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Jose Penagaricano

Publications and source records attributed to Jose Penagaricano.

3 recordsLinked to original sources
PubMed2005

Fast radiographic film calibration procedure for helical tomotherapy intensity modulated radiation therapy dose verification.

Film dosimetry offers an advantageous in-phantom planar dose verification tool in terms of spatial resolution and ease of handling for quality assurance (QA) of intensity modulated radiation therapy (IMRT) plans. A critical step in the success of such a technique is that the film calibration be appropriately conducted. This paper presents a fast and efficient film calibration method for a helical tomotherapy unit using a single sheet of film. Considering the unique un-flattened cone shaped profile from a helical tomotherapy beam, a custom leaf control file (sinogram) was created, to produce a valley shaped intensity pattern. There are eleven intensity steps in the valley pattern, representing varying dose values from 38 to 265 cGy. This dose range covers the most commonly prescribed doses in fractionated IMRT treatments. An ion chamber in a solid water phantom was used to measure the dose in each of the eleven steps. For daily film calibration the whole procedure, including film exposure, processing, digitization and analysis, can be completed within 15 min, making it practical to use this technique routinely. This method is applicable to film calibration on a helical tomotherapy unit and is particularly useful in IMRT planar dose verification due to its efficiency and reproducibility. In this work, we characterized the dose response of the KODAK EDR2 ready-pack film which was used to develop the step valley dose maps and the IMRT QA planar doses. A comparison between the step valley technique and multifilm based calibration showed that both calibration methods agreed with less than 0.4% deviation in the clinically useful dose ranges.

Calibration↗
PubMed2004

Intensive chemoradiotherapy as a primary treatment for organ preservation in patients with advanced cancer of the head and neck: efficacy, toxic effects, and limitations.

OBJECTIVES: To evaluate the efficacy and toxic effects of intensive chemoradiotherapy as a primary modality for organ preservation in patients with advanced squamous cell carcinoma of the head and neck (SCCHN) and to define the patterns of treatment failure associated with this therapy. DESIGN: Retrospective review. SETTING: Tertiary care referral center. PATIENTS: A total of 127 consecutive patients with advanced SCCHN treated with primary concurrent chemoradiotherapy. MAIN OUTCOME MEASURES: Efficacy data included the rates of tumor response to therapy, organ preservation, disease recurrence, overall and disease-specific survival, and patterns of treatment failure. Toxic effect data included the rate and grade of treatment-related complications and the rate of unscheduled hospital admissions for managing treatment-related toxic effects. RESULTS: Ninety-six patients (76%) were men and 31 (24%) were women. Average age at diagnosis was 62 years (range, 37-85 years). The primary tumor site was the oropharynx in 58 patients (46%), the larynx in 36 (28%), the hypopharynx in 20 (16%), the oral cavity in 10 (8%), and another site in 3 (2%). Most patients (91%) had stage III or IV disease. Average follow-up was 36 months. Primary chemoradiotherapy achieved complete response at the primary tumor site in 109 patients (86%). Patients with partial response, stable or progressive disease, or recurrence at the primary site underwent salvage surgery. Overall, at mean follow-up of 3 years, local disease control was achieved in 113 patients (89%), and organ preservation was possible in 102 patients (80%). Two thirds of all patients (n = 83) had clinical N+ disease. Complete clinical response to chemoradiotherapy in the neck was achieved in 57 of these patients (69%). However, complete response to chemoradiotherapy was 93%, 62%, and 47% for N1, N2, and N3 disease, respectively (P <.001). Patients achieving less than complete clinical response underwent salvage neck dissection. Overall, at an average follow-up of 36 months, regional disease control was achieved in 76 (92%) of the 83 patients with neck metastasis. Despite this high locoregional control rate, distant metastasis occurred in 18 patients (14%), was the most common site of disease recurrence (53%), and accounted for almost 40% of all treatment failures. Severe (grade 3 or 4) mucositis and neutropenia occurred in 33% and 25% of patients, respectively. Two patients (2%) died of treatment-related toxic effects. At 3-year mean follow-up, disease-specific and overall survival were 72% and 57%, respectively. Most deaths were due to distant metastasis, comorbidity, and second primary tumors. CONCLUSIONS: High rates of locoregional disease control and organ preservation are achievable with primary chemoradiotherapy in patients with advanced SCCHN, but they are associated with severe treatment-related toxic effects. Despite this effective local and regional disease control, improved survival is hampered by the relatively high incidence of distant metastasis, second primary tumors, and comorbidity.

Adult↗