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Purpose: To evaluate a commercial silicone diode dosimeter for a patient dosimetry quality assurance program., Methods and Materials: The diode dosimeter was calibrated against an ion chamber and percentage depth dose, linearity, anisotropy, virtual source position, and field size factor studies were performed. Correction factors for lack of full scatter medium in the diode entrance and exit dose measurements were acquired. Dosimetry equations were proposed for calculation of dose delivered at isocenter. Diode dose accuracy and reproducibility were tested on phantom and on four patients. A patient dosimetry quality assurance program based on diode measured dose was instituted and patient dose data were collected., Results: Diode measured percentage depth dose and field factors agreed to within 3% with those measured with an ion chamber. The diode exhibited less than 1.7% angular dose anisotropy and less than 0.5% nonlinearity up to 4 Gy. Diode dose measurements in phantom showed that the calculated doses differed from the prescribed dose by less than 1.5%; the diode exhibited a daily dose reproducibility of better than 0.2%. On four selected patients, the measured dose reproducibility was 1.5%; the average calculated doses were all within +/- 7% of the prescribed doses. For 33 of 40 patients treated with a 6 MV beam, measured doses were within +/- 7% of the prescribed doses. For 58 of 63 patients treated with an 18 MV beam, measured doses were within +/- 7% of the prescribed doses. For 11 out of 12 patients, a second repeat measurements yielded doses within +/- 7% of the prescribed doses., Conclusions: The proposed diode-based patient dosimetry quality assurance program with dose tolerance at +/- 7% is simple and feasible. It is capable of detecting certain serious treatment errors such as incorrect daily dose greater than 7%, incorrect wedge use, incorrect photon energy and patient setup errors involving some incorrect source-to-surface-distance vs. source-to-axis-distance treatments.

Seventy-two patients with advanced breast carcinoma (42% bone, 25% visceral, 5.5% soft tissue, and 27.5% multiple site metastases) were evaluated to determine the relationship between tumor expression of the estrogen-regulated protein pS2, estrogen receptor (ER) or progesterone receptor (PgR) content, and response to hormonal therapy. Twenty-nine % of tumors were pS2 positive, 64% were ER positive, and 29% were PgR positive. Of the ER-positive patients (n = 43), 15 (35%) had greater than 10% of the invasive carcinoma which immunostained for pS2 (these were considered pS2 positive). Only 3 of 24 ER-negative tumors were pS2 positive. A weak association between pS2 expression and ER content (P = 0.08) but not PgR content was observed. Of pS2-positive patients, 52% had a partial or complete response to hormonal therapy. In 24% of pS2-positive patients the disease stabilized with treatment. In contrast, 27% of pS2-negative patients had a partial or complete response. In 10% of these patients the disease stabilized. Similar associations between therapeutic response and ER or PgR were not observed. The odds of having a clinical response to hormonal therapy was greater for pS2-positive than for ER- or PgR-positive tumors. pS2 expression may define a subset of ER-positive tumors that are more likely to respond to hormonal treatment.

A 17% frequency of cytologically negative pericardial effusion (CNPE), accompanied in some cases by tamponade, occurred a median of 12.6 months from the onset of treatment for localized small-cell carcinoma of the lung. CNPE was apparently caused by toxicity of radiation/chemotherapy treatment rather than recurrent cancer. The occurrence of CNPE does not appear to represent enhanced toxicity of immediate (as opposed to delayed) concurrent chemoradiotherapy, but may be a consequence of the superior survival status of patients treated in this way. The onset of chest pain and/or dyspnea associated with increase in cardiac silhouette and positive echocardiogram allowed accurate diagnosis. Each instance was relatively easily managed by catheter drainage, and, for some patients, with the addition of nonsteroidal antiinflammatory drugs. It is important to recognize the possibility that a radiation/chemotherapy-related syndrome of pericardial effusion/tamponade may occur so that early diagnosis can be made and the risk of fatal tamponade avoided.

The accuracy of physical examination is compared with that of computed tomography (CT) of the chest in determining the extent of disease in 42 patients with local and/or regional recurrence of breast cancer. Of the 33 patients with clinical evidence of chest wall recurrence, 16 (49%) had areas of disease visible by CT that were clinically unsuspected. Similarly, in the nine patients who presented with supraclavicular and/or axillary recurrence, five (56%) had additional sites of involvement discovered on CT. Since many of these patients are treated with radiotherapy, the information gained by CT of the chest can be of great value in treatment planning.