PURPOSE: To develop a method for verifying a treatment setup in stereotactic radiotherapy by matching portal images to DRRs. MATERIALS AND METHODS: Four pairs of orthogonal portal images of one patient immobilized by a thermoplastic mask frame for fractionated stereotactic radiotherapy were compared with DRRs. Portal images are obtained in AP (anterior/posterior) and lateral directions with a target localizer box containing fiducial markers attached to a stereotactic frame. DRRs superimposed over a planned isocenter and fiducial markers are printed out on transparent films. And then, they were overlaid over orthogonal portal images by matching anatomical structures. From three different kind of objects (isocenter, fiducial markers, anatomical structure) on DRRs and portal images, the displacement error between anatomical structure and isocenters (overall setup error), the displacement error between anatomical structure and fiducial markers (immobilization error), and the displacement error between fiducial markers and isocenters (localization error) were measured. RESULTS: Localization errors were 1.5+/-0.3 mm (AP), 0.9+/-0.3 mm (lateral), and immobilization errors were 1.9+/-0.5 mm (AP), 1.9+/-0.4 mm (lateral). In addition, overall setup errors were 1.6+/-0.9 mm (AP), 1.3+/-0.4 mm (lateral). From these orthogonal displacement errors, maximum 3D displacement errors(sqrt{(Delta AP)^2 +(Delta Lat)^2}) were found to be 1.7+/-0.4 mm for localization, 2.6+/-0.6 mm for immobilization, and 2.3+/-0.7 mm for overall treatment setup. CONCLUSION: By comparing orthogonal portal images with DRRs, we find out that it is possible to verify treatment setup directly in stereotactic radiotherapy.
Fiducial Markers ; Humans ; Immobilization ; Masks ; Radiotherapy*

PURPOSE: To setup procedures of quality assurance (QA) for implementing intensity modulated radiation therapy (IMRT) clinically, report QA procedures performed for one patient with prostate cancer. MATERIALS AND METHODS: P3IMRT (ADAC) and linear accelerator (Siemens) with multileaf collimator are used to implement IMRT. At first, the pos itional accuracy, reproducibility of MLC, and leaf transmission factor were evaluated. RTP commissioning was performed again to considers mall field effect. After RTP recommissioning, a test plan of a C-s haped PTV was made using 9 intensity modulated beams, and the calculated isocenter dose was compared with the measured one insolid water phantom. As a patient-specific IMRT QA, one patient with prostate cancer was planned us ing 6 beams of total 74 segmented fields. The same beams were used to recalculate dose in a solid water phantom. Dose of these beams were meas ured with a 0.015cc microionization chamber, a diode detector, films, and a narray detector and compared with calculated one. RESULTS: The pos itioning accuracy of MLC was about 1 mm, and the reproducibility was around 0.5 mm. For leaf transmission factor for 10 MV photon beams, interleaf leakage was measured 1.9% and midleaf leakage 0.9% relative to 10x10 cm2 open filed. Penumbra meas ured with film, diode detector, microionization chamber, and conventional 0.125 cc chambers howed that 80~20% penumbra width meas ured with a 0.125cc chamber was 2 mm larger than that of film, which means a 0.125 ccionization chamber was unacceptable for meas urings mall fields uch like 0.5 cm beamlet. After RTP recommissioning, the discrepancy between the meas ured and calculated dose profile for a small field of 1x1 cm2 size was less than 2%. The isocenter dose of the test plan of C-s haped PTV was meas ured two times with microionization chamber in solid phantom showed that the errors upto 12% for individual beam, but total dose delivered were agreed with the calculated within 2%. The transverse dose distribution meas ured with EC-L film was agreed with the calculated one ingeneral. The isocenter dose for the patient meas ured in solid phantom was agreed within 1.5%. Off-axis dose profiles of each individual beam at the position of the central leaf measured with film and array detector were found that at out-of-the-field region, the calculated dose underestimates about 2%, at inside-the-field the meas ured one was agreed within 3%, except some position. CONCLUSION: It is necessary more tight quality control of MLC for IMRT relative to conventional large field treatment and to develop QA procedures to check intensity pattern more efficiently. At the conclusion, we did setup an appropriate QA procedures for IMRT by a series of verifications including the measurement of absolute dose at the isocenter with a microionization chamber, film dosimetry for verifying intensity pattern, and another meas urement with an array detector for comparing off-axis dose profile.
Film Dosimetry ; Humans ; Particle Accelerators ; Prostatic Neoplasms ; Quality Control ; Water

BACKGROUND: The study examined the correlations among the results of the European Organization for Research and Treatment of Cancer (EORTC)-Quality of Life Questionnaire, Core 30 (QLQ-C30) completed by elderly cancer patients and their family caregivers and the Eastern Cooperative Oncology Group (ECOG)-performance status (PS) evaluated by medical doctors. METHODS: The study sample included 269 persons with cancer aged 55 years or older and their family caregivers recruited from hospitals located in Seoul and Gyeonggi-do. The results of the ECOG-PS evaluated by medical doctors were obtained from medical records. Intra-class correlation analysis was used to assess rater reliability between the elderly cancer patients and their family caregivers. Correlations among the EORTC QLQ-C30 and the ECOG-PS were tested using the Kruskal-Wallis test and Spearmen's correlation. RESULTS: The results showed that four subscales of quality of life (physical functioning, emotional functioning, social functioning, and global health status) and three items under symptoms (fatigue, pain, and financial difficulties) in the EORTC QLQ-C30 were highly consistent between patients and their family caregivers. From the EORTC QLQ-C30 results, social functioning, role functioning, health status, fatigue, pain, and appetite loss (patients results) and physical functioning (family caregivers results) were highly consistent with the results of the ECOG-PS by the physicians. CONCLUSIONS: The findings suggest that when the older persons with cancer have difficulty expressing their own thoughts or feelings, the EORTC QLQ-C30 completed by their family caregivers and the results of the ECOG-PS completed by the physicians could be used as substitutes.
Aged ; Appetite ; Caregivers* ; Fatigue ; Gyeonggi-do ; Humans ; Medical Records ; Medical Staff* ; Quality of Life* ; Seoul

To determine the appropriate method out of various available methods to measure build-up doses, the measurements and comparisons of depth doses of build-up region including the surface dose were executed using the Attix parallel-plate ionization chamber, the Markus chamber, a cylindrical ionization chamber, and a diode detector. Based on the measurements using the Attix chamber, discrepancies of the Markus chamber were within 2% for the open field and increased up to 3.9% in the case of photon beam containing the contaminant electrons. The measurements of an cylindrical ionization chamber and a diode detector accord with those of the Attix chamber within 1.5% and 1.0% after those detectors were completely immersed in the water phantom. The results suggest that the parallel-plate chamber is the best choice to measure depth doses in the build-up region containing the surface, however, using cylindrical ionization chamber or diode detector would be a reasonable choice if no special care is necessary for the exact surface dose.
Water

PURPOSE : We conducted a phase II trial of the addition of a paclitaxel and cisplatin regimen as induction chemotherapy to concurrent thoracic radiation therapy and weekly paclitaxel and cisplatin in locally advanced unresectable stage III non-small cell lung cancer. The endpoints were to determine the applicability, safety, response rate and survival statistics. MATERIALS AND METHODS : The induction chemotherapy consisted of paclitaxel 175 mg/m2 given 3 hours on day 1 and cisplatin 75 mg/m2 given over 1 hour on day 2 repeated 3 weeks for two cycles. Thoracic radiation therapy 63 Gy/35 fractions in daily 1.8 Gy fractions along with paclitaxel 45 mg/m2/1 hr and cisplatin 20 mg/m2/1 hr given 2~4 hours before irradiation repeated every week for 6 cycles. To minimize the toxicities of a concurrent portion of treatment, the treatment planning for thoracic radiation therapy was done throughly with the assistance of a planning CT scans and computerized radiation treatment planning system. RESULTS : Twenty-nine patients were enrolled between Sep 1999 to Sep 2002. The overall response rate after the induction chemotherapy was 79.3%. Due to the refusal of further treatment, 1 patient left the trial. Twenty-three (79.3%) of the 29 patients received the concurrent portion of treatment. Five (17.2%) patients received the radiation therapy alone, two due to refusal, two for decreased performance stati, one due to pulmonary abscess. After completion of the entire course of treatment, 5 (17.2%) patients gained the complete remission and the overall response rate of 79.3%. With a median follow-up of 22 months, the 1-, 2- and 3-year overall survival rates were 75.7, 53.4 and 41.6%. The progression free survival rates were 52.5 and 20.5% at 1- and 2-year, respectively. Induction chemotherapy was well tolerated. Among 23 patients who completed the entire course of treatment including the concurrent portion, 6 (34.8%) suffered hematologic toxicities more than grade 3, 2 (8.7%) had esophagitis greater than grade 3 and 3 (13.3%) had radiation pneumonitis greater than grade 3. CONCLUSION : We concluded that weekly Paclitaxel+ Cisplatin with concurrent radiotherapy following 2 cycles of induction chemotherapy with Paclitaxel+Cisplatin repeated 3 weeks is effective and welltolerated, should be further evaluated in a randomized phase III trial
Carcinoma, Non-Small-Cell Lung* ; Chemoradiotherapy* ; Cisplatin ; Disease-Free Survival ; Disulfiram ; Esophagitis ; Follow-Up Studies ; Humans ; Induction Chemotherapy* ; Lung Abscess ; Paclitaxel ; Radiation Pneumonitis ; Radiotherapy ; Survival Rate ; Tomography, X-Ray Computed

INTRODUCTION: Stereotactic radiation therapy (SRT) can deliver highly focused radiation to a small and spherical target lesion with very high degree of mechanical accuracy. For non-spherical and large lesions, however, inclusion of the neighboring normal structures within the high dose radiation volume is inevitable in SRT. This is to report the beam shaping using the partial closure of the independent jaw in SRT and the verification of dose calculation and the dose display using a home-made soft ware. MATERIALS & METHODS: Authors adopted the idea to partially close one or more independent collimator jaw(s) in addition to the circular collimator cones to shield the neighboring normal structures while keeping the target lesion within the radiation beam field at all angles along the arc trajectory. The output factors (OF's) and the tissue-maximum ratios (TMR's) were measured using the micro ion chamber in the water phantom dosimetry system, and were compared with the theoretical calculations. A film dosimetry procedure was performed to obtain the depth dose profiles at 5 cm, and they were also compared with the theoretical calculations, where the radiation dose would depend on the actual area of irradiation. Authors incorporated this algorithm into the home-made SRT software for the isodose calculation and display, and was tried on an example case with single brain metastasis. The dose-volume histograms (DVH's) of the planning target volume (PTV) and the normal brain derived by the control plan were reciprocally compared with those derived by the plan using the same arc arrangement plus the independent collimator jaw closure. RESULTS: When using 5.0 cm diameter collimator, the measurements of the OF's and the TMR's with one independent jaw set at 30 mm (unblocked), 15.5 mm, 8.6 mm, and 0 mm from the central beam axis showed good correlation to the theoretical calculation within 0.5% and 0.3% error range. The dose profiles at 5 cm depth obtained by the film dosimetry also showed very good correlation to the theoretical calculations. The isodose profiles obtained on the home-made software demonstrated a slightly more conformal dose distribution around the target lesion by using the independent jaw closure, where the DVH's of the PTV were almost equivalent on the two plans, while the DVH's for the normal brain showed that less volume of the normal brain receiving high radiation dose by using this modification than the control plan employing the circular collimator cone only. CONCLUSION: With the beam shaping modification using the independent jaw closure, authors have realized wider clinical application of SRT with more conformal dose planning. Authors believe that SRT, with beam shaping ideas and efforts, should no longer be limited to the small spherical lesions, but be more widely applied to rather irregularly shaped tumors in the intracranial and the head and neck regions.
Axis, Cervical Vertebra ; Brain ; Film Dosimetry ; Head ; Jaw* ; Neck ; Neoplasm Metastasis ; Radiotherapy* ; Water

Less execution of the electron arc treatment could in large part be attributed to the lack of an adequate planning system. Unlike most linear accelerators providing the electron arc mode, no commercial planning systems for the electron arc plan are available at this time. In this work, with the expectation that an easily accessible planning system could promote electron arc therapy, a commercial planning system was commissioned and evaluated for the electron arc plan. For the electron arc plan with use of a Varian 21-EX, Pinnacle3 (ver. 7.4f), with an electron pencil beam algorithm, was commissioned in which the arc consisted of multiple static fields with a fixed beam opening. Film dosimetry and point measurements were executed for the evaluation of the computation. Beam modeling was not satisfactory with the calculation of lateral profiles. Contrary to good agreement within 1% of the calculated and measured depth profiles, the calculated lateral profiles showed underestimation compared with measurements, such that the distance-to-agreement (DTA) was 5.1 mm at a 50% dose level for 6 MeV and 6.7 mm for 12 MeV with similar results for the measured depths. Point and film measurements for the humanoid phantom revealed that the delivered dose was more than the calculation by approximately 10%. The electron arc plan, based on the pencil beam algorithm, provides qualitative information for the dose distribution. Dose verification before the treatment should be mandatory.
Electrons ; Film Dosimetry ; Particle Accelerators

Most brachytherapy treatment planning systems employ a dosimetry formalism based on the AAPM TG-43 report which does not appropriately consider tissue heterogeneity. In this study we aimed to set up a simple Monte Carlo-based intracavitary high-dose-rate brachytherapy (IC-HDRB) plan verification platform, focusing particularly on the robustness of the direct Monte Carlo dose calculation using material and density information derived from CT images. CT images of slab phantoms and a uterine cervical cancer patient were used for brachytherapy plans based on the Plato (Nucletron, Netherlands) brachytherapy planning system. Monte Carlo simulations were implemented using the parameters from the Plato system and compared with the EBT film dosimetry and conventional dose computations. EGSnrc based DOSXYZnrc code was used for Monte Carlo simulations. Each (192)Ir source of the afterloader was approximately modeled as a parallel-piped shape inside the converted CT data set whose voxel size was 2x2x2 mm3. Bracytherapy dose calculations based on the TG-43 showed good agreement with the Monte Carlo results in a homogeneous media whose density was close to water, but there were significant errors in high-density materials. For a patient case, A and B point dose differences were less than 3%, while the mean dose discrepancy was as much as 5%. Conventional dose computation methods might underdose the targets by not accounting for the effects of high-density materials. The proposed platform was shown to be feasible and to have good dose calculation accuracy. One should be careful when confirming the plan using a conventional brachytherapy dose computation method, and moreover, an independent dose verification system as developed in this study might be helpful.
Accounting ; Brachytherapy ; Film Dosimetry ; Humans ; Monte Carlo Method ; Organoplatinum Compounds ; Population Characteristics ; Uterine Cervical Neoplasms ; Water

PURPOSE: This study was performed to assess frequency, timings of occurrence, and predictors of radiologic lung damage (RLD) after forward-planned intensity-modulated radiotherapy (FIMRT) for whole breast irradiation. METHODS: We retrospectively reviewed medical records of 157 breast cancer patients and each of their serial chest computed tomography (CT) taken 4, 10, 16, and 22 months after completion of breast radiotherapy (RT). FIMRT was administered to whole breast only (n=152), or whole breast and supraclavicular regions (n=5). Dosimetric parameters, such as mean lung dose and lung volume receiving more than 10 to 50 Gy (V10-V50), and clinical parameters were analyzed in relation to radiologic lung damage. RESULTS: In total, 104 patients (66.2%) developed RLD after whole breast FIMRT. Among the cases of RLD, 84.7% were detected at 4 months, and 15.3% at 10 months after completion of RT. More patients of 47 or younger were found to have RLD at 10 months after RT than patients older than the age (11.7% vs. 2.9%, p=0.01). In univariate and multivariate analyses, age >47 and V40 >7.2% were significant predictors for higher risk of RLD. CONCLUSION: RLD were not infrequently detected in follow-up CT after whole breast FIMRT. More detected cases of RLD among younger patients are believed to have developed at later points after RT than those of older patients. Age and V40 were significant predictors for RLD after whole breast intensity-modulated radiotherapy.
Breast Neoplasms ; Breast* ; Follow-Up Studies ; Humans ; Lung Injury* ; Lung* ; Medical Records ; Multivariate Analysis ; Radiotherapy ; Radiotherapy, Intensity-Modulated* ; Retrospective Studies ; Thorax

We aimed to setup an adaptive radiation therapy platform using cone-beam CT (CBCT) and multileaf collimator (MLC) log data and also intended to analyze a trend of dose calculation errors during the procedure based on a phantom study. We took CT and CBCT images of Catphan-600 (The Phantom Laboratory, USA) phantom, and made a simple step-and-shoot intensity-modulated radiation therapy (IMRT) plan based on the CT. Original plan doses were recalculated based on the CT (CTplan) and the CBCT (CBCTplan). Delivered monitor unit weights and leaves-positions during beam delivery for each MLC segment were extracted from the MLC log data then we reconstructed delivered doses based on the CT (CTrecon) and CBCT (CBCTrecon) respectively using the extracted information. Dose calculation errors were evaluated by two-dimensional dose discrepancies (CTplan was the benchmark), gamma index and dose-volume histograms (DVHs). From the dose differences and DVHs, it was estimated that the delivered dose was slightly greater than the planned dose; however, it was insignificant. Gamma index result showed that dose calculation error on CBCT using planned or reconstructed data were relatively greater than CT based calculation. In addition, there were significant discrepancies on the edge of each beam while those were less than errors due to inconsistency of CT and CBCT. CBCTrecon showed coupled effects of above two kinds of errors; however, total error was decreased even though overall uncertainty for the evaluation of delivered dose on the CBCT was increased. Therefore, it is necessary to evaluate dose calculation errors separately as a setup error, dose calculation error due to CBCT image quality and reconstructed dose error which is actually what we want to know.
Cone-Beam Computed Tomography ; Organothiophosphorus Compounds ; Uncertainty ; Weights and Measures