Investigation of the changes in the prostate, bladder, and rectal wall sizes during external beam radiotherapy.

AIM AND BACKGROUND: The change in the prostate size for radiotherapy has not yet been elucidated. The coverage of radiation dose is affected by changes in the prostate size. We evaluated the changes in the prostate, rectum, and bladder wall sizes during IMRT of fraction 2 Gy/day using MRI. MATERIALS AND METHODS: Twenty-four patients with prostate cancer were enrolled in this study. MRI was performed at three time points. While the initial MRI was performed before the start of radiotherapy (RT), the second MRI was performed at 38 Gy (range: 36-40 Gy), which represented the halfway point of the RT course. The last MRI was performed on the day of completion of the RT course (76 Gy; range: 74-78 Gy). We estimated the prostate, rectum, and bladder wall sizes at three time points. RESULTS: We observed no significant difference between the estimated sizes of the prostate during RT in all three phases. In addition, the volume of the rectal wall remained unchanged in all phases. However, the volume of the bladder wall significantly decreased from the initial to the last time points. Furthermore, the standard deviation (SD) obtained by subtracting the final size from the initial one was large (mean, 30.1; SD, 10.1). CONCLUSIONS: The volume of the bladder wall decreased during IMRT. The range of subtraction of the volume of the bladder wall was extensive. Thus, the estimation of the bladder wall may be useful to reduce the inter-fraction variation.

Hemostasis radiotherapy for gastric cancer: Usefulness of the gastric cancer to spleen apparent diffusion coefficient ratio.

The hemostatic effect of radiation therapy on gastric cancer with bleeding is known. However, blood tests and endoscopes are mainly used to determine the therapeutic effect. Additionally, magnetic resonance imaging has been reported to be useful when needed because endoscopes are invasive. In this study, magnetic resonance diffusion-weighted imaging was used to evaluate the hemostatic effect of gastric cancer. The hemostatic effect and apparent diffusion coefficient value were correlated. The apparent diffusion coefficient value was also effective in salvage irradiation during rebleeding. Although the apparent diffusion coefficient value of gastric cancer did not change during rescue irradiation, the degree of hemostatic effect could be evaluated in more detail by using the ratio of the apparent diffusion coefficient values of diffusion-weighted imaging of gastric cancer and the spleen. In the future, it would be desirable to use diffusion-weighted imaging instead of endoscopy to evaluate the gastric cancer to spleen apparent diffusion coefficient ratio in a large number of cases.

Radiotherapy for prostate cancer: Effect of gold fiducial markers on diffusion-weighted magnetic resonance imaging.

PURPOSE: There has been an increase in the use of gold fiducial markers to ensure precise radiotherapy delivery in prostate cancer patients. However, metal artifacts may affect the quality of subsequent imaging used to assess disease status following treatment. In this study, we evaluated the effect of gold fiducial markers on magnetic resonance imaging (MRI), particularly on diffusion-weighted imaging (DWI). MATERIAL AND METHODS: Among 57 patients with prostate cancer, 21 patients in whom two gold markers were placed in the prostate tumor with abnormal signal intensity on DWI were evaluated. The effect of the markers on DWI was evaluated on a scale of 1-5, with a high score indicating clinical usefulness. Change inapparent diffusion coefficient (ADC; 10-3 mm2 /s) from before to after marker placement was also evaluated. RESULTS: The mean effect of the markers on DWI was 4.3 (standard deviation [SD] 1.3, range 2-5) points. The mean change in ADC was 0.045 (SD 0.041, range 0.025-0.089) × 10-3 mm2 /s. CONCLUSIONS: The gold fiducial markers demonstrated negligible effect on DWI quality. Therefore, gold markers do not affect MRI quality, particularly DWI, and may be used during follow-up in prostate cancer patients.

Dosimetric evaluation of the heart and left anterior descending artery dose in radiotherapy for Japanese patients with breast cancer.

Intensity-modulated radiotherapy (IMRT) has been used for breast cancer as well as in field-in-field techniques. Few dosimetric comparison studies have been conducted using IMRT and volumetric modulated arc therapy (VMAT) for Japanese patients. We aimed to study such patients. Thirty-two patients with left-sided breast cancer were enrolled. We conducted the following five treatment plans: two field-static IMRT (2F-S-IMRT), four field-static IMRT (4F-S-IMRT), 40° dual partial arc VMAT (40d-VMAT), 80° dual partial arc VMAT (80d-VMAT) and 210° partial VMAT (210p-VMAT). We evaluated the following: level of coverage of planning target volume (PTV) of 95% for irradiation at a dose of 50 Gy (D95) and the percentage of the heart and left anterior descending artery (LAD) volume that received 10 Gy or more (V10). As a result, the coverage of 40d-VMAT for the prescribed PTV dose of D95 was significantly lower than that of the other treatment plans (P < 0.05). Regarding heart V10 and LAD V10, 2F-S-IMRT, 40d-VMAT and 80d-VMAT showed significantly lower dose than the other treatment plans (P < 0.05). In conclusion, among the five plans, 2F-S-IMRT is recommended for Japanese patients because of high coverage of D95 of PTV, low V10 of the heart and LAD and the monitor unit value was the lowest.

How Long Should We Immobilize the Wrist after Vascularized Bone Grafting for the Treatment of Scaphoid Nonunion?

Background: Although vascularized bone grafting can effectively treat scaphoid nonunion, the optimal duration of the immobilization period after bone grafting is unclear. Therefore, we aimed to examine the difference in the union rate and range of motion between short and long immobilization periods and infer the optimal post-immobilization period after pedicled vascularized bone grafting for scaphoid nonunion treatment. Methods: A total of 23 wrists (21 men and 1 woman) with scaphoid nonunion treated using an intercompartmental supraretinacular artery pedicled vascularized bone graft were analyzed. We examined the difference in the union rate and range of motion between patients immobilized for less than 49 days (short immobilization group) and those immobilized for more than 49 days (long immobilization group). The range of motion of the wrist joint was measured before and after surgery. Patient outcomes were also assessed. Results: The overall union rate was 95.6%. A significant difference was found in postoperative extension and flexion between the two groups, but not in terms of the functional outcome. If the intraoperative fixation is solid, intraoperative proximal pole bleeding is confirmed, and the follow-up radiograph shows a normal healing process, we propose immobilization of the wrist for ≤ 7 weeks. Conclusions: The immobilization duration should depend on the solidity of intraoperative fixation and a satisfactory appearance on follow-up radiography: absence of a gap at the graft interface, surrounding lucency, or movement of the implant and displacement of the graft. If there are no signs of graft failure and fixation is solid, immobilization of the wrist for 7 weeks or less is recommended.

Scores of Child-Pugh Classification Impact Overall Survival After Stereotactic Body Radiation Therapy for Primary and Metastatic Liver Tumors.

BACKGROUND: Stereotactic body radiotherapy (SBRT) delivers high-dose radiation to tumor tissues in few fractions, thereby reducing radiation damage to at-risk organs. There are more potential effects of SBRT owing to the higher biological equivalent dose delivered. Herein, we retrospectively analyzed its effectiveness and toxicity at our institution. METHODS: Data from patients with hepatocellular carcinoma (HCC; n = 10) and liver metastases (n = 10) who underwent SBRT (total dose of 30-50 Gy in 5-10 fractions) between 2013 and 2016 were analyzed. Adverse events were recorded at the end of RT, 6 months after treatment, or upon death. Overall survival (OS) was calculated according to the biological effective dose (BED α/ß = 10) and liver function (Child-Pugh [CP] classification 5 or 6 vs. 7 or 8) after SBRT, using Kaplan-Meier analyses. RESULTS: Of the 20 patients, 6 declined the CP classification score after SBRT; grade 3 adverse events were not seen in any patient. A higher OS rate was seen in patients receiving a higher BED and in those with better CP classification after SBRT. Kaplan-Meier survival analysis yielded a median OS of 401 days and 1- and 2-year OS of 45% and 15%, respectively. CONCLUSION: The higher BED was significantly associated with tumor control, and there were no differences in the tumor control rate between HCC and metastatic tumors. Changes in CP scores after SBRT also affected the survival rate. Good liver function may permit multiple rounds of SBRT.

Usefulness of diffusion-weighted magnetic resonance imaging for evaluating the effect of hemostatic radiotherapy for unresectable gastric cancer.

There are several reports that vouch for the usefulness of diffusion-weighted image (DWI) in making a diagnosis before treatment. However, no study has evaluated the effect of radiotherapy (RT) for unresectable gastric cancer. In the present case report, we evaluated the effectiveness of RT using DWI. An 81-year-old man was hospitalized with a broken bone and then diagnosed with advanced gastric cancer with breeding. He had chorionic renal failure and surgery was impossible. Further, contrast-enhanced computed tomography and magnetic resonance imaging (MRI) were not performed due to renal failure, whereas palliative RT was performed. We followed up the patient using blood test and MRI (DWI) to estimate whether bleeding had stopped or not after radiotherapy. Hemostasis effect was found after 2 weeks of RT. In DWI examination, there was a decrease in the tumor signal intensity 30 days after RT. Similarly, at day 60, the tumor signal intensity further decreased on DWI and the blood test results indicated no progression of anemia. At 4 months after the RT, the patient died because of respiratory failure without any bleeding. DWI is useful not only for the initial diagnosis but also for evaluating the effectiveness of RT.Trial registration: National clinical study registered number: UMIN000026362.

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

INTRODUCTION: 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. METHODS: Twenty-seven patients underwent CT/MRI fusion-based intensity-modulated radiotherapy. Markers were placed by urologists under local anesthesia. Gold Anchor (GA; diameter: 0.28 mm; length: 10 mm), an iron-containing marker, was placed on the right side of the prostate using a 22-G needle and VISICOIL (VIS; diameter: 0.35 mm; length: 10 mm), a non-iron-containing marker, was placed on the left side using a 19-G needle. T2*-weighted images MRI sequences were obtained. Two radiation oncologists and a radiation technologist evaluated and assigned scores for visual quality on a five-point scale (1, poor; 5, best visibility). RESULTS: Artifact generation on CT was slightly greater with GA than with VIS. The mean marker visualization scores on MRI of all three observers were significantly superior for GA than for VIS (3.5 vs 3.2, 3.9 vs 3.2, and 4.0 vs 2.9). The actual size of the spherical GA was about 2 mm in diameter, but the signal void on MRI was approximately 5 mm. CONCLUSION: Although both markers were well visualized and can be recommended clinically, the results suggest that GA has some subtle advantages for quantitative visualization that could prove useful in certain situations of stereotactic body radiotherapy and intensity-modulated radiotherapy.