Radiotherapy Techniques Research Articles

Spinal laser interstitial thermal therapy and radiotherapy for thoracic metastatic epidural spinal cord compression.

Spinal laser interstitial thermal therapy (sLITT) is a less invasive alternative to surgery for metastatic epidural spinal cord compression. Here, we analyze outcomes of patients treated with sLITT either in conjunction with radiotherapy or as a standalone salvage therapy. We included patients with thoracic vertebral metastatic cord compression treated with sLITT. Outcomes included freedom from local failure (FFLF) and overall survival (OS). Factors associated with FFLF were identified with univariable and multivariable analyses via a Cox proportional hazards model. Between 2013-2022, 129 patients received sLITT to 144 vertebral segments; 69% were radiotherapy naïve, 81% were radioresistant histologies, and 74% were centered in the vertebral body. Median age was 61 years. Pre-sLITT Bilsky score was 3 in 28%, 2 in 33%, and 1c in 37%. Radiotherapy was delivered in conjunction with sLITT for 80% of cases, including 68% that received stereotactic radiotherapy, at a median of 5 days after sLITT. Median follow-up was 9.1 months. One-year FFLF and OS was 80% and 78%, respectively. On multivariable analysis, variables independently associated with adverse FFLF included paraspinal/foraminal disease location (p = 0.001), and post-sLITT imaging Bilsky score of 2 (p = 0.073) or 3 (p = 0.011). Prior radiotherapy, technique of radiotherapy, and time between radiotherapy and sLITT were not associated with FFLF. sLITT with radiotherapy is an effective minimally invasive treatment approach for thoracic metastatic epidural spinal cord compression. Early treatment response may serve as a prognostic imaging biomarker.

Cardiac Conduction System as an OAR in Radiation Therapy: Doses to SA/AV Nodes and Their Reduction

PurposeDespite advancements in radiation techniques, concerns persist regarding the adverse effects of radiation therapy, particularly cardiotoxicity or radiation-induced heart disease. Recently, arrhythmogenic toxicity has come to the forefront—the impact of radiation therapy on the cardiac conduction system. Our objective was to conduct a dosimetric study and subsequently investigate the feasibility of optimizing the sinoatrial (SA) and atrioventricular (AV) nodes as organs at risk (OARs) in proton radiation therapy for non–small cell lung cancer with N3 disease. Patients and MethodsThirty-two non–small cell lung cancer patients with N3 disease undergoing proton radiation therapy were included. Sinoatrial and AV nodes, along with standard OARs, were delineated. Dosimetric analysis and optimization were performed using intensity-modulated proton therapy. ResultsPatients surpassing a predefined SA node dose threshold underwent dose optimization. Proton radiation therapy with pencil beam scanning demonstrated a significant reduction in SA and AV node doses without compromising target volume coverage or significant shift in the dose to other monitored OARs. ConclusionDose reduction to the SA and AV nodes for pencil beam scanning is a relatively simple task, and the reduction can be very substantial. Larger cohort studies and diverse radiotherapeutic modalities are needed for further validation and refinement of dose constraints.

National radiotherapy dosimetry audit in the UK – A vision and roadmap

Radiotherapy dosimetry audit is an important element in the overall quality assurance of radiotherapy delivery and has become established as best practice prior to implementation of new equipment, techniques or clinical trials.The Institute of Physics and Engineering in Medicine (IPEM) Interdepartmental Dosimetry Audit group (IDA) facilitates regional audits across the UK through a network of 8 regional chairs. This is a well-established and successful network utilising local staff resources and dosimetry equipment from each region to conduct audits for new radiotherapy equipment, techniques and annual reference audits. All dosimeters used are traceable to the National Physical Laboratory's (NPL) primary standard.NPL and the National Radiotherapy Trials Quality Assurance Group (RTTQA) perform audits for new techniques and clinical trials in the UK. The IPEM IDA, NPL and RTTQA have a joint vision of a national audit network so that comprehensive audits can be offered to all UK centres and bring together all UK dosimetry audit data within a centralised database to facilitate coordinated national audits. This will also allow centres to access and review their data for anonymous benchmarking against other UK centres to support quality improvement.Increasing the frequency and complexity of national audits to reflect current clinical practice is often inhibited by the cost of purchasing appropriate equipment. IPEM have now funded two phantoms that will enable national audits of gynae brachytherapy and head and neck external beam treatments through 2024–25.The aim of this Position Paper is to provide an update on the activities of the IPEM IDA and present the future vision and roadmap for the three UK dosimetry audit groups.

Recent developments in the field of radiotherapy for the management of lung cancer.

Lung cancer has a poor prognosis, and further improvements in outcomes are needed. Radiotherapy plays an important role in the treatment of unresectable lung cancer, and there have been recent developments in the field of radiotherapy for the management of lung cancer. However, to date, there have been few reviews on the improvement in treatment outcomes associated with high precision radiotherapy for lung cancer. Thus, this review aimed to summarize the recent developments in radiotherapy techniques and indicate the future directions in the use of radiotherapy for lung cancer. Stereotactic body radiotherapy (SBRT) for unresectable stage I lung cancer has been reported to improve local control rates without severe adverse events, such as radiation pneumonitis. For locally advanced lung cancer, a combination of chemoradiotherapy and adjuvant immune checkpoint inhibitors dramatically improves treatment outcomes, and intensity-modulated radiotherapy (IMRT) enables safer radiation therapy with less frequent pneumonitis. Particle beam therapy, such as carbon-ion radiotherapy and proton beam therapy, has been administered as advanced medical care for patients with lung cancer. Since 2024, it has been covered under insurance for early stage lung cancer with tumors ≤ 5cm in size in Japan. In addition to chemotherapy, local ablative radiotherapy improves treatment outcomes in patients with oligometastatic stage IV lung cancer. A particular problem with radiotherapy for lung cancer is that the target location changes with respiratory motion, and various physical methods have been used to control respiratory motion. Recently, coronavirus disease has had a major impact on lung cancer treatment, and cancer treatment during situations, such as the coronavirus pandemic, must be performed carefully. To improve treatment outcomes for lung cancer, it is necessary to fully utilize evolving radiotherapy modalities, and the role of radiotherapy in lung cancer treatment is expected to increase.

Improved quality of life in head and neck cancer patients treated with modern arc radiotherapy techniques - A prospective longitudinal analysis.

The present longitudinal study aimed to evaluate the potential impact of modern radiotherapy (RT) techniques on quality of life (QOL) in patients with head and neck (HNC) cancer. In this single-center prospective study, participants were asked to complete QOL questionnaires that included the EORTC QLQ-C30, QLQ-H&N 35 and utility score by time trade-off (TTO) at three time points (2 weeks, 3 months and 6 months) after completion of RT. All patients were treated by modern RT techniques [volumetric modulated arc therapy (VMAT) or helical tomotherapy (HT)]. Patients who developed recurrence or died before the 6-month follow-up were excluded. Linear mixed models with random intercepts for participants and restricted maximum likelihood estimates were used to assess the effect of our study variables (age, sex, primary site, cancer stage, treatment, radiation dose and radiation method). Overall changes in QOL, utility scores and symptom burdens at different time points were tested using paired t tests. A total of 45 patients were recruited from 2022 to 2023. Those who completed the surveys at 2 weeks with at least 1 follow-up (30 patients, 67%) were enrolled in the final analysis. The majority of these 30 patients were men (76.7%), had oral cancer (40%), had stage III or IV disease (60%), received surgical intervention (63%) and were treated with chemoradiation (80%). A curative total dose of 66 to 70 Gy was delivered to 23 (76.7%) patients, half of whom received HT. Patients who received chemotherapy had significantly lower global QoL scales (mean difference, 27.94; 95% CI, 9.33-46.55; p=0.005). Global QOL, physical function, symptoms of sticky saliva, cough, feelings of illness and weight loss improved significantly between 2 weeks and 3 months. There was no significant difference between 3 and 6 months. Interestingly, improvements in social function, social contact, pain and nutrition reached significance at 6 months. Subgroup analysis revealed greater pain relief over time for patients who underwent HT (p=0.030). Moreover, patients who participated in swallowing rehabilitation programs had a greater decrease in nausea and vomiting (p=0.036). HNC patients treated with modern RT techniques experience improved QOL and physical function over time. The most significant improvement occurs between 2 weeks and 3 months, after which the improvement plateaus. However, social function, social contact, pain and nutrition may require longer recovery intervals after treatment. HT with daily image guidance could provide a therapeutic opportunity for improving pain relief in patients with HNC.

Dose advantage of abdominal deep inspiratory breath-hold (aDIBH) in postoperative adjuvant radiotherapy for left breast cancer

PurposeWe explored the dosimetric efficacy of the abdominal deep inspiration breath hold (aDIBH) technique using an audio-guided device in patients with left breast cancer undergoing postoperative adjuvant radiotherapy compared to free breathing (FB).MethodsA total of 35 patients with early stage left breast cancer underwent two computed tomography simulation scans each with aDIBH and FB after breast-conserving surgery. Treatment planning was optimized using the Pinnacle3 9.10 planning system. The heart, left anterior descending coronary artery (LADCA), and left lung was defined as organs at risk (OARs). The dosimetric differences in the planning target volume (PTV) and OARs were compared between aDIBH and FB.ResultsCompared with FB, the heart moved farther caudally and away from the chest wall, and the volume of heart became smaller under aDIBH due to expansion of the lungs. The D mean of the heart, LADCA and left lung of aDIBH were respectively reduced by 332.79 ± 264.61 cGy (P < 0.001), 1290.37 ± 612.09 cGy (P < 0.047) and 69.94 ± 117.73 cGy (P < 0.001). The V20 and V30 of the OARs were also significantly reduced with statistical differences (P < 0.05). In addition, there was no significant difference in the dosimetric parameters of the PTV between the two groups (P > 0.05).ConclusionsImplementation of the aDIBH technique for postoperative radiotherapy after breast-conserving surgery of the left breast cancer could reduce irradiation of the heart dose, LADCA dose and left lung dose, without compromising target coverage.

Physician reported toxicities and patient reported quality of life of transperineal ultrasound-guided radiotherapy of prostate cancer

PurposeThis study aims to address therapy-related toxicities and quality of life in prostate cancer patients undergoing transperineal ultrasound (TPUS) guided radiotherapy (RT). MethodsAcute and late gastrointestinal (GI) and genitourinary (GU) toxicities were assessed by physicians using CTCAE v5.0. Patient-reported quality of life outcomes were evaluated using EORTC QLQ-C30, -PR25 and IPSS. We utilized Volumetric Modulated Arc Therapy (VMAT) or intensity modulated radiation therapy (IMRT) as the RT technique for this study. The assessments were carried out before RT, at RT end, 3 months after RT and subsequently at 1-year intervals. Prostate-specific antigen (PSA) was also evaluated at each follow-up. ResultsIn this study, a total of 164 patients were enrolled, while among them, 112 patients delivered quality-of-life data in a prospective evaluation. The median pre-treatment PSA was 7.9 ng/mL (range: 1.8–169 ng/ml). At the median follow-up of 19 months (3–82 months), the median PSA decreased to 0.22 ng/ml. Acute grade II GI and GU toxicities occurred in 8.6 % and 21.5 % patients at RT end. Regarding late toxicities, 2.2 % patients experienced grade II GI toxicities at 27 months and only one patient at 51 months, whereas no grade II GU late toxicities were reported at these time points. Quality of life scores also indicated a well-tolerated treatment. Patients mainly experienced acute clinically relevant symptoms of fatigue, pain, as well as deterioration in bowel and urinary symptoms. However, most symptoms normalized at 3 months and remained stable thereafter. Overall functioning showed a similar decline at RT end but improved over time. ConclusionThe outcomes of TPUS-guided RT demonstrated promising results in terms of minimal physician-reported toxicities and satisfactory patient-reported QoL.

Feasibility, Safety, and Factors Predicting Completion of CROSS Protocol–Based Neoadjuvant Chemoradiotherapy for Esophageal Squamous Carcinoma: Experience from an Indian Tertiary Care Cancer Center

Background Neoadjuvant chemoradiotherapy (NACRT) using the ChemoRadiotherapy for Oesophageal cancer followed by Surgery Study (CROSS) protocol has improved esophageal cancer outcomes. This study reports the real-world experience of the CROSS regimen for esophageal squamous cell carcinoma (ESCC) regarding its feasibility, safety, and predictors of treatment completion from an Indian tertiary center. Methodology A retrospective review was conducted for patients with ESCC receiving CROSS (radiation dose: 41.4 Gy) or a modified CROSS (mCROSS; radiation dose: 45 Gy) protocol NACRT between 2015 and 2022. We studied the treatment tolerability, factors predicting NACRT completion, and the effect of completion of its chemotherapy component on the pathological outcomes. Results Of the109 patients (68.8% males; mean age, 56 ± 9 years; Charlson's comorbidity index [CCI] &gt;2, 19.3%; stage III–IVA, 58%; mean tumor length, 5.5 ± 2.1cm; CROSS, 70.6%; mCROSS, 29.4%), all except 4 completed radiotherapy but only 58 (53.2%) patients completed ≥4 cycles of chemotherapy. Forty-nine patients belonged to the “extended” CROSS trial inclusion criteria. Among the 60 patients who fulfilled the CROSS inclusion criteria, only 51.7% were able to complete ≥4 chemotherapy cycles. The commonest reason for noncompletion of chemotherapy was the occurrence of neutropenia (60.8%). Pretreatment hemoglobin (≥12 vs. &lt;12 g%; odds ratio [OR]: 2.76; 95% confidence interval [CI]: 1.10–6.96; p = 0.031), a low CCI (≤2 vs. &gt;2; OR: 2.98; 95% CI: 1.02–8.73; p = 0.047), and radiation therapy techniques (conformal vs. conventional; OR: 3.29; 95% CI: 1.14–9.50; p = 0.028) were associated with completion of chemotherapy (≥4 cycles). Although there was a trend toward improved R0 resection (95.7 vs. 91.4%), reduced node positivity (17.0 vs. 31.4%), and a high pCR (57.4 vs. 48.6%) in patients completing chemotherapy (≥4 cycles) compared with those not completing chemotherapy (&lt;4 cycles), these differences were statistically nonsignificant. Conclusion In this study, ESCC patients receiving the CROSS protocol NACRT could complete their radiotherapy component, but a significant proportion exhibited poor chemotherapy tolerance. Neutropenia was a major factor limiting chemotherapy delivery, but anemia, high CCI, and conventional radiation techniques were also associated with noncompletion of chemotherapy. The omission of a few chemotherapy cycles had no significant effect on the pathological response; however, its impact on cancer survival requires further evaluation.

Development of a 3D-printed phantom for total skin electron therapy dose assessment.

Total skin electron therapy (TSET) is a complex radiotherapy technique, posing challenges in commissioning and quality assurance (QA), especially due to significant variability in patient body shapes. Previous studies have correlated dose with factors such as obesity index, height, and gender. However, current treatment planning systems cannot simulate TSET plans, necessitating heavy reliance on QA methods using standardized anthropomorphic phantoms and in-vivo dosimetry. Given the relatively few studies on rotational techniques, comprehensive data in commissioning could streamline the process. Developing a full-body phantom would enable a more thorough TSET commissioning process, including testing for position-specific dose distributions and comprehensive measurements across all body surfaces, unlike the typical torso-only phantoms. This was created using digital modeling software, fabricated using 3D-printing FDM technology, and filled with tissue-equivalent gelatine. The phantom was positioned at an SSD of 340cm and irradiated with a standard rotational TSET plan using the 6E HDTSE mode on a Varian TrueBeam linac at gantry angles of±18° from the horizontal. The dose was measured at over 50 points across the surface using Gafchromic EBT3 film. Dose distributions were generally consistent with existing literature values from in-vivo dosimetry, with several position-specific differences identified, including the hands and scalp compared to conventional positions. Hotspots were observed for the mid-dorsum of the foot and nose, with areas under 80% of the dose identified as the soles of the feet, perineum, vertex of the scalp, top of the shoulder, and palm of the hand. Additionally, analysis using an interpolated dose heatmap found that 90% of the pixel area received a dose within 10% of the prescribed dose, indicating good uniformity with the commissioned technique. With high agreement with the current literature, a 3D-printed phantom proves effective for measuring doses in areas typically unmeasurable in TSET commissioning.

Overview of irradiation techniques for esophageal cancer.

Rak przełyku stanowi około 2% wszystkich nowotworów złośliwych. Zastosowanie leczenia u pacjenta z rakiem przełyku zależy od dokładnej lokalizacji nowotworu i jego stadium. Pacjenci ze zmianami naciekającymi naczynia krwionośne, serce, płuca i węzły chłonne kwalifikują się do radykalnej chemioradioterapii. Celem tego badania było przejrzenie technik napromieniowania w przypadku raka przełyku. W tym artykule przedstawiono techniki konwencjonalnej radioterapii 2D i 3D konformalnej radioterapii (3DCRT). Systemy komputerowe do planowania leczenia wpłynęły na rozwój dynamicznych technik, umożliwiając nowocześniejszą radioterapię z modulacją intensywności (IMRT) i terapię łukiem wolumetrycznym (VMAT) lub stosowanie terapii protonowej.

Updates for newly diagnosed and recurrent glioblastoma: a review of recent clinical trials.

Glioblastoma (GBM) is the most common and devastating primary malignant brain tumor. We summarize recent advances in radiotherapy, immunotherapy, and targeted therapy approaches for the treatment of newly diagnosed and recurrent glioblastoma. We also introduce ongoing clinical trials. Recent clinical trials have explored multiple novel strategies to treat GBM including the use of oncoviruses, chimeric antigen receptor (CAR) T cell therapy, vaccines, radiotherapy, and novel drug delivery techniques to improves drug penetrance across the blood brain barrier. Approaches to improve drug delivery to brain tumors have the potential to expand treatment options of existing therapies that otherwise have poor brain tumor penetrance. Immunotherapy has been of keen interest in both newly diagnosed and recurrent glioblastoma. Vaccines SurVaxM and DCVax-L have shown initial promise in phase II and III trials, respectively. CAR T cell therapy trials are in their early phases but hold promise in both newly diagnosed and recurrent glioblastoma. Although progress to improve outcomes for GBM patients has been modest, multiple novel strategies utilizing combination therapies, focused ultrasound to improve drug delivery, and novel immunotherapies are underway.

Radiation-associated cardiovascular disease in patients with cancer: current insights from a cardio-oncologist.

Radiation-associated cardiovascular disease (RACD), a complex disease characterized with pericarditis, myocardial damage, valvular heart diseases, heart failure, vasculopathy and ischemic heart disease, has a generally poor prognosis. While RACD may be acute, it often manifests in the late years or even decades following radiation exposure to the chest. With an increasing number of cancer survivors, RACD is likely to become an important issue in cardio-oncology. This review discusses pre-radiation therapy (RT) preparation, peri-RT patient management and long follow-up planning post-RT from a cardiology perspective. Additionally, a novel technique of stereotactic radiotherapy, which has been applied for the treatment of intractable cardiac arrhythmias, is presented. Appropriate patient examination and management during and after RT are essential to support patients undergoing cancer treatment to improve long life expectancy. A multidisciplinary team is needed to determine how to manage patients who receive RT to reduce RACD, to detect early phases of RACD and to provide the best treatment for RACD. Recent studies increasingly report advances in diagnosis using new equipment that has the potential to detect early phases of RACD, along with growing evidence for the optimal treatment for RACD. This review provides an overview of recent studies and guidelines to report on the latest findings, and to identify unresolved issues surrounding RACD that require validation in future studies.

Exploring the impact of field shape on predicted dose distribution in breast cancer patients using deep learning in radiation therapy

BackgroundGeometrical information such as field shape is essential for dose calculation in radiation therapy. However, new methods of dose prediction based on deep learning only use CT images and contouring of patients. The aim of this study is to develop a deep learning method for three-dimensional dose prediction for breast cancer radiotherapy using field shape as well as CT and contouring images of patients. MethodsA total of 150 breast cancer patients' data treated with 3D conformal radiation therapy (CRT) technique were used to train and test 3D-U-Res-F-Net model. The model inputs were CT images, patients' contouring and field shape. The network output was the corresponding the patients’ dose distribution. Then, the dosimetric parameters extracted from the dose volume histograms related to the planned and predicted dose distributions were compared and were statistically analysed with the paired-samples t-test. These parameters include Dmean and Dmax for planning target volume and organs at risk, D95%, D50%, V47.5Gy for PTV, V30Gy and V25Gy for heart and V20Gy for left lung. The gamma index with 3%/3 mm criteria was calculated for PTV and OARs. ResultsThe average absolute difference of the Dmean relative to the prescribed dose for the PTV, heart, left lung, right lung and spinal cord were 1.37 ± 0.4%, 2.02 ± 2%, 2.12 ± 1%, 0.37 ± 0.3% and 0.41 ± 0.3%, respectively. The average absolute difference of the Dmax relative to the prescribed dose for the PTV and OARs varied from 0.23 ± 0.2% to 2.04 ± 2%. The 3D gamma pass rate with 3mm/3% criteria for planning target volume, heart, left lung, right lung, spinal cord and body were 89 ± 3%, 91 ± 5%, 93 ± 5%, 99 ± 3%, 99 ± 1% and 96 ± 2% respectively. ConclusionsThe results of the proposed model demonstrate that there is no significant difference between the predicted and planned dose distributions. The deep learning model can directly predict the 3D dose distribution faster than treatment planning systems. Further studies with more patients and on other cancer sites are essential to fully validate the proposed method.

Non-irradiated area of intraoperative radiotherapy with electron technique: outcomes and pattern of failure in early-stage breast cancer from a single-center, registry study

IntroductionIntraoperative radiotherapy (IORT) with electrons has revealed to have higher rates of ipsilateral breast tumor recurrence (IBTR) than external beam radiotherapy in updated large-scale, randomized controlled trials in 2021. This study details the oncological outcomes of IORT with electron beams using our strict IORT policies. We have found new and important observations regarding the location of recurrence.Methods and materialsThis is a single institution registry of early-stage breast cancer patients who underwent lumpectomy and electron beam IORT with appropriate cone size. All patients met our pre-excision requirements. The primary endpoint was 5-year IBTR rate, with secondary endpoints being 5-year locoregional failure rate, 5-year distant metastasis rate, 5-year overall survival and, importantly, the failure patterns.ResultsBetween January 2011 and December 2022, 124 patients were recruited. The median follow-up was 6.7 years. The 5-year IBTR rate was 1.87% (95% CI 0.47–7.29%), which is much lower than the ELIOT trial and comparable with other accelerated partial breast irradiation (APBI) techniques. The 5-year locoregional failure rate was 3.68% (95% CI 1.40–9.52%), and the 5-year distant metastasis rate was 0.88% (95% CI 0.13–6.12%), while the 5-year overall survival rate was 97.52% (95% CI 92.44–99.19%). Six patients experienced IBTR. All recurrences were in surgical area, occurring superficial to the tumor bed and within 1 cm of the skin dermis. This failure pattern is very unique and might be explained by our hypothesis of the non-irradiated area beneath the skin.ConclusionsIORT with electron beams with strict patient selection criteria and strict large cone size is still an acceptable treatment for select patients with early-stage breast cancer. However, our new findings support extreme caution in the non-irradiated area beneath the skin around the tumor cavity. Given the constraints of our sample size, these findings should be interpreted cautiously and warrant further investigation in larger, more comprehensive studies.

Evaluation of Inverse Planned and Forward Planned Intensity Modulated Radiotherapy Techniques in Breast Cancer

Introduction: The objective of this study is to compare the dosimetric parameters of radiation to the whole breast between the two intensity-modulated radiotherapy (IP IMRT) techniques, i.e. Inverse planned IMRT (IP IMRT) and Forward Planned IMRT (FP IMRT) with regard to target coverage (PTV) and irradiation of organs at risk (OAR). Material and Methods: Plain and Contrast enhanced computed tomography (CECT) datasets were created for 41 patients treated with whole breast radiation therapy. CT simulation and treatment is performed using deep inspiratory breath hold technique (DIBH). Radiotherapy treatment Planning is done using Eclipse Treatment Planning System (version 13.7) with a prescription dose of 40 Gy in 15#. The developed treatment plans were subjected to objective comparison of PTV and OARs using dose volume histograms (DVH). Results: IP IMRT plans provided better coverage (99.5% vs 97.6%), comparable though higher maximum dose (Dmax 45.0 VS 44.1 Gy), higher hot spot (PTV105% 49.2 vs 33), lower volumes receiving 20, 25, 30 Gy (V20, V25, V30) for heart, more homogeneous (homogeneity index 0.10 vs. 0.14) and conformal dose distribution (conformity Index 1.0 vs 0.98) compared to FP IMRT. Regarding OAR dosimetry it is observed that FP IMRT showed reduced mean dose to Coronary artery (LADCA), Contralateral Lung (CL), Contralateral breast (CB) along with reduction in low dose region (V5) to all OARs under study. It was also observed that Monitor units used and planning time were lower for FP IMRT. Conclusion: On weighing different dosimetric factors, both the techniques have displayed their own advantages and disadvantages. Choosing a planning technique needs to be customized taking into consideration various factors such as breast topography, size and volumes of breast, availability of expertise planning skills and resources.

Analysis of Wedge Angle Variations in the Treatment Planning System Based on Dose Volume Histogram on Ca Mammae Sinistra

Breast cancer ranks first in terms of the highest number of cancers in Indonesia and is one of the first contributors to cancer deaths. According to IARC, radiotherapy is one of the most important modalities in the treatment of breast cancer. Radiotherapy is a type of treatment that uses ionizing radiation to kill cancer cells without damaging surrounding healthy tissue. To obtain an even or homogeneous dose distribution on an uneven skin surface, a wedge is used so that the radiation given to the tumor area is truly optimal and the surrounding healthy tissue receives a minimum dose. This research was carried out by evaluating the Planning Target Volume (PTV) value based on ICRU-83 and dose distribution in Organs at Risk (OAR) based on QUANTEC standards at four different wedge angles, namely 15°, 30°, 45°, and 60°, used the 3D-CRT technique of tangential radiation with a dose of 50 Gy in 25 fractions on 5 left-sided breast cancer patients. The research results showed that the average Homogeneity Index (HI) values for the 15°, 30°, 45° and 60° wedges were 0.286, 0.346, 0.436 and 0.578, respectively. In the left and right lung dose distribution, the results obtained for the 15°, 30°, 45°, and 60° wedge were respectively 2231.4 and 116.2 cGy, 2257.8 and 114.6 cGy, 2141 and 100 cGy, and 2059.4 and 88.8 cGy. For the average dose distribution to the heart, the values obtained at the 15°, 30°, 45°, and 60° wedges were 2005.6 cGy, 2040.4 cGy, 1930.6 cGy, and 1844.4 cGy, respectively. where the average dose received by OAR is still below the limit allowed by QUANTEC. Using a wedge angle of 15° provides a homogeneous dose distribution for the PTV and a wedge angle of 60° provides the lowest dose distribution for the OAR.

Stereotactic body radiotherapy using CyberKnife versus interstitial brachytherapy in accelerated partial breast irradiation on left-sided breast: A comparison of dosimetric characteristics and preliminary clinical results

IntroductionWe compared the dosimetric characteristics of the target and organs at risk (OARs) as well as the preliminary clinical outcomes between two accelerated partial breast irradiation (APBI) techniques. MethodsForty-four patients diagnosed with left-sided early breast cancer who underwent APBI using either interstitial brachytherapy (IB) or stereotactic body radiation therapy (SBRT) with CyberKnife (CK) were retrospectively reviewed. The dosimetric parameters of the target and OARs were compared. Preliminary clinical outcomes, including tumor control and acute toxicity, were analyzed. ResultsTreatment plans with CK demonstrated a better cardiac dose-sparing effect. Radiation doses to the heart at V150cGy for the CK and IB groups were 24.4 % and 60.4 %, respectively (p < 0.001), while the mean heart doses for the CK and IB groups were 107.4 cGy and 204 cGy, respectively (p < 0.001). The heart D1c.c. and the ipsilateral lung received a lower dose in the IB group, without any significant differences. The median follow-up time in the CK and IB groups was 28.6 and 61.3 months, respectively. No patients died from either breast cancer or cardiac events during follow-up. A locoregional recurrence event at the neck occurred in one patient within the IB group. ConclusionsAPBI planned by CK was shown to have a better dose-sparing effect on the heart, as well as better conformity and homogeneity to the target. CK is a non-invasive treatment which showed minimal acute toxicity and promising tumor control.

Moving beyond mean heart dose: The importance of cardiac substructures in radiation therapy toxicity.

Normal tissue tolerance dose limits to the heart have been established to reduce the risk of radiation-induced cardiac disease (RICD). Dose constraints have been developed based on either the mean dose delivered to the whole heart (MHD) or the dose delivered to a specific volume, for example, volume of heart receiving equal to or greater than 30 Gy (V30). There is increasing evidence that the impact of thoracic radiation on cardiac morbidity and mortality has been underestimated. Consequently, there is a need to reduce the dose delivered to the heart in radical radiotherapy treatment planning. The pathophysiology of RICD may relate to dose to specific cardiac substructures (CS) rather than the traditionally observed MHD for common toxicities. The MHD or V30 Gy threshold dose rarely represents the true dose delivered to individual CS. Studies have shown the dose to specific areas may be more strongly correlated with overall survival (OS). With advances in modern radiotherapy techniques, it is vital that we develop robust, evidence-based dose limits for CS, to fully understand and reduce the risk of RICD, particularly in high-risk populations with cardiac risk factors. The following review will summarise the existing evidence of dose limits to CS, explain how dose limits may vary according to different disease sites or radiation techniques and propose how radiotherapy plans can be optimised to reduce the dose to these CS in clinical practice.

Measurement Techniques for Low-Concentration Tritium Radiation in Water: Review and Prospects.

Tritium (3H) is one of the most critical nuclides for environmental monitoring, yet it is challenging to measure. Its high natural mobility and its potential to enter the human body through the food chain underscore the importance of not overlooking the radiation safety risks associated with tritium. The need for the online measurement of tritium at low concentrations is becoming increasingly apparent. This review examines the two principal stages of current measurement methodologies: sample preparation and radiation signal detection. It provides a summary of the tritium sample preparation and detection techniques, highlighting advances in the research with potential applications in online monitoring. The review concludes with an analysis of the issues inherent in the current techniques and offers perspectives on possible technological enhancements and future trajectories for the development of online monitoring systems for trace tritium levels.

A review of diamond dosimeters in advanced radiotherapy techniques.

This review article synthesizes key findings from studies on the use of diamond dosimeters in advanced radiotherapy techniques, showcasing their applications, challenges, and contributions to enhancing dosimetric accuracy. The article explores various dosimeters, highlighting synthetic diamond dosimeters as potential candidates especially due to their high spatial resolution and negligible ion recombination effect. The clinically validated commercial dosimeter, PTW microDiamond (mD), faces limitations in small fields, proton and hadron therapy and ultra-high dose per pulse (UHDPP) conditions. Variability in reported values for field sizes 2 2 is noted, reflecting the competition between volume averaging and density perturbation effects. PTW's introduction of flashDiamond (fD) holds promise for dosimetric measurements in UHDPP conditions and is reliable for commissioning ultra-high dose rate (UHDR) electron beam systems, pending the clinical validation of the device. Other advancements in diamond detectors, such as in 3D configurations and real-time dose per pulse x-ray detectors, are considered valuable in overcoming challenges posed by modern radiotherapy techniques, alongside relative dosimetry and pre-treatment verifications. The studies discussed collectively provide a comprehensive overview of the evolving landscape of diamond dosimetry in the field of radiotherapy, and offer insights into future directions for research and development in thefield.