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Background To review a single institutional experience of the Radiation Therapy Oncology Group (RTOG) 8502 “QUAD shot” regimen using volumetric modulated arc radiotherapy (VMAT) for incurable head and neck cancer (HNC). Methods Thirty-four consecutive patients with HNC were treated with at least one cycle of the RTOG 8502 regimen. Treatment plans included the use of VMAT with 6 MV photons generated by a linear accelerator. Two daily fractions of 3.7 Gy were delivered with an interval of at least 6 h for 2 consecutive days, totaling 14.8 Gy over 4 fractions. This was repeated every 3–4 weeks for a total of three cycles. No concurrent systemic therapy was performed. Results The number of completed cycles was 1 in 6 (18%) patients, 2 in 5 (15%), and 3 in 23 (68%). Tumor response was achieved in 29 (85%) patients and symptom relief in 20 (77%) of 26 patients. Overall response (tumor response or symptom relief) was achieved in 32 (94%) patients. All patients who received 2 or more treatment cycles achieved overall response. Median overall survival (OS) was 5.7 months. Multivariate analysis revealed that completion of all three treatment cycles was significantly associated with better OS (P = 0.002). Grade 2 toxicity was observed in four (12%) patients, but no acute Grade ≥ 3 or late toxicity was observed. Conclusions The RTOG 8502 “QUAD shot” regimen using VMAT is effective for incurable HNC with highly reduced toxicity. Treatment with multiple cycles is recommended for better treatment response and/or survival.

BACKGROUND/AIM We evaluated the diagnostic value of functional imaging with [18F]-fluoro-2-deoxy-D-glucose (FDG)-positron emission tomography/computed tomography (PET/CT) for the identification of extranodal extension (ENE) in patients with head and neck squamous cell carcinoma (HNSCC). PATIENTS AND METHODS In this study, 94 patients with HNSCC who underwent FDG-PET/CT were enrolled. We recorded the maximum standardized uptake value (SUVmax), compared the results with pathologic findings, and evaluated the diagnostic performance of using a SUVmax cut-off value for ENE. RESULTS Of the 566 dissected levels examined, 53 (9.4%) exhibited ENE. The mean SUVmax of LN with and without ENE were 6.67 and 1.64, respectively (p

Background There is limited evidence concerning radiotherapy for painful lymph node metastases (PLM). We evaluated the effectiveness of radiotherapy for PLM using the International Consensus Endpoint in a subgroup analysis of a prospective observational study. Methods In the primary study, 302 patients received radiotherapy for painful tumors. Among them, those treated with palliative radiotherapy for PLM were analyzed in the present study. We used the Brief Pain Inventory short form to evaluate the intensity of pain and the pain interference in patient's life. We collected the Brief Pain Inventory and analgesic data at baseline and at 1, 2, and 3 months after the start of radiotherapy. Pain response was assessed using the International Consensus Endpoint. Patients were diagnosed with a predominance of other pain (POP) if non-index pain of a malignant or unknown origin was present and had a greater 'worst pain' score than the index pain. Results Radiotherapy for PLM was performed on 25 patients. In total, 15 (60%) patients experienced a pain response. The pain response rates for evaluable patients were 66%, 67%, and 57% at 1-, 2-, and 3-month follow-ups, respectively. At baseline and at 1, 2, and 3 months, the median index pain scores were 7, 2, 0, and 0.5, respectively. At 1 month, all pain interference scores were significantly reduced from baseline. Four (16%) patients experienced POP within three months. Conclusion Radiotherapy for PLM improved pain intensity and pain interference. Palliative radiotherapy may be a viable treatment option for PLM.

Background Reports on the treatment results of chemoradiotherapy (CRT) for T3 N0 glottic carcinoma without vocal cord fixation are limited. We retrospectively evaluated the efficacy and toxicity of concurrent chemoradiotherapy (CCRT) with docetaxel, cisplatin, and 5-fluorouracil (TPF) for T3 N0 glottic carcinoma without vocal cord fixation. Methods Twenty-five patients were treated with TPF-CCRT. The chemotherapy consisted one or two cycles of TPF as follows: docetaxil (50 mg/m2), cisplatin (60 mg/m2), and 5-FU (600 mg/m2/day for 5 days). RT was delivered with a once-daily fraction of 2 Gy without elective nodal irradiaion (ENI). After the RT of 40 Gy and one cycle of chemotherapy, five patients (20%) were judged as having no tumor regression and underwent surgery. The remaining 20 patients underwent RT with a median total dose of 66 Gy. Results Of the five patients who underwent surgery after the delivery of 40 Gy, two showed residual carcinoma pathologically and the other three were confirmed to have complete pathological response to the treatment. During the follow-up period after a series of therapies, one patient had local failure. None of the patients exhibited regional or distant failure. The 5-year local control, laryngeal preservation, and overall survival rates were 87%, 92%, and 95%, respectively. Neutropenia was frequently observed during the treatment but was manageable in all the cases. No acute toxicities of grade 5 or late toxicities ≥ grade 3 were observed. Conclusions In this study, TPF-CCRT provided excellent tumor control with acceptable toxicities. Intensive local treatment with CCRT while omitting ENI is a reasonable approach for T3 N0 glottic carcinoma without vocal cord fixation.

Palliative radiotherapy seems to be rarely performed for incurable gastric cancer. In this first multicenter study, we examined the effectiveness of palliative radiotherapy and investigated whether biologically effective dose (BED) is associated with survival, response, or re-bleeding. Eligibility criteria included blood transfusion or hemoglobin levels

Background/aim We compared three-dimensional conformal RT (3D-CRT), intensity-modulated radiotherapy (IMRT), and volumetric modulated arc therapy (VMAT) for gastric mucosa-associated lymphoid tissue (MALT) lymphoma using four-dimensional computed tomography (4D-CT) images. Patients and methods Three treatment plans of 3D-CRT, IMRT, and VMAT with 30 Gy were created based on 4D-CT images of seven patients. We calculated D95, homogeneity index (HI), and conformity index (CI) of planning target volume, and organs at risk doses. Results There was no significant difference among the three plans in D95. HI of the IMRT plan was significantly better than that of the VMAT (p=0.047) and 3D-CRT (p=0.047) plans. CIs of the IMRT and VMAT plans were significantly better than those of the 3D-CRT plan (p=0.047 and p=0.047, respectively). Dmean of the liver for 3D-CRT was significantly higher than that for the IMRT (p=0.047) and VMAT (p=0.047) plans. Conclusion The IMRT plan yields the best plan quality for gastric MALT lymphoma.

Background: Previous planning studies in radiotherapy (RT) for gastric mucosa-associated lymphoid tissue (MALT) lymphoma have been based on three-dimensional computed tomography (3D-CT) images, which do not contain information on the respiratory motion of the stomach. Therefore, we compared the plan quality between 3D conformal radiotherapy (3D-CRT), intensity-modulated radiotherapy (IMRT), and volumetric modulated arc therapy (VMAT) for gastric MALT lymphoma using four-dimensional computed tomography (4D-CT).Methods: Three different treatment plans of four-field 3D-CRT, seven-field IMRT, and double arc VMAT were created based on 4D-CT images of seven patients with gastric MALT lymphoma. An RT dose of 30 Gy was prescribed to the planning target volume (PTV) in 20 fractions. We calculated the minimum dose coverage for 95% of the PTV (D95), homogeneity index (HI), and conformity index (CI) of the PTV, and organs at risk (OARs) doses for the liver, kidneys, spinal cord, and small bowel. Plan quality metric (PQM) scores were also calculated for a comprehensive and objective assessment.Results: There was no significant difference among the three plans in D95 of PTV. HI of PTV for the IMRT plan was significantly better than that of the VMAT (p = 0.047) and 3D-CRT (p = 0.047) plans. HI of PTV for the VMAT plan was significantly better than that of the 3D-CRT plan (p = 0.047). CIs of PTV for the IMRT and VMAT plans were significantly better than that of the 3D-CRT plan (p = 0.047 and p = 0.047, respectively). Dmean of the liver for 3D-CRT was significantly higher than that for the IMRT (p = 0.047) and VMAT (p = 0.047) plans. The PQM scores of the VMAT and IMRT plans were significantly higher than that of the 3D-CRT plan (p = 0.047 and p = 0.047, respectively). The PQM score of the IMRT plan was significantly higher than that of the VMAT plan (p = 0.047).Conclusions: The IMRT plan yields the best plan quality for gastric MALT lymphoma. In terms of plan quality, as opposed to the 3D-CRT plan, we recommend the IMRT and VMAT plans.

PURPOSE/OBJECTIVE(S) In the largest prospective study to date, we examined the effectiveness of palliative radiation therapy for bleeding gastric cancer, and the association of the biologically effective dose (BED) with survival, bleeding response, or re-bleeding. MATERIALS/METHODS We recruited patients with incurable gastric cancer for whom palliative radiation therapy was planned. Eligibility criteria included blood transfusion or hemoglobin levels < 8.0 g/dL. The primary endpoint was the intention-to-treat (ITT) response rate at four weeks. Response entailed all of the following criteria: 1) hemoglobin levels ≥ 8.0 g/dL, 2) seven consecutive days from enrollment to blood sampling without blood transfusion, and 3) no salvage treatment (surgery, endoscopic treatment, transcatheter embolization, or reirradiation) for bleeding gastric cancer. Re-bleeding was defined as the need for blood transfusion or salvage treatment. Response was assessed at 2, 4, and 8 weeks after enrollment; re-bleeding was assessed monthly during the 6-month follow-up. Sample size was designed with the probability of obtaining a 90% confidence interval (CI) ≤ ± 15% being set at 0.8, assuming a per-protocol (PP) response rate of 70% at 4 weeks. RESULTS We enrolled 55 patients from 15 institutions. A median total radiation dose of 20 Gy (range, 8-45 Gy) was delivered in a median of five fractions. Of the 55 patients, 38 responded to treatment; of the 38 responders, 19 (50%) died and 12 (32%) experienced re-bleeding. The ITT response rates were 47%, 53% (95% CI, 39%-66%), and 49% at 2, 4, and 8 weeks, respectively. The PP response rates were 55%, 78%, and 90% at 2, 4, and 8 weeks, respectively. Restricted mean response and re-bleeding time up to 8 months were 2.3 months and 0.8 months, respectively. The median overall survival was 3.8 months (median follow-up, 12.1 months). The multivariable Cox model showed that neither response (a time-dependent covariate) (hazard ratio [HR], 1.04; 95% CI, 0.44-2.48) nor BED (alpha/beta = 10) (HR, 0.98; 95% CI, 0.95-1.02) were significant predictors of overall survival. The multivariable Fine-Gray model showed that BED was not a significant predictor of response (subdistribution HR, 1.02; 95% CI, 0.99-1.06). The univariable Cox model on transition hazard from response to re-bleeding showed that BED was not significantly associated with re-bleeding (HR, 0.98; 95% CI, 0.92-1.04). Grade 1, 2, 3, and ≥ 4 radiation-related adverse events were reported in 11, 9, 1, and 0 patients, respectively. CONCLUSION The PP bleeding response rate increased to 90% during the 8-week follow-up period. The frequent occurrence of death from shortly after enrollment lowered the ITT response rate and shortened the duration of response. BED was not significantly associated with survival, bleeding response, or re-bleeding.

Background Radiotherapy of gastric mucosa-associated lymphoid tissue (MALT) lymphoma should be delivered to the entire stomach with planning target volume (PTV) that accounts for variations in stomach volume, respiratory movement, and patient set-up error. In this study, we evaluated whether the use of four-dimensional cone-beam computed tomography (4D-CBCT) reduces the PTV. Methods Eight patients underwent radiotherapy with 15 fractions of gastric MALT lymphoma using 4D-CBCT. PTV structures of 5–30 mm margins (5 mm intervals) from the clinical target volume (CTV) delineated based on the 4D-CT images (CTV-4D) were generated. For the target localization, we performed matching based on skin marking (skin matching), bone anatomy (bone matching), and stomach anatomy (4D soft-tissue matching) based on registration between planning CT and 4D-CBCT images from 10 phases. For each patient, we calculated the covering ratio (CR) of the stomach with variable PTV structures, based on the 4D-CBCT images, with a total of 150 phases [CR (%) = (number of covering phases/150 phases) × 100], for three target localization methods. We compared the CR values of the different target localization methods and defined the PTV with an average CR of ≥ 95% for all patients. Results The average CR for all patients increased from 17.9 to 100%, 19.6 to 99.8%, and 33.8 to 100%, in the skin, bone, and 4D soft-tissue matchings, respectively, as the PTV structures increased from 5 to 30 mm. The CR obtained by 4D soft-tissue matching was superior to that obtained by skin (P = 0.013) and bone matching (P = 0.008) for a PTV structure of 15 mm margin. The PTV required an additional margin of 20 mm (average CR: 95.2%), 25 mm (average CR: 99.1%), and 15 mm (average CR: 98.0%) to CTV-4D for the skin, bone, and 4D soft-tissue matchings, respectively. Conclusions This study demonstrates that the use of 4D-CBCT reduces the PTV when applying 4D soft-tissue matching, compared to skin and bone matchings. Additionally, bone matching does not reduce the PTV as compared with traditional skin matching.

The influence of pre-radiotherapy pain duration on post-treatment outcomes was assessed. Patients that received palliative radiotherapy were analyzed in a prospective observational study investigating curative and palliative radiotherapy. Brief Pain Inventory data were acquired at baseline and 1, 2, and 3 months after commencing irradiation. The pain response in terms of the index pain (i.e., pain caused by the irradiated tumors) was assessed using the International Consensus Endpoint. Patients were diagnosed with predominance of other pain (POP) if non-index pain of malignant or unknown origin was present and showed a higher pain score than the index pain. Competing risk analyses were performed in which deaths without the pain endpoints were considered as competing events. Of 229 patients analyzed, 123 (54%) experienced a pain response and 43 (19%) experienced POP. Multivariable analyses using the Fine-Gray model revealed that patients with shorter pain duration (

Background: Radiotherapy of gastric mucosa-associated lymphoid tissue (MALT) lymphoma should be delivered to the whole stomach with optimal planning target volume (PTV) margins that account for variations in stomach volume, respiratory movement, and patient set-up error. In this study, we evaluated whether the use of four-dimensional cone-beam computed tomography (4D-CBCT) reduces the PTV margin.Methods: Eight patients underwent radiotherapy with 15 fractions of gastric MALT lymphoma using 4D-CBCT. Structures with PTV margins of 5–30 mm (5 mm intervals) from the internal target volume of the stomach defined based on the 4D-CT images were generated. For the target localization, we performed matching based on skin marking (skin matching), bone anatomy (bone matching), and stomach anatomy (4D soft-tissue matching) based on registration between planning CT and 4D-CBCT images from 10 phases. For each patient, we calculated the covering ratio (CR) of the stomach with variable PTV margins, based on the 4D-CBCT images, with a total of 150 phases [CR (%) = (number of covering phases / 150 phases) × 100], for three target localization methods. We compared the CR values of the different target localization methods and defined a minimal PTV margin with an average CR of ≥ 95 % for all patients as optimal.Results: The average CR for all patients increased from 17.9 % to 100 %, 19.6 % to 99.8 %, and 33.8 % to 100 %, in the skin, bone, and 4D soft-tissue matchings, respectively, as the PTV margins increased from 5 to 30 mm. The CR obtained by 4D soft-tissue matching was superior to that obtained by skin (P = 0.013) and bone matching (P = 0.008) for a PTV margin of 15 mm. The optimal PTV margins were 20 mm (average CR: 95.2 %), 25 mm (average CR: 99.1 %), and 15 mm (average CR: 98.0 %) for the skin, bone, and 4D soft-tissue matchings, respectively.Conclusions: This study demonstrates that the use of 4D-CBCT reduces the PTV margin when applying 4D soft-tissue matching, compared to skin and bone matchings. Additionally, bone matching does not reduce the PTV margin as compared with traditional skin matching.

Surgery with or without post-operative radiotherapy is the mainstay treatment for salivary gland carcinoma (SGC); however, palliative radiotherapy or supportive observation is considered for elderly patients. An 87-year-old female who was diagnosed with SGC in the left parotid gland, with a clinical stage T4aN2bM0 Stage IVA, underwent the Radiation Therapy Oncology Group 8502 “QUAD shot” regimen (14.8 Gy/4 fractions, twice-daily treatment with a 6 h interval, on 2 consecutive days), which were repeated every 4 weeks 3 times using volumetric modulated arc therapy. During and after the treatment, she experienced no acute toxicity but had Grade 1 xerostomia. At 4 months after completion of the treatment, [18F]-fluoro-2-deoxy-D-glucose positron emission tomography/CT revealed a complete metabolic response to the treatment. She is still alive without any evidence of recurrence 9 months after completion of the treatment. The Radiation Therapy Oncology Group 8502 “QUAD shot” regimen using VMAT may be an effective palliative treatment for SGC with minimal toxicity.

Background: To review a single institutional experience of the Radiation Therapy Oncology Group (RTOG) 8502 “QUAD shot” regimen using volumetric modulated arc radiotherapy (VMAT) for incurable head and neck cancer (HNC).Methods: Thirty-four consecutive patients with HNC were treated with at least one cycle of the RTOG 8502 regimen. Treatment plans included the use of VMAT with 6 MV photons generated by a linear accelerator. Two daily fractions of 3.7 Gy were delivered with an interval of at least 6 h for 2 consecutive days, totaling 14.8 Gy over 4 fractions. This was repeated every 3–4 weeks for a total of three cycles. No concurrent systemic therapy was performed.Results: The number of completed cycles was 1 in 6 (18%) patients, 2 in 5 (15%), and 3 in 23 (68%). Tumor response was achieved in 29 (85%) patients and symptom relief in 20 (77%) of 26 patients. Overall response (tumor response or symptom relief) was achieved in 32 (94%) patients. All patients who received 2 or more treatment cycles achieved overall response. Median overall survival (OS) was 5.7 months. Multivariate analysis revealed that completion of all three treatment cycles was significantly associated with better OS (P = 0.002). Grade 2 toxicity was observed in four (12%) patients, but no acute Grade ≥3 or late toxicity was observed.Conclusions: The RTOG 8502 “QUAD shot” regimen using VMAT is effective for incurable HNC with highly reduced toxicity. Treatment with multiple cycles is recommended for better treatment response and/or survival.

Background/aim To evaluate the utility of high spatial resolution digital positron emission tomography images with the source-to-background ratio (SBR) algorithm for gross tumour volume (GTV) delineation. Materials and methods The bowl and spheres (10-37 mm) were filled with fluoro-2-deoxy-D-glucose to achieve 4-16 times background radioactivity. The images were reconstructed using three isotropic voxel sizes. The SBR and percentage threshold (TH) to SUVmax were calculated. The plots between SBR and TH were fitted using a regression equation. The contoured volumes (CVs) of the spheres were calculated by applying TH. Results TH was 38.6+75.0/SBR for 4 mm voxel size; 39.6+37.0/SBR for 2 mm; and 38.8+35.2/SBR for 1 mm. The mean relative errors between CV and true volume for 4, 2, and 1 mm voxel sizes were 15%, 7%, and 7%, respectively. Conclusion The present technique is useful for GTV delineation with reduced contouring error.

Purpose Even when index pain (pain caused by the irradiated tumor) is palliated after radiation therapy (RT), patients may not derive the full benefits of RT in the presence of another, more intense pain. In this case-control study with prospectively collected data, we sought to identify predictors of the predominance of nonindex pain after palliative RT. Methods and Materials Brief Pain Inventory data were collected from patients who received RT for painful tumors. The treating radiation oncologists prospectively evaluated the intensity and origin of nonindex pain. Patients were diagnosed with predominance of other pain (POP) if nonindex pain of malignant or unknown origin was present and had a greater worst pain score than the index pain at the 1- or 2-month follow-up. Changes in pain interference from baseline to follow-up were compared between the 2 groups using Mann-Whitney U tests. Using variables that were identified as significant in a multivariable logistic regression analysis, we developed a prediction model for POP. Results Of the 170 patients who were evaluable at the 2-month follow-up, 24 (14%) were diagnosed with POP. At the 2-month follow-up examination of the patients with POP, none of the items of the pain interference scores were reduced from baseline; in contrast, patients without POP experienced significant reductions in all items. Multivariable analysis using the backward elimination method indicated that age ≤65 years, the presence of nonindex pain of malignant or unknown origin at baseline, and no opioid analgesic use at baseline were significant independent predictors of POP. As the number of the risk factors increased, the proportion of patients with POP increased. Conclusions We identified three predictors of POP. For patients likely to have POP, careful follow-up is important, and new palliative RT or analgesics should be used when needed.

Purpose: To evaluate the impact of 99mTc-labeled diethylene triamine pentaacetate-galactosyl human serum albumin (99mTc-GSA) single-photon emission computed tomography (SPECT) image-guided inverse planning on the dose–function histogram (DFH) parameters for stereotactic body radiation therapy planning in patients with hepatocellular carcinoma (HCC). Methods: Eleven patients were enrolled in this study. The functional liver structure (FLS) was derived from SPECT thresholds of 60% to 80% of the maximum pixel value. Two treatment plans optimized without FLS (plan C) and with FLS (plan F) were designed for 50 Gy to the planning target volume (PTV). The DFH parameters were calculated as follows: Fx = (sum of the counts within the liver volume receiving a dose >x Gy/sum of the counts within the whole liver volume) × 100. Other parameters for the PTV included D95, mean dose, conformity index (CI), and homogeneity index (HI). Results: Compared with plan C, plan F significantly reduced DFH parameters of F5 to F40 (P < .05). There were no significant differences in the parameters of the PTV of D95, mean dose, CI, and HI and organs at risks (stomach, duodenum, spinal cord, and kidneys) between plans C and F. Conclusion: DFH analyses revealed that 99mTc-GSA SPECT image-guided inverse planning provided dosimetric benefits related to sparing of liver function and may reduce hepatic toxicities.

Background We previously demonstrated that patients with painful hematologic tumors were more likely to experience pain response after palliative radiotherapy (RT) than those with painful solid tumors. However, it is unknown whether change in pain interference differs between these two tumor types. In the present study, we carried out a secondary analysis of our previous prospective observational study to investigate this matter. Methods From patients undergoing palliative RT to treat painful tumors, Brief Pain Inventory data were collected at the start of RT and at the 1-, 2-, and 3- month follow-ups. The Mann-Whitney U test was used to compare changes in pain interference score from baseline between the two groups. Results Of the 237 patients, 203 (86%) had solid and 34 (14%) had hematologic index tumors planned to receive RT. At baseline, the groups did not differ significantly in terms of pain score, analgesic use, or pain interference score. At the 1-, 2-, and 3-month follow-ups, the changes in pain interference score from baseline did not differ significantly between the two groups. In both groups, all seven pain interference items, other than sleep in patients with hematologic tumors at the 2-month follow-up, were significantly improved (P < 0.05). Conclusions The two groups showed comparable benefit from RT in terms of improvement in pain interference. Patients with tumor-related pain should be offered the option of palliative RT, irrespective of whether the painful tumor is solid or hematologic.

Aim: Our study sought to identify dosimetric predictors of treatment-related lymphopenia during chemoradiotherapy for esophageal cancer. Materials and Methods: Patients with esophageal cancer who had received definitive chemoradiotherapy at our Institution were retrospectively assessed. The absolute volume of the spleen, body, and bone marrow that had received 5, 10, 20, and 30 Gy and the mean splenic dose were recorded. Results: Multivariate linear regression analysis revealed that docetaxel use and spleen dose–volume parameters (V5, V10, V20, V30, and mean splenic dose) were significant independent factors negatively influencing the absolute lymphocyte count at nadir. An increase of 1 Gy in mean splenic dose predicted a 2.9% decrease in nadir absolute lymphocyte count. Univariable logistic regression analysis showed that the mean splenic dose was a significant predictor of grade 4 lymphopenia. None of the body or bone marrow dose–volume parameters significantly predicted lymphopenia. Conclusion: Higher spleen dose–volume parameters were associated with severe lymphopenia during chemoradiotherapy

BACKGROUND/AIM We evaluated the influence of previous treatments on the parametric discrepancies between dose-volume histograms (DVHs) and dose-function histograms (DFHs) generated based on 99mTc-GSA SPECT images of hepatocellular carcinoma (HCC) patients treated with stereotactic body radiation therapy (SBRT). PATIENTS AND METHODS Twelve patients underwent SBRT at 30-40 Gy. Registration between planning CT and SPECT/CT images was performed, and DFH parameters were calculated as follows: Fx=(sum of the counts within the liver volume receiving a dose of more than x Gy/sum of the counts within the whole liver volume) ×100. The discrepancy between Fx and Vx (Dx) was also calculated. RESULTS The number of previous treatments for lesions other than SBRT-treated lesions (≥2 vs.

We evaluated the influence of previous treatments on the parametric discrepancies between dose-volume histograms (DVHs) and dose-function histograms (DFHs) generated based onTwelve patients underwent SBRT at 30-40 Gy. Registration between planning CT and SPECT/CT images was performed, and DFH parameters were calculated as follows: Fx=(sum of the counts within the liver volume receiving a dose of more than x Gy/sum of the counts within the whole liver volume) ×100. The discrepancy between Fx and Vx (Dx) was also calculated.The number of previous treatments for lesions other than SBRT-treated lesions (≥2 vs.2) exhibited a significant influence on the absolute values of DPrevious treatment significantly influences the parametric discrepancy between DFH and DVH.

We describe a treatment method with four-dimensional cone-beam computed tomography (4D-CBCT)-guided radiotherapy for gastric lymphoma. We performed image-guided radiotherapy (IGRT) with 15 fractions for a gastric mucosa-associated lymphoid tissue lymphoma patient, using 4D-CBCT. The stomach was delineated based on 4D-CT images. For image guidance, an automatic registration between planning CT and 4D-CBCT images was performed based on the bony anatomy (bone matching), followed by manual registration based on the stomach in 4D-CBCT images of all 10 phases (4D matching). We calculated the covering ratio (CR) with variable stomach-to-planning target volume (PTV) margins, based on the images of all phases [CR (%) = the number of covering phases/all 150 phases × 100]. The patient underwent radiotherapy (RT) as scheduled, without any significant adverse effects. The appropriate PTV margins (CR ≥ 95%) were 25 mm (CR 99.3%) and 15 mm (CR 98.7%) for bone and 4D matching, respectively. 4D matching using 4D-CBCT is appropriate for IGRT of gastric lymphomas.

Purpose:To evaluate the impact of 99mTc-labeled diethylene triamine pentaacetate-galactosyl human serum albumin (99mTc-GSA) single-photon emission computed tomography (SPECT) image-guided inverse p...