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In CT-guided percutaneous punctures—an image-guided puncture method using CT images—physicians treat targets such as lung tumors, liver tumors, renal tumors, and intervertebral abscesses by inserting a puncture needle into the body from the exterior while viewing images. By recognizing two-dimensional CT images prior to a procedure, a physician determines the least invasive puncture route for the patient. Therefore, the candidate puncture route is limited to a two-dimensional region along the cross section of the human body. In this paper, we aim to construct a three-dimensional puncture space based on multiple two-dimensional CT images to search for a safer and shorter puncture route for a given patient. If all puncture routes starting from a target in the three-dimensional space were examined from all directions (the brute-force method), the processing time to derive the puncture route would be very long. We propose a more efficient method for three-dimensional puncture route selection in CT-guided percutaneous punctures. The proposed method extends the ray-tracing method, which quickly derives a line segment from a given start point to an end point on a two-dimensional plane, and applies it to three-dimensional space. During actual puncture route selection, a physician can use CT images to derive a three-dimensional puncture route that is safe for the patient and minimizes the puncture time. The main novelty is that we propose a method for deriving a three-dimensional puncture route within the allowed time in an actual puncture. The main goal is for physicians to select the puncture route they will use in the actual surgery from among the multiple three-dimensional puncture route candidates derived using the proposed method. The proposed method derives a three-dimensional puncture route within the allowed time in an actual puncture. Physicians can use the proposed method to derive a new puncture route, reducing the burden on patients and improving physician skills. In the evaluation results of a computer simulation, for a 3D CT image created by combining 170 two-dimensional CT images, the processing time for deriving the puncture route using the proposed method was approximately 59.4 s. The shortest length of the puncture route from the starting point to the target was between 20 mm and 22 mm. The search time for a three-dimensional human body consisting of 15 CT images was 4.77 s for the proposed method and 2599.0 s for a brute-force method. In a questionnaire, physicians who actually perform puncture treatments evaluated the candidate puncture routes derived by the proposed method. We confirmed that physicians could actually use these candidates as a puncture route. [ABSTRACT FROM AUTHOR]

This study assessed the significance of hands-on-training (HoT) and questionnaire-based surveys on 3D image-guided brachytherapy (3D-IGBT) and a combination of intracavitary and interstitial brachytherapy, the so-called 'hybrid' BT (HBT), in uterine cervical cancer. In October 2023, 29 radiation oncologists, nurses, radiologic technologists and medical physicists from 10 Japanese facilities participated in an HoT on 3D-IGBT and HBT. Questionnaires were distributed to each participant before and after the HoT, and feedback was obtained through online channels. The questionnaire response rate was 83% (24/29), with at least one participant responding from each facility. 'Insertion of applicators and needles', 'human resource shortage' and 'pain relief and sedation' were the primary concerns of radiation oncologists. 'Applicator reconstruction', ' optimization of dwell positions', ' treatment planning' and ' human resource shortages ' were the primary concerns of radiological technologists and medical physicists. The HoT content was adjusted according to the results of preliminary surveys. The concerns expressed by the participants were addressed during the lectures and practical training. Significant reductions in anxiety were observed toward all items of the 10-point self-assessment after the HoT, regardless of the profession. The average score on satisfaction with the HoT (on a 10-point scale) was 9.52 (minimum of 8 and maximum of 10). In conclusion, HoT tailored in response to a pre-questionnaire-based survey effectively reduced participants' anxiety regarding the implementation of 3D-IGBT and HBT. [ABSTRACT FROM AUTHOR]

Objective: We developed fiducial imaging‐guidance markers for the prostate with less imaging artifacts than currently commercially available markers. The aim of this study was to evaluate the imaging artifacts and potential usefulness and safety of these novel fiducial imaging markers in preclinical experiments. Methods: We selected specific metal materials and a shape that can minimize artifacts in line with a license we obtained for a metal with a gold‐platinum (Au‐Pt) alloy composition that maximized artifact‐free MRI images. Both phantom and canine prostate tests were conducted in order to evaluate the imaging artifacts for three imaging modalities, MRI, CT and ultrasound, and the risk of migration of the markers from the site of insertion to elsewhere, as well as crushing. Results: The newly developed Au‐Pt material had less imaging artifacts in the MRI, CT and ultrasound imaging modalities in comparison with current commercially available fiducial markers made from gold materials only. The Au‐Pt markers had sufficient strength and durability and were considered to be potentially clinically useful and safe markers. Conclusion: The developed Au‐Pt markers could be potential tools for accurate lesion‐targeted, organ‐preserving therapies such as lesion‐targeted focal therapy and active surveillance in addition to conventional radiation therapies. [ABSTRACT FROM AUTHOR]

This study aimed to assess the current state of brachytherapy (BT) resources, practices and resident education in Japan. A nationwide survey was undertaken encompassing 177 establishments facilitating BT in 2022. Questionnaires were disseminated to each BT center, and feedback through online channels or postal correspondence was obtained. The questionnaire response rate was 90% (159/177), and every prefecture had a response in at least one center. The number of centers in each prefecture ranged from 0.6 to 3.6 (median: 1.3) per million population. The annual number of patients in each center ranged from 0 to 272 (median: 31). While most prefectures provided intracavitary (IC) BT for gynecological cancers and interstitial (IS) BT for prostate cancer, only one-third of the prefectures provided IS BT for cancer sites other than the prostate. The institutional image-guided BT implementation rate was 71%. IC and IS BT was performed for 15.4% of IC BT cases of gynecological cancer. Only 47% of the BT training centers answered that they could provide adequate training in BT for residents. The most common reason for this finding was the insufficient number of patients in each center. The results show that, although BT has achieved uniformity in terms of facility penetration, new technologies are not yet widespread enough. Furthermore, IS BT, which requires advanced skills, is limited to a few BT centers, and considerable number of BT training centers do not have sufficient caseloads to provide the necessary experience for their residents. [ABSTRACT FROM AUTHOR]

Simple Summary: NCCN risk classifications for prostate cancer do not include elevated initial PSA levels as a single very-high-risk factor. However, an ultra-high initial PSA level (>50 ng/mL) showed a similar hazard ratio in the biochemical disease-free survival rate and the distant metastasis-free survival rate to the other single very-high-risk factors of T3b–4 and a Gleason score of 9–10. Therefore, an ultra-high initial PSA level has the potential to be a single very-high-risk factor for localized prostate cancer. To examine the impact of ultra-high iPSA levels of >50 ng/mL (uhPSA) after modern radiotherapy, we compared outcomes of 214 patients with uhPSA levels to 1161 other high-risk patients. Radiotherapy included brachytherapy ± external beam radiotherapy (EBRT) and EBRT alone (intensity-modulated radiotherapy or stereotactic body radiotherapy). The biochemical disease-free survival rate (bDFS), the distant metastasis-free survival rate (DMFS), local control, and pelvic lymph node control were analyzed. Patients with uhPSA levels had an inferior bDFS (84.8% at 5 years) and DMFS (93.9% at 5 years) compared to other high-risk patients (92.7% and 97.2%, both p < 0.001). The uhPSA group showed more distant metastases than the non-uhPSA group; however, the frequencies of local failure and pelvic lymph node recurrence were similar. The uhPSA group demonstrated hazard ratios (HRs) of 2.74 for bDFS and 2.71 for DMFS, similar to those of T3b–4 (HR 2.805 and 2.678 for bDFS and DMFS) and GS 9–10 (HR 2.280 and 2.743 for bDFS and DMFS). An uhPSA level could be a candidate for a single VHR factor to identify high-risk patients who require intensified treatment. [ABSTRACT FROM AUTHOR]

Simple Summary: In general, brachytherapy (BT) improves biochemical control in intermediate-to high-risk prostate cancer. We previously reported that importance of very high-risk factors (VHR: T3b–4 or Gleason score 9–10) and patients with double VHR (VHR-2) showed the worst prognosis among high-risk groups. We explored the role of BT-boost in patients with VHR and compared it to intermediate- and other high-risk groups. We confirmed that BT-boost improved prostate-specific antigen (PSA) control but resulted in equivalent overall survival rates for the intermediate- and high-risk groups, except for the patients with VHR. In the VHR-1 group (single VHR), BT-boost showed superior PSA control to conventional-dose RT (EQD2 ≤ 72 Gy) but not to the dose-escalated radiotherapy group (EQD2 ≥ 74 Gy). In the VHR-2 group, BT-boost did not improve the biochemical control rate of either Conv RT or DeRT. BT-boost showed no benefit over modern DeRT in the patients with VHR. This study examined the role of brachytherapy boost (BT-boost) and external beam radiotherapy (EBRT) in intermediate- to high-risk prostate cancer, especially in patients with very high-risk factors (VHR: T3b–4 or Gleason score 9–10) as patients with double very high-risk factors (VHR-2: T3b–4 and Gleason score 9–10) previously showed worst prognosis in localized prostate cancer. We retrospectively reviewed multi-institutional data of 1961 patients that were administered radiotherapy (1091 BT-boost and 872 EBRT: 593 conventional-dose RT (Conv RT: equivalent to doses of 2 Gy per fraction = EQD2 ≤ 72 Gy) and 216 dose-escalating RT (DeRT = EQD2 ≥ 74 Gy). We found that BT-boost improved PSA control and provided an equivalent overall survival rate in the intermediate- and high-risk groups, except for patients within the VHR factor group. In the VHR-1 group (single VHR), BT-boost showed a superior biochemical control rate to the Conv RT group but not to the DeRT group. In the VHR-2 group, BT-boost did not improve outcomes of either Conv RT or DeRT groups. In conclusion, BT-boost showed no benefit to modern DeRT in the patients with VHR; therefore, they are not good candidates for BT-boost to improve outcome and may be amenable to clinical trials using multimodal intensified systemic treatments. [ABSTRACT FROM AUTHOR]

It has been postulated that the combination of intracavitary and interstitial brachytherapy (IC/IS) is effective and safe for large and irregularly shaped uterine cervical cancer patients. However, due to its invasiveness compared to conventional intracavitary brachytherapy (ICBT), it has to be said that the implementation speed of IC/IS is slow. Until now, there have been no guidelines for required equipment, human resources, and procedural guide focusing solely on IC/IS. The purpose of this guideline is to provide radiation oncologists and medical physicists who wish to start IC/IS with practical and comprehensive guidance for a safe IC/IS introduction and to help accelerate the spread of the utilization of IC/IS nationwide. This is the English translation of the Japanese IC/IS Guidelines, and it was created in an effort to share the Japanese approach to the management of locally advanced uterine cervical cancer worldwide. [ABSTRACT FROM AUTHOR]

Prostate squamous cell carcinoma (pSCC) rarely develops as a secondary cancer after treatment with low-dose-rate brachytherapy (LDR-BT). There is no established effective treatment for the disease condition. Herein, we present a 78-year-old man who developed pSCC 8 years after LDR-BT. He was subsequently selected to receive a combined multimodal treatment with high-dose-rate interstitial brachytherapy (HDR-ISBT), external beam radiation therapy, and chemotherapy for his pSCC. Eleven months later, he displayed no biochemical failure nor clinical radiographic recurrence. However, MRI detected a newly developed prostatic-rectal fistula (grade 4), and a colostomy was performed to relieve pain and inflammation. To our knowledge, this is the first report to perform a combined multimodal treatment with HDR-ISBT for pSCC suspected as a secondary cancer due to LDR-BT. [ABSTRACT FROM AUTHOR]

The present study aimed to report the efficacy and toxicity of our high-dose-rate (HDR) brachytherapy for early stage lip cancer (LC) using customized dental spacers. A retrospective analysis was performed among six patients with early stage LC treated with HDR interstitial brachytherapy between April 2015 and August 2019 using customized dental spacers. The total treatment dose was 49 Gy/7 fractions or 54 Gy/9 fractions. The median follow-up duration for the patients was 13 (range: 2–52) months. All patients completed the entire brachytherapy protocol safely and have experienced no local recurrence thus far. The CTV D100 and D90 values per fraction were median 100 (range: 98.3–100) % prescribed dose (PD) and median 133.4 (range: 129.3–138.9) % PD, respectively. The D2cc and D0.1cc values per fraction for the mandible were median 1.07 (range, 0.79–1.88) Gy and median 1.65 (range: 1.21–2.83) Gy, D2cc and D0.1cc values per fraction for oral cavity were median 1.48 (range, 1.31–1.72) Gy and median 2.73 (range: 1.79–2.88) Gy, respectively. Acute toxicities encountered were mucositis and lip edema limited to the irradiated area; none of them was beyond grade 2 and all were resolved within 1–2 months after treatment. We did not observe any late grade 2 adverse events or worse. This study shows that the adverse effects of HDR brachytherapy for early stage LC can be minimized using a dental spacer. Cooperation with the dentistry department is essential to make spacers that are individually customized for each patient. [ABSTRACT FROM AUTHOR]

Objective: To examine the effect of permanent salvage brachytherapy in prostate cancer patients suffering recurrence after three‐dimensional conformal external beam radiotherapy. Methods: The ultra‐focal (target lesion alone), hemi‐lobe (within a hemi‐lobe) or focused whole‐gland (focusing on the lesion, but extending into the whole gland) pattern was selected based on the Gleason score for the targeted biopsy, the numbers of positive cores in the targeted and systematic biopsies, and the locations of the positive cores. Novel dosimetry criteria derived from three‐dimensional cancer mapping, which was based on targeted magnetic resonance imaging/transrectal ultrasound fusion biopsies, were used in these cases. Results: Permanent salvage brachytherapy was carried out in 13 patients who suffered prostate‐specific antigen failure (prostate‐specific antigen 2.1–6.8 ng/mL; age range 57–75 years; Gleason score ≤7 [n = 10], Gleason score ≥8 [n = 2] and Gleason score not available [n = 1]) since 2012. The targeted biopsy showed a single focus in three patients. The ultra‐focal, hemi‐lobe and focused whole‐gland patterns were chosen in three, five and five patients, respectively. During the follow‐up period (median duration 48 months), prostate‐specific antigen failure occurred in zero of three, one of five and three of five of the patients treated with the ultra‐focal, hemi‐lobe and focused whole‐gland patterns, respectively. The 4‐year biochemical recurrence‐free survival rate was 74%. No grade 3–4 adverse intestinal or urological events occurred. Conclusions: Targeted fusion biopsy‐based three‐dimensional cancer mapping should be used for permanent salvage brachytherapy treatment planning to reduce the incidence of treatment‐related adverse events while maintaining good oncological outcomes. [ABSTRACT FROM AUTHOR]

Perirectal hyaluronate gel injection (HGI) appears to be a promising technique for healthy tissue dose sparing in pelvic radiotherapy. In this analysis, we report our initial experience of HGI in gynecologic brachytherapy, focusing on its safety and effectiveness for dose reduction to the rectum. Between July 2013 and May 2014, 36 patients received HGI for primary/salvage gynecologic brachytherapy. Dosimetric effect analysis was based on pre- and post-HGI computed tomography dataset registration with corresponding dose–volume histogram evaluation. The maximum dose to the most exposed 0.1 cm3 (D0.1cm3) and 2.0 cm3 (D2.0cm3) were used as index values for rectum and bladder dose evaluation. The dose indexes for target volume (TV) coverage were TV D90/V100. In all cases, HGI was well tolerated, with no acute or late adverse events documented at a median follow-up of 220 days (range, 18–1046 days). Rectum D2.0cm3 and D0.1cm3 were significantly decreased by HGI (P < 0.001 and P = 0.003, respectively), with no significant impact on dosimetric parameters of bladder and TV coverage. Factors correlating negatively with the dosimetric effect of HGI were an increasing number of interstitial catheters (P = 0.003) as well as Lcranial100% (P = 0.014) and Lcranial80% (P = 0.001) [i.e. the length from the anal verge to the most cranial point at which the 100% and 80% isodose lines, respectively, crossed the rectum]. The concept of HGI for gynecologic brachytherapy is plausible, and our initial experience indicates it to be an effective technique for rectal dose reduction in radiotherapy of intrapelvic tumours. [ABSTRACT FROM AUTHOR]

Real-time fluoroscopic verification of the active source position during actual treatment is the only established method to prevent high-dose-rate (HDR) brachytherapy events. The challenge is spurious signals from an HDR 192Ir source that result in image halation, making source positions indiscernible when using a non-modified image intensifier fluoroscope. We have previously reported a method for observing an HDR 192Ir source by using an elaborately modified image intensifier system. The newly developed flat-panel detector fluoroscope is, by contrast, inherently halation-free thanks to the wider dynamic range (12–14 bits), compared with image intensifier fluoroscopes (8 bits). To explore the feasibility, we applied a commercially available flat-panel detector fluoroscope without modification to actual treatment. We successfully observed source positions without halation for all 107 patients, with a total of 522 HDR treatment sessions during a 3-year period from 2014 to 2017. Actual source positions were compared with planned positions on the planning hard copy. With this method, we detected a total of 1 error (0.2%) among the 522 sessions, at a similar detection rate of 0.1% with our previous experience using a modified image intensifier fluoroscope. We found that a commercially available flat-panel detector fluoroscope is ready for use for real-time verification and outweighs the need for elaborate modifications of an image intensifier fluoroscope. A flat-panel detector fluoroscope will help the global radiation oncology community promote real-time verification programs, leading to safer HDR brachytherapy. [ABSTRACT FROM AUTHOR]

The present study aimed to describe the clinical results of re-irradiation (Re-RT) for spine or pelvic bone metastasis at the same initial irradiated area. Between April 2010 and March 2014, cases involving 98 patients with spine or pelvic bone metastasis who had undergone Re-RT at five institutions were reviewed. The clinical outcomes following Re-RT were evaluated, including overall survival (OS) and severe adverse events. The median time interval from initial radiation therapy (RT) to Re-RT was 439 days (range, 23-4,993 days), and the median duration of patient follow-up was 256 days (range, 11-2,284 days). The median biological effective dose for the Re-RT was 150 Gy2 (range, 17-240 Gy2; α/β = 2). Severe late adverse events occurred in two patients who underwent three-dimensional conformal radiotherapy for lumbar spine or pelvic bone metastases, which may be associated with tumor progression. The median survival time following Re-RT was 255 days, and the actuarial OS rate at 1 year was 36%. The interval between initial RT and Re-RT, and their performance statuses (PS) were significant independent prognostic factors for OS rates in multivariate analysis. Re-RT for spine or pelvic bone metastases is a relatively acceptable option with low risk of anticipated severe adverse events, particularly for patients with good PS following a long disease-free interval. [ABSTRACT FROM AUTHOR]