Osamu Tanaka

Impact of [11C]Methionine Positron Emission Tomography for Target Definition of Glioblastoma Multiforme in Radiation Therapy Planning

PURPOSEnThe purpose of this work was to define the optimal margins for gadolinium-enhanced T(1)-weighted magnetic resonance imaging (Gd-MRI) and T(2)-weighted MRI (T(2)-MRI) for delineating target volumes in planning radiation therapy for postoperative patients with newly diagnosed glioblastoma multiforme (GBM) by comparison to carbon-11-labeled methionine positron emission tomography ([(11)C]MET-PET) findings.nnnMETHODS AND MATERIALSnComputed tomography (CT), MRI, and [(11)C]MET-PET were separately performed for radiation therapy planning for 32 patients newly diagnosed with GBM within 2 weeks after undergoing surgery. The extent of Gd-MRI (Gd-enhanced clinical target volume [CTV-Gd]) uptake and that of T(2)-MRI of the CTV (CTV-T(2)) were compared with the extent of [(11)C]MET-PET (CTV--[(11)C]MET-PET) uptake by using CT--MRI or CT--[(11)C]MET-PET fusion imaging. We defined CTV-Gd (x mm) and CTV-T(2) (x mm) as the x-mm margins (where x = 0, 2, 5, 10, and 20 mm) outside the CTV-Gd and the CTV-T(2), respectively. We evaluated the relationship between CTV-Gd (x mm) and CTV-- [(11)C]MET-PET and the relationship between CTV-T(2) (x mm) and CTV-- [(11)C]MET-PET.nnnRESULTSnThe sensitivity of CTV-Gd (20 mm) (86.4%) was significantly higher than that of the other CTV-Gd. The sensitivity of CTV-T(2) (20 mm) (96.4%) was significantly higher than that of the other CTV-T(2) (x = 0, 2, 5, 10 mm). The highest sensitivity and lowest specificity was found with CTV-T(2) (x = 20 mm).nnnCONCLUSIONSnIt is necessary to use a margin of at least 2 cm for CTV-T(2) for the initial target planning of radiation therapy. However, there is a limit to this setting in defining the optimal margin for Gd-MRI and T(2)-MRI for the precise delineation of target volumes in radiation therapy planning for postoperative patients with GBM.

Low dose palliative radiotherapy for refractory aggressive lymphoma

AIMnTo determine the efficacy of low-dose palliative radiotherapy in patients with refractory aggressive lymphoma.nnnBACKGROUNDnThere are few reports on the administration of palliative radiotherapy to patients with aggressive lymphoma.nnnMATERIALS AND METHODSnThe present study included 11 patients with 30 sites of aggressive lymphoma (diffuse large cell lymphoma, nxa0=xa07; mantle cell lymphoma, nxa0=xa02; follicular large cell lymphoma, nxa0=xa01; and peripheral T cell lymphoma, nxa0=xa01). The patients received local palliative radiotherapy after receiving a median of 4 chemotherapy regimens. The radiotherapy doses administered to the 30 sites were as follows: 8xa0Gy, single fraction (nxa0=xa027); 6xa0Gy, single fraction (nxa0=xa01); 4xa0Gy, single fraction (nxa0=xa01); and 4xa0Gy, 2 fractions (nxa0=xa01).nnnRESULTSnThe complete response rate was 45% (5/11); the partial response rate was 36% (4/11). Toxicity occurred at one irradiated site (the mandibular), which showed temporal acute gingivitis; however, medication was not required. Retreatment was required for 3 sites on the head (parotid, face and mandible) due to persistent discomfort. None of the other sites (27/30) required retreatment. A patient with refractory DLBCL underwent radiotherapy (4xa0Gy, single fraction) for hepatic hilar lymph node involvement but did not recover from jaundice and died of DLBCL.nnnCONCLUSIONSnEight Gray single fraction radiotherapy was one of meaningful options for the treatment of refractory aggressive lymphoma in terms of its efficacy and the incidence of adverse events. The use of 8xa0Gy single fraction radiotherapy is therefore recommended for achieving local control in patients with refractory aggressive lymphoma.

Initial experience of using an iron-containing fiducial marker for radiotherapy of prostate cancer: Advantages in the visualization of markers in Computed Tomography and Magnetic Resonance Imaging

Abstract Visualization of markers is critical for imaging modalities such as computed tomography (CT) and magnetic resonance imaging (MRI). However, the size of the marker varies according to the imaging technique. While a large-sized marker is more useful for visualization in MRI, it results in artifacts on CT and causes substantial pain on administration. In contrast, a small-sized marker reduces the artifacts on CT but hampers MRI detection. Herein, we report a new ironcontaining marker and compare its utility with that of non-iron-containing markers. Five patients underwent CT/MRI fusion-based intensity-modulated radiotherapy, and the markers were placed by urologists. A Gold Anchor™ (GA; diameter, 0.28 mm; length, 10 mm) was placed using a 22G needle on the right side of the prostate. A VISICOIL™ (VIS; diameter, 0.35 mm; length, 10 mm) was placed using a 19G needle on the left side. MRI was performed using T2*-weighted imaging. Three observers evaluated and scored the visual qualities of the acquired images. The mean score of visualization was almost identical between the GA and VIS in radiography and cone-beam CT (Novalis Tx). The artifacts in planning CT were slightly larger using the GA than using the VIS. The visualization of the marker on MRI using the GA was superior to that using the VIS. In conclusion, the visualization quality of radiography, conebeam CT, and planning CT was roughly equal between the GA and VIS. However, the GA was more strongly visualized than was the VIS on MRI due to iron containing.

Radiotherapy for Gastric Bleeding from Tumor Invasion of Recurrent Colon Cancer with Liver Metastasis After Resection

Palliative radiotherapy has been reported to be effective for hemostasis [1–3]; however, there is no consensus on the dosage and number of fractions. Lee et al. reported in a retrospective study that a dose higher than the biological effective dose (BED) of 36 Gy was effective for hemostasis of bleeding gastric cancer [1]. Hemostatic radiotherapy is useful for primary gastric cancer. Moreover, we believed that radiotherapy for an invasion from peritoneum to stomach would be useful. Here, we report the case of a patient who had rectal cancer with liver and gastric metastases that responded to palliative, hemostatic radiotherapy.

Two Sessions of Radiotherapy Were Successful in Treating Gastric Cancer with Bleeding

The radical treatment for gastric cancer, which accounts for the highest malignancy-related morbidity in Japan, is surgery, and chemotherapy is often provided in addition to surgical treatment [1–5]. On the other hand, in Europe and America, chemoradiotherapy is often provided after and/or before perioperative therapy. Radiotherapy is a well-known treatment option to achieve hemostasis in patients with bleeding organs [1, 2, 6–11], the most common of which are the esophagus, stomach, colon (rectum), bronchus, and uterus. However, the optimal protocol of radiotherapy is not established. The protocol followed in Murakami Memorial Hospital to treat gastric cancer cases with organ bleeding is as follows: to initially irradiate the entire organ at 20 Gy/5 fractions. In cases that rebleed, 3–5 clips are placed endoscopically near the tumor and salvage radiation of the bleeding site at 15 Gy/5 fractions is performed [12]. Herein, we report a case of successful salvage radiotherapy for bleeding gastric cancer, which resulted to 15 months of local control and enabled the patient to resume his activities of daily living in 12 months and subsequently received chemotherapy as an outpatient. Case

Visibility of an iron-containing fiducial marker in magnetic resonance imaging for high-precision external beam prostate radiotherapy

Visualization of fiducial gold markers is critical for registration on computed tomography (CT) and magnetic resonance imaging (MRI) for imaging‐guided radiotherapy. Although larger markers provide better visualization on MRI, they tend to generate artifacts on CT. MRI is strongly influenced by the presence of metals, such as iron, in the body. Here we compared efficacies of a 0.5% iron‐containing gold marker (GM) and a traditional non‐iron‐containing marker.