centre at Oldham is one of two satellite radiotherapy centres of the Christie NHS Foundation Trust in the Greater Manchester and Cheshire area. An oncologist at the Centre in Oldham describes the rationale behind its formation, theway it works and the type of patient treated