Validation of the RayStation Monte Carlo dose calculation algorithm using a realistic lung phantom.

Purpose: Our purposes are to compare the accuracy of RaySearch's analytical pencil beam (APB) and Monte Carlo (MC) algorithms for clinical proton therapy and to present clinical validation data using a novel animal tissue lung phantom.

Methods: We constructed a realistic lung phantom composed of a rack of lamb resting on a stack of rectangular natural cork slabs simulating lung tissue. The tumor was simulated using 70% lean ground lamb meat inserted in a spherical hole with diameter 40 ± 5 mm carved into the cork slabs.

Proton therapy delivery: what is needed in the next ten years?

Proton radiation therapy has been used clinically since 1952, and major advancements in the last 10 years have helped establish protons as a major clinical modality in the cancer-fighting arsenal. Technologies will always evolve, but enough major breakthroughs have been accomplished over the past 10 years to allow for a major revolution in proton therapy. This paper summarizes the major technology advancements with respect to beam delivery that are now ready for mass implementation in the proton therapy space and encourages vendors to bring these to market to benefit the cancer population worldwide.

Validation of the RayStation Monte Carlo dose calculation algorithm using realistic animal tissue phantoms.

Purpose: The aim of this study is to validate the RayStation Monte Carlo (MC) dose algorithm using animal tissue neck phantoms and a water breast phantom.

Methods: Three anthropomorphic phantoms were used in a clinical setting to test the RayStation MC dose algorithm. We used two real animal necks that were cut to a workable shape while frozen and then thawed before being CT scanned.

Using stable distributions to characterize proton pencil beams.

Purpose: To introduce and evaluate the use of stable distributions as a methodology to quantify the behavior of proton pencil beams in a medium.

Methods: The proton pencil beams of a clinically commissioned proton treatment facility are replicated in a Monte Carlo simulation system (FLUKA). For each available energy, the beam deposition in water medium is characterized by the dose deposition.

MRI-based treatment planning and dose delivery verification for intraocular melanoma brachytherapy.

Purpose: Episcleral plaque brachytherapy (EPB) planning is conventionally based on approximations of the implant geometry with no volumetric imaging following plaque implantation. We have developed an MRI-based technique for EPB treatment planning and dose delivery verification based on the actual patient-specific geometry.

Methods And Materials: MR images of 6 patients, prescribed 85 Gy over 96 hours from Collaborative Ocular Melanoma Study-based EPB, were acquired before and after implantation.

A comparison between hydrogel spacer and endorectal balloon: An analysis of intrafraction prostate motion during proton therapy.

The purpose of this study was to evaluate intrafraction prostate motion in patients treated with proton therapy and an endorectal balloon or a hydrogel spacer using orthogonal x-rays acquired before and after each treatment field. This study evaluated 10 patients (662 fields throughout treatment) treated daily with an endorectal balloon (ERB) and 16 patients (840 fields throughout treatment) treated with a hydrogel spacer (GEL) without an ERB. Patient shifts were recorded before and after each treatment field, correlated with a treatment time, using x-ray imaging and implanted fiducial alignment.

Validation of rectal sparing throughout the course of proton therapy treatment in prostate cancer patients treated with SpaceOAR.

The purpose of this study was to investigate the consistency of rectal sparing using multiple periodic quality assurance computerized tomography imaging scans (QACT) obtained during the course of proton therapy for patients with prostate cancer treated with a hydrogel spacer. Forty-one low- and intermediate-risk prostate cancer patients treated with image-guided proton therapy with rectal spacer hydrogel were analyzed. To assess the reproducibility of rectal sparing with the hydrogel spacer, three to four QACTs were performed for each patient on day 1 and during weeks 1, 3, and 5 of treatment.

The Impact of Axillary Lymph Node Surgery on Breast Skin Thickening During and After Radiation Therapy for Breast Cancer.

Purpose: This prospective study was conducted to determine predictors of epidermal thickening during and after whole-breast radiation therapy (XRT) using objective measurements acquired with ultrasound.

Methods And Materials: After breast-conserving surgery, 70 women received a definitive course of whole-breast XRT (50 Gy plus boost). Prior to XRT, at week 6 of XRT, and 6 weeks after XRT, patients underwent objective ultrasound measurements of epidermal thickness over the lumpectomy cavity and all 4 quadrants of the treated breast.

Proton therapy for pediatric and adolescent esthesioneuroblastoma.

Background: Esthesioneuroblastoma (EN) of the paranasal sinus comprises less than 3% of tumors of in pediatric and adolescent patients [1]. The collective adult literature indicates a critical role for radiotherapy in attaining cure [2], yet pediatric outcome data is limited. Radiation in pediatric patients with EN can cause significant morbidity due to the proximity of critical structures.