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Although proton therapy has become a well-established radiation modality, continued efforts are needed to improve our understanding of the molecular and cellular mechanisms occurring during treatment. Such studies are challenging, requiring many resources. The purpose of this study was to create a phantom that would allow multiple in vitro experiments to be irradiated simultaneously with a spot-scanning proton beam.

The setup included a modified patient-couch top coupled with a high-precision robotic arm for positioning. An acrylic phantom was created to hold 4 6-well cell-culture plates at 2 different positions along the Bragg curve in a reproducible manner. The proton treatment plan consisted of 1 large field encompassing all 4 plates with a monoenergetic 76.8-MeV posterior beam. For robust delivery, a mini pyramid filter was used to broaden the Bragg peak (BP) in the depth direction. Both a Markus ionization chamber and EBT3 radiochromic film measurements were used to verify absolute dose.

A treatment plan for the simultaneous irradiation of 2 plates irradiated with high linear energy transfer protons (BP, 7 keV/μm) and 2 plates irradiated with low linear energy transfer protons (entrance, 2.2 keV/μm) was created. Dose uncertainty was larger across the setup for cell plates positioned at the BP because of beam divergence and, subsequently, variable proton-path lengths. Markus chamber measurements resulted in uncertainty values of ±1.8% from the mean dose. Negligible differences were seen in the entrance region (<0.3%).

The proposed proton irradiation setup allows 4 plates to be simultaneously irradiated with 2 different portions (entrance and BP) of a 76.8-MeV beam. Dosimetric uncertainties across the setup are within ±1.8% of the mean dose.

The proposed proton irradiation setup allows 4 plates to be simultaneously irradiated with 2 different portions (entrance and BP) of a 76.8-MeV beam. Dosimetric uncertainties across the setup are within ±1.8% of the mean dose.

To investigate and quantify the potential benefits associated with the use of stopping-power-ratio (SPR) images created from dual-energy computed tomography (DECT) images for proton dose calculation in a clinical proton treatment planning system (TPS).

The DECT and single-energy computed tomography (SECT) scans obtained for 26 plastic tissue surrogate plugs were placed individually in a tissue-equivalent plastic phantom. Relative-electron density (ρ

) and effective atomic number (



) images were reconstructed from the DECT scans and used to create an SPR image set for each plug. Next, the SPR for each plug was measured in a clinical proton beam for comparison of the calculated values in the SPR images. The SPR images and SECTs were then imported into a clinical TPS, and treatment plans were developed consisting of a single field delivering a 10 × 10 × 10-cm

spread-out Bragg peak to a clinical target volume that contained the plugs. To verify the accuracy of the TPS dose calculated from the SPR imagesof clinical treatment plans at our center. The calculated doses from the SPR image-based treatment plans showed better agreement to measured doses than identical plans created with standard SECT scans.

To clarify the dose distribution characteristics for early-stage glottic cancer by comparing the dose distribution between intensity-modulated radiation therapy (IMRT) and passive scattering proton therapy (PSPT) and to examine the usefulness of PSPT for early-stage glottic cancer.

Computed tomography datasets of 8 patients with T1-2 glottic cancer who had been treated by PSPT were used to create an IMRT plan in Eclipse with 7 fields and a PSPT plan in XiO-M with 2 fields. Organs at risk (OARs) included the carotid arteries, arytenoids, inferior constrictor muscles, strap muscles, thyroid cartilage, cricoid cartilage, and spinal cord. The prescription dose was 66 GyRBE in 33 fractions to the planning target volume (PTV). All plans were optimized such that 95% of the PTV received 90% of the prescription dose considering that the skin was slightly spared.

The superiority of the PSPT was confirmed in all OARs. In the PSPT, the dose to the contralateral carotid artery and the spinal cord, which is slightly distant from the PTV, was dramatically reduced while maintaining the dose distribution uniformity of the PTV by comparison with IMRT.

PSPT for early-stage glottic cancer resulted in good target dose homogeneity and significantly spared the OARs as compared with the IMRT. learn more PSPT is expected to be effective in reducing late effects and particularly useful for young people.

PSPT for early-stage glottic cancer resulted in good target dose homogeneity and significantly spared the OARs as compared with the IMRT. PSPT is expected to be effective in reducing late effects and particularly useful for young people.

Carbon ion radiotherapy (CIRT) is an emerging radiotherapy modality with potential advantages over conventional photon-based therapy, including exhibiting a Bragg peak and greater relative biological effectiveness, leading to a higher degree of cell kill. Currently, 13 centers are treating with CIRT, although there are no centers in the United States. We aimed to estimate the number of patients eligible for a CIRT center in the United States.

Using the National Cancer Database, we analyzed the incidence of cancers frequently treated with CIRT internationally (glioblastoma, hepatocellular carcinoma, cholangiocarcinoma, locally advanced pancreatic cancer, non-small cell lung cancer, localized prostate cancer, soft tissue sarcomas, and specific head and neck cancers) diagnosed in the United States in 2015. The percentage and number of patients likely benefiting from CIRT was estimated with inclusion criteria from clinical trials and retrospective studies, and that ratio was applied to 2019 cancer statistics.0 years.

Our analysis suggests a need for CIRT in the United States in 2019, with the number of patients possibly eligible to receive CIRT expected to increase during the coming 5 to 10 years.

The RadTox assay measures circulating cell-free DNA released in response to radiotherapy (RT)-induced tissue damage. The primary objectives for this clinical trial were to determine whether cell-free DNA numbers measured by the RadTox assay are (1) correlated with body integral dose, (2) lower with proton RT compared with photon RT, and (3) higher with larger prostate cancer RT fields.

Patients planned to receive proton or photon RT for nonmetastatic prostate cancer in the setting of an intact prostate or postprostatectomy were eligible for the trial. Plasma was collected pre-RT and at 5 additional daily collection points beginning 24 hours after the initiation of RT. Data from 54 evaluable patients were analyzed to examine any correlations among RadTox scores with body-integral dose, RT modality (photon versus proton), and RT field size (prostate or prostate bed versus whole pelvis).

Body integral dose was significantly associated with the peak post-RT RadTox score (

 = .04). Patients who received photon RT had a significant increase in peak post-RT RadTox score (

 = .