Investigation of linear energy transfer (LET)-dependence behavior and dosimetric response of a flat-panel detector in pencil beam scanning proton therapy.

Purpose: This study aims to elucidate the dependence of the flat-panel detector's response on the linear energy transfer (LET) and evaluate the practical viability of employing flat-panel detectors in proton dosimetry applications through LET-dependent correction factors.

Methods: The study assessed the flat-panel detector's response across varying depths using solid water and distinct 100, 150, and 200 MeV proton beams by comparing the flat-panel readings against reference doses measured with an ionization chamber. A Monte Carlo code was used to derive LET values, and an LET-dependent response correction factor was determined based on the ratio of the uncorrected flat-panel dose to the ionization chamber dose.

Disease Control after Radiotherapy for Adult Craniopharyngioma: Clinical Outcomes from a Large Single-Institution Series.

Purpose: To report disease control and treatment-related side effects among adult patients with craniopharyngioma treated with radiotherapy.

Methods: We performed a single-institution review of adult patients (> 21 years old) with craniopharyngioma treated with radiotherapy either definitively or postoperatively for gross residual disease. We report disease control, survival, and radiotherapy-related side effects.

Effective Organs-at-Risk Dose Sparing in Volumetric Modulated Arc Therapy Using a Half-Beam Technique in Whole Pelvic Irradiation.

Background: Although there are some controversies regarding whole pelvic radiation therapy (WPRT) due to its gastrointestinal and hematologic toxicities, it is considered for patients with gynecological, rectal, and prostate cancer. To effectively spare organs-at-risk (OAR) doses using multi-leaf collimator (MLC)'s optimal segments, potential dosimetric benefits in volumetric modulated arc therapy (VMAT) using a half-beam technique (HF) were investigated for WPRT.

Methods: While the size of a fully opened field (FF) was decided to entirely include a planning target volume in all beam's eye view across arc angles, the HF was designed to use half the FF from the isocenter for dose optimization.

Image-guided hypofractionated double-scattering proton therapy in the management of centrally-located early-stage non-small cell lung cancer.

Background: The treatment of centrally-located early-stage non-small cell lung cancer (NSCLC) with image-guided stereotactic body radiotherapy (SBRT) is challenging due to the proximity of critical normal structures to the tumor target. The purpose of this study was to report the results of our experience in treating centrally-located early-stage NSCLC with hypofractionated proton therapy (PT).

Material And Methods: Between 2009 and 2018, 23 patients with T1-T2N0M0 NSCLC (T1, 46%; T2, 54%) were treated with image-guided hypofractionated double-scattering PT.

Clinical outcomes following proton therapy for adult craniopharyngioma: a single-institution cohort study.

Background: Craniopharyngioma is a benign tumor that commonly develops within the suprasellar region. The tumor and treatment can have debilitating consequences for pediatric and adult patients, including vision loss and pituitary/hypothalamic dysfunction. Most craniopharyngioma series focus on treatment of the pediatric population.

Pencil beam scanning versus passively scattered proton therapy for unresectable pancreatic cancer.

Background: With an increasing number of proton centers capable of delivering pencil beam scanning (PBS), understanding the dosimetric differences in PBS compared to passively scattered proton therapy (PSPT) for pancreatic cancer is of interest.

Methods: Optimized PBS plans were retrospectively generated for 11 patients with locally advanced pancreatic cancer previously treated with PSPT to 59.4 Gy on a prospective trial.

Long-Term Outcomes of Fractionated Stereotactic Proton Therapy for Vestibular Schwannoma: A Case Series.

Purpose: Evaluate clinical outcomes in patients with vestibular schwannoma (VS) treated with fractionated proton therapy (PT) at a single institution.

Materials And Methods: We retrospectively reviewed the medical records of patients treated with fractionated PT for definitive management of VS between November 2007 and December 2013 at our institution. No patient had received prior treatment for VS.

Arthroscopic Reduction and Transportal Screw Fixation of Acetabular Posterior Wall Fracture: Technical Note.

Acetabular fractures can be treated with variable method. In this study, acetabular posterior wall fracture was treated with arthroscopic reduction and fixation using cannulated screw. The patient recovered immediately and had a satisfactory outcome.

A Phase 2 Trial of Concurrent Chemotherapy and Proton Therapy for Stage III Non-Small Cell Lung Cancer: Results and Reflections Following Early Closure of a Single-Institution Study.

Purpose: Proton therapy has been shown to reduce radiation dose to organs at risk (OAR) and could be used to safely escalate the radiation dose. We analyzed outcomes in a group of phase 2 study patients treated with dose-escalated proton therapy with concurrent chemotherapy for stage 3 non-small cell lung cancer (NSCLC).

Methods And Materials: From 2009 through 2013, LU02, a phase 2 trial of proton therapy delivering 74 to 80 Gy at 2 Gy/fraction with concurrent chemotherapy for stage 3 NSCLC, was opened to accrual at our institution.

Proton therapy for pancreatic cancer.

Radiotherapy is commonly offered to patients with pancreatic malignancies although its ultimate utility is compromised since the pancreas is surrounded by exquisitely radiosensitive normal tissues, such as the duodenum, stomach, jejunum, liver, and kidneys. Proton radiotherapy can be used to create dose distributions that conform to tumor targets with significant normal tissue sparing. Because of this, protons appear to represent a superior modality for radiotherapy delivery to patients with unresectable tumors and those receiving postoperative radiotherapy.

A dosimetric comparison of ultra-hypofractionated passively scattered proton radiotherapy and stereotactic body radiotherapy (SBRT) in the definitive treatment of localized prostate cancer.

Background: We compared target and normal tissue dosimetric indices between ultra-hypofractionated passively scattered proton radiotherapy and stereotactic body radiotherapy (SBRT) in the definitive treatment of localized prostate cancer.

Material And Methods: Ten patients were treated definitively for localized prostate cancer with SBRT to a dose of 36.25 Gy in 5 fractions prescribed to a volume encompassing the prostate only.

Protons offer reduced bone marrow, small bowel, and urinary bladder exposure for patients receiving neoadjuvant radiotherapy for resectable rectal cancer.

Background: To assess the potential benefit of proton therapy (PT) over photon therapy, we compared 3-dimensional conformal radiotherapy (3DCRT), intensity-modulated radiotherapy (IMRT), and PT plans in patients undergoing neoadjuvant chemoradiation for resectable rectal cancer at our institution.

Methods: Eight consecutive patients with resectable (T2-T3) rectal cancers underwent 3DCRT, IMRT, and 3-dimensional conformal PT treatment planning. Initial target volumes (PTV1) were contoured using the Radiation Therapy Oncology Group anorectal atlas guidelines.

Proton therapy may allow for comprehensive elective nodal coverage for patients receiving neoadjuvant radiotherapy for localized pancreatic head cancers.

Background: Neoadjuvant radiotherapy has the potential to improve local disease control for patients with localized pancreatic cancers. Concern about an increased risk of surgical complications due to small bowel and gastric exposure, however, has limited enthusiasm for this approach. Dosimetric studies have demonstrated the potential for proton therapy to reduce intestinal exposure compared with X-ray-based therapy.

Proton-based chemoradiation for synchronous bilateral non-small-cell lung cancers: A case report.

In this case report, we present the history and treatment of a 70-year-old man with synchronous bilateral non-small-cell lung cancers with proton-beam radiation. Surgical treatment was not feasible and optimized photon intensity-modulated radiotherapy (IMRT) to the primary tumors would have resulted in unacceptably high normal-tissue exposures. Proton-beam radiation enabled radiation dose escalation and concurrent chemotherapy while maintaining normal-tissue tolerance.

Proton therapy with concomitant capecitabine for pancreatic and ampullary cancers is associated with a low incidence of gastrointestinal toxicity.

Background: To review treatment toxicity for patients with pancreatic and ampullary cancer treated with proton therapy at our institution.

Material And Methods: From March 2009 through April 2012, 22 patients were treated with proton therapy and concomitant capecitabine (1000 mg PO twice daily) for resected (n = 5); marginally resectable (n = 5); and unresectable/inoperable (n = 12) biopsy-proven pancreatic and ampullary adenocarcinoma. Two patients with unresectable disease were excluded from the analysis for reasons unrelated to treatment.

Dosimetric rationale and early experience at UFPTI of thoracic proton therapy and chemotherapy in limited-stage small cell lung cancer.

Background: Concurrent chemoradiotherapy (CRT) is the standard of care in patients with limited-stage small cell lung cancer (SCLC). Treatment with conventional x-ray therapy (XRT) is associated with high toxicity rates, particularly acute grade 3+ esophagitis and pneumonitis. We present outcomes for the first known series of limited-stage SCLC patients treated with proton therapy and a dosimetric comparison of lung and esophageal doses with intensity-modulated radiation therapy (IMRT).

Proton therapy versus photon radiation therapy for the management of a recurrent desmoid tumor of the right flank: a case report.

Desmoid tumors are benign mesenchymal tumors with a strong tendency for local recurrence after surgery. Radiotherapy improves local control following incomplete resection, but nearby organs at risk may limit the dose to the target volume. The patient in this report presented with a recurrent desmoid tumor of the right flank and underwent surgery with microscopically positive margins.

Selective nodal irradiation of regionally advanced non-small-cell lung cancer with proton therapy and IMRT: A dosimetric comparison.

Objectives:   Evaluate the dosimetric impact of selective/elective nodal treatment with dose-escalated radiotherapy for regionally advanced non-small-cell lung cancer (NSCLC) using proton therapy (PT) or intensity-modulated radiotherapy (IMRT).

Methods:   Five consecutive patients with regionally advanced NSCLC underwent treatment planning for high-dose involved-field (IF) treatment (positron emission tomography-positive gross disease) with or without selective/elective nodal irradiation, defined as the extended field (EF). Four treatment plans were developed for each patient: i) IMRT to treat IF to 74 Gy (IFrT); ii) IMRT to treat high-risk nodes to 44 Gy and IF to 74 Gy (EFrT); iii) PT to treat IF to 74CGE (IFpT); and iv) PT to treat high-risk nodes to 44CGE and IF to 74CGE (EFpT).

Proton therapy for lung cancer.

Proton therapy is an emerging radiotherapy technology with the potential to improve the therapeutic index in the treatment of lung cancer patients. Since charged particles, such as protons, have a penetration length that can be modified by using different energies, protons offer the clinician the ability to modulate radiation dose deposition along the beam path. This facilitates an increase of the dose to the tumor target while minimizing the volume of normal tissue irradiation.

Proton therapy with concurrent chemotherapy for non-small-cell lung cancer: technique and early results.

Background: Proton therapy can deliver a more conformal dose distribution than photon radiation and may allow safe dose escalation in stage III lung cancer. Early outcomes are presented here for patients who received proton therapy with concurrent chemotherapy for non-small-cell lung cancer (NSCLC).

Materials And Methods: Nineteen patients with regionally advanced NSCLC were treated with concurrent chemotherapy (carboplatin and paclitaxel [n = 18]) and proton therapy from August 2008 to April 2010 either with (n = 7) or without (n = 12) induction chemotherapy.

Protons offer reduced normal-tissue exposure for patients receiving postoperative radiotherapy for resected pancreatic head cancer.

Purpose: To determine the potential role for adjuvant proton-based radiotherapy (PT) for resected pancreatic head cancer.

Methods And Materials: Between June 2008 and November 2008, 8 consecutive patients with resected pancreatic head cancers underwent optimized intensity-modulated radiotherapy (IMRT) treatment planning. IMRT plans used between 10 and 18 fields and delivered 45 Gy to the initial planning target volume (PTV) and a 5.

Proton radiation therapy offers reduced normal lung and bone marrow exposure for patients receiving dose-escalated radiation therapy for unresectable stage iii non-small-cell lung cancer: a dosimetric study.

Introduction: The purpose of this study was to determine the potential benefit of proton radiation therapy over photon radiation therapy in patients with unresectable stage III non-small-cell lung cancer.

Materials And Methods: Optimized 3-dimensional conformal photon (3DCRT), intensity-modulated radiation therapy (IMRT) and proton therapy (PT) plans were generated for 8 consecutive patients with unresectable stage III non-small-cell lung cancer using the same target goals and normal tissue constraints. The radiation exposure to non-targeted normal structures, including lung, bone marrow, esophagus, heart, and spinal cord, were compared.

Dosimetric comparison study between intensity modulated radiation therapy and three-dimensional conformal proton therapy for pelvic bone marrow sparing in the treatment of cervical cancer.

The objective was to compare intensity-modulated radiation therapy (IMRT) with 3D conformal proton therapy (3DCPT) in the treatment of cervical cancer. In particular, each technique's ability to spare pelvic bone marrow (PBM) was of primary interest in this study. A total of six cervical cancer patients (3 postoperative and 3 intact) were planned and analyzed.