Publications by authors named "Ashish K Chawla"
Purpose: To design a patient specific quality assurance (PSQA) process for the CyberKnife Synchrony system and quantify its dosimetric accuracy using a motion platform driven by patient tumor traces with rotation.
Methods: The CyberKnife Synchrony system was evaluated using a motion platform (MODUSQA) and a SRS MapCHECK phantom. The platform was programed to move in the superior-inferior (SI) direction based on tumor traces.
Article Synopsis
- The study aimed to assess patient-specific quality assurance (PSQA) for three targets using a new spherical film-based phantom designed for simultaneous measurements.
- Fifteen test plans were implemented using the CyberKnife system, applying both automatic and marker-based registration methods to analyze the irradiated films with high gamma analysis passing rates.
- The novel phantom demonstrated good PSQA results, confirming its effectiveness for robotic radiosurgery and marking a significant advance in concurrent targeting assessments on the CyberKnife system.
Background: Pencil beam scanning (PBS) proton therapy allows for far superior dose conformality compared with passive scattering techniques. However, one drawback of PBS is that the beam delivery time can be long, particularly when treating superficial disease. Minimizing beam delivery time is important for patient comfort and precision of treatment delivery.
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- - The study aimed to assess a high-resolution diode array for patient-specific quality assurance in CyberKnife brain stereotactic radiosurgery and radiotherapy, testing 33 different treatment plans using various delivery techniques.
- - Results showed that before registration, the gamma passing rates were above 90% across all treatment methods, with improvements observed after registration, particularly under tighter criteria.
- - The average delivery times for the different techniques ranged from approximately 17 to 34 minutes, indicating that the SRS MapCHECK could effectively serve as a routine quality assurance tool for CyberKnife treatments.
Combined modality therapy (CMT) with radiation therapy and chemotherapy plays an important role in the management of rectal cancer. Postoperatively, pelvic irradiation and 5-fluorouracil-based chemotherapy have been used to improve local control and survival for high-risk patients after local excision, as well as for patients undergoing abdominoperineal or low anterior resection. For patients treated preoperatively, CMT can also be used to facilitate sphincter-sparing surgery for distal rectal tumors.
View Article and Find Full Text PDFPurpose: Radiotherapy (RT) has an important role in breast cancer treatment after modified radical mastectomy. Many of these patients also undergo breast reconstruction. We reviewed our institutions' experience to determine the outcome of patients treated with breast reconstruction and RT.
View Article and Find Full Text PDFObjectives: To determine the probability of biochemical control for patients treated with salvage irradiation and identify prognostic factors associated with successful salvage. The optimal management of prostate cancer in patients with an elevated prostate-specific antigen (PSA) level after radical prostatectomy remains unclear.
Methods: We reviewed the records of 54 patients with node-negative prostate cancer treated with radiotherapy alone between 1991 and 1998 for isolated biochemical relapse after prostatectomy.