Lateral response artifact correction method using image stitching technique in radiochromic film dosimetry.

PURPOSE: Lateral response artifact (LRA) is caused by the interaction between film and flatbed scanner in the direction perpendicular to the scanning direction. This can significantly affect the accuracy of patient-specific quality assurance (QA) in cases involving large irradiation fields. We hypothesized that by utilizing the central area of the flatbed scanner, where the magnitude of LRA is relatively small, the LRA could be mitigated effectively. This study proposes a practical solution using the image-stitching technique to correct LRA for patient-specific QA involving large irradiation fields. METHODS: Gafchromic™ EBT4 film and Epson Expression ES-G11000 flatbed scanner were used in this study. The image-stitching algorithm requires a spot between adjacent images to combine them. The film was scanned at three locations on a flatbed scanner, and these images were combined using the image-stitching technique. The combined film dose was then calculated and compared with the treatment planning system (TPS)-calculated dose using gamma analysis (3%/2 mm). Our proposed LRA correction was applied to several films exposed to 18 × 18 cm2 open fields at doses of 200, 400, and 600 cGy, as well as to four clinical Volumetric Modulated Arc Therapy (VMAT) treatment plans involving large fields. RESULTS: For doses of 200, 400, and 600 cGy, the gamma analysis values with and without LRA corrections were 95.7% versus 67.8%, 95.5% versus 66.2%, and 91.8% versus 35.9%, respectively. For the clinical VMAT treatment plan, the average pass rate ± standard deviation in gamma analysis was 94.1% ± 0.4% with LRA corrections and 72.5% ± 1.5% without LRA corrections. CONCLUSIONS: The effectiveness of our proposed LRA correction using the image-stitching technique was demonstrated to significantly improve the accuracy of patient-specific QA for VMAT treatment plans involving large irradiation fields.

Phase II Study: The Outcome of Hypofractionated Involved-Field Radiation Therapy With Concurrent Chemotherapy for the Treatment of Locally Advanced Non-small Cell Lung Cancer.

PURPOSE: This phase II study aimed to evaluate the efficacy and safety of hypofractionated involved-field radiation therapy (HypoFx-IFRT) in 2.5 Gy fractions and concurrent chemotherapy for locally advanced stage IIIA and B nonsmall cell lung cancer (LA-NSCLC) without prolonging treatment delivery time beyond 6 weeks. We analyzed the overall survival (OS), progression-free survival, and safety of the treatment. METHODS AND MATERIALS: This prospective, single center, single-arm trial was initiated in 2010. All LA-NSCLC patients were treated with HypoFx-IFRT using 3-dimensional conformal radiation therapy. The median total dose of HypoFx-IFRT was 67.5 Gy (range, 60-70). RESULTS: From December 2010 to October 2016, 36 patients were ultimately enrolled and evaluated. The trial closed early owing to slow accrual. The median follow-up duration was 50 months in all patients and 65 months in surviving patients. The 1-, 3-, and 5-year OS rates were 88.9% (95% confidence interval [CI], 78.6%-99.2%), 61.1% (95% CI, 45.2%-77.0%), and 54.1% (95% CI, 37.3%-70.9%), respectively. The median time for OS was not reached. The median time for progression-free survival was 10.7 months. The incidence rates of grade 3 radiation pneumonitis, esophagitis and esophageal stenosis were 8.3%, 2.8%, and 2.8%, respectively, and no acute or late toxicities of grade 4 or 5 were observed. CONCLUSIONS: This study indicated that HypoFx-IFRT with concurrent chemotherapy yielded an acceptable safety profile and might be beneficial in the survival outcomes of patients with LA-NSCLC.

Characterization of casein-based nanoparticles formed upon freezing by in situ SAXS measurement.

The formation of casein-based nanoparticles from sodium caseinate and sodium caseinate-pectin solutions was investigated in a frozen system by protein self-aggregation and protein-polysaccharide complexation, respectively. Casein-based nanoparticles were prepared by controlling the pH levels of the solutions followed by freezing. The formation of precipitates was confirmed in the casein solutions at pH<5.5. However, an obvious effect of the freezing on the formation of aggregates could not be confirmed, although the freezing did have an effect on accelerating the formation of precipitates. The mean particle sizes analyzed from the produced nanoparticles suggested that freezing did not have any significant effects on altering the particle sizes. Similar trends were observed in the casein-pectin solution in terms of phase separation and particle sizes. A difference was confirmed in the solution at pH 4.6; that is, a clear phase separation was observed due to freezing. Nevertheless, it was found, both in the casein and casein-pectin systems, that the degradation rates of the freeze-thawed nanoparticles were considerably slower than that of the original nanoparticles. This suggested that the casein-based nanoparticles formed through freezing had structural features different from the ones in the unfrozen solution. It could be concluded from the SAXS analysis that the formation of the protein-based particulate systems certainly occurred in the cryoconcentrated phase associated with freezing. The present technique is advantageous for the encapsulation of heat-sensitive and/or acid-sensitive ingredients in protein nanoparticles.

Clinical results of external beam radiotherapy alone with a concomitant boost program or with conventional fractionation for cervical cancer patients who did not receive intracavitary brachytherapy.

A combination of external beam radiotherapy (EBRT) and intracavitary brachytherapy (ICBT) is well established as the standard radical radiotherapy (RT) for cervical cancer. However, it is sometimes necessary to perform EBRT alone for patients where ICBT is not feasible. For these patients, we initiated EBRT alone with three-dimensional conformal radiotherapy (3DCRT). The purpose of this study is to evaluate the results of EBRT alone without ICBT for patients with cervical cancer. Sixteen patients were treated with EBRT alone between 2002 and 2009. There were three stage IIB, six stage IIIB and seven patients with stage IVA disease. A total of 10 patients were treated with a median dose of 66 Gy with a median overall treatment time (OTT) of 40 days delivered by a concomitant boost (CCB), and a median dose of 60 Gy with a median OTT of 47 days was administered for six patients by conventional fractionation (CF). The 3-year overall survival (OAS) and local control (LC) rates were 43.8% and 75.0%, respectively. The 3-year LC rate was 90.0% for the CCB group, 50.0% for the CF group (P = 0.0692); 100% for OTT ≤42 days, 42.9% for OTT ≥43 days (P = 0.0095). No severe acute and late adverse effects were encountered for any of the patients. These outcomes suggest that EBRT with a CCB program may be a promising radical treatment for cervical cancer that provides better LC with minimal complications, especially in cases where ICBT cannot be performed.

Stereotactic directional vacuum-assisted breast biopsy using lateral approach.

BACKGROUND: In recent years, stereotactic vacuum-assisted breast biopsy [so-called Mammotome® biopsy (ST-MMT)] has been established as a reliable method for diagnosis of nonpalpable and mammographically detected lesions with microcalcification. However, there are few reports regarding the lateral approach. We performed ST-MMT using the lateral approach. The purpose of this study was to determine the usefulness of the lateral approach. MATERIALS AND METHODS: 124 women with microcalcifications underwent stereotactic vacuum-assisted breast biopsy (median age, 52.5 years). All underwent stereotactic biopsy using the lateral approach. We compared our data with those of other institutes using the vertical approach. RESULTS: We removed microcalcifications and used an 11-gauge vacuum-assisted probe in all cases. The range of breast thickness was 10-45 mm. 12 patients had vasovagal reactions, however they quickly recovered without drug intervention. No patients had major complications. Of 124 cases, cancer was diagnosed in 37 patients. In other institutes using the vertical approach, it was impossible to use 11G probes in some cases due to the breast being too thin. In our study, minimum breast thickness was 10 mm (7 cases) and we were able to use 11G probes in all 7 cases with only polyethylene foam. CONCLUSION: With the lateral approach, it is possible to use 11G probes if the breast is thin (in our study minimum thickness was 10 mm) with only polyethylene foam. We believe this to be an advantage of the lateral approach. This advantage is very important in stereotactic biopsy, especially in Japan, as Japanese women's breasts are generally thinner than most Western women's.

Results of a preliminary study using hypofractionated involved-field radiation therapy and concurrent carboplatin/paclitaxel in the treatment of locally advanced non-small-cell lung cancer.

BACKGROUND: We aimed to evaluate the feasibility and efficacy of hypofractionated involved-field radiation therapy (IFRT) omitting elective nodal irradiation (ENI) with concurrent chemotherapy for locally advanced non-small-cell lung cancer (NSCLC). METHODS: Between July 2004 and July 2006, ten patients with locally advanced NSCLC were included in this study. One had stage IIIA and 9 had stage IIIB disease. The treatment consisted of IFRT in fractions of 2.5 Gy and weekly carboplatin (CBDCA)/paclitaxel (PTX). Hypofractionated IFRT with a median total dose of 65 Gy with median percent total lung volume exceeding 20 Gy (V20) of 20.2%, and a median of five courses of chemotherapy with weekly CBDCA (area under the curve, 1.5-2.0)/PTX (30-35 mg/m(2)) were given to all patients. RESULTS: The median survival time and the 1-, 2-, and 3-year overall survival rates were 29.5 months and 90.0%, 58.3%, and 43.8%, respectively. No elective nodal failure was encountered during the median follow up of 18.2 months. No acute or late toxicities of grade 3 or worse were observed. No in-field recurrence occurred in the group with a total dose of 67.5 Gy or more, but there was such recurrence in 83.3% of those in the group with less than 67.5 Gy. CONCLUSION: Hypofractionated IFRT with weekly CBDCA/PTX was a feasible treatment regimen. Hypofractionated IFRT with a total dose of 67.5 Gy or more could be a promising modality to improve the treatment results in patients with locally advanced NSCLC.

Development of digital subtraction angiography for coronary artery.

The purpose of this research is to develop a new method of digital subtraction angiography (DSA) that can be applied to real time with reducing motion artifacts caused by heart movement and respiration. To create the mask image for DSA, the maximum pixel value at each pixel (which is the opposite pixel value to that of a vessel filled by contrast medium) was selected from the previous 14 image frames. The search area for the maximum pixel value was selected using the value of the standard deviation (SD) for each pixel from the previous 14 image frames. When the SD value in the 14 frames was greater than a threshold level, the search area of the maximum value became 1 pixel x 1 pixel x 14 frames; otherwise, 7 pixels x 7 pixels x 7 frames. The image quality of new DSA was evaluated on 20 coronary arteriogram images, including various degrees of occlusion or stenosis. The results indicated a considerable improvement in DSA image quality; thus, the coronary arteries, carotid artery, and vein were clearly enhanced.

[Prediction of response to primary systemic chemotherapy involving weekly paclitaxel followed by FEC 100 for advanced breast cancer].

To predict the response to primary systemic chemotherapy (PSC) involving weekly paclitaxel (PTX) followed by FEC100, we analyzed the therapeutic effects of PSC on 58 cases of stage II - III advanced breast cancer, 2 cases of PD, 4 cases of suspension due to adverse events, and 52 successful cases (89.7%). As for clinical effect, CR was observed in 12 cases (23.1%) and PR in 33 cases (63.5%) and for histological effects, grade 3 (pCR) was observed in 7 cases (13.5%) and grade 2 in 13 cases (25.0%). At the time of completion of 4 courses of PTX, SD was observed in 34 out of 52 cases, but the number of SD decreased to 28 cases on completion of 8 courses of PTX, to 19 cases on completion of 12 courses of PTX, and to 7 cases on completion of 4 courses of FEC. In examining the 7 cases of pCR in whom the histological effect was observed, 3 cases of SD were observed on completion of 4 courses of PTX and 2 cases on completion of 8 courses of PTX. Unless PD is observed during the course of PSC, continuation of therapy would be indicated because of the delayed response.

[Improvement of overall performance for lung nodule detection in chest CT images].

We have developed an automated computerized schema for the detection of lung nodules in 3D CT images obtained by helical CT. In our previous schema, linear discriminant analysis (LDA) and a rule-based method with 53 image features were employed in order to reduce false positives. However, several false positives have remained. Therefore, in this study, we improved the false-positive reduction technique by using the edge image and radial image analysis. Overall performance for the detection of lung nodules was greatly improved. Sensitivity was higher than that of our previous study. Moreover, we evaluated the overall performance of the new scheme by using 69 cases acquired from four hospitals. The average number of false positives was 5.2 per case at a percent sensitivity of 95.8%. Our new scheme would assist in the detection of early lung cancer.

[Development of computer-aided diagnostic system for detection of lung nodules in three-dimensional computed tomography images].

We have developed an automated computerized method for the detection of lung nodules in three-dimensional (3D) computed tomography (CT) images obtained by helical CT. In this scheme, a lung segmentation technique for the determination of the nodule search area is performed based on a gray-level thresholding technique. To enhance lung nodules, we employed the 3D cross-correlation method by using a 3D Gaussian template with zero-surrounding as a model of lung nodule. False positives are then eliminated by using a rule-base with 53 features. For further reduction of false positives, we performed linear discriminant analysis using these 53 features. The average number of false positives was 6.7 per case at a percent sensitivity of 85.0%. This computerized scheme will be useful to radiologists by providing a "second opinion" in case of possible early lung cancer.

[A report of two cases in which radiation therapy was effective for distant lymph node metastases after curative resection of gastric cancer].

Long-term survival is difficult after manifestation of distant lymph node metastasis following curative resection for advanced gastric cancer. Two patients who achieved long survival with linac therapy after curative treatment of gastric cancer, are reported. Case 1: 45 years old, male. Distal gastrectomy with D2 dissection was carried out for such gastric cancer as L.M, less.Post.Ant, fType 3, T2 (MP), fStage II, on July 13, 1994. As paraaortic lymph nodes metastases was observed with CT examination on October 12, 1995, irradiation therapy using linac was conducted, and CR was achieved. Though Virchow's lymph nodes metastases was followed that episode, PR was achieved with 4,750 cGy of linac therapy. Finally, however, the patient died with metastases to lung and bone on May 19, 2002. Case 2: 62 years old, male. Distal gastrectomy with D2 + No.8p and also No.16b1 interaorticocaval dissection was conducted for such advanced gastric cancers as M, less, fType 3, T3 (SE), fStage III B on June 7, 1995. Paraaortic lymph nodes metastases were observed through CT examination on October 12, 1995. Irradiation therapy using linac resulted in CR. Virchows lymph node metastasis, which appeared on December 12, 1997, was also treated with 5,000 cGy of linac, and CR was also achieved. The patient is surviving today without recurrence.

[A case of cardiac cancer for which radiation therapy was effective in improving stenosis of the esophagogastric junction].

The patient was a seventy-seven-year old woman, who was diagnosed with advanced gastric cancer with stenosis of the esophagocardiac junction. Her cancer was diagnosed as Stage IV (T3N3H0P3M0). As there was no indication for surgery, radiation therapy (Linac electron beam, 1.8 Gy/day, total 50.4 Gy) was selected to improve the stenosis, after which she was able to eat food. Subjective complaints such as nausea and vomiting were also decreased, promoting her QOL. We conclude that radiation therapy treatment can be a treatment option for far advanced cardiac cancer.