Voxel-wise dose rate calculation in clinical pencil beam scanning proton therapy.

. Clinical outcomes after proton therapy have shown some variability that is not fully understood. Different approaches have been suggested to explain the biological outcome, but none has yet provided a comprehensive and satisfactory rationale for observed toxicities.

Remote dose imaging from Cherenkov light using spatially resolved CT calibration in breast radiotherapy.

Purpose: Imaging Cherenkov light during radiotherapy allows the visualization and recording of frame-by-frame relative maps of the dose being delivered to the tissue at each control point used throughout treatment, providing one of the most complete real-time means of treatment quality assurance. In non-turbid media, the intensity of Cherenkov light is linear with surface dose deposited, however the emission from patient tissue is well-known to be reduced by absorbing tissue components such as hemoglobin, fat, water, and melanin, and diffused by the scattering components of tissue. Earlier studies have shown that bulk correction could be achieved by using the patient planning computed tomography (CT) scan for attenuation correction.

Optimization of in vivo Cherenkov imaging dosimetry via spectral choices for ambient background lights and filtering.

Significance: The Cherenkov emission spectrum overlaps with that of ambient room light sources. Choice of room lighting devices dramatically affects the efficient detection of Cherenkov emission during patient treatment.

Aim: To determine optimal room light sources allowing Cherenkov emission imaging in normally lit radiotherapy treatment delivery rooms.

Estimation of diffuse Cherenkov optical emission from external beam radiation build-up in tissue.

Significance: Optical imaging of Cherenkov emission during radiation therapy could be used to verify dose delivery in real-time if a more comprehensive quantitative understanding of the factors affecting emission intensity could be developed.

Aim: This study aims to explore the change in diffuse Cherenkov emission intensity with x-ray beam energy from irradiated tissue, both theoretically and experimentally.

Approach: Derivation of the emitted Cherenkov signal was achieved using diffusion theory, and experimental studies with 6 to 18 MV energy x-rays were performed in tissue phantoms to confirm the model predictions as related to the radiation build-up factor with depth into tissue.

Verification of field match lines in whole breast radiation therapy using Cherenkov imaging.

Purpose: In mono-isocentric radiation therapy treatment plans designed to treat the whole breast and supraclavicular lymph nodes, the fields meet at isocenter, forming the match line. Insufficient coverage at the match line can lead to recurrence, and overlap over weeks of treatment can lead to increased risk of healthy tissue toxicity. Cherenkov imaging was used to assess the accuracy of delivery at the match line and identify potential incidents during patient treatments.

Initial Clinical Experience of Cherenkov Imaging in External Beam Radiation Therapy Identifies Opportunities to Improve Treatment Delivery.

Purpose: The value of Cherenkov imaging as an on-patient, real-time, treatment delivery verification system was examined in a 64-patient cohort during routine radiation treatments in a single-center study.

Methods And Materials: Cherenkov cameras were mounted in treatment rooms and used to image patients during their standard radiation therapy regimen for various sites, predominantly for whole breast and total skin electron therapy. For most patients, multiple fractions were imaged, with some involving bolus or scintillators on the skin.

Correcting Cherenkov light attenuation in tissue using spatial frequency domain imaging for quantitative surface dosimetry during whole breast radiation therapy.

Imaging Cherenkov emission during radiotherapy permits real-time visualization of external beam delivery on superficial tissue. This signal is linear with absorbed dose in homogeneous media, indicating potential for quantitative dosimetry. In humans, the inherent heterogeneity of tissue optical properties (primarily from blood and skin pigment) distorts the linearity between detected Cherenkov signal and absorbed dose.