Older patients with unresectable locally advanced non-small-cell lung cancer (NSCLC) frequently receive concurrent chemoradiotherapy (CCRT) with daily low-dose carboplatin; however, real-world data on its efficacy, safety, and prognostic factors remain limited. We aimed to retrospectively evaluate the clinical outcomes of this regimen and examined whether systemic inflammation-based indices predict prognosis in this setting. We reviewed 52 consecutive patients with locally advanced NSCLC treated with first-line CCRT using daily low-dose carboplatin at three Japanese institutions between April 2007 and December 2019. The median progression-free survival (PFS) and overall survival (OS) were 11.5 and 40.1 months, respectively. Twenty patients received durvalumab as consolidation therapy. In the overall cohort, multivariate analysis identified the Glasgow Prognostic Score (GPS) as an independent predictor of PFS. A GPS of 0-1 was also associated with a significantly longer OS in univariate analysis. CCRT with daily low-dose carboplatin provided durable disease control with acceptable toxicity in older patients with unresectable stage II/III NSCLC. The GPS appears to be a simple marker for PFS in this population and may aid in pretreatment risk stratification alongside histology and consolidation strategies.

Purpose:This study aimed to develop and evaluate a mixed reality-guided intraoperative visual support system for safe and accurate needle applicator insertion for combined intracavitary and interstitial brachytherapy (IC/IS-BT). Materials and Methods:A QR code was printed as a position and scale alignment reference when merging the real and virtual worlds. The QR code was positioned near the RANDO phantom, and MRI and CT scanning were performed. Treatment planning data, including the target and organs at risk structures and dose distribution from a cervical cancer patient who underwent brachytherapy, were attached to MRI and CT images of the RANDO phantom using a radiation treatment planning system and stored as DICOM data. DICOM data were then converted to object files (OBJ) that represent 3D shapes. These OBJ files were imported into the computer-generated virtual world, and the mixed reality application was built and executed on head-mounted displays (HMDs). Results:The system successfully merged the real and virtual worlds through the HMD, displaying 3D support data on the phantom. This system allows all HMD wearers to share 3D support data. Positions and scales between the real and virtual worlds are aligned using the upper left-hand corner of the QR code as the reference point, and the worlds are merged. Phantom-based evaluations demonstrated that projection errors measured by Operator A were 3.1 ± 1.1 mm in the anterior-posterior (A-P) direction and 2.6 ± 1.1 mm in the right-left (R-L) direction; corresponding projection errors for Operator B were 2.1 ± 1.4 mm in the A-P direction and 2.4 ± 1.1 mm in the R-L direction (n = 10 measurements per operator). The average frame rate was 69.7 ± 11.5 fps, corresponding to a latency of 14 msec. Conclusions:This report presents the system configuration, accuracy assessment and potential clinical applications for IC/IS-BT.

One of the most serious complications of cranial radiotherapy is the development of radiation-induced glioma, which is estimated to occur in 1%-4% of patients who have received cranial irradiation and has a worse prognosis than sporadic glioblastoma. Although comprehensive genetic analysis has recently uncovered the molecular characteristics of radiation-induced glioma, the full picture remains unclear due to its rarity. A 45-year-old man presented with generalized seizures caused by multiple brain tumors involving the right frontal lobe, thalamus, and brainstem. The patient had a history of whole-brain radiotherapy for recurrent Burkitt's lymphoma at the age of 12. He underwent craniotomy, and the histological diagnosis revealed a high-grade glioma with isocitrate dehydrogenase-wildtype, which was presumed to be a radiation-induced glioma that developed 33 years after whole-brain irradiation. Next-generation sequencing identified a CDKN2A/B deletion, as well as coamplification of several receptor tyrosine kinases-encoding genes, including PDGFRA, KIT, and KDR, all of which are located at 4q12. Amplification of this region is broadly observed across cancers and is associated with poor prognosis in sporadic glioblastoma. Nevertheless, the patient received chemoradiotherapy with temozolomide, followed by temozolomide maintenance therapy, resulting in a complete response of all lesions. Although radiation-induced gliomas are generally difficult to treat, our patient unexpectedly responded well to conventional chemoradiotherapy despite the coamplification of multiple receptor tyrosine kinases-encoding genes, which is typically suggestive of an aggressive phenotype. Our case indicates that some radiation-induced gliomas may have distinct molecular characteristics influencing the therapeutic response, which differ from those of sporadic glioblastomas.

BACKGROUND/AIM:Liver metastases are a major cause of cancer-related mortality and present significant therapeutic challenges. Chemotherapy is preferred for multiple metastases, while surgery or stereotactic body radiotherapy (SBRT) is used for solitary or few metastases, particularly in oligometastatic cases. This study aimed to evaluate the safety and efficacy of CyberKnife SBRT (CK-SBRT) for liver oligometastases. PATIENTS AND METHODS:This retrospective study analyzed patients with one to three liver metastases treated with CK-SBRT. The prescribed dose was typically 60 Gy in four fractions to 95% of the target volume, with reductions allowed if organ-at-risk (OAR) constraints could not be met. The local control (LC) and overall survival (OS) rates were estimated using the Kaplan-Meier method, and liver dose-volume parameters were assessed. RESULTS:A total of 39 liver lesions in 27 patients were treated. At a median follow-up of 17 months, the 1-year LC and OS rates were 90% and 80%, respectively. In patients receiving 60 Gy in four fractions, these rates were 95% and 86%. No severe liver toxicity or radiation-induced liver disease occurred. Most patients met liver dose constraints, with low liver V15 and mean liver dose values. CONCLUSION:CK-SBRT provides effective tumor control with minimal toxicity for liver oligometastases. Careful dose planning and adherence to OAR constraints are essential to minimize toxicity risks.

Overall survival (OS) among patients with limited-disease small-cell lung cancer (LD-SCLC) receiving chemoradiotherapy can be significantly influenced by subsequent treatments. Thus, the present study aimed to examine the interplay between progression-free survival (PFS), post-progression survival (PPS) and OS in patients with LD-SCLC undergoing chemoradiotherapy. This study retrospectively analyzed 84 patients with relapsed LD-SCLC who received chemoradiotherapy between April 2007 and June 2021. The correlations between PFS and OS as well as PPS and OS post-chemoradiotherapy were analyzed at the individual patient level. Spearman's rank correlation and linear regression analyses revealed a robust correlation between PPS and OS (r=0.76; P<0.05; R2=0.85). PFS was moderately correlated with OS (r=0.57; P<0.05; R2=0.25). Furthermore, the presence of liver metastases upon relapse and the administration of platinum re-challenge chemotherapy were significantly associated with PPS (P<0.05). The analysis of relationships between OS and PFS as well as OS and PPS in this patient cohort revealed that OS was more strongly correlated with PPS than PFS. These findings suggest that factors such as liver metastases at relapse and the administration of platinum re-challenge chemotherapy may influence PPS.

This retrospective claims analysis characterized contemporary ulcerative colitis (UC) treatment patterns and investigated the economic burden of UC in Japan. This study used anonymized claims data in the Medical Data Vision database. Patients were included if they had a confirmed UC diagnosis and ≥ 1 claim of systemic treatment for UC (index date) between June 2018 and December 2022, in addition to continuous enrollment for ≥ 6 months before and ≥ 12 months after the index date. Patients were excluded if they were aged < 18 years at index or if they had claimed systemic UC treatment during the pre-index period, had a confirmed diagnosis of Crohn’s or Behçet’s disease, or had a record of colectomy during the pre-index period. Outcomes of interest were treatment patterns, healthcare resource utilization (HCRU), and UC-related costs per person per month (PPPM). Further exploratory analyses were conducted to understand whether real-world treatment patterns with conventional therapy were optimally aligned with guideline recommendations. Two definitions of suboptimal treatment with conventional therapies were identified: prolonged treatment with corticosteroids (i.e., consecutive use for > 90 days) and corticosteroid cycling (i.e., three or more ≥ 30-day corticosteroid courses over 1 year, with a ≥ 60-day gap between courses). Overall, 15,429 patients were included. The most frequently observed class of first-line treatment was 5-aminosalicylic acid monotherapy (75.0

The purpose of this systematic review and meta-analysis was to evaluate the efficacy and safety of stereotactic body radiotherapy using CyberKnife (CK) for liver-confined hepatocellular carcinoma (HCC). A systematic review was performed on studies published between 2000 and 2024 that reported treatment outcomes including overall survival (OS), local control (LC), and complications. A literature search was performed using MEDLINE/PubMed with the following terms: ('Carcinoma, Hepatocellular'[MeSH Terms] OR 'hepatocellular carcinoma' OR 'HCC') AND ('CyberKnife' OR 'robotic radiosurgery'). Additional searches were conducted on Scopus and the Cochrane library using following terms: 'Hepatocellular carcinoma' AND 'CyberKnife.' A meta-analysis was performed to assess OS and LC using weighted random effects models. Five retrospective studies and one prospective study were included in the meta-analysis, comprising a total of 697 patients with a median follow-up duration was 31 months (range: 15-48 months). The pooled 3-year LC and OS rates were 82.5% (95% confidence interval [CI], 75.0%-90.0%) and 58.7% (95% CI, 47.2%-70.1%), respectively, which is comparable to previous reported outcomes for non-device-limited SBRT and similar to that of surgery and local ablative therapies. The incidence of radiation-induced liver disease was 4.3%-15.3%. Stereotactic body radiotherapy using CK appears to be an effective and well-tolerated treatment for liver-confined HCC. However, further prospective studies with standardized methodologies are warranted to establish solid evidence of its clinical utility.

Background: The standard treatment for patients in good general condition with limited-disease small cell lung cancer (LD-SCLC) is concurrent platinum/etoposide chemotherapy and thoracic radiotherapy (TRT). However, the efficacy and safety of chemoradiotherapy (CRT) in older patients with LD-SCLC has not been fully explored; moreover, the optimal treatment for this patient group remains unclear. This study aimed to investigate the feasibility and efficacy of CRT in older patients with LD-SCLC. Patients and methods: From April 2007 to June 2021, consecutive older patients (aged >= 75 years) with stage I to III SCLC who received concurrent or sequential CRT at two institutions were retrospectively evaluated for efficacy and toxicity of CRT. Results: A total of 32 older patients underwent concurrent (n = 19) or sequential (n = 13) CRT for LD-SCLC. The median ages of the patients in the concurrent and sequential CRT groups were 77 (range: 75-81) years and 79 (range: 76-92) years, respectively. The median number of chemotherapeutic treatment cycles was four (range, 1-5), and the response rate was 96.9% in all patients (94.7% in concurrent and 100% in sequential CRT groups). The median progression-free survival (PFS) and median overall survival (OS) for all patients were 11.9 and 21.1 months, respectively. The median PFS was 13.0 and 9.0 months in the concurrent CRT and sequential CRT groups, respectively, with no statistically significant difference (p = 0.67). The median OS from the initiation of CRT was 19.2 and 23.5 months in the concurrent and sequential CRT groups, respectively (p = 0.46). The frequencies of Grade >= 3 hematological adverse events were as follows: decreased white blood cell count, 20/32 (62.5%); decreased neutrophil count, 23/32 (71.9%); anemia, 6/32 (18.8%); decreased platelet count, 7/32 (21.9%); and febrile neutropenia, 3/32 (9.4%). Treatment-related deaths occurred in one patient from each group. Conclusions: Although hematological toxicities, particularly reduced neutrophil count, were severe, CRT showed favorable efficacy in both concurrent and sequential CRT groups. However, concurrent CRT may not be feasible for all older patients with LD-SCLC; accordingly, sequential CRT may be considered as a treatment of choice for these patients. Further prospective trials are warranted to identify optimal treatment strategies for this patient group.

BACKGROUND:End-to-end dosimetry audit for brachytherapy is challenging due to the steep dose gradient. However, it is an efficient method to detect unintended errors in actual clinical practice. PURPOSE:We aimed to develop an on-site end-to-end test phantom for three-dimensional image-guided brachytherapy (IGBT) for cervical cancer. METHODS:The test phantom we developed consisted of a water tank with an applicator/detector holder. The holder was designed to accommodate the applicator and insert an ionization chamber (PinPoint; PTW, Freiburg, Germany) to measure the dose at point A. Imaging and reconstruction were performed in the same way as performed for a patient. The feasibility of our test phantom was assessed in two different hospitals using tandem and ovoid (made of either metal or carbon) applicators that the hospitals provided. RESULTS:The measured and calculated doses at point A were compared for each applicator. We observed that the values obtained using metal applicators were consistently lower, on an average by -2.3%, than the calculated values, while those obtained using carbon applicators were comparable to the calculated values. This difference can be attributed to the attenuation of the dose by the metal applicators, resulting in a lower dose at point A. The majority of treatment planning system, including the one used in this study, do not account for the material of applicator. CONCLUSIONS:An end-to-end test phantom for IGBT was developed, tested, and applied in a dosimetry audit in hospitals and showed favorable results for evaluating the point A dose.

BACKGROUND:To evaluate the efficacy of a catheter system using a 3-Fr sheath with a steerable microcatheter through right upper limb artery access for superselective intra-arterial cisplatin infusion and concomitant radiotherapy (RADPLAT) to treat right maxillary sinus squamous cell carcinoma (MS-SCC). MATERIAL AND METHODS:We retrospectively studied 46 sessions in eight patients treated between November 2020 and February 2023 using the catheter system briefly described below. A 3-Fr sheath was inserted into the distal radial, conventional radial, or brachial arteries. A coaxial catheter system with a 2.9-Fr steerable microcatheter and a 1.9-Fr microcatheter was advanced into the brachiocephalic artery. The right common carotid artery was selected by bending the tip of the steerable microcatheter. Coil embolization and intra-arterial cisplatin infusion after selecting each external carotid artery branch were achieved using this catheter system. RESULTS:Cisplatin infusion and coil embolization were successful in all sessions. Arterial occlusion at the sheath insertion sites was found in 29.4% (5/17) of the distal radial arteries and 33.3% (3/9) of the conventional radial arteries. No other major complications were observed during the procedure. CONCLUSION:Using a 3-Fr catheter system with a steerable microcatheter through right upper limb artery access is a feasible method for RADPLAT in treating right MS-SCC.

Hospitalization for ulcerative colitis (UC) is potentially life-threatening. Severe disease in the Japanese criteria which modifies the Truelove–Witts’ criteria might encompass more fulminant cases than the definition for acute severe UC. However, few studies have investigated the predictive factors for clinical remission (CR) after medical treatments for severe hospitalized patients by Japanese criteria. Medical treatment selection, CR rates, and factors contributing to CR on day 14 were assessed in severe patients by Japanese criteria. We also investigated whether the reduction rate in patient-reported outcome 2 (PRO2) on day 3 could predict short-term prognosis. Eighty-five severe hospitalized patients were selected. Corticosteroids, tacrolimus, and infliximab were mainly selected as first-line treatments (76/85; 89.4

The incidence of neuroendocrine carcinomas arising from the bile duct is low, and that of mixed neuroendocrine-non-neuroendocrine neoplasms (MiNENs) is even lower; therefore, there is no standard treatment for MiNENs. Choosing the appropriate treatment in clinical practice is difficult. We herein report a case of unresectable extrahepatic bile duct MiNEN in a 66-year-old man who received curative chemoradiotherapy and achieved a complete response, remaining recurrence-free for 2.5 years. We consider the findings of this case to be valuable in selecting a treatment strategy for unresectable bile duct MiNENs.

Introduction: Established biomarkers for predicting chemoradiotherapy efficacy for limited-disease small cell lung cancer (LD-SCLC) are lacking. The inflammation-based Glasgow Prognostic Score (GPS), comprising serum C-reactive protein (CRP) and albumin levels, can predict survival in advanced cancer. This study investigated whether metabolic and inflammatory markers, including the GPS, can predict the efficacy of chemoradiotherapy in patients with LD-SCLC. Methods: We retrospectively analyzed 124 patients who underwent chemoradiotherapy for LD-SCLC at two institutions between April 2007 and June 2021, and assessed the prognostic significance of various metabolic and inflammatory markers. The GPS was calculated using the CRP and albumin concentrations, and categorized as follows: 0, CRP <1.0 mg/dL and albumin >= 3.5 mg/dL; 1, elevated CRP or decreased albumin; and 2, CRP >= 1.0 mg/dL and albumin<3.5 mg/dL. Differences in progression-free survival (PFS) and overall survival (OS) were examined using Kaplan-Meier curves and Cox proportional-hazard models. Results: The overall response rate was 95.1% (95% confidence interval [CI]: 89.6-97.9%). The median PFS and OS from chemoradiotherapy initiation were 12.6 (95% CI: 9.9-15.4) and 29.0 (95% CI: 24.8-45.5) months, respectively. The GPS demonstrated independent predictive ability for the effectiveness of chemoradiotherapy, wherein favorable scores (GPS 0-1) were significantly correlated with superior PFS and OS compared to unfavorable scores (GPS 2: PFS: 14.8 vs. 6.7 months, p = 0.0001; OS: 35.4 vs. 11.0 months, p < 0.0001). Conclusion: This preliminary examination revealed that the GPS was significantly associated with PFS and OS in patients undergoing chemoradiotherapy for LD-SCLC, indicating its potential utility in assessing the therapeutic outcomes in LD-SCLC.

BACKGROUND AND AIM:The PillCam patency capsule (PC) without a radio frequency identification tag was released to preclude retention of the small bowel capsule endoscope (CE) in Japan in 2012. We conducted a multicenter study to determine tag-less PC-related adverse events (AEs).METHODS:We first conducted a retrospective survey using a standardized data collection sheet for the clinical characteristics of PC-related AEs among 1096 patients collected in a prospective survey conducted between January 2013 and May 2014 (Cohort 1). Next, we retrospectively investigated additional AEs that occurred before and after Cohort 1 within the period June 2012 and December 2014 among 1482 patients (Cohort 2).RESULTS:Of the 2578 patients who underwent PC examinations from both cohorts, 74 AEs occurred among 61 patients (2.37%). The main AEs were residual parylene coating in 25 events (0.97%), PC-induced small bowel obstruction, suspicious of impaction, in 23 events (0.89%), and CE retention even after patency confirmation in 10 events (0.39%). Residual parylene coating was significantly associated with Crohn's disease (P < 0.01). Small bowel obstruction was significantly associated with physicians with less than 1 year of experience handling the PC and previous history of postprandial abdominal pain (P < 0.01 and P < 0.03, respectively). CE retention was ascribed to erroneous judgment of PC localization in all cases.CONCLUSIONS:This large-scale multicenter study provides evidence supporting the safety and efficiency of a PC to preclude CE retention. Accurate PC localization in patients without excretion and confirmation of previous history of postprandial abdominal pain before PC examinations is warranted (UMIN000010513).

BACKGROUND/AIM:Concurrent cisplatin-based chemoradiotherapy (CCRT) is the standard treatment for locally advanced cervical cancer. Especially, CCRT with magnetic resonance imaging (MRI) or computed tomography-based image-guided brachytherapy (CT-based 3D-IGBT) for cervical cancer has resulted in good LC rates. However, progression-free survival (PFS) and overall survival (OS) rates for locally advanced cervical cancer are still low and could be improved. The aim of the study was to evaluate treatment efficacy and late toxicity of external beam radiotherapy (EBRT) and CT-based IGBT with or without concurrent chemotherapy in patients with squamous cell carcinoma of the uterine cervix and investigate patterns of failure.PATIENTS AND METHODS:We retrospectively analyzed clinical data of cervical squamous cell carcinoma patients treated with definitive radiotherapy with or without concurrent chemotherapy at Saitama Medical University International Medical Center. Local control (LC), PFS, patterns of failure, and late toxicity were the evaluated outcomes.RESULTS:Overall, 290 patients were enrolled in the study. Median follow-up was 51.5 months. During follow-up, 74 patients developed recurrence: 10 patients with intra-pelvic failure only, 45 with extra-pelvic failure only, and 19 with both. The 3-year LC was 100% for T1b-T2a, 96.8% for T2b, 89.5% for T3b, and 88.5% for T4 disease. The 3-year PFS was 100% for stage IB-IIA, 89.0% for stage IIB, 70.7% for stage IIIB, 72.6% for stage IIIC1r, and 40.1% for stage IVA. The incidence of grade 3-4 gastrointestinal and genitourinary toxicities was 3.0% and 1.7%, respectively.CONCLUSION:Combination of EBRT and CT-based IGBT with or without concurrent chemotherapy produced favorable LC with acceptable rates of late toxicities. However, extra-pelvic failures frequently occurred and PFS was less satisfactory in patients with stage III-IVA disease, which indicated the need for additional treatment in these patients.

Purpose Cases of adenocarcinoma of the uterine cervix (AUC) have poorer prognoses than those of squamous cell carcinoma. Carbon-ion radiation therapy (CIRT) outcomes for AUC have been reported in retrospective or single-institutional prospective studies but not prospective multicenter studies. We present the results of CIRT for AUC in a prospective multicenter study using a nationwide hospital-based registry in Japan. Methods and Materials Patients with locally advanced untreated AUC who received CIRT at 4 Japanese centers between June 2016 and April 2020 were included in this study. In the absence of organ dysfunction, up to 5 weekly 40 mg/m2 cisplatin courses were administered. The primary endpoints were 2-year overall survival and local control rates. The secondary endpoints were 2-year disease-free survival rate and late adverse events (AEs). Results Forty-two patients were enrolled with a median age of 54 years (range, 34-76 years). Patients were diagnosed with stage IIB (n = 26), IIIB (n = 12), or IVA (n = 4) disease. The median follow-up period was 24 months. The 2-year overall survival, local control, and disease-free survival rates were 97.5% (95% CI, 92.7%-100.0%), 80.9% (95% CI, 66.9%-94.8%), and 64.3% (48.1%-80.4%), respectively. Two patients developed grade 3 rectum/sigmoid AE. One patient required urinary diversion surgery during a salvage operation for local tumor recurrence (grade 3 genitourinary AE). No other grade 3 or worse toxicities were reported. Conclusion CIRT is an effective treatment for locally advanced AUC. Further research is required to validate the safety and efficacy of CIRT for AUC.

Background This multicenter observational cohort study aimed to evaluate the utilization and short-term efficacy of advanced therapy (AT) in hospitalized patients with acute severe ulcerative colitis (ASUC).Methods In total, 221 patients with ASUC were enrolled between August 2020 and July 2021. The primary endpoint was clinical remission (CR, defined as a patient-reported outcome score < 2 with no blood in the stool) rate on Day 7 and 14 in hospitalized patients who received corticosteroids (CS) and AT.Results Among patients with ASUC, 120 and 101 patients received CS or any AT as first-line treatment, respectively. The CR rates on Day 7 and 14 were 22.5% and 35.0%, respectively, in hospitalized patients who received CS as first-line treatment. Most patients who used ATs had CS-dependent or frequent recurrences. Eight different ATs (apheresis, tacrolimus, infliximab, golimumab, tofacitinib, vedolizumab, ustekinumab, and cyclosporine) were used as first-line treatment in patients with ASUC, and the CR rates on Day 7 and 14 were 16.8% and 29.7%, respectively. Twenty-five patients received the second ATs after hospitalizations, and the CR rates on Day 7 and 14 were 0% and 12%, respectively. The CR rates on Day 14 were significantly higher in patients who changed to AT than in those whose dose of CS increased (34.0% vs 10.7%, p = 0.020) among patients who had already used CS before hospitalization.Conclusion Most first-use ATs were effective for patients with ASUC, while second-use ATs might have had limited benefits in inducing CR. These findings may contribute to considerations for the management of hospitalized patients.

Background/Aim: Combined intracavitary and interstitial brachytherapy (IC/IS-BT) is an effective treatment for extensive and bulky cervical cancer. However, the optimum number of interstitial needle applicators (“needles”) inserted in IC/IS-BT can be difficult to determine. To examine the number of needles required for adequate dose coverage of cervical tumors, we retrospectively analyzed IC/IS-BT plans. Patients and Methods: IC/IS-BT plans for cervical cancer patients treated from January 2014 to January 2021 were analyzed. All tumors were controlled locally at the time of analysis (August 2022). The relationship between the number of needles and several volumetric parameters of high-risk clinical target volume (CTVHR) were analyzed, including maximum diameter, maximum cross-sectional area, and the volume of CTVHR. Spearman’s rank correlation coefficients (r) were used to evaluate correlations. Results: Eighty-two plans in 32 patients were analyzed. The median maximum cross-sectional area and volume of CTVHR were 18.9 (12.3-42.5) cm2 and 53.8 (30.1-152.2) cm3, respectively. The mean D90% and D98% of CTVHR at each BT session were 7.0±0.8 Gy and 5.9±0.8 Gy, respectively. There was a positive correlation between the number of needles and the maximum cross-sectional area of CTVHR (r=0.53). The average numbers of needles were 1.3, 1.9, 2.2, 3.1, and 4.0 when the maximum cross-sectional area of CTVHR were ≤15 cm2, 15-20 cm2, 20-25 cm2, 25-30 cm2, and >30 cm2, respectively. Conclusion: The optimal number of needles can be determined from the maximum cross-sectional area of CTVHR.