Satoshi Nomoto

Advantage of early induction of opioid to control pain induced by irradiation in head and neck cancer patients

OBJECTIVE Although radiotherapy is effective for head and neck cancer patients, the local pain evoked by the irradiation itself reduces food intake and frequently halts the treatment. Thus, pain control is an important problem in radiotherapy for head and neck cancer. We performed to examine whether early induction of low-dose, opioid from mild pain improves dietary and caloric intake, while reducing weight loss. METHODS The subjects were 43 patients who were hospitalized for head and neck cancer from 2004 to 2008. They were patients who underwent radiation treatment but those who did not undergo preoperative treatment. They were divided into two groups, depending on whether the pain was mild or moderate when an opioid was introduced (MILD and MODERATE, N=23 and 20, respectively). RESULTS The visual analog scale scores for pain were significantly lower in the MILD than in the MODERATE group at between 25 and 50 Gy. The amount of oxycodone used for pain was significantly lower in the MILD than the MODERATE group. A regular diet was maintained for significantly longer in the MILD group. Caloric intake was significantly higher in the MILD group at over 20 Gy. Weight loss was significantly lower in the MILD group at over 20 Gy. The incidence of side effects was equal in both groups. CONCLUSION Our results indicated that the introduction of opioids for mild pain during radiotherapy controls the level of pain, improving food intake in head and neck cancer patients.

Advanced olfactory neuroblastoma treated with combined conventional and hypofractionated stereotactic radiotherapy

Three patients with olfactory neuroblastoma (ONB) of the nasal and/or paranasal cavity were treated with a combination of conventional radiotherapy (RT) and hypofractionated stereotactic radiation therapy (SRT). Radiation doses of 30 to 50 Gy were delivered in 12 to 25 fractions using conventional RT, and then an additional 20 to 25 Gy was delivered in 5 fractions using SRT. Follow-up time was 42, 53, 65 months, three patients were alive, and local control was obtained in all, complete response (CR) in 2 and partial response (PR) in 1. Two patients had recurrence out of the radiation field and received salvage therapy. According to the Radiation Therapy Oncology Group (RTOG) acute/late radiation morbidity scoring criteria, there were no adverse effects of grade 3 or higher. The combined treatment with conventional RT and hypofractionated SRT achieved excellent local control without serious adverse effects.

SU‐GG‐J‐58: Stereotactic Body Radiotherapy: Computer‐Assisted Verification of a Lung Tumor Region Using EPID without Implanted Markers

Purpose: Our purpose of this study was to develop a computer‐assisted verification method for lungtumor regions using a Gaussian image enhancement based on second derivatives of Gaussian functions in cine images on an EPID without implanted markers during SBRT.Method and Materials: The localization for a lungtumor was based on a template matching technique between a “tumor template” image obtained from a first EPID cine image and the subsequent image. The irradiation field region was cropped from an original EPID cine image by analyzing the histogram of this image. The “tumor template” image was segmented from the first EPID cine image, i.e., reference portal image, by using a Gaussian image enhancement based on second derivatives of Gaussian functions and a region growing technique. The tumor region was determined within the irradiation field as the position where the tumor template image took the maximum cross‐correlation value within each subsequent cine image. For performance evaluation of the proposed method, we applied the proposed method to EPIDimages acquired from twelve cases (age: 51–83 years old, mean: 72) with a non‐small cell lungcancer, and calculated the following two values: (1) the location error, i.e., the Euclidean distance from “tumor” point to the candidate point and (2) the overlap measure between the target candidate regions obtained by the manual method and our automated segmentation method. Results: The average location deviation between tumor center points obtained by the proposed method and the manual method was 1.80 ± 0.73 mm. The average overlap measure was 66.0 ± 10.0% for 12 cases. Conclusion: The results of this study suggest that the proposed method based on the tumor template matching technique might be feasible for localization of a lungtumor without implanted markers in SBRT.

SU‐GG‐J‐41: Automated Estimation of a Tumor Region and Its Displacement On EPID Cine Images Without Implanted Markers in Lung Stereotactic Body Radiotherapy

Purpose: The purpose of this study was to develop a method for automated estimation of a lungtumor region and its displacement on an electronic portal imaging device(EPID) during lung stereotactic body radiotherapy(SBRT) without implanted markers. Method and Materials: Our method for automated estimation of the tumor region and its displacement was based on a template matching technique with cross‐correlation coefficient between a target template image and each consecutive portal (CP) image, which was acquired in cine mode with the EPID in each treatment. Each target region was segmented in the first EPID cine image, which was referred to as the reference portal (RP) image, based on a multiple‐gray level thresholding technique and a region growing technique, and then a target template image was extracted as “a tumor template”. The displacement vector of a target was determined from the position in which the target template image took the maximum cross‐correlation value within the CP image.EPIDimages with 512×384 pixels (pixel size: 0.56 mm) were acquired in a cine mode at a sampling rate of 0.5 frame/sec by using x‐ray energies of 4, 6, or 10 MV on linear accelerators. We applied our proposed method to EPID cine images of 12 cases (ages: 51–83, mean: 73) with a non‐small cell lungcancer.Results: For 12 cases, the target displacements obtained by our method agreed with those determined by the manual method by a mean correlation value of 0.839. Each tumor region segmented by our proposed method was overlapped by 60% on average with that determined by the manual method. Conclusion: This preliminary result suggested that our proposed method may be useful for estimating of displacements of target positions without implanted markers in lungSBRT.