ABSTRACTIntroductionProstate motion during external beam radiotherapy (EBRT) is common and typically managed using fiducial markers and cone beam CT (CBCT) scans for inter‐fractional motion correction. However, real‐time intra‐fractional motion management is less commonly implemented. This study evaluated the extent of intra‐fractional prostate motion using transperineal ultrasound (TPUS) and examined the impact of treatment time on prostate motion.MethodsPatients undergoing prostate EBRT with TPUS at a single institution from August 2016 to August 2021 were analysed. Pre‐treatment daily CBCT corrected inter‐fractional prostate shift. Continuous intra‐fractional prostate motion was recorded at two frames per second in three dimensions, with three‐dimensional (3D) displacement calculated as a vector. Motion data were modelled to determine the probability of the prostate remaining within pre‐specified PTV margins relative to treatment delivery time.ResultsThe study analysed 3364 fractions delivered to 122 patients. The mean treatment delivery time was 3.8 min. The prostate remained within a 5 mm margin with high frequencies in the superior–inferior (SI) and left–right (LR) directions, 97.8% and 98.4% of fractions respectively while 5.5% of fractions had deviations greater than 5 mm in the anterior–posterior (AP) direction. By contrast, the 3D vector exceeded a 5 mm margin in 14.5% of fractions. Drift motion modelling indicated a 99% probability of the vector staying within a 3 mm margin for 2 min, while for a 5 mm margin, the duration extended to 3.4 min.ConclusionsIntra‐fractional prostate motion monitoring is increasingly important as SABR with reduced PTV margins are utilised in prostate radiotherapy. Smaller PTV margins and longer treatment time require real‐time monitoring to avoid geographical miss.

PURPOSE:The use of magnetic resonance imaging (MRI) in radiotherapy planning is becoming more widespread, particularly with the emergence of MRI-guided radiotherapy systems. Existing guidelines for defining the prostate bed clinical target volume (CTV) show considerable heterogeneity. This study aimed to establish baseline interobserver variability (IOV) for prostate bed CTV contouring on MRI, develop international consensus guidelines, and evaluate its effect on IOV. METHODS AND MATERIALS:Participants delineated the CTV on 3 MRI scans, obtained from the Elekta Unity MR-Linac, as per their normal practice. Radiation oncologist contours were visually examined for discrepancies, and interobserver comparisons were evaluated against simultaneous truth and performance level estimation (STAPLE) contours using overlap metrics (Dice similarity coefficient and Cohen's kappa), distance metrics (mean distance to agreement and Hausdorff distance), and volume measurements. A literature review of postradical prostatectomy local recurrence patterns was performed and presented alongside IOV results to the participants. Consensus guidelines were collectively constructed, and IOV assessment was repeated using these guidelines. RESULTS:Sixteen radiation oncologists' contours were included in the final analysis. Visual evaluation demonstrated significant differences in the superior, inferior, and anterior borders. Baseline IOV assessment indicated moderate agreement for the overlap metrics while volume and distance metrics demonstrated greater variability. Consensus for optimal prostate bed CTV boundaries was established during a virtual meeting. After guideline development, a decrease in IOV was observed. The maximum volume ratio decreased from 4.7 to 3.1 and volume coefficient of variation reduced from 40% to 34%. The mean Dice similarity coefficient rose from 0.72 to 0.75 and the mean distance to agreement decreased from 3.63 to 2.95 mm. CONCLUSIONS:Interobserver variability in prostate bed contouring exists among international genitourinary experts, although this is lower than previously reported. Consensus guidelines for MRI-based prostate bed contouring have been developed, and this has resulted in an improvement in contouring concordance. However, IOV persists and strategies such as an education program, development of a contouring atlas, and further refinement of the guidelines may lead to additional improvements.

Background: Online adaptive MR-guided radiotherapy allows for the reduction of safety margins in dose escalated treatment of rectal tumors. With the use of smaller margins, precise tumor delineation becomes more critical. In the present study we investigated the impact of rectal ultrasound gel filling on interobserver variability in delineation of primary rectal tumor volumes. Methods: Six patients with locally advanced rectal cancer were scanned on a 1.5 T MRI-Linac without (MRI_e) and with application of 100 cc of ultrasound gel transanally (MRI_f). Eight international radiation oncologists expert in the treatment of gastrointestinal cancers delineated the gross tumor volume (GTV) on both MRI scans. MRI_f scans were provided to the participating centers after MRI_e scans had been returned. Interobserver variability was analyzed by either comparing the observers' delineations with a reference delineation (approach 1) and by building all possible pairs between observers (approach 2). Dice Similarity Index (DICE) and 95 % Hausdorff-Distance (95 %HD) were calculated. Results: Rectal ultrasound gel filling was well tolerated by all patients. Overall, interobserver agreement was superior in MRI_f scans based on median DICE (0.81 vs 0.74, p < 0.005 for approach 1 and 0.76 vs 0.64, p < 0.0001 for approach 2) and 95 %HD (6.9 mm vs 4.2 mm for approach 1, p = 0.04 and 8.9 mm vs 6.1 mm, p = 0.04 for approach 2). Delineated median tumor volumes and inter-quartile ranges were 26.99 cc [18.01-50.34 cc] in MRI_e and 44.20 [19.72-61.59 cc] in MRI_f scans respectively, p = 0.012. Conclusions: Although limited by the small number of patients, in this study the application of rectal ultrasound gel resulted in higher interobserver agreement in rectal GTV delineation. The endorectal gel filling might be a useful tool for future dose escalation strategies.

INTRODUCTION:The magnetic resonance linear accelerator (MRL) combines both magnetic resonance imaging and a linear accelerator, allowing for daily treatment adaptation. This study aimed to assess the impact of radiologist-delivered training in magnetic resonance (MR) contouring of relevant structures within the male pelvis.METHODS:Two radiation oncologists, two radiation oncology registrars and seven radiation therapists completed contouring on 10 male pelvis MR datasets both pre- and post-training. A 2-hour MR anatomy training session was delivered by a radiologist, who also provided the 'gold standard' contours. The pre- and post-training contours were compared against the gold standard with Dice similarity coefficient (DSC) and Hausdorff distances calculated; and the pre- and post-confidence scores and timing were compared.RESULTS:The improvement in DSC were significant in prostate, rectum and seminal vesicles, with a post-training median DSC of 0.87 ± 0.06, 0.92 ± 0.04 and 0.80 ± 0.14, respectively. The median Hausdorff improved with a median of 1.46 ± 0.78 mm, 0.52 ± 0.32 mm and 1.11 ± 0.86 mm for prostate, rectum and seminal vesicles, respectively. Bladder concordance was high both pre- and post-training. Urethra contours improved post-training, however, remained difficult to contour with a median post-DSC of 0.51 ± 0.24. Overall, confidence scoring improved (P < 0.001) and timing decreased by an average of 4.4 ± 16.4 min post-training.CONCLUSION:Radiologist-delivered training improved concordance of male pelvis contouring on MR datasets. Further work is required in the identification of urethra on MRs. These findings are of importance in the MRL adaptive workflow.

Purpose: To assess the literature on men's preferences and perceptions regarding prostate cancer radiation therapy. Methods: A scoping review was undertaken as per JBI guidelines. Searches were conducted in PubMed, CINAHL, Scopus and Science Direct with search terms including "prostate cancer," "radiotherapy," "radiation therapy," "radiation oncology," "patient preferences," "patient perceptions" and "patient experience." The resultant studies were mapped and grouped according to the emergent themes and pathway stages. Results: A total of 779 titles and abstracts were screened by two independent reviewers. Fifty-two full-text studies were reviewed, with 27 eligible for inclusion. There were 4 pre-treatment, 13 during treatment and 10 post-treatment studies covering broad themes of information needs (n = 3), preferences and decisions (n = 6), general experiences (n = 8), side effects (n = 6), and support (n = 4). There were a mix of methodologies, including 11 qualitative, 14 quantitative (including four preference studies), one mixed methods and one narrative review. Conclusion: There were only four preference studies, with the remaining 23 reporting on perceptions. Overall, there is a paucity of literature regarding patient preferences and perceptions of prostate cancer radiation therapy, particularly when considering how many clinical and technical studies are published in the area. This highlights opportunities for future research.

INTRODUCTION:There are several options for real-time prostate monitoring during radiation therapy including fiducial markers (FMs) and transperineal ultrasound (TPUS). However, the patient experience for these procedures is very different. This study aimed to determine patient preferences around various aspects of prostate image-guidance, focusing on FMs and TPUS.METHODS:A discrete choice experiment (DCE) was conducted, describing the image-guidance approach by: pain, cost, accuracy, side effects, additional appointments, and additional time. Participants were males with prostate cancer (PCa) and from the general Australian population. A DCE survey required participants to make hypothetical choices in each of 8 choice sets. Multinomial logit modelling and Latent Class Analysis (LCA) were used to analyse the responses. Marginal willingness to pay (mWTP) was calculated.RESULTS:476 respondents completed the survey (236 PCa patients and 240 general population). The most important attributes for both cohorts were pain, cost and accuracy (p < 0.01). PCa patients were willing to pay more to avoid the worst pain than the general population, and willing to pay more for increased accuracy. LCA revealed 3 groups: 2 were focused more on the process-related attributes of pain and cost, and the third was focused on the clinical efficacy attributes of accuracy and side effects.CONCLUSION:Both cohorts preferred less cost and pain and improved accuracy, with men with PCa valuing accuracy more than the general population. In addition to the clinical and technical evidence, radiation oncology centres should consider the preferences of patients when considering choice of image-guidance techniques.

Background:The complexity of prostate cancer care can impact on patient understanding and participation in shared decision-making. This study used a survey-based approach to investigate patients' recall of their prostate cancer treatment, and more broadly, to understand the perceptions of patients and the general population of prostate cancer treatment.Method:The survey was completed by 236 patients with prostate cancer (PCa cohort) and 240 participants from the general population of Australia (GenPop cohort). Free-text comments from both cohorts were analysed using content analysis. The PCa cohort reported which treatments and image-guidance related procedures they had received. These patient-reports were compared to medical records and analysed using proportion agreement, kappa statistics and regression analysis.Results:135 (57%) PCa and 99 (41%) GenPop respondents provided at least one comment. Five major themes were identified by both cohorts: sharing experiences of treatment; preferences insights and reflections; mindsets; general commentary on the survey; and factors missing from the survey. There was overall good treatment recall amongst the PCa cohort, with proportions of correct recall ranging from 97.3% for chemotherapy to 66.8% for hormone therapy. There was a tendency for younger patients (<70 years old) to recall their hormone treatment more correctly.Conclusion:Participant comments suggest the complexity of prostate cancer diagnosis and treatment, and the varying perceptions and experiences of participants with prostate cancer. Patients' recall overall was good for both treatment and image-guidance related procedures/approaches, however the poorer recall of hormone therapy requires further investigation.

Background and objectivesUsual practice for the insertion of prostate fiducial markers involves at least one week delay between insertion and simulation. An evidence-based practice change was implemented whereby fiducial marker insertion occurred on the same day as radiotherapy simulation. The aim of this study was to quantify the health service costs and clinical outcomes associated with this practice change.MethodsA cost-minimisation analysis was undertaken from the perspective of the local health service. A retrospective chart audit was conducted to collect data on 149 patients in the pre-implementation cohort and 138 patients in the post-implementation cohort. Associated costs with insertion and simulation were calculated and compared across the two cohorts; this included subsided travel costs for rural and remote patients. Fiducial marker positions on planning CT and first treatment CBCT were measured for all patients as the surrogate clinical outcome measure for oedema.ResultsThe health service saved an average of AU$ 361 (CI $311 – $412) per patient after the practice change. There was no significant difference in fiducial marker position pre- and post- implementation (p < 0.05).ConclusionThe practice change to perform insertion and radiotherapy simulation on the same day resulted in substantial savings to the health system, without compromising clinical outcomes. The decrease in number of required patient attendances is of real consequence to rural and remote populations. The practice change increases both the value and accessibility of best-practice health care to those most at risk of missing out.

INTRODUCTION:Inaccuracies in prostate apex contour delineation based on simulation computed tomography (CT) imaging can impact treatment outcomes and toxicity profiles for prostate cancer radiotherapy. Transperineal ultrasound (TPUS) is a non-invasive imaging modality that can improve delineation of prostate volumes. We performed a pilot analysis to assess for differences in anatomical position between conventional CT and a TPUS delineated prostate apex and determined whether these translated into a clinically significant difference in apical point dose.METHODS:A 2D 5 MHz TPUS autoscan image guidance system was utilised during definitive intensity-modulated radiotherapy (IMRT) for prostate cancer. Distances were measured from a fixed reference point to prostate apex on both US and CT in the mid-sagittal plane. Differences between groups were assessed using the Wilcoxon sign rank test with a two-tailed significance of α = 0.05.RESULTS:Fifty-nine consecutive patients were independently assessed. There was strong evidence of a difference between CT and TPUS delineated apex position (P = 0.0075). Median apex position was 3.6 mm caudal on TPUS vs. CT imaging (95% CI: 2.5-4.8 mm). There was strong evidence of a difference in point dose between CT and TPUS delineated apex (P = 0.0029). Median point dose at the TPUS contoured apex was 1.9 Gy lower than CT (95% CI: 0.7-3.1 Gy) corresponding to 98% of prescribed dose.CONCLUSIONS:This study demonstrates a difference in anatomical delineation of prostate apex position between CT imaging compared to TPUS, corresponding to a statistically significant difference in apex point dose. Further analysis will determine whether this translates to a clinically significant difference in outcomes.

BACKGROUND:Rectal cancer treatment outcomes for socioeconomically disadvantaged and regional patients have been suggested to be suboptimal in Australia. We investigate outcomes at a regional tertiary centre in order to determine the prognostic impact of patient and treatment factors.METHODS:Patients who underwent short and long course neoadjuvant therapy followed by surgery for stage II-III rectal cancer over an 11-year period were identified. Results were analysed to determine oncological and surgical outcomes along with whether patient and treatment-related variables were prognostic. Accessibility/Remoteness Index of Australia (ARIA) and Index of Relative Socioeconomic Disadvantage (IRSD) was used to determine remoteness and socioeconomic status, respectively.RESULTS:A total of 207 patients underwent short (n = 103, 49.8%) and long course (n = 104, 50.2%) over the time period; 81.6% (n = 169) were from outer regional, remote or very remote communities and 55.1% travelled >200 km for treatment; 57.0% were in the most disadvantaged three IRSD deciles. Five-year cancer-specific survival, recurrence-free survival and local recurrence were 83.1% (n = 172), 76.3% (n = 158) and 7.3% (n = 15), respectively. Wound complications were higher in outer regional, remote or very remote patients (25.4% versus 13.2%, P = 0.03). Remoteness, socioeconomic indices, distance to treatment and neoadjuvant type were not prognostic for any other oncological or surgical outcomes on univariate or multivariate analysis.CONCLUSIONS:Despite demography suggesting geographic and socioeconomic barriers, oncological and surgical outcomes at our regional centre were comparable to international and Australian trials. Further, these factors were not prognostic. Geographically remote patient's may safely have neoadjuvant modality individualized without compromising care.

Introduction: Fiducial markers (FMs) are commonly inserted into the prostate for image guided radiation therapy. This study aimed to quantify prostate oedema immediately following FM insertion compared to prostate volumes measured a week later, at the time of simulation for radiation therapy. Methods: Thirty patients underwent a verification computed tomography (VCT) scan in treatment position immediately after the fiducial insertion and their planning computed tomography scan (PCT) one week after. Patient data sets were retrospectively evaluated, comparing prostate volumes and planning target volumes (PTV). Volumes were delineated by a single radiation oncologist, blinded to whether the scan was VCT or PCT. Distances between the FMs were measured on both scans. Descriptive statistics described the data, DICE similarity co-efficient (DSC) calculated, and paired t-tests were used to compare paired data. Results: The median prostate volume was 35.09 cc and 36.31 cc for VCT and PCT data sets, respectively, and median PTV was 118.56 cc and 127.04 cc for VCT and PCT, respectively. There was no significant difference in prostate volumes (P = 0.3037) or PTV (P = 0.1279), with a DSC of 0.87 (range 0.76-0.91) and 0.91 (range 0.85 to 0.95), respectively. Similarly, there was no significant difference in distance between fiducial markers (P > 0.05). Conclusion: This study demonstrates no statistically significant difference in prostate or PTV volumes (P > 0.05) between the CT acquired at fiducial marker insertion compared with the CT acquired a week later. Therefore, oedema is not significant enough to justify a delay between FM insertion and simulation.

INTRODUCTION:Motion of the prostate is problematic in the accurate delivery of external beam radiation therapy (EBRT) for prostate cancer. This study investigated the relationship between body mass index (BMI), an easily measured indicator of obesity, and prostate motion.METHODS:Prostate motion during EBRT was assessed by measuring the displacement of fiducial markers implanted within the prostate in 130 prostate cancer patients. Interfractional motion was corrected on daily imaging through pre-treatment cone-beam-computed tomography (CBCT) and intrafractional motion measured using movie sequences captured using an electronic portal imaging device (EPID) during treatment delivery.RESULTS:There was no statistically significant relationship between the mean intrafractional motion and BMI, except in the left-right (LR) translation (P = 0.049) over the study population. For each BMI category, there was no statistical significance (P > 0.05) between any of the translations/rotations except LR (P = 0.003).CONCLUSION:While intrafractional motion is an important consideration, prostate motion cannot be reliably predicted through measurement of patient's BMI.

PurposeTo assess whether online adaptive radiotherapy for bladder cancer is feasible across multiple Radiation Oncology departments using different imaging, delivery and recording technology.Materials and methodsA multi-centre feasibility study of online adaptive radiotherapy, using a choice of three “plan of the day”, was conducted at 12 departments. Patients with muscle-invasive bladder cancer were included. Departments were activated if part of the pilot study or after a site-credentialing visit. There was real time review of the first two cases from each department.Results54 patients were recruited, with 50 proceeding to radiotherapy. There were 43 males and 7 females with a mean age of 78years. The tumour stages treated included T1 (1 patient), T2 (35), T3 (10) and T4 (4). One patient died of an unrelated cause during radiotherapy. The three adaptive plans were created before the 10th fraction in all cases. In 8 (16%) of the patients, a conventional plan using a ‘standard’ CTV to PTV margin of 1.5cm was used for one or more fractions where the pre-treatment bladder CTV was larger than any of the three adaptive plans. The bladder CTV extended beyond the PTV on post treatment imaging in 9 (18%) of the 49 patients.ConclusionsFrom a technical perspective an online adaptive radiotherapy technique can be instituted in a multi-centre setting. However, without further bladder filling control or imaging, a CTV to PTV margin of 7mm is insufficient.

Long-term hormonal therapy has long been regarded as the mainstay of treatment for men with locally advanced prostate cancer. 1 NICE: Prostate cancer: diagnosis and treatment. Full guideline. http://www.nice.org.uk/nicemedia/pdf/CG58FullGuideline.pdfDate: February 2008 Google Scholar , 2 Aus G Abbou CC Bolla M et al. EAU guidelines on prostate cancer. Eur Urol. 2005; 48: 546-551 Summary Full Text Full Text PDF PubMed Scopus (475) Google Scholar Four key randomised controlled trials 3 Studer U Whelan P Albrecht W et al. Immediate or deferred androgen deprivation for patients with prostate cancer not suitable for local treatment with curative intent: European Organisation for Research and Treatment of Cancer (EORTC) trial 30891. J Clin Oncol. 2006; 24: 1868-1876 Crossref PubMed Scopus (307) Google Scholar , 4 Bolla M Collette L Blank L et al. Long-term results with immediate androgen suppression and external irradiation in patients with locally advanced prostate cancer (an EORTC study): a phase III randomised trial. Lancet. 2002; 360: 103-108 Summary Full Text Full Text PDF PubMed Scopus (1581) Google Scholar , 5 Pilepich M Winter K Lawton C et al. Androgen suppression adjuvant to definitive radiotherapy in prostate carcinoma—long-term results of phase III RTOG 85–31. Int J Radiat Oncol Biol Phys. 2005; 61: 1285-1290 Summary Full Text Full Text PDF PubMed Scopus (814) Google Scholar , 6 McLeod DG Iversen P See WA et al. on behalf of the Casodex Early Prostate Cancer Trialists' GroupBicalutamide 150 mg plus standard care vs standard care alone for early prostate cancer. BJU Int. 2006; 97: 247-254 Crossref PubMed Scopus (250) Google Scholar have shown that early use of hormonal therapy leads to improved overall survival. There has been no consensus about whether or not radical local treatment should be used in addition to hormonal therapy, 7 Payne HA Gillatt DA Differences and commonalities in the management of locally advanced prostate cancer: results from a survey of oncologists and urologists in the UK. BJU Int. 2007; 99: 545-553 Crossref PubMed Scopus (23) Google Scholar , 8 Chong C Austen L Kneebone A Lalak A Jalaludin B Patterns of practice in the management of prostate cancer: results from multidisciplinary surveys of clinicians in Australia and New Zealand in 1995 and 2000. BJU Int. 2006; 97: 975-980 Crossref PubMed Scopus (7) Google Scholar and SPCG-7/SFUO-3, reported in The Lancet today, 9 Widmark A Klepp O Solberg A et al. the Scandinavian Prostate Cancer Group Study 7 and Swedish Association for Urological Oncology 3Endocrine treatment, with or without radiotherapy, in locally advanced prostate cancer (SPCG-7/SFUO-3): an open randomised phase III trial. Lancet. 2008; (published online Dec 16.)https://doi.org/10.1016/S0140-6736(08)61815-2 Summary Full Text Full Text PDF PubMed Scopus (715) Google Scholar is the first randomised trial to address this issue. Endocrine treatment, with or without radiotherapy, in locally advanced prostate cancer (SPCG-7/SFUO-3): an open randomised phase III trialIn patients with locally advanced or high-risk local prostate cancer, addition of local radiotherapy to endocrine treatment halved the 10-year prostate-cancer-specific mortality, and substantially decreased overall mortality with fully acceptable risk of side-effects compared with endocrine treatment alone. In the light of these data, endocrine treatment plus radiotherapy should be the new standard. Full-Text PDF Open Access

Large-scale HA/DR typically requires massive rescue operations from many organizations. Among the involved parties, ephemeral groups - those volunteers that happen to be readily available for help - are critical to a timely and massive rescue effort. Timely and accurate processing of crisis information and effective communication have been documented as critical elements of disaster relief operations. Despite the lessons learned from previous crises, preparing information for HA/DR and ineffective information sharing remain a recurring and almost unattainable task for relief agencies, especially in situations involving numerous ad-hoc groups. The purpose of this paper is to extend our earlier work that uses a template-based methodology to archive past disaster relief operations and communications, create "descriptive" templates for advanced preparedness, and design "normative" templates for fast execution of operations, while reducing miscommunications among aid agencies and ephemeral groups

Background Post-radiation sarcoma (PRS) is an uncommon disease manifesting as sarcoma in a previously irradiated field, usually with a latent period of 5 years or more. Literature is limited to small series. Optimal management of this disease is unclear. Positive margins are common following attempted curative surgery and outcomes are poor. Radiotherapy is hardly used and its effect on PRS is not known. We described a case of PRS treated with preoperative radiotherapy followed by margin-negative wide excision. Case presentation The 59-year-old patient presented with a mass in the left supraclavicular fossa and numbness in the arm, six years following radical irradiation of the head and neck for nasopharyngeal carcinoma. Open biopsy showed pleomorphic spindle cell sarcoma. She was treated with pre-operative hyperfractionated radiotherapy followed by margin-negative wide excision and nerve grafting. Cumulative radiation dose to the supraclavicular fossa was 98 Gy. Histological examination of the post-irradiation tumor specimens showed evidence of significant tumor response to re-irradiation. The patient remained free of disease five years after surgery with excellent functional outcome. Conclusion Role of radiotherapy in PRS is uncertain. We described a case that was successfully managed with preoperative radiotherapy and margin-negative wide excision in terms of tumor control and functional outcomes. The impact of radiotherapy was demonstrated in the post-irradiation resected specimen. Further investigation using re-irradiation and surgery in PRS is warranted.

PURPOSE:To determine the relationship between various parameters derived from lung dose-volume histogram analysis and the risk of symptomatic radiation pneumonitis (RP) in patients undergoing radical radiotherapy for primary lung cancer. METHODS AND MATERIALS:The records of 156 patients with lung cancer who had been treated with radical radiotherapy (>/=45 Gy) and for whom dose-volume histogram data were available were reviewed. The incidence of symptomatic RP was correlated with a variety of parameters derived from the dose-volume histogram data, including the volume of lung receiving 10 Gy (V(10)) through 50 Gy (V(50)) and the mean lung dose (MLD). RESULTS:The rate of RP at 6 months was 15% (95% confidence interval 9-22%). On univariate analysis, only V(30) (p = 0.036) and MLD (p = 0.043) were statistically significantly related to RP. V(30) correlated highly positively with MLD (r = 0.96, p < 0.001). CONCLUSION:V(30) and MLD can be used to predict the risk of RP in lung cancer patients undergoing radical radiotherapy.