High Dose Rate Brachytherapy Research Articles

2155: Development of an independent calculation program for plan verification in HDR brachytherapy

2155: Development of an independent calculation program for plan verification in HDR brachytherapy

1161: HDR brachytherapy as monotherapy for prostate cancer: comparison of two fractionation schedules

1161: HDR brachytherapy as monotherapy for prostate cancer: comparison of two fractionation schedules

198: Single-insertion with four sessions high dose rate brachytherapy for advanced cervical cancer

198: Single-insertion with four sessions high dose rate brachytherapy for advanced cervical cancer

527: A novel integrated measure of cervical HDR brachytherapy plan quality

527: A novel integrated measure of cervical HDR brachytherapy plan quality

2605: HDR brachytherapy boost plus EBRT in unfavorable prostate cancer: results in more then 700 patients

2605: HDR brachytherapy boost plus EBRT in unfavorable prostate cancer: results in more then 700 patients

Robotic MR-guided high dose rate brachytherapy needle implantation in the prostate (ROBiNSon)—a proof-of-concept study

Objective. A robotic needle implant device for MR-guided high-dose-rate (HDR) prostate brachytherapy was developed. This study aimed to assess the feasibility and spatial accuracy of HDR brachytherapy using the robotic device, for a single intraprostatic target point. Approach. Five patients were treated from November 2019–June 2022 with the robot. The robot fits a 1.5 T MR scanner and the needle can be shifted and angulated. An intraprocedural MR scan was fused with the diagnostic MR and one preplanned needle position was selected for robotic insertion. The needle entry point and angles were set for a needle tip target point within the intraprostatic target volume. The needle was tapped stepwise towards the target point pneumatically. Final needle position was verified with MR, followed by plan optimization and dose delivery. Any remaining planned needles were inserted manually. Needle tip to geometrical target error (NTG-error) was defined as the deviation of the actual tip position relative to the predefined geometric target point, using MR-coordinates. Needle tip to treatment target error (NTT-error) was defined as the deviation of the actual tip position relative to the treatment target point, using fused MR-images pre- and post-needle implantation taking into account prostate deformation. Difference between NTT-error and NTG-error and fiducial marker shifts indicated prostate movement. For determining prostate deformation, the Jaccard index and prostate volumes were assessed. Main results. The robotic device was able to tap the needle to the planned depth for all patients. Mean robotic procedure duration was 142 min. NTG-error was 3.2 (range 1.1–6.7) mm and NTT-error 4.5 (range 2.6–9.6) mm. Marker displacements were smaller than 3 mm. No treatment-related acute toxicity was reported. Feasibility of needle placement within the prostate was considered adequate. Significance. MR-guided robotic needle insertion is feasible with a mean geometric accuracy of 3.2 mm and <3 mm prostate movement.

Sociodemographic and clinicopathologic characteristics of patients treated with high dose rate prostate brachytherapy in Nigeria.

Prostate cancer is the most commonly diagnosed malignancy in adult males. High dose rate brachytherapy (HDRB) recently became available in the country for the management of localized prostate cancer in addition to other treatment modalities. HDRB offers a less invasive option to radical prostatectomy and also has a better side effects profile. To report the socio-demographic features of the patients treated with HDRB, the clinicopathologic pattern of their disease and possible predictors of these features. A retrospective study of patients with histopathologically confirmed prostate cancer, who had HDRB at the Department of Radiation Oncology, University College Hospital, Ibadan, Nigeria, between July 2020 and 2023 was done. Patients' socio-demographic and clinicopathologic characteristics were extracted from their treatment records. A total of 73 patients had HDRB within the period under review. The median age was 66 years (51-78 years). About 40% had prostate cancer diagnosed following routine prostate-specific antigen (PSA) screening. The median screening PSA was 20.5 ng/mL (5.83-75.35 ng/mL). About a quarter (24.7%) were asymptomatic at presentation while frequency (60.3%), nocturia (45.2%) and urgency (35.6%) were the most common symptoms. The median initial PSA was 26.00 ng/mL (5.10-124.50 ng/mL) and the median PSA before brachytherapy was 6.25 ng/mL (0.03-175.30 ng/mL), the majority (75.3%) had androgen deprivation therapy before brachytherapy. Forty-seven patients (64.4%) presented with TNM stages 1 and 2 while grade group 2 (24.7%) and high risk (76.7%) were the commonest grade group and risk group, respectively. There was a significant association between age group and TNM stage (p = 0.043), level of education (LOE) and TNM stage (p = 0.037) as well as PSA screening and grade group (p = 0.007). The majority of the patients who presented for prostate brachytherapy were elderly, had higher initial PSA, were in the high-risk group and had early-stage disease. About 25% of the patients were asymptomatic at presentation. Patients with tertiary LOE and elderly patients presented more with stage 1 and 2 diseases.

High-Dose-Rate Brachytherapy in Cervical and Endometrial Cancer Patients: A Retrospective Study From a Tertiary Cancer Center in the UAE.

Purpose This study evaluates the therapeutic outcomes and practical application of high-dose-rate (HDR) brachytherapy in managing cervical and endometrial cancers at a tertiary hospital in the UAE, focusing on treatment efficacy, safety, and patient-reported outcomes. Methods A retrospective analysis was conducted on 368 female patients treated between January 2008 and January 2022. Data included demographic information, cancer type, histopathology, treatment details, and survival outcomes. Statistical analyses were performed using descriptive and inferential statistics. Results The cohort comprised 275 cervical cancer patients (74.73%) and 93 endometrial cancer patients (25.27%). The majority were non-nationals (79.62%). The mean age was 57 years. Squamous cell carcinoma was the most common histopathological type (63.59%). HDR brachytherapy was administered to 290 patients (79.89%). The 12-month survival probability was significantly higher in the HDR-Brachy group (75%, 95% CI: 60% to 85%) compared to the noHDR-Brachy group (50%, 95% CI: 35% to 65%), with a hazard ratio of 0.953 (p=0.0035). At the last review, 86.68% of patients were alive, and disease progression was observed in 37.88% of patients. Conclusion HDR brachytherapy significantly improves survival outcomes in cervical and endometrial cancer patients. Continued efforts to enhance access and standardize brachytherapy protocols are essential to optimize treatment efficacy and patient outcomes in similar healthcare settings.

Three-dimensional trans-rectal and trans-abdominal ultrasound image fusion for the guidance of gynecologic brachytherapy procedures: a proof of concept study

High dose-rate brachytherapy is a treatment technique for gynecologic cancers where intracavitary applicators are placed within the patient’s pelvic cavity. To ensure accurate radiation delivery, localization of the applicator at the time of insertion is vital. This study proposes a novel method for acquiring, registering, and fusing three-dimensional (3D) trans-abdominal and 3D trans-rectal ultrasound (US) images for visualization of the pelvic anatomy and applicators during gynecologic brachytherapy. The workflow was validated using custom multi-modal pelvic phantoms and demonstrated during two patient procedures. Experiments were performed for three types of intracavitary applicators: ring-and-tandem, ring-and-tandem with interstitial needles, and tandem-and-ovoids. Fused 3D US images were registered to magnetic resonance (MR) and computed tomography (CT) images for validation. The target registration error (TRE) and fiducial localization error (FLE) were calculated to quantify the accuracy of our fusion technique. For both phantom and patient images, TRE and FLE across all modality registrations (3D US versus MR or CT) resulted in mean ± standard deviation of 4.01 ± 1.01 mm and 0.43 ± 0.24 mm, respectively. This work indicates proof of concept for conducting further clinical studies leveraging 3D US imaging as an accurate, accessible alternative to advanced modalities for localizing brachytherapy applicators.

Outcome of intraoperative brachytherapy as asalvage treatment for locally recurrent rectal cancer.

Locally advanced recurrent rectal cancer (RRC) requires amultimodal approach. Intraoperative high-dose-rate brachytherapy (HDR-BT) may reduce the risk of local recurrence. However, the optimal therapeutic regimen remains unclear. The aim of this retrospective monocentric study was to evaluate the toxicity of HDR-BT after resection of RRC. Between 2018 and 2022, 17patients with RRC received resection and HDR-BT. HDR-BT was delivered alone or as an anticipated boost with amedian dose of 13 Gy (range 10-13 Gy) using an 192iridium microSelectron HDR remote afterloader (Elekta AB, Stockholm, Sweden). All participants were followed for assessment of acute and late adverse events using the Common Terminology Criteria for Adverse Events version5.0 and the modified Late Effects in Normal Tissues criteria (subjective, objective, management, and analytic; LENT-SOMA) at 3‑ to 6‑month intervals. Atotal of 17patients were treated by HDR-BT with median dose of 13 Gy (range 10-13 Gy). Most patients (47%) had an RRC tumor stage of cT3‑4 N0. At the time of RRC diagnosis, 7patients (41.2%) had visceral metastases (hepatic, pulmonary, or peritoneal) in the sense of oligometastatic disease. The median interval between primary tumor resection and diagnosis of RRC was 17months (range 1-65months). In addition to HDR-BT, 2patients received long-course chemoradiotherapy (CRT; up to 50.4 Gy in 1.8-Gy fractions) and 2patients received short-course CRT up to 36 Gy in 2‑Gy fractions. For concomitant CRT, all patients received 5‑fluorouracil (5-FU) or capecitabine. Median follow-up was 13months (range 1-54). The most common acute grade1-2 toxicities were pain in 7patients (41.2%), wound healing disorder in 3patients (17.6%), and lymphedema in 2patients (11.8%). Chronic toxicities were similar: grade1-2 pain in 7patients (41.2%), wound healing disorder in 3patients (17.6%), and incontinence in 2patients (11.8%). No patient experienced agrade ≥3 event. Reirradiation using HDR-BT is well tolerated with low toxicity. An individualized multimodality approach using HDR-BT in the oligometastatic setting should be evaluated in prospective multi-institutional studies.

Inversion-recovery ultrashort-echo-time (IR-UTE) MRI-based detection of radiation dose heterogeneity in gynecologic cancer patients treated with HDR brachytherapy

PurposeTo evaluate the relationship between delivered radiation (RT) and post-RT inversion-recovery ultrashort-echo-time (IR-UTE) MRI signal-intensity (SI) in gynecologic cancer patients treated with high-dose-rate (HDR) brachytherapy (BT).MethodsSeven patients underwent whole-pelvis RT (WPRT) followed by BT to the high-risk clinical target volume (HR-CTV). MR images were acquired at three time-points; pre-RT, post-WPRT/pre-BT, and 3–6 months post-BT. Diffuse-fibrosis (FDiffuse) was imaged with a non-contrast dual-echo IR (inversion time [TI] = 60 ms) UTE research application, with image-subtraction of the later echo, only retaining the ultrashort-echo SI. Dense-fibrosis (FDense) imaging utilized single-echo Late-Gadolinium-Enhanced IR-UTE, acquired ∼ 15 min post-Gadavist injection. Resulting FDiffuse and FDense SI were normalized to the corresponding gluteal-muscle SI. Images were deformably registered between time-points based on normal tissue anatomy. The remnant tumor at both time-points was segmented using multi-parametric MRI. Contours corresponding to the 50%, 100%, 150%, and 200% isodose lines (IDLs) of the prescription BT-dose were created. Mean FDiffuse and FDense SI within (i) each IDL contour and (ii) the remnant tumor were calculated. Post-BT FDiffuse and FDense SI were correlated with prescribed BT-dose. To determine the relationship between BT-dose and IR-UTE SI, the differences in the post-BT FDense across IDLs was determined using paired t-tests with Bonferroni correction.ResultsFDense was higher in regions of higher dose for 6/7 patients, with mean ± SD values of 357 ± 103% and 331 ± 97% (p = .03) in the 100% and 50% IDL, respectively. FDense was higher in regions of higher dose in the responsive regions with mean ± SD values of 380 ± 122% and 356 ± 135% (p = .03) in the 150% and 50% IDL, respectively. Within the segmented remnant tumor, an increase in prescribed dose correlated with an increase in FDense post-BT (n = 5, r = .89, p = .04). Post-BT FDiffuse inversely correlated (n = 7, r = -.83, p = .02) with prescribed BT-dose within the 100% IDL.ConclusionsResults suggest that FDense SI 3–6 months post-BT is a sensitive measure of tissue response to heterogeneous BT radiation-dose. Future studies will validate whether FDiffuse and FDense are accurate biomarkers of fibrotic radiation response.

Setting up a new radiation therapy centre in Malawi: Opportunities and challenges

Radiotherapy (RT) is one of the three pillars of cancer treatment (with surgery and systemic therapies) and has proven to be a cost–effective modality for curative and palliative treatment. In low and middle-income countries, access to RT treatment is limited posing many challenges to patients and caregivers. Many patients living in low and middle-income countries (LMICs) such as Malawi spend enormous sums of money to be treated abroad, through Government schemes, or, more commonly, go without treatment. This paper reviews the progress of the Malawi Government in establishing the first dedicated cancer treatment center with RT facilities at Kamuzu Central Hospital in Lilongwe. Malawi is expected to have a fully functional dedicated RT centre towards the end of 2024 equipped with one cobalt machine, two linear accelerators (LINAC), and a high dose rate (HDR) Brachytherapy unit. More cancer patients will have access to RT services locally, resulting in the Government saving on the foreign currency required to treat patients out of the country. While there has been great progress towards establishment of services in Malawi, careful and strategic planning is needed for the sustainability of required resources to avoid long-term disruption of treatments.

Assessment of integrated electromagnetic tracking for dwell position monitoring in a clinical HDR brachytherapy setting for prostate cancer

BackgroundElectromagnetic Tracking (EMT) technology has been integrated in a prototype high-dose-rate brachytherapy (HDR-BT) afterloading device. Its potential for dwell position (DP) monitoring has earlier been demonstrated in prostate phantoms. However, its performance for prostate BT in the clinical setting remains to be assessed. AimAssess the reliability and value of EMT measurements in transrectal ultrasound-based (TRUS-based) and computed tomography-based (CT-based) prostate HDR-BT. MethodsEMT measurements were conducted on 20 patients undergoing dual-fraction prostate HDR-BT monotherapy. In each treatment fraction an individual TRUS-based or CT-based treatment plan was generated. The measurements were compared to DPs of manually reconstructed needles in those TRUS-based or CT-based treatment plans. An internal reference sensor was also placed in one needle to assess internal movement levels and its potential for movement correction. ResultsFor TRUS-based treatments, median Euclidean distances (ED) of 1.00 mm were observed between EMT measurements and manual DP determination. Reference sensor movement was minimal at a median of 0.18 mm. For DPs measured in the CT-room and treatment room, median EDs of 1.60 mm and 2.24 mm compared to CT-based DP determination respectively were observed, indicating the system’s ability to detect changes in implant geometry over time and after patient repositioning. Median reference sensor movement of 0.97 mm was observed. Implementing reference sensor-based movement correction led to a significant but small decrease in ED for CT-based treatments. ConclusionEMT is suitable for TRUS-based prostate HDR-BT quality assurance and error detection. While EMT can identify changes in implant geometry in CT-based prostate HDR-BT treatments, it showed lower accuracy in this setting.

Determination of the optimal time for planning SAVI brachytherapy for APBI

INTRODUCTIONAccelerated partial breast irradiation with high dose rate brachytherapy treats early-stage carcinoma. Strut-adjusted volume implant applicators are inserted into the cavity post-lumpectomy. For an unstable applicator, changes in distance are seen each day between struts. If an applicator is asymmetrical with no strut movement on subsequent days, then it is stable. If an asymmetrical applicator continues to change strut distances, it is unstable. Waiting for applicator stabilization improves treatment reproducibility but increases infection risk. There is currently no consensus on stability, with ranges from 24 hours (h) to 72 h. Therefore, this study aims to determine when stability is achieved. MATERIALS AND METHODSWe retrospectively reviewed 242 female breast cancer patients (2014–2022). CT was performed the same day as applicator insertion (Day 0) and repeated each treatment day. If applicators were initially asymmetrical, the distance between adjacent struts was measured, and the percentage change between the next and previous treatment day was calculated to determine how many applicators stabilized. Less than 5% change indicated stability. RESULTSOn Day 0, 208 out of 242 patients (86%) had stable and symmetrical applicators that maintained stability each treatment day, and 34 out of 242 patients (14%) had applicators with asymmetrical struts. Within 24 h post-insertion, 229 out of 242 (95%) patients had stabilized applicators that maintained stability on subsequent treatment days. CONCLUSIONNarrows previously suggested stability (24–72 h) to 24 h, leading to improved treatment efficiency and decreased infection risk as less time is needed to achieve applicator stability.

210 20 years of HDR brachytherapy boost in high-risk prostate cancer patients: long-term outcomes

210 20 years of HDR brachytherapy boost in high-risk prostate cancer patients: long-term outcomes

HIGH DOSE RATE BRACHYTHERAPY IN THE TREATMENT OF OPERATED ENDOMETRIAL CANCERS: ABOUT 60 CASES

Introduction:Endometrial cancer is the third gyneco-mammary cancer in the radiotherapy-brachytherapy department of the RABAT national oncology institute.Brachytherapy has an important place in the therapeutic strategy. The objective of the study:Is to analyze the coverage of target volumes as well as the dose to organs at risk with three-dimensional dosimetric planning and toxicity assessment. Material and methods:This is a retrospective study of 60 cases of operated endometrial cancers treated by high dose rate brachytherapy without external radiotherapy or chemotherapy collected in the radiotherapy department of the National Institute of Oncology RABAT between January 2018 and December 2020. A dosimetric scan without injection was performed at the first session and was used to delineate the clinical anatomic target volume (CTV). We evaluated the D100 of the clinical target volume and the D2 cm3 of the bladder, rectum and small intestine. We also analyzed acute genitourinary and gastrointestinal toxicity. Results:The average age of the patients was 49 years. Endometrioid carcinoma accounted for 98.5%, with one case of mucinous carcinoma. All patients underwent surgery.The brachytherapy protocol used was 3 × 7 Gy (75%) or 4 × 5.5 Gy (17%) in weekly sessions A single patient received a reduced total dose of 19.8 Gy in 3 fractions of 5.5 Gy due to a high rectal dose.The average target volume coverage (D100) was 96.50%.The average D2 cm3 per session received by the bladder, rectum and small intestine were 4.06 Gy, 4.9 Gy and 2.8 Gy, respectively.Regarding genitourinary toxicity, we noted two grade 1 cystitis, one grade 2, two grade 1 mucositis and one grade 2.For gastrointestinal toxicity, no cases of grade greater than 1 were noted.No grade 3 or 4 toxicities were recorded. Conclusion:High dose rate brachytherapy has an important place in the therapeutic strategy for endometrial cancer.The very low toxicity recalls the good tolerance of this treatment whichapplies to the entire population.

Neoadjuvant radiotherapy followed by hysterectomy in locally advanced endometrial cancer: Outcomes from a tertiary government hospital in the Philippines

ObjectiveManaging endometrial cancer with suspected or gross cervical involvement lacks a standard approach. This study evaluated outcomes in patients with cervical and/or parametrial involvement treated with neoadjuvant radiation followed by hysterectomy. MethodsFourteen patients from 2007 to 2022 with locally advanced endometrial cancer and cervical and/or parametrial involvement were retrospectively analyzed. They received neoadjuvant external beam radiotherapy (45–50.4 Gy in 25–30 fractions) and high-dose rate brachytherapy (5.5–7.0 Gy per fraction in 3–4 fractions), followed by extrafascial hysterectomy. Clinical data, pathologic response, and survival outcomes were assessed, along with factors associated with pathologic response. ResultsMost patients (86%) had stage III disease with cervical extension, 93% had parametrial involvement, and 14% had nodal involvement. Chemotherapy was given to 86% either concurrently or adjuvantly. Post-surgery, 86% had no pathologic cervical involvement, and 93% had negative surgical margins. Pathologic complete response was seen in 43%. Locoregional recurrence occurred in 14%. Median follow-up was 30 months, with recurrence-free survival and overall survival rates of 86% and 100%, respectively. Lower grade tumors significantly correlated with pathologic complete response (Φ = 0.72, p = 0.026). No significant correlation was found between pathologic complete response and other factors. No late grade 3–4 toxicities were reported. ConclusionNeoadjuvant radiation followed by hysterectomy, with or without chemotherapy, is a viable strategy for managing endometrial cancer with cervical and/or parametrial involvement. This approach enhances resectability, yielding high rates of pathologic complete response and negative resection margins, showing promise for this challenging patient group.

169Yb-based high dose rate intensity modulated brachytherapy for focal treatment of prostate cancer

PurposeThis study compares conventional 192Ir-based high dose rate brachytherapy (HDR-BT) with 169Yb-based HDR intensity modulated brachytherapy (IMBT) for focal prostate cancer treatment. Additionally, the study explores the potential to generate less invasive treatment plans with IMBT by reducing the number of catheters needed to achieve acceptable outcomes. Methods and MaterialsA retrospective dosimetric study of ten prostate cancer patients initially treated with conventional 192Ir-based HDR-BT and 5-14 catheters was employed. RapidBrachyMCTPS, a Monte Carlo-based treatment planning system was used to calculate and optimize dose distributions. For 169Yb-based HDR IMBT, a custom 169Yb source combined with 0.8 mm thick platinum shields placed inside 6F catheters was used. Furthermore, dose distributions were investigated when iteratively removing catheters for less invasive treatments. ResultsWith IMBT, the urethra D10 and D0.1cc decreased on average by 15.89 and 15.65 percentage points (pp) and the rectum V75 and D2cc by 1.53 and 11.54 pp, respectively, compared to the conventional clinical plans. Similar trends were observed when the number of catheters decreased. On average, there was an observed increase in PTV V150 from 2.84 pp with IMBT when utilizing all catheters to 8.83 pp when four catheters were removed. PTV V200 increased from 0.42 to 2.96 pp on average. Hotspots in the body were however lower with IMBT compared to conventional clinical plans. Conclusions169Yb-based HDR IMBT for focal treatment of prostate cancer has the potential to successfully deliver clinically acceptable, less invasive treatment with reduced dose to organs at risk.

Salvage radiotherapy for locally recurrent cervical and endometrial carcinoma: clinical outcomes and toxicities

BackgroundThe management of locally recurrent gynecological carcinoma remains a challenge due to the limited availability of data. This study aims to share our institutional experience in using definitive radiotherapy (RT) for the treatment of locally recurrent cervical and endometrial carcinoma.MethodsThe study retrospectively reviewed 20 patients in our hospital completing salvage 3D image-based HDR brachytherapy, with or without EBRT, for locally recurrent cervical and endometrial carcinoma after surgery. The Kaplan–Meier method was applied to estimate the disease-free survival (DFS) and overall survival (OS). The toxicities were assessed by CTCAEv5.ResultsDuring a median observation period of 21 months, the study reported a tumor objective response rate of 95%. The 3-year DFS and OS rates were 89.4% and 90.9%, respectively. The EBRT combined with brachytherapy achieved a median cumulative dose of 88 Gy to CTV D90. 14 patients received concurrent and/or systemic chemotherapy. Two patients suffered locoregional recurrence after salvage treatment, one of whom only received salvage brachytherapy for prior RT history. The analysis identified significant predictors for DFS, including tumor histology and FIGO stage. 5 patients observed acute grade 1–2 rectal (15%) or genitourinary (10%) toxicities. Late toxicities including grade 1–2 rectal bleeding (10%) and grade 2 pelvic fracture (5%) were seen in 3 patients.Conclusions3D image-guided brachytherapy combined with EBRT shows effective tumor control and acceptable toxicity profile for women with locally recurrent gynecologic cancer. The success in managing vaginal recurrence is notably influenced by histologic subtype and FIGO staging.

HDR brachytherapy versus robotic-based and linac-based stereotactic ablative body radiotherapy in the treatment of liver metastases – A dosimetric comparison study of three radioablative techniques

PurposeThe aim of our study was to compare dosimetric aspects of three radioablation modalities – direct high-dose-rate brachytherapy (HDR-BT) and virtually planned stereotactic body radiation therapy performed on CyberKnife (SBRTck) and Elekta Versa HD LINAC (SBRTe) applied in patients with liver metastases. Material and methodsWe selected 30 patients with liver metastases, who received liver interstitial HDR-BT and virtually prepared plans for SBRTck and SBRTe. In all the cases, the prescribed dose was a single fraction of 25 Gy. Treatment delivery time, doses delivered to PTV and organs at risk, as well as conformity indices, were calculated and compared. ResultsThe longest median treatment delivery time was observed in SBRTck in contrast to HDR-BT and SBRTe which were significantly shorter and comparable. HDR-BT plans achieved better coverage of PTV (except for D98%) in contrast to SBRT modalities. Between both SBRT modalities, SBRTck plans resulted in better dose coverage in Dmean, D50%, and D90% values compared to SBRTe without difference in D98%. The SBRTe was the most advantageous considering the PCI and R100%. SBRTck plans achieved the best HI, while R50% value was comparable between SBRTe and SBRTck. The lowest median doses delivered to uninvolved liver volume (V5Gy, V9.1Gy) were achieved with HDR-BT, while the difference between SBRT modalities was insignificant. SBRT plans were better regarding more favourable dose distribution in the duodenum and right kidney, while HDR-BT achieved lower doses in the stomach, heart, great vessels, ribs, skin and spinal cord. There were no significant differences in bowel and biliary tract dose distribution between all selected modalities. ConclusionsHDR-BT resulted in more favourable dose distribution within PTVs and lower doses in organs at risk, which suggests that this treatment modality could be regarded as an alternative to other local ablative therapies in carefully selected patients’ with liver malignancies. Future studies should further address the issue of comparing treatment modalities in different liver locations and clinical scenarios.