Assessing the feasibility of adaptive planning for prostate radiotherapy using Smartadapt deformable image registration.

Background: The purpose of this study is to assess the feasibility of adaptive planning for prostate cancer using SmartAdapt deformable image registration (DIR), in an effort to reduce the effect of patient-specific variations.

Methods: 18 prostate patients (74 Gy in 37 fractions) were selected. Each patient had a planning CT and cone-beam CT (CBCT) images acquired at different fractions.

Image-guided radiotherapy of the prostate using daily CBCT: the feasibility and likely benefit of implementing a margin reduction.

Objective: To investigate whether planning target volume (PTV) margins may be safely reduced in radiotherapy of localized prostate cancer incorporating daily online tube potential-cone beam CT (CBCT) image guidance and the anticipated benefit in predicted rectal toxicity.

Methods: The prostate-only clinical target volume (CTV2) and rectum were delineated on 1 pre-treatment CBCT each week in 18 randomly selected patients. By transposing these contours onto the original plan, dose-volume histograms (DVHs) for CTV2 and the rectum were each calculated and combined, for each patient, to produce a single mean DVH representative of the dose delivered over the treatment course.

Dose calculation software for helical tomotherapy, utilizing patient CT data to calculate an independent three-dimensional dose cube.

Purpose: Treatment plans for the TomoTherapy unit are produced with a planning system that is integral to the unit. The authors have produced an independent dose calculation system, to enable plans to be recalculated in three dimensions, using the patient's CT data.

Methods: Software has been written using MATLAB.

Evaluation of implanted gold seeds for breast radiotherapy planning and on treatment verification: a feasibility study on behalf of the IMPORT trialists.

Background And Purpose: We describe a feasibility study testing the use of gold seeds for the identification of post-operative tumour bed after breast conservation surgery (BCS).

Materials And Methods: Fifty-three patients undergoing BCS for invasive cancer were recruited. Successful use was defined as all six seeds correctly positioned around the tumour bed during BCS, unique identification of all implanted seeds on CT planning scan and ≥ 3 seeds uniquely identified at verification to give couch displacement co-ordinates in 10/15 fractions.

Tumour shrinkage and contour change during radiotherapy increase the dose to organs at risk but not the target volumes for head and neck cancer patients treated on the TomoTherapy HiArt™ system.

Aims: To quantify the changes in contours of the target and organs at risk and the differences between planned and delivered doses to the target and organs at risk during the course of radiotherapy in head and neck cancer patients treated with intensity-modulated radiotherapy on the TomoTherapy HiArt™ system.

Materials And Methods: Five patients with squamous cell carcinoma of the head and neck treated with radical chemoradiotherapy using the TomoTherapy HiArt system were included in the study. The target volumes were treated to three different dose levels depending on the level of clinical risk for harbouring disease.

Planning with intensity-modulated radiotherapy and tomotherapy to modulate dose across breast to reflect recurrence risk (IMPORT High trial).

Purpose: To establish planning solutions for a concomitant three-level radiation dose distribution to the breast using linear accelerator- or tomotherapy-based intensity-modulated radiotherapy (IMRT), for the U.K. Intensity Modulated and Partial Organ (IMPORT) High trial.

Practical aspects of implementation of helical tomotherapy for intensity-modulated and image-guided radiotherapy.

Aims: Image-guided radiotherapy (IGRT) and intensity-modulated radiotherapy (IMRT) represent two important technical developments that will probably improve patient outcome. Helical tomotherapy, provided by the TomoTherapy HiArt system, provides an elegant integrated solution providing both technologies, although others are available. Here we report our experience of clinical implementation of daily online IGRT and IMRT using helical tomotherapy.

Skull base meningioma - comparison of intensity-modulated radiotherapy planning techniques using the moduleaf micro-multileaf collimator and helical tomotherapy.

Aims: Therapeutic radiotherapy to lesions of the skull base is limited by complex target shapes and their proximity to organs at risk. Intensity-modulated radiotherapy (IMRT) using helical tomotherapy may result in improved dose distributions and safer dose escalation. The aim of this study was to compare plan efficacy and efficiency using, linac-based micro-multileaf collimator (mMLC) IMRT and helical tomotherapy.

An assessment of action levels in imaging strategies in head and neck cancer using TomoTherapy. Are our margins adequate in the absence of image guidance?

Aims: To assess the effectiveness of different on-treatment correction strategies on set-up accuracy in patients with head and neck cancer (HNC) treated on a TomoTherapy HiArt system. To assess the adequacy of clinical target volume (CTV) to planning target volume (PTV) treatment planning margins when treating with intensity-modulated radiotherapy without daily image guidance.

Materials And Methods: The set-up accuracy measured by daily online volumetric imaging was retrospectively reviewed for the first 15 patients with HNC treated on the TomoTherapy unit at Addenbrooke's Hospital.

Practical issues in the implementation of image-guided radiotherapy for the treatment of prostate cancer within a UK department.

Aims: To study the feasibility of using implanted gold seeds in combination with a commercial software system for daily localisation of the prostate gland during conformal radiotherapy, and to assess the effect this may have on departmental workload.

Materials And Methods: Six patients had three gold radio-opaque seeds implanted into the prostate gland before starting a course of radiotherapy. The seeds were identified on daily portal images and an automated online system provided immediate vector analysis of discrepancies between the planned and actual daily position of the intraprostatic seeds.

Quantitative analysis of patient-specific dosimetric IMRT verification.

Patient-specific dosimetric verification methods for IMRT treatments are variable, time-consuming and frequently qualitative, preventing evidence-based reduction in the amount of verification performed. This paper addresses some of these issues by applying a quantitative analysis parameter to the dosimetric verification procedure. Film measurements in different planes were acquired for a series of ten IMRT prostate patients, analysed using the quantitative parameter, and compared to determine the most suitable verification plane.