Clinical pilot study for EPID-based in vivo dosimetry using EPIgray™ for head and neck VMAT.

This work details the clinical pilot study methodology used at Wellington Blood and Cancer Centre (WBCC) before the clinical release of in vivo dosimetry (IVD) system EPIgray™ for head and neck (H&N) volumetric modulated arc therapy (VMAT) treatments. Clinical pilot studies make it possible to select appropriate, department-specific tolerance ranges for the treatment type and site under investigation. An IVD clinical pilot study of H&N VMAT treatments was conducted over 3 months at WBCC using EPIgray™ dose reconstruction software and included 12 patients and 32 individual treatment fractions.

Report of the ACPSEM radiation oncology medical physics workforce modelling project task group.

The ACPSEM radiation oncology medical physics workforce modelling project task group was formed to acquire a snapshot of practices in Australia and New Zealand and to develop an activity-based workforce model. To achieve this, two surveys were carried out, capturing the work practices of 98 radiation oncology departments and 182 college members. The member survey provided a snapshot of the current workforce: their demographics, work conditions, professional recognition, and future plans.

Relapse patterns after low-dose-rate prostate brachytherapy.

Purpose: When biochemical failure (BF) develops after low-dose-rate prostate brachytherapy, the relapse site is frequently not found. We set out to find whether prostate-specific membrane antigen positron emission tomography -CT (PSMA PET-CT) scanning has improved knowledge of relapse patterns.

Methods And Materials: A database was analyzed, which contained information and long-term followup on 903 men who had an iodine-125 seed implant as monotherapy for early-stage prostate cancer.

A prospective audit of the 10-year outcomes from low dose-rate brachytherapy for early stage prostate cancer.

Aim: New Zealand men diagnosed with early stage prostate cancer need to know what outcomes to expect from management options.

Methods: Between 2001 and 2016, 951 men were treated with low dose-rate brachytherapy (permanent iodine-125 seed implantation) by the Wellington Prostate Brachytherapy Group based at Southern Cross Hospital, Wellington. At follow up after treatment, men had their PSA measured and were scored for urinary, bowel and sexual side effects.

The validity of Acuros BV and TG-43 for high-dose-rate brachytherapy superficial mold treatments.

Purpose: The purpose of this work is to validate the Acuros BV dose calculation algorithm for high-dose-rate (HDR) brachytherapy superficial mold treatments in the absence of full scatter conditions and compare this with TG-43 dose calculations. We also investigate the impact of additional back scatter material (bolus) applied above surface molds to the dose distributions under the mold.

Methods And Materials: The absorbed dose at various depths was compared for simulations performed using either TG-43 or Acuros BV dose calculations.

Validation of Varian's SmartAdapt® deformable image registration algorithm for clinical application.

Background: Re-contouring of structures on consecutive planning computed tomography (CT) images for patients that exhibit anatomical changes is elaborate and may negatively impact the turn-around time if this is required for many patients. This study was therefore initiated to validate the accuracy and usefulness of automatic contour propagation for head and neck cancer patients using SmartAdapt® which is the deformable image registration (DIR) application in Varian's Eclipse™ treatment planning system.

Methods: CT images of eight head and neck cancer patients with multiple planning CTs were registered using SmartAdapt®.

Time-resolved dosimetry using a pinpoint ionization chamber as quality assurance for IMRT and VMAT.

Purpose: To develop a method to verify the dose delivery in relation to the individual control points of intensity modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT) using an ionization chamber. In addition to more effective problem solving during patient-specific quality assurance (QA), the aim is to eventually map out the limitations in the treatment chain and enable a targeted improvement of the treatment technique in an efficient way.

Methods: Pretreatment verification was carried out for 255 treatment plans that included a broad range of treatment indications in two departments using the equipment of different vendors.

Patterns of failure after iodine-125 seed implantation for prostate cancer.

Purpose: To determine the site of relapse when biochemical failure (BF) occurs after iodine-125 seed implantation for prostate cancer.

Materials And Methods: From 2001-2009, 500 men underwent implantation in Wellington, New Zealand. Men who sustained BF were placed on relapse guidelines that delayed restaging and intervention until the prostate-specific antigen (PSA) was ⩾20 ng/mL.