Radiation therapy has historically used margins for target volume to ensure dosimetric planning criteria. The size of margin for a given treatment site is still uncertain particularly for moving targets along with set-up variations leading to a fuzziness of target volume. In this study, we have estimated the dosimetric benefit of normal structures using biological-based optimal margins. The treatment margins are derived by knowledge-based fuzzy logic technique which is considering the radiotherapy uncertainties in treatment planning.

All treatment plans were performed using stepped increments of asymmetric margins to estimate prostate radiobiological indices such as tumour control probability (TCP) and normal tissue complication probability (NTCP). An absolute NTCP of 5% was considered to be the maximum acceptable value while TCP of 85% was considered to be the minimal acceptable limit for each volumetric modulated arc therapy (VMAT) plan of localised prostate cancer radiotherapy. Results were used to formulate rules and membership functions for Mamdani-type fuzzy inference system (FIS). In implementing the rules for the fuzzy system for ΔNTCP values above 10%, the PTV margin was not permitted to exceed 5 mm to avoid rectal complications due to margin selection. The new margins were applied in VMAT planning of prostate cancer for standard displacement errors. The dosimetric results of normal tissue predictors were estimated such as organ mean doses, rectum V60 (volume receiving 60 Gy), bladder V65 (volume receiving 65 Gy) and other clinically significant dose–volume indicators and compared with VMAT plans using current margin formulations.

Dosimetric results compared well to the results obtained by current techniques. Good agreement was obtained between proposed fuzzy model margins and currently used margins in lower error magnitude, but significant results were observed at higher error magnitude when organ toxicity concerned without compromising the target volumes.

The new margins may be helpful to estimate possible outcomes of normal tissue complications and thus may improve complication free survival particularly when organ motion errors are inevitable, case by case.

This study dosimetrically compared volumetric-modulated arc therapy (VMAT) to intensity-modulated arc therapy (IMRT) for patients with liver carcinoma.

Ten patients with liver carcinoma previously treated with IMRT or VMAT were retrospectively selected for this study. Each patient received a total dose of 54 Gy in 1·8 Gy fractions. Dosimetric evaluations for each patient were performed using the dose–volume histograms (DVHs) for planning target volumes (PTVs) and organs at risk (OAR). All dosimetric parameters were statistically analysed using mean values, standard deviations and p-values for determining the significance. The conformality index (CI) and homogeneity index (HI) were calculated and compared. For efficiency evaluation, monitor units (MUs) and beam on times (BOT) were recorded.

Compared to IMRT, VMAT plans showed significant differences in the heterogeneity with p < 0·01 and insignificant differences in both conformality and normal tissue sparing. VMAT required marginally fewer mean MU and shorter BOT when compared to IMRT with insignificant differences.

For radiation therapy treatment of liver carcinoma, IMRT and VMAT can achieve similar PTV coverage and normal tissue sparing. Treatment time is only marginally shorter with VMAT versus IMRT with insignificant differences.

A middle-aged gentleman presenting with dyspnoea was presumptively assumed to be a novel coronavirus suspect.

Nasopharyngeal and oropharyngeal swabs were reported negative, and clinico-radiological workup revealed a case of adenoid cystic carcinoma (ACC) of the lung with metastases to the contralateral lung and the lumbar vertebrae.

ACC is a rare malignancy of exocrine glands. Most commonly found in the minor salivary glands, they may rarely occur in other sites. Primary ACC of the lung is a rare histologic subtype that is encountered infrequently in clinical practice for which standard guidelines do not exist.

Bullous pemphigoid (BP) is the most common autoimmune bullous disease, which is usually seen in older ages. Rarely, radiotherapy (RT) has been reported as a localised trigger factor for BP.

We present a case of a 64-year-old woman who underwent radical mastectomy and radiation therapy for breast cancer. Two months after the completion of RT with adjuvant Trastuzumab, a BP eruption developed in the irradiated area, spreading thereafter to other skin areas. The patient was treated with oral corticosteroids and the lesions evolved favourably.

This case demonstrates a relatively benign skin reaction that could develop during the course of cancer treatment, which required co-management by oncologists, pathologists and dermatologists.

To investigate the use of co-registration of the computerised tomography (CT) planning scan with transperineal ultrasound (TPUS) as an aid to the delineation of the clinical target volume (CTV), and the use of TPUS as a tool for inter- and intra-fractional monitoring in men with bilateral hip prostheses (b-P) undergoing prostate radiotherapy.

We marked the CTV of three patients with and without the co-registered TPUS images. A metal artefact reduction algorithm was utilised. Two patients were treated with intensity-modulated radiotherapy (IMRT) and one with volumetric-modulated arc therapy (VMAT). The inter- and intra-fractional monitoring details were reviewed retrospectively.

Clinician marking with TPUS/CT fusion improved the confidence of prostate CTV delineation leading to a consistent change in volumes across two observers. Inter- and intra-fractional monitoring was possible using TPUS as image guidance, as it is for those patients with non-prosthetic hips.

Using TPUS in the radiotherapy workflow has enabled us to more confidently plan, treat and monitor patients with b-HP. Due to transperineal image acquisition, the ultrasound images are not affected by the presence of hip prostheses, which are outside the field of view.