Commissioning considerations for the Bravos high-dose-rate afterloader: Towards improving treatment delivery accuracy.

Background And Purpose: The upgrade of major equipment can be disruptive to clinical operations and introduce risk as policy and procedures need to adapt to new technical possibilities and constraints. We describe here the transition from GammaMedPlus-iX to Bravos in a busy brachytherapy clinic, involving four afterloaders across two sites.

Material And Methods: Our clinic employs three high-dose-rate remote afterloaders in four dedicated treatment vaults at the main site and a fourth afterloader at a regional location.

Extended Follow-Up Outcomes from Pooled Prospective Studies Evaluating Efficacy of Interstitial Alpha Radionuclide Treatment for Skin and Head and Neck Cancers.

The initial favorable efficacy and safety profile for Alpha DaRT have been demonstrated (NCT04377360); however, the longer-term safety and durability of the treatment are unknown. This pooled analysis of four prospective trials evaluated the long-term safety and efficacy of Alpha DaRT for the treatment of head and neck or skin tumors. A total of 81 lesions in 71 patients were treated across six international institutions, with a median follow-up of 14.

AAPM Task Group 334: A guidance document to using radiotherapy immobilization devices and accessories in an MR environment.

Use of magnetic resonance (MR) imaging in radiation therapy has increased substantially in recent years as more radiotherapy centers are having MR simulators installed, requesting more time on clinical diagnostic MR systems, or even treating with combination MR linear accelerator (MR-linac) systems. With this increased use, to ensure the most accurate integration of images into radiotherapy (RT), RT immobilization devices and accessories must be able to be used safely in the MR environment and produce minimal perturbations. The determination of the safety profile and considerations often falls to the medical physicist or other support staff members who at a minimum should be a Level 2 personnel as per the ACR.

A finite element method for modeling diffusion of alpha-emitting particles in tissue.

Background: Diffusing alpha-emitters Radiation Therapy ("DaRT") is a promising new modality for the treatment of solid tumors. Interstitial sources containing Ra are inserted into the tumor, producing alpha particles via the decay of Ra and its daughters. The alpha particles are able to produce a "kill region" of several mm due to the diffusion of the alpha-emitting atoms.

Feasibility and Safety of Diffusing Alpha-Emitter Radiation Therapy for Recurrent or Unresectable Skin Cancers.

Importance: Patients with recurrent or unresectable skin cancers have limited treatment options. Diffusing alpha-emitter radiation therapy (DaRT), a novel solid tumor management strategy using alpha-particle interstitial brachytherapy, may address this challenge.

Objective: To evaluate the feasibility and safety of using DaRT to manage recurrent or unresectable skin cancers.

AAPM medical physics practice guideline 13.a: HDR brachytherapy, part A.

The American Association of Physicists in Medicine (AAPM) is a nonprofit professional society whose primary purposes are to advance the science, education, and professional practice of medical physics. The AAPM has more than 8000 members and is the principal organization of medical physicists in the United States. The AAPM will periodically define new practice guidelines for medical physics practice to help advance the science of medical physics and to improve the quality of service to patients throughout the United States.

Salvage resection plus cesium-131 brachytherapy durably controls post-SRS recurrent brain metastases.

Background: Salvage of recurrent previously irradiated brain metastases (rBrM) is a significant challenge. Resection without adjuvant re-irradiation is associated with a high local failure rate, while reirradiation only partially reduces failure but is associated with greater radiation necrosis risk. Salvage resection plus Cs131 brachytherapy may offer dosimetric and biologic advantages including improved local control versus observation, with reduced normal brain dose versus re-irradiation, however data are limited.

Protocol for the measurement of the absorbed dose rate to water for a planar P beta emitting brachytherapy source: A multi-institutional validation.

Purpose: This is a multi-institutional report on inter-observer and inter-instrument variation in the calibration of the absorbed dose rate for a planar P beta emitting brachytherapy source. Measurement accuracy is essential since the dose profile is steep and the source is used for the treatment of tumors that are located in close proximity to healthy nervous system structures.

Methods And Materials: An RIC-100 P source was calibrated by three institutions using their own equipment and following their standard procedures.

Quantifying clinical severity of physics errors in high-dose rate prostate brachytherapy using simulations.

Purpose: To quantitatively evaluate through automated simulations the clinical significance of potential high-dose rate (HDR) prostate brachytherapy (HDRPB) physics errors selected from our internal failure-modes and effect analysis (FMEA).

Methods And Materials: A list of failure modes was compiled and scored independently by 8 brachytherapy physicists on a one-to-ten scale for severity (S), occurrence (O), and detectability (D), with risk priority number (RPN) = SxOxD. Variability of RPNs across observers (standard deviation/average) was calculated.

Safety practices and opportunities for improvement in brachytherapy: A patient safety practices survey of the American Brachytherapy Society membership.

Purpose: Safe delivery of brachytherapy and establishing a safety culture are critical in high-quality brachytherapy. The American Brachytherapy Society (ABS) Quality and Safety Committee surveyed members regarding brachytherapy services offered, safety practices during treatment, quality assurance procedures, and needs to develop safety and training materials.

Methods And Materials: A 22-item survey was sent to ABS membership in early 2019 to physicians, physicists, therapists, nurses, and administrators.

The American Brachytherapy society consensus statement for skin brachytherapy.

Purpose: Keratinocyte carcinoma (KC, previously nonmelanoma skin cancer) represents the most common cancer worldwide. While surgical treatment is commonly utilized, various radiation therapy techniques are available including external beam and brachytherapy. As such, the American Brachytherapy Society has created an updated consensus statement regarding the use of brachytherapy in the treatment of KCs.

The American Brachytherapy Society consensus statement on intraoperative radiation therapy.

Purpose: Although radiation therapy has traditionally been delivered with external beam or brachytherapy, intraoperative radiation therapy (IORT) represents an alternative that may shorten the course of therapy, reduce toxicities, and improve patient satisfaction while potentially lowering the cost of care. At this time, there are limited evidence-based guidelines to assist clinicians with patient selection for IORT. As such, the American Brachytherapy Society presents a consensus statement on the use of IORT.

Novel intraoperative radiotherapy utilizing prefabricated custom three-dimensionally printed high-dose-rate applicators.

Background: Intraoperative radiotherapy (IORT) is an effective strategy for the delivery of high doses of radiotherapy to a residual tumor or resection cavity with relative sparing of nearby healthy tissues. This strategy is an important component of the multimodality management of pediatric soft tissue sarcomas, particularly in cases where patients have received prior courses of external beam radiotherapy.

Purpose: Tumor beds with significant topographic irregularity remain a therapeutic challenge because existing IORT technologies are typically most reliable with flat surfaces.

Endoluminal high-dose-rate brachytherapy for locally recurrent or persistent esophageal cancer.

Purpose: Management of locally recurrent or persistent esophageal cancer (EC) after standard chemoradiation is challenging. This study updates our experience of treating medically inoperable EC patients with endoluminal high-dose-rate brachytherapy (EHDRBT) including the patients treated with a novel multiballoon channel centering esophageal applicator.

Methods And Materials: Thirty-three consecutive patients with early-stage primary (n = 7), posttreatment persistent (n = 7), and recurrent (n = 19) EC treated with EHDRBT at our institution were included.

Placement of an absorbable rectal hydrogel spacer in patients undergoing low-dose-rate brachytherapy with palladium-103.

Purpose: Rates of rectal toxicity after low-dose-rate (LDR) brachytherapy for prostate cancer are dependent on rectal dose, which is associated with rectal distance from prostate and implanted seeds. Placement of a hydrogel spacer between the prostate and rectum has proven to reduce the volume of the rectum exposed to higher radiation dose levels in the setting of external beam radiotherapy. We present our findings with placing a rectal hydrogel spacer in patients following LDR brachytherapy, and we further assess the impact of this placement on dosimetry and acute rectal toxicity.

Intraoperative implantation of a mesh of directional palladium sources (CivaSheet): Dosimetry verification, clinical commissioning, dose specification, and preliminary experience.

Purpose: To present the clinical commissioning of a novel Pd directional brachytherapy device (CivaSheet) for intraoperative radiation therapy.

Methods And Materials: Clinical commissioning for the CivaSheet consisted of establishing: (1) source strength calibration capabilities, (2) experimental verification of TG-43 dosimetry parameters, (3) treatment planning system validation, and (4) departmental practice for dose specification and source ordering. Experimental verification was performed in water with radiochromic film calibrated with a 37 kVp X-ray beam.

Magnetic resonance imaging basics for the prostate brachytherapist.

Magnetic resonance imaging (MRI) is increasingly being used in radiation therapy, and integration of MRI into brachytherapy in particular is becoming more common. We present here a systematic review of the basic physics and technical aspects of incorporating MRI into prostate brachytherapy. Terminology and MRI system components are reviewed along with typical work flows in prostate high-dose-rate and low-dose-rate brachytherapy.

Real-time intraoperative evaluation of implant quality and dose correction during prostate brachytherapy consistently improves target coverage using a novel image fusion and optimization program.

Purpose: Our purpose was to describe the process and outcome of performing postimplantation dosimetric assessment and intraoperative dose correction during prostate brachytherapy using a novel image fusion-based treatment-planning program.

Methods And Materials: Twenty-six consecutive patients underwent intraoperative real-time corrections of their dose distributions at the end of their permanent seed interstitial procedures. After intraoperatively planned seeds were implanted and while the patient remained in the lithotomy position, a cone beam computed tomography scan was obtained to assess adequacy of the prescription dose coverage.

Hip-related toxicity after prostate radiotherapy: Treatment related or coincidental?

Background And Purpose: To evaluate the incidence and predictors of hip toxicity postradiotherapy for localized prostate cancer.

Methods And Materials: 4067 prostate cancer patients were treated with external beam radiotherapy (EBRT; n=2569; 63%) or brachytherapy with or without supplemental EBRT (n=1508; 27%). 43% (n=1738) were treated with neo-adjuvant and concurrent ADT and 57% (n=2329) with radiotherapy alone.

High-dose-rate brachytherapy of rhabdomyosarcoma limited to the external auditory canal.

Purpose: To report on the single-catheter high-dose-rate brachytherapy treatment of a 21-month-old girl child with an embryonal, botryoid-type, rhabdomyosarcoma limited to the external auditory canal (EAC).

Methods And Materials: A 2.4-mm diameter catheter was inserted into the right EAC and placed against the tympanic membrane.

Impact of source position on high-dose-rate skin surface applicator dosimetry.

Purpose: Skin surface dosimetric discrepancies between measured and treatment planning system predicted values were traced to source position sag inside the applicator and to source transit time. We quantified their dosimetric impact and propose corrections for clinical use.

Methods And Materials: We measured the dose profiles from the Varian Leipzig-style high-dose-rate (HDR) skin applicator, using EBT3 film, photon diode, and optically stimulated luminescence dosimeter for three different GammaMedplus HDR afterloaders.

Long-term outcome of magnetic resonance spectroscopic image-directed dose escalation for prostate brachytherapy.

Purpose: To report the long-term control and toxicity outcomes of patients with clinically localized prostate cancer, who underwent low-dose-rate prostate brachytherapy with magnetic resonance spectroscopic image (MRSI)-directed dose escalation to intraprostatic regions.

Methods And Materials: Forty-seven consecutive patients between May 2000 and December 2003 were analyzed retrospectively. Each patient underwent a preprocedural MRSI, and MRS-positive voxels suspicious for malignancy were identified.