Three-dimensional Winston-Lutz test using reusable polyvinyl alcohol-iodide (PVA-I) radiochromic gel dosimeter.

Medical linear-accelerator-based stereotactic radiosurgery (SRS) using a stereotactic apparatus or image-guided radiotherapy system for intracranial lesions is performed widely in clinical practice. In general, Winston-Lutz (WL) tests using films or electric portal imaging devices (EPIDs) have been performed as pre-treatment and routine quality assurance (QA) for the abovementioned treatment. Two-dimensional displacements between the radiation isocentre and mechanical isocentre are analysed from the test; therefore, it is difficult to identify the three-dimensional (3D) isocentre position intuitively. In this study, we developed an innovative 3D WL test for SRS-QA using a novel radiochromic gel dosimeter based on a polyvinyl alcohol-iodide (PVA-I) complex that can be reused after annealing. A WL gel phantom that was consisted of the PVA-I gel dosimeter poured into a tall acrylic container and an embedded small tungsten sphere was used as a position detector. A flatbed scanner was used to analyse the isocentre position. The measured 3D isocentre accuracy from the gel-based WL test was within 0.1 mm compared with that obtained from the EPID-based WL test. Furthermore, excellent reusability of the WL gel phantom was observed in long-term SRS isocentre verification, in which clinical SRS cases involving repeated irradiation and annealing were analysed. These results demonstrate the high accuracy and reliable evaluation of the isocentre position using an innovative test. In addition, the clinical-based routine SRS-QA using the PVA-I gel dosimeter demonstrates a highly convenience while affording an easy and fast analysis process.

Clinical implications of 18F-sodium fluoride uptake in subclinical aortic valve calcification: Its relation to coronary atherosclerosis and its predictive value.

BACKGROUND: Uptake of 18F-sodium fluoride (18F-NaF) on positron emission tomography (PET) reflects active calcification. Application of this technique in the early phase of aortic valve calcification (AVC) is of clinical interest. We investigated clinical implications of 18F-NaF uptake in subclinical AVC evaluated simultaneously with coronary atherosclerosis, and the utility of 18F-NaF uptake in predicting AVC progression. METHODS: We studied 25 patients with subclinical AVC and coronary plaques detected on computed tomography (CT) who underwent 18F-NaF PET/CT. AVC score, volume, mean density, and the presence of high-risk coronary plaque were evaluated on CT in each patient. Focal 18F-NaF uptake in AVC and in coronary plaques was quantified with the maximum tissue-to-background ratio (TBRmax). RESULTS: There were positive correlations between AVC TBRmax (A-TBRmax) and AVC parameters on CT. The 14 patients with high-risk coronary plaque had significantly higher A-TBRmax than those without such plaque (1.60 ± 0.18 vs 1.42 ± 0.13, respectively; P = 0.012). A-TBRmax positively correlated with maximum TBRmax of coronary plaque per patient (r = 0.55, P = 0.0043). In the 11 patients who underwent follow-up CT scan, A-TBRmax positively correlated with subsequent increase in AVC score (r = 0.74, P = 0.0091). CONCLUSION: Our 18F-NaF PET- and CT-based data indicate relationships between calcification activity in subclinical AVC and characteristics of coronary atherosclerosis. 18F-NaF PET may provide new information regarding molecular conditions and future progression of subclinical AVC.

Effect of dose-delivery time for flattened and flattening filter-free photon beams based on microdosimetric kinetic model.

The effect of dose-delivery time with flattening filter (FF) and flattening filter-free (FFF) photon beams based on microdosimetric kinetic model (MKM) was investigated in this study. Monte Carlo simulation with the particle and heavy ion transport code system (PHITS) was performed to calculate the dose-mean lineal energy yD (keV/µm) of FF and FFF 6 MV photon beams using the IAEA phase-space files of Varian TrueBeam linear accelerator. Human non-small cell lung cancer NCI-H460 cells were used to determine the MKM parameters under the condition that dose-delivery times with continuous irradiation were 1, 5, 10, 30, and 60 min, and the adsorbed dose was 2, 4, and 8 Gy in this study. In addition, the relative biological effectiveness (RBE) of FF and FFF photon beams were calculated for evaluating the effect of dose delivery time. The RBE of FF decreased to 99.8% and 97.5% with 5 and 60 min for 2 Gy in comparison to 99.6% and 95.1% for 8 Gy, respectively. Meanwhile, that of FFF decreased to 99.5% and 94.9% with 5 and 60 min for 2 Gy in comparison to 99.5% and 94.9% for 8 Gy, respectively. Dose-delivery time has an effect on the RBE with photon beams. In other words, the dose-delivery time should be considered during radiation therapy. Furthermore, FFF photon beams were an effective irradiation method compared to FF in dose-delivery time on account of improving clinic throughput.

Successful radiotherapy for endometrial serous carcinoma with local repeated recurrence.

The incidence of endometrial serous carcinoma (ESC) has been increasing, and ESC is resistant to treatment. We report a patient with ESC who responded to radiotherapy for multiple recurrences. The first recurrence was detected in the vaginal wall and left internal iliac lymph node 5 months after the initial treatment. Concurrent chemoradiotherapy (CCRT) was administered. Radiation was delivered using the intensity modulated radiation therapy technique. The second recurrent tumor was detected in the right internal iliac lymph node after 4 months, and CCRT was conducted. After 4 months, the third recurrence was detected in the right common iliac node, and CCRT was performed. After 8 months, the fourth recurrence was detected in the horizontal portion of the duodenum, and radiotherapy was administered. After 9 months, the fifth recurrence was detected in the vaginal wall. Interstitial brachytherapy was conducted. Grade 2 gastrointestinal injury, nausea and radiodermatitis were observed. During the subsequent 13-month follow-up, there has been no recurrence. Although ESC is resistant to treatment, radiotherapy could be effective in some cases. Even when multiple recurrences occur, radiotherapy may be considered a treatment option if the irradiation level is permissible.

[Evaluation of 3D Dose Distribution and Clinical Applications Using Polymer Gel Dosimeter].

Evaluation of dosimetric impact of the interplay effect between multi-leaf collimator (MLC) movement and tumor respiratory motion during volumetric modulated arc therapy (VMAT) delivery using polymer gel dosimeter was taken as an example in this article. An excellent gas barrier PAN (polyacrylonitrile) bottle filled with polyacrylamide-based gel dosimeter contained magnesium chloride as a sensitizer (iPAGAT dosimeter) was set to the QUASAR™ respiratory motion phantom (Modus), and was moved with motion amplitudes (peak-to-peak amplitude) of 1 and 2 cm with a 4 second period during VMAT delivery by the Novalis Tx linear accelerator (Varian/BrainLAB). Two spherical GTVs with 2 cm diameter and two PTVs were defined considering the respiratory motion and setup uncertainties. Three-dimensional (3D) dose distribution in iPAGAT dosimeter was read out by the 3T MRI system, and was evaluated by the dose profiles, gamma analysis and the dose-volume histogram (DVH) using in-house developed software. As a result, interplay effect was negligible since dose coverage of GTV was sufficient during VMAT delivery with simulated respiratory motion.

[An examination of the utility of high-precise radiation therapies for the recurrence of postoperative esophageal cancer].

We analyzed 16 cases (23 therapeutic sites) of post-operative recurrence of esophageal cancers that were treated with high-precise radiation therapies.The recurrence sites were cervical lymph nodes (5 cases), superior mediastinal lymph nodes (5 cases), posterior mediastinal lymph nodes (3 cases), regional lymph nodes with anastomosis (2 cases), abdominal paraaortic lymph node (3 cases), and regions with hematogenous metastasis (5 cases: liver, lung, spleen, and dissemination to the diaphragm bottom).By recurrence number, 10 cases presented with a single lesion, and 6 cases had multiple lesions.The effect of the treatment was complete response (CR) in all cases, and 6 cases maintained CR.The median of the overall survival after radiotherapy was 562 (132-1,231) days.Analysis of the prognostic factors for the overall survival from a recurrence revealed that the metastatic number (single) (p=0.003), and the metastatic pattern(hematogenous metastasis) (p= 0.004), significantly improved prognosis.We conclude that radiotherapy is an option to extend prognosis in some recurrence cases.

Effect of lapatinib on hepatic parenchymal enhancement on gadoxetate disodium (EOB)-enhanced MRI scans of the rat liver.

PURPOSE: The purpose of this study was to investigate the effect of lapatinib treatment on hepatic parenchymal enhancement on Gd-EOB-MRI scans in rat. MATERIALS AND METHODS: Institutional animal review board approval was received prior to the commencement of all studies. Five rats received a single oral dose of 100 mg/kg/day lapatinib for 7 consecutive days. The controls (n = 5) were given 0.5 % (w/v) aqueous hydroxypropyl methyl cellulose containing 0.1 % (v/v) Tween 80 for 7 days. After the acquisition of gadoxetate disodium-enhanced MR images using 0.025 mmol gadolinium/kg, their livers were subjected to pathologic study to determine the expression level of organic anion-transporting polypeptide 1 (oatp1) and multi-drug resistance-associated protein 2 (mrp2). RESULTS: Relative enhancement of the liver was similar in both groups. At the hepatobiliary phase, which in rats occurs 3 min after the injection of Gd-EOB, it was 0.90 ± 0.06 in lapatinib-treated rats and 0.84 ± 0.08 in the controls (p = 0.30). There was also no difference in the expression level of oatp1 and mrp2. CONCLUSION: In rats, the administration of lapatinib for 7 days had no effect on hepatic parenchymal enhancement on Gd-EOB-MRI scans.

[Comparison of setup accuracy between ExacTrac X-ray 6 dimensions and cone-beam computed tomography for intracranial and pelvic image-guided radiotherapy].

The aim of this study was to compare the setup difference measured with ExacTrac X-ray 6D (ETX6D) and cone-beam computed tomography (CBCT) for non-invasive fractionated radiotherapy. Setup data were collected on a Novalis Tx treatment unit for both a head phantom and patients with intracranial tumors and a pelvic phantom and patients with prostate cancer. Initially, setup was done for a phantom using ETX6D. Secondly, a treatment couch was shifted or rotated by each already known value. Thirdly, ETX6D and CBCT scans were obtained. Finally, setup difference was determined: the registrations of ETX6D images with the corresponding digitally reconstructed radiographs using ETX6D fusion, and registrations of CBCT images with the planning CT using online 6D fusion. The setup difference between ETX6D and CBCT was compared. The impact of shifts and rotations on the difference was evaluated. Patients' setup data was similarly analyzed. In phantom experiments, the root mean square (RMS) of difference of the shift and rotation was less than 0.45 mm for translations, and 0.17 degrees for rotations. In intracranial patients' data, the RMS of that was 0.55 mm and 0.44 degree, respectively. In prostate cancer patients' data, the RMS of that was 0.77 mm and 0.79 degree, respectively. In this study, we observed modest setup differences between ETX6D and CBCT. These differences were generally less than 1.00 mm for translations, and 1.00 degrees for rotations, respectively.

[Influence of high-definition multileaf collimator for three-dimensional conformal radiotherapy and intensity-modulated radiotherapy of prostate cancer].

The focus of this work is to evaluate the dosimetric impact of treatment planning for three-dimensional conformal radiotherapy (3DCRT) and intensity-modulated radiotherapy (IMRT) of prostate cancer using Varian/BrainLAB 120-leaf high-definition multileaf collimator (HD120 MLC) with 2.5 mm leaf width and Varian 120-leaf millennium multileaf collimator (M120 MLC) with 5 mm leaf width. We measured the leaf transmission and dosimetric leaf gap (DLG) of two multileaf collimator (MLC) systems using Farmer ionization chamber. The dosimetric impact of treatment planning for 3DCRT and IMRT of prostate cancer for ten clinical cases using two MLC systems was evaluated quantitatively. 3DCRT was divided to 3DCRT(middle) as fitting at middle of leaf tip and 3DCRT(outside) as fitting at outside of leaf tip. The leaf transmission factor and DLG of HD120 MLC for 6 and 10 MV X-ray decreased by 0.2% and 1 mm, respectively, compared to M120 MLC. The mean conformity index of PTV of treatment planning for prostate 3DCRT(middle), 3DCRT(outside) , and IMRT decreased by 0.9%, 6.6%, and 0.9% and the mean homogeneity index increased 2.3%, 13.0%, and 4.2%, respectively. The mean V20, V40, and V65 decreased by 2.4%, 6.6%, and 4.5% for bladder and 3.3%, 6.1%, and 5.9% for rectum, respectively. The results of this work demonstrated that the dose conformity of PTV improved and the dose of bladder and rectum decreased for 3DCRT and IMRT of prostate cancer using HD120 MLC compared to M120 MLC, because of reduction of leaf width, leaf transmission, and rounded leaf end transmission.

Dosimetric verification of the anisotropic analytical algorithm in lung equivalent heterogeneities with and without bone equivalent heterogeneities.

PURPOSE: In this study, the authors evaluated the accuracy of dose calculations performed by the convolution/superposition based anisotropic analytical algorithm (AAA) in lung equivalent heterogeneities with and without bone equivalent heterogeneities. METHODS: Calculations of PDDs using the AAA and Monte Carlo simulations (MCNP4C) were compared to ionization chamber measurements with a heterogeneous phantom consisting of lung equivalent and bone equivalent materials. Both 6 and 10 MV photon beams of 4 x 4 and 10 x 10 cm(2) field sizes were used for the simulations. Furthermore, changes of energy spectrum with depth for the heterogeneous phantom using MCNP were calculated. RESULTS: The ionization chamber measurements and MCNP calculations in a lung equivalent phantom were in good agreement, having an average deviation of only 0.64 +/- 0.45%. For both 6 and 10 MV beams, the average deviation was less than 2% for the 4 x 4 and 10 x 10 cm(2) fields in the water-lung equivalent phantom and the 4 x 4 cm(2) field in the water-lung-bone equivalent phantom. Maximum deviations for the 10 x 10 cm(2) field in the lung equivalent phantom before and after the bone slab were 5.0% and 4.1%, respectively. The Monte Carlo simulation demonstrated an increase of the low-energy photon component in these regions, more for the 10 X 10 cm(2) field compared to the 4 x 4 cm(2) field. CONCLUSIONS: The low-energy photon by Monte Carlo simulation component increases sharply in larger fields when there is a significant presence of bone equivalent heterogeneities. This leads to great changes in the build-up and build-down at the interfaces of different density materials. The AAA calculation modeling of the effect is not deemed to be sufficiently accurate.

Clinical utility of three-dimensional integrated 18F-fluorodeoxyglucose positron-emission tomography/computed tomography virtual mediastinoscopy.

The objectives of this study were to devise a new image processing technique to reconstruct dynamic three-dimensional (3D) virtual mediastinoscopic images on the basis of positron-emission tomography/computed tomography (PET/CT) datasets, and to examine the clinical utility of this technique for preoperative simulation of and intraoperative guidance during mediastinoscopic nodal biopsy. Of 54 patients with suspected or proven lung cancer (LC) who underwent mediastinoscopy between January 2005 and December 2007, 37 also underwent preoperative PET/CT. Of these 37 patients, we tested our image processing protocol in 15 consecutive patients with significant mediastinal uptake of fluorodeoxyglucose (FDG). We reconstructed 3D virtual mediastinoscopy movies in two mutually complementary demonstration modes--the tracheobronchial- and vessel-modes--with accurate representation of actual mediastinoscopic procedures. The benefit of these virtual imaging was evaluated with regard to their utility in mediastinoscopic nodal biopsy. Our new technique enabled better understanding of the spatial interrelationship between FDG-avid nodes and mediastinal structures. It facilitated more accurate and safer nodal biopsy under virtual guidance. In conclusion, we showed the feasibility of our virtual mediastinoscopic technique, which may improve the procedural safety and diagnostic accuracy of mediastinoscopic nodal biopsy and nodal staging in LC.

Impaired myocardial blood flow reserve in subjects with metabolic syndrome analyzed using positron emission tomography and N-13 labeled ammonia.

PURPOSE: Coronary vasomotor response might be impaired in metabolic syndrome (MS); however, the precise abnormality has not been elucidated. The aim of this study was to assess coronary-vasomotor response in MS subjects using N-13 labeled ammonia and positron emission tomography. METHODS AND RESULTS: Myocardial blood flow (MBF) was measured at rest and during adenosine infusion in MS subjects (n = 13, MS group) with no definite evidence of heart disease and in subjects without MS (n = 14, non-MS group). Coronary vascular resistance (CVR) was calculated by dividing the mean aortic blood pressure by MBF. Myocardial blood flow reserve (MFR) was calculated as the ratio of the MBF during adenosine infusion to that during rest. Blood chemical parameters were measured to evaluate their relationship with MFR. During adenosine infusion, MBF was lower (p = 0.0085) and CVR higher (p = 0.0128) in the MS group than in the non-MS group and MFR was significantly lower in the MS group than in the non-MS group (2.13 +/- 0.99 vs. 3.38 +/- 0.95, p = 0.0027). Multivariate analysis demonstrated that the homeostasis model assessment-insulin resistance (p < 0.05) and the presence of hypertension (p < 0.05) were independent determinants of MFR. CONCLUSIONS: The results indicate that MFR was impaired in MS subjects, suggesting that an abnormal coronary microvascular response occurred in these subjects. This abnormality may have been partially due to insulin resistance and hypertension.

FDG positron emission tomography/computed tomography for the detection of extrahepatic metastases from hepatocellular carcinoma.

AIMS: To compare the efficacy of positron emission tomography (PET) computed tomography (CT), multi-detector helical computed tomography (MDCT) and bone scintigraphy for the detection of extrahepatic metastases in patients with hepatocellular carcinoma (HCC). METHODS: Thirty-four patients diagnosed with metastatic HCC were enrolled in this study. The lesions included lung (n = 18), bone (n = 12) and lymph node (n = 16) metastases. For receiver operating characteristic (ROC) analysis, lesions were diagnosed as metastatic HCC by two experienced abdominal radiologists. Another three physicians independently reviewed both positive and negative images. Each physician read three sets of images of MDCT, PET-CT and bone scintigraphy for bone metastasis. RESULTS: The mean sensitivity and specificity for diagnosis of lung metastasis were 85.2 and 88.9% for MDCT, and 59.2 and 92.6% for PET-CT, respectively. For lymph node metastasis, these values were 62.5 and 79.2% for MDCT, and 66.7 and 91.7% for PET-CT, respectively; and for bone metastasis 41.6 and 94.5% for MDCT, 83.3 and 86.1% for PET-CT, and 52.7 and 83.3% for bone scintigraphy, respectively. The mean Az values were 0.95 and 0.77 for MDCT and PET-CT in lung metastasis, respectively, 0.75 and 0.80 for MDCT and PET-CT for lymph node metastasis, respectively, and 0.59, 0.88 and 0.62 for MDCT, PET-CT and bone scintigraphy for bone metastasis, respectively. CONCLUSION: PET-CT has high sensitivity and is more suitable for the detection of bone metastases from primary HCC, relative to MDCT and bone scintigraphy.

IL12RB2 and ABCA1 genes are associated with susceptibility to radiation dermatitis.

PURPOSE: Severe acute radiation dermatitis is observed in approximately 5% to 10% of patients who receive whole-breast radiotherapy. Several factors, including treatment-related and patient-oriented factors, are involved in susceptibility to severe dermatitis. Genetic factors are also thought to be related to a patient's susceptibility to severe dermatitis. To elucidate genetic polymorphisms associated with a susceptibility to radiation-induced dermatitis, a large-scale single-nucleotide polymorphism (SNP) analysis using DNA samples from 156 patients with breast cancer was conducted. EXPERIMENTAL DESIGN: Patients were selected from more than 3,000 female patients with early breast cancer who received radiotherapy after undergoing breast-conserving surgery. The dermatitis group was defined as patients who developed dermatitis at a National Cancer Institute Common Toxicity Criteria grade of > or =2. For the SNP analysis, DNA samples from each patient were subjected to the genotyping of 3,144 SNPs covering 494 genes. RESULTS: SNPs that mapped to two genes, ABCA1 and IL12RB2, were associated with radiation-induced dermatitis. In the ABCA1 gene, one of these SNPs was a nonsynonymous coding SNP causing R219K (P = 0.0065). As for the IL12RB2 gene, the strongest association was observed at SNP-K (rs3790568; P = 0.0013). Using polymorphisms of both genes, the probability of severe dermatitis was estimated for each combination of genotypes. These analyses showed that individuals carrying a combination of genotypes accounting for 14.7% of the Japanese population have the highest probability of developing radiation-induced dermatitis. CONCLUSION: Our results shed light on the mechanisms responsible for radiation-induced dermatitis. These results may also contribute to the individualization of radiotherapy.

Radiation therapy for cancer. The fifteenth anniversary of Hiroshima Cancer Seminar Foundation, the Seventeenth International Symposium of Hiroshima Cancer Seminar, November 2007.

This symposium presented what we do to really know about new technology for radiation therapy and what we do to realize our final goal of selective radiation therapy and CRT for cancer. It no doubt provided us for a great deal of information on technological and conceptual advances in radiation therapy and radiation biology.

CT appearance of radiation injury of the lung and clinical symptoms after stereotactic body radiation therapy (SBRT) for lung cancers: are patients with pulmonary emphysema also candidates for SBRT for lung cancers?

PURPOSE: The purpose of this study was to analyze the computed tomographic (CT) appearance of radiation injury to the lung and clinical symptoms after stereotactic body radiation therapy (SBRT) and evaluate the difference by the presence of pulmonary emphysema (PE) for small lung cancers. METHODS AND MATERIALS: In this analysis, 45 patients with 52 primary or metastatic lung cancers were enrolled. We evaluated the CT appearance of acute radiation pneumonitis (within 6 months) and radiation fibrosis (after 6 months) after SBRT. Clinical symptoms were evaluated by Common Terminology Criteria for Adverse Events, version 3.0. We also evaluated the relationship between CT appearance, clinical symptoms, and PE. RESULTS: CT appearance of acute radiation pneumonitis was classified as follows: (1) diffuse consolidation, 38.5%; (2) patchy consolidation and ground-glass opacities (GGO), 15.4%; (3) diffuse GGO, 11.5%; (4) patchy GGO, 2.0%; (5) no evidence of increasing density, 32.6%. CT appearance of radiation fibrosis was classified as follows: (1) modified conventional pattern, 61.5%; (2) mass-like pattern, 17.3%; (3) scar-like pattern, 21.2%. Patients who were diagnosed with more than Grade 2 pneumonitis showed significantly less no evidence of increased density pattern and scar-like pattern than any other pattern (p=0.0314, 0.0297, respectively). Significantly, most of these patients with no evidence of increased density pattern and scar-like pattern had PE (p=0.00038, 0.00044, respectively). CONCLUSION: Computed tomographic appearance after SBRT was classified into five patterns of acute radiation pneumonitis and three patterns of radiation fibrosis. Our results suggest that SBRT can be also safely performed even in patients with PE.

Evaluation of dose delivery accuracy of Gamma Knife by polymer gel dosimetry.

The BANG polymer gel dosimeter was used to evaluate 3D absorbed dose distributions in tissue delivered with Gamma Knife stereotactic radiosurgery systems. We compared dose distributions calculated with Leksell GammaPlan (LGP) treatment-planning software with dose distributions measured with the polymer gel dosimeter for single-shot irradiations. Head-sized spherical glass vessels filled with the polymer gel were irradiated with Gamma Knife. The phantoms were scanned with a 1.0T MRI scanner. The Hahn spin-echo sequence with two echoes was used for the MRI scans. Calibration relations between the spin-spin relaxation rate and the absorbed dose were obtained by using small cylindrical vials, which were filled with the polymer gel from the same batch as for the spherical phantom. We made voxel-by-voxel comparisons of measured and calculated dose distributions for 31 x 31 x 31 dose matrix elements. With the 3D dose data we calculated the tumor control probability (TCP) and normal tissue complication probability (NTCP) for a simple model. For the maximum dose of 100 Gy, the mean and one standard deviation of differences between the measured and the calculated doses were the following: -0.38+/-4.63 Gy, 1.49+/-2.77 Gy, and -1.03+/-4.18 Gy for 8-mm, 14-mm, and 18-mm collimators, respectively. Tumor control probability values for measurements were smaller than the calculations by 0% to 7%, whereas NTCP values were larger by 7% to 24% for four of six experiments.

Reproducibility of organ position using voluntary breath-hold method with spirometer for extracranial stereotactic radiotherapy.

PURPOSE: To evaluate in healthy volunteers the reproducibility of organ position using a voluntary breath-hold method with a spirometer and the feasibility of this method for extracranial stereotactic radiotherapy in a clinical setting. METHODS AND MATERIALS: For this study, 5 healthy volunteers were enrolled. After training sessions, they held their breath at the end-inspiration and the end-expiration phase under spirometer-based monitoring. Computed tomography (CT) scans were performed twice at each respiratory phase, with a 10-min interval, on 2 separate days. The total number of CT scans was four at each respiratory phase. After CT volume data were transferred to a three-dimensional treatment-planning system, digitally reconstructed radiographs (DRRs) were calculated for anterior-posterior and left-right beams. Verification was performed with DRRs relative to the diaphragm position, bony landmarks, and the isocenter in each healthy volunteer at each respiratory phase. To evaluate intrafraction reproducibility, we measured the distance between diaphragm position and bony landmarks. To evaluate interfraction reproducibility, we measured the distance between diaphragm position and the isocenter. Reproducibility and setup error were defined as the average value of the differences between each DRR with regard to the first DRR. RESULTS: Intrafraction reproducibility of the caudal-cranial direction was 4.0 +/- 3.5 mm at the end-inspiration phase and 2.2 +/- 2.0 mm at the end-expiration phase. Interfraction reproducibility of the caudal-cranial direction was 5.1 +/- 4.8 mm at the end-inspiration phase and 2.1 +/- 1.8 mm at the end-expiration phase. The end-expiration phase was more stable than the end-inspiration phase. CONCLUSIONS: The voluntary breath-hold method with a spirometer is feasible, with relatively good reproducibility. We are encouraged about the use of this technique clinically for extracranial stereotactic radiotherapy.

Stereotactic hypofractionated high-dose irradiation for stage I nonsmall cell lung carcinoma: clinical outcomes in 245 subjects in a Japanese multiinstitutional study.

BACKGROUND: Stereotactic irradiation (STI) has been actively performed using various methods to achieve better local control of Stage I nonsmall cell lung carcinoma (NSCLC) in Japan. The authors retrospectively evaluated results from a Japanese multiinstitutional study. METHODS: Patients with Stage I NSCLC (n = 245; median age, 76 years; T1N0M0, n = 155; T2N0M0, n = 90) were treated with hypofractionated high-dose STI in 13 institutions. Stereotactic three-dimensional treatment was performed using noncoplanar dynamic arcs or multiple static ports. A total dose of 18-75 gray (Gy) at the isocenter was administered in 1-22 fractions. The median calculated biologic effective dose (BED) was 108 Gy (range, 57-180 Gy). RESULTS: During follow-up (median, 24 months; range, 7-78 months), pulmonary complications of National Cancer Institute-Common Toxicity Criteria Grade > 2 were observed in only 6 patients (2.4%). Local progression occurred in 33 patients (14.5%), and the local recurrence rate was 8.1% for BED > or = 100 Gy compared with 26.4% for < 100 Gy (P < 0.05). The 3-year overall survival rate of medically operable patients was 88.4% for BED > or = 100 Gy compared with 69.4% for < 100 Gy (P < 0.05). CONCLUSIONS: Hypofractionated high-dose STI with BED < 150 Gy was feasible and beneficial for curative treatment of patients with Stage I NSCLC. For all treatment methods and schedules, local control and survival rates were better with BED > or = 100 Gy compared with < 100 Gy. Survival rates in selected patients (medically operable, BED > or = 100 Gy) were excellent, and were potentially comparable to those of surgery.

Process and preliminary outcome of a patterns-of-care study of esophageal cancer in Japan: patients treated with surgery and radiotherapy.

PURPOSE: To evaluate the quality of radiotherapy (RT) in Japan, we have been carrying out a national survey through patterns-of-care studies (PCSs) since 1996. We present the preliminary results of surgery combined with RT with or without chemotherapy for thoracic esophageal cancer. METHODS AND MATERIALS: A Japanese PCS data format for esophageal cancer was established based on one used in the United States and including information used in the surgical registration system in Japan, so that the results in both countries could be compared. An independent panel of radiation oncologists surveyed randomly selected institutions and patients between September 1998 and March 2001. There were 767 esophageal cancer patients, of whom 220 had undergone preoperative or postoperative RT. RESULTS: The median age of the 220 patients was 62.3 years (range 31-89); of them, 88.1% were men. Pathologically, 218 patients (99.5%) had squamous cell carcinoma, predominantly located in the middle and lower thoracic esophagus, 41.7% of the patients had Stage III disease; they accounted for 52.6% of patients in nonacademic institutions and for 37.7% of those in academic institutions (p = 0.016). Sixty-nine patients received preoperative RT; of them, 60.9% received chemotherapy; 145 patients received postoperative RT with or without chemotherapy. The spinal cord of 23 (11.7%) of 196 patients was irradiated with >/=50 Gy. In academic institutions, extended radical "three-field" lymphatic dissection was performed for 72 (48.7%) of 148 patients; however, this sophisticated surgical procedure was done in only 13 (25.5%) of 51 patients in nonacademic settings (p = 0.004). In all large academic institutions (those treating >/=300 patients annually), >/=6 MV of photon energy was used; 30.5% of nonacademic institutes had linear accelerators of <6 MV photon (p = 0.001). No deviations occurred in the radiation dose (median 46 Gy), fractionations, or fields between the two types of institutions. Univariate analyses showed that the statistically significant prognostic factors affecting overall survival were stage (p = 0.001), extended radical "three-field" lymphatic dissection (p = 0.001), no residual tumor (p = 0.001), supraclavicular RT (p = 0.001), mediastinal RT (p = 0.025), Karnofsky performance status (p = 0.006) photon energy (p = 0.011), and stratification of the institutions (p = 0.001). Multivariate analysis showed that the type of institution (p = 0.045, risk ratio = 0.604), stage (p 0.029, risk ratio = 0.572), no residual tumor (p = 0.006, risk ratio = 0.487), photon energy (p = 0.043, risk ratio = 0.579), and use of chemotherapy (p = 0.012, risk ratio = 1.907) significantly affected overall survival. CONCLUSION: This PCS showed that in Japan important issues are present regarding RT for esophageal cancer that should be solved immediately, namely, treatment strategy, photon energy, and dose applied to the spinal cord. The PCS provided important information on how much improvement in structure and process would be required nationwide for RT of esophageal cancer.