Static beam tomotherapy as an optimisation method in whole-breast radiation therapy (WBRT)

Incidental Axillary Dose of Tomotherapy in Hypofractionated Whole Breast Radiotherapy for Early Breast Cancer: A Dosimetrical Analysis

Background and Objectives: Intensity-modulated radiation therapy (IMRT) is becoming a more common method of performing whole breast irradiation (WBI) for early breast cancer. This study aimed to examine the incidental dose to the axillary region using tomotherapy, a unique form of IMRT. Patients and Methods: This study included 30 patients with early-stage breast cancer who underwent adjuvant WBI using TomoDirect IMRT. A hypofractionation scheme of 42.4 Gy delivered in 16 fractions was prescribed. The plan comprised of two parallel-opposed beams, along with two additional beams positioned anteriorly at gantry angles of 20° and 40° from the medial beam. The incidental dose received at axillary levels I, II, and III was evaluated using several dose-volume parameters. Results: The study participants had a median age of 51 years, and 60% had left-sided breast cancer. The mean dose of the axilla for levels I, II, and III were 15.5 ± 4.8 Gy, 14.9 ± 4.2 Gy, and 1.5 ± 1.6 Gy, respectively. Adequate coverage of the axilla, defined as V95%[%], was achieved for 4.7 ± 3.9%, 4.8 ± 3.7%, and 0 ± 0% for levels I, II, and III, respectively. The results were compared with those of previously published studies, and the axillary mean dose and V95%[%] of TomoDirect IMRT were low, comparable to other IMRT techniques, and lower than those of traditional tangential therapy. Conclusions: While incidental axillary radiation during WBI has been proposed to assist in regional disease control, the TomoDirect plan was demonstrated to decrease this dose, and a hypofractionation scheme would further lower its biological effectiveness. Future clinical studies should incorporate dosimetrical analysis of incidental axillary dose, in order to facilitate hypofractionated IMRT planning with risk-adjusted axilla coverage in early breast cancer.

Comparison of Jaw Mode and Field Width for Left-Breast Cancer Using TomoDirect Three-Dimensional Conformal Radiation Therapy: A Phantom Study

It is very important to use effective parameters in the treatment plan of breast cancer patients in TomoDirect (TD)-three-dimensional conformal radiation therapy (TD-3DCRT). The objective of this study was to compare the radiation treatment plans to the parameters (jaw width and jaw mode) of TD-3DCRT for left-breast cancer. This study was conducted using the phantom, the jaw mode (fixed and dynamic) and field width (2.5 cm and 5.0 cm) were controlled to compare the TD-3DCRT treatment plans. There was small difference in the conformity index (CI) and homogeneity index (HI) values for target according to the jaw mode for each field width. As a result of observation in terms of dose, treatment time and unnecessary damage to surrounding normal organs could be minimized when dynamic jaw with a field width of 5.0 cm was used. In conclusion, we verified that the use of dynamic jaws and 5.0 cm field width was effective in left-breast cancer radiotherapy plan using TD-3DCRT.

Radiation Oncology-Where to from Here? A Global Inquiry into the Perspectives of Radiation Oncology Professionals in Light of the Growing Cancer Epidemic

INTRODUCTION

Radiation oncology is a vital tool in resisting the cancer epidemic affecting millions worldwide. This study queried the perspectives of radiation oncology professionals and sought their solutions in regard to current practice, future practice, outsourcing, and common values.

METHODS

A mass consumer survey was distributed globally that collected quantitative and qualitative data from 245 radiation oncology professionals based in 47 countries.

RESULTS

Participants scored the sector highly on the quality of current practice. The United States was identified as the perceived global leader in the practice of radiation oncology. The sector was considered moderately open to reform with suggestions of better training, greater resources, and incorporation of data informatics. A preference for paradigms involving private enterprise emerged. Appropriate outsourcing tasks and companies were identified and industry leaders evaluated. Remarkable accord was observed in values and priorities across professional groups and examined subsets.

CONCLUSIONS

There is an opportunity to realize value through the application of successful global paradigms. Our research generated a unique performance evaluation of the sector by identifying the current situation and areas open to reform. The required shift in the role of government from provider to regulator implied a mandate for a reorientation of policy settings with greater emphasis on free enterprise solutions that maximize value and ultimately advance patient care.

Treatment outcome for locally advanced non-small-cell lung cancer using TomoDirect plan and its characteristics compared to the TomoHelical plan

Introduction

TomoDirect (TD) is an intensity‐modulated radiotherapy system that uses a fixed gantry angle instead of the rotational beam delivery used in the TomoHelical (TH) system. This study was performed (1) to evaluate the treatment outcome of the TD plan for locally advanced non‐small‐cell lung cancer (NSCLC) and (2) to compare the characteristics of TD plans with those of TH plans.

Methods

Twenty‐one patients with NSCLC were treated using the TD system. The prescribed dose was 40 Gy/20 Fx for the initial planning target volume (PTV), which included the gross tumour volume (GTV) and lymph node regions. A boost plan of 20 Gy/10 Fx was then applied, focusing on the GTV. For the planning study, matched TH plans of 40 Gy for the initial PTV were created for each patient, to meet the same dosimetric constraints specified in the TD plans.

Results

The 2‐year overall survival, progression‐free survival and local control rates were 47%, 45% and 74% respectively. Grade 2 treatment‐related pneumonitis occurred in three (14%) patients. The planning study comparing TD and TH showed that dose distribution to GTV and PTV were not significantly different. The lung V5 Gy was lower in the TD plans than TH plans (46.4 ± 5.4 vs. 52.3 ± 8.5), while the V20 Gy was higher (26.2 ± 4 vs. 24 ± 4.3). The TD plans had a significantly shorter treatment time than TH plans (4.5 ± 1.3 min vs. 9.8 ± 1.5 min).

Conclusions

TD is a clinically acceptable treatment option for NSCSL. The quality of the TD and TH plans are comparable.

Static beam tomotherapy as an optimisation method in whole-breast radiation therapy (WBRT)

INTRODUCTION

TomoTherapy (Accuray, Sunnyvale, CA) has recently introduced a static form of tomotherapy: TomoDirect™ (TD). This study aimed to evaluate TD against a contemporary intensity modulated radiation therapy (IMRT) alternative through comparison of target and organ at risk (OAR) doses in breast cancer cases. A secondary objective was to evaluate planning efficiency by measuring optimisation times.

METHODS

Treatment plans of 27 whole-breast radiation therapy (WBRT) patients optimised with a tangential hybrid IMRT technique were replanned using TD. Parameters included a dynamic field width of 2.5 cm, a pitch of 0.251 and a modulation factor of 2.000; 50 Gy in 25 fractions was prescribed and planning time recorded. The planning metrics used in analysis were ICRU based, with the mean PTV minimum (D99 ) used as the point of comparison.

RESULTS

Both modalities met ICRU50 target heterogeneity objectives (TD D99 = 48.0 Gy vs. IMRT = 48.1 Gy, P = 0.26; TD D1 = 53.5 Gy vs. IMRT = 53.0 Gy, P = 0.02; Homogeneity index TD = 0.11 vs. IMRT = 0.10, P = 0.03), with TD plans generating higher median doses (TD D50 = 51.1 Gy vs. IMRT = 50.9 Gy, P = 0.03). No significant difference was found in prescription dose coverage (TD V50 = 85.5% vs. IMRT = 82.0%, P = 0.09). TD plans produced a statistically significant reduction in V5 ipsilateral lung doses (TD V5 = 23.2% vs. IMRT = 27.2%, P = 0.04), while other queried OARs remained comparable (TD ipsilateral lung V20 = 13.2% vs. IMRT = 14.6%, P = 0.30; TD heart V5 = 2.7% vs. IMRT = 2.8%, P = 0.47; TD heart V10 = 1.7% vs. IMRT = 1.8%, P = 0.44). TD reduced planning time considerably (TD = 9.8 m vs. IMRT = 27.6 m, P < 0.01), saving an average planning time of 17.8 min per patient.

CONCLUSIONS

TD represents a suitable WBRT treatment approach both in terms of plan quality metrics and planning efficiency.

A Feasibility Study on the Use of TomoTherapy Megavoltage Computed Tomography Images for Palliative Patient Treatment Planning

Dedicated rapid access palliative radiation therapy improves patients' access to care, allowing more timely treatment which would positively impact on quality of life. The TomoTherapy (Accuray, Sunnyvale, CA) system provides megavoltage (MV) fan-beam computed tomography (FBCT) as the image guidance technique, and a module called "statRT" that allows the use of these MV FBCT images for direct planning. The possibility of using this imaging modality for palliative radiotherapy treatment planning is assessed against accepted planning CT standards by performing tests following AAPM TG 66 and an end-to-end measurement. Results have shown that MV FBCT images acquired by TomoTherapy are of sufficient quality for the purpose of target delineation and dose calculation for palliative treatments. Large image noise and extended scan acquisition time are the two main drawbacks, so this imaging modality should only be used for palliative treatments at areas with well-known, easily distinguishable, and relatively immobile targets such as spine and whole brain.