This study compared the plan dosimetry between the intensity-modulated radiation therapy (IMRT) and field-in-field (FIF) technique for head-and-neck cancer using the Elekta Monaco treatment planning system (TPS).

A total of 20 head-and-neck cancer patients were selected in this study. IMRT and FIF plans for the patients were created on the Monaco TPS (ver. 5.11.02) using the 6-MV photon beam generated by the Elekta Synergy linear accelerator. The dose–volume histograms, maximum doses, minimum doses, mean doses of the target volumes and organs-at-risk (OARs), conformity index (CI), homogeneity index (HI) and monitor units (MUs) were determined for each IMRT and FIF plan. All IMRT plans passed the patient-specific quality assurance tests from the 2D diode array measurements (MatriXX Evolution System, IBA Dosimetry, Germany).

The results showed that the dose distribution to the target volumes of IMRT plans was better than FIF plans, while the dose (mean or max dose) to the OAR was significantly lower than FIF plan, respectively. IMRT and FIF resulted in planning target volume coverage with mean dose of 71·32 ± 0·76 and 73·12 ± 0·62 Gy, respectively, and HI values of 0·08 ± 0·01 (IMRT) and 0·19 ± 0·06 (FIF). The CI for IMRT was 0·98 ± 0·01 and FIF was 0·97 ± 0·01. For the spinal cord tolerance (maximum dose < 45 Gy), IMRT resulted in 39·85 ± 2·04 Gy compared to 41·37 ± 2·42 Gy for FIF. In addition, the mean doses to the parotid grand were 27·27 ± 7·48 and 48·68 ± 1·62 Gy for the IMRT and FIF plans, respectively. Significantly more MUs were required in IMRT plans than FIF plans (on average, 846 ± 100 MU in IMRT and 467 ± 41 MU in FIF).

It is concluded that the IMRT technique could provide a better plan dosimetry than the FIF technique for head-and-neck patients.

This study aims to compare the dosimetric parameters among four different external beam radiotherapy techniques used for the treatment of retinoblastoma.

Computed tomography (CT) sets of five retinoblastoma patients who required radiotherapy to one globe were included. Four different plans were generated for each patient using three dimensional conformal radiotherapy (3DCRT), intensity modulated radiotherapy (IMRT), volumetric modulated arc therapy (VMAT) and VMAT using flattening filter free (VMAT-FFF) beam techniques. Plans were compared for target coverage and organs at risk (OARs) sparing.

The target coverage of planning target volume (PTV) for all the four modalities were clinically acceptable with a V95 of 95 ± 0%, 97·6 ± 1·87%, 99·3 ± 0·5% and 99·17 ± 0·45% for 3DCRT, IMRT, VMAT and VMAT-FFF respectively. The VMAT and IMRT plans had better target coverage than the 3DCRT plans (p = 0·001 and p = 0·07 respectively). IMRT and VMAT plans were also found superior to 3DCRT plans in terms of OAR sparing like brainstem, optic chiasm, brain (p < 0·05). VMAT delivered significantly lower dose to the brainstem and contralateral optic nerve in comparison to IMRT. Use of VMAT-FFF beams did not show any benefit over VMAT in target coverage and OAR sparing.

VMAT should be preferred over 3DCRT and IMRT for treatment of retinoblastoma owing to better target coverage and less dose to most of the OARs. However, IMRT and VMAT should be used with caution because of the increased low dose volumes to the OARs like contralateral lens and eyeball.

Incidence rates of Human Papillomavirus (HPV) positive head and neck cancer (HNC) are increasing. The aim of this study was to explore the availability of information and the knowledge and confidence of healthcare professionals (HCPs) involved in the cancer pathway to provide information on HPV to patients.

An online questionnaire was designed using closed and open questions to investigate the availability of patient information for patients diagnosed with HPV-associated HNC; health professional’s knowledge of the information available; and their confidence in discussing the topic. The questionnaire was advertised to health professionals through the British Association of Head and Neck Oncologists website. Twenty-five health professionals from six professions across five UK Cancer Alliances completed the questionnaire between November and December 2018.

Nearly half of the participants did not know whether patients were routinely provided with information on HPV following an HPV-positive (HPV+) cancer diagnosis; 52% indicated that specific information was available within their hospital trust, however, there were inconsistencies with participants’ knowledge of the content of the information leaflets currently available. On a scale of 1–100, the mean confidence in providing HPV-related information was 58.

Inconsistencies appear to exist with respect to information about HPV available to patients presenting with HNC. A need has been identified for the education of health professionals involved in the patient care to support information provision.

Studying the use of Aperture Shape Controller (ASC) and Convergence Mode (CM) in Eclipse (Varian Medical System) in terms of plan quality and complexity of volumetric modulated arc therapy (VMAT).

Forty VMAT plans were re-optimised for the prostate, prostate + lymph nodes, breast and head & neck patients retrospectively, changing the ASC settings (off, moderate, very high) and CM settings (off, on and extended).

Using ‘on’ or ‘extended’ CM increased plan quality in terms of planning target volume homogeneity and low-dose spread to the organs at risk (OAR). ‘Extended’ CM increased the optimisation time 4·3-fold compared to ‘on’, and deteriorated the plan quality in several simple planning cases. ‘Moderate’ ASC decreased plan complexity with minor effect on plan quality compared to ‘off’, but ‘very high’ ASC had larger adverse dosimetric effects. However, the ASC decreased the plan complexity only if the CM was turned ‘on’.

Using ‘on’ CM increases the plan quality but using ‘extended’ CM is not recommended. The ‘moderate’ ASC decreased complexity without significant adverse effects on plan quality, and even ‘very high’ ASC may be used when plan simplicity is prioritised. However, if CM is not used, the ASC should also be turned off.

Lung cancer is the most commonly diagnosed cancer in Canada and the leading cause of cancer-related mortality in both men and women in North America. Surgery is usually the primary treatment option for early-stage non-small cell lung cancer (NSCLC). However, for patients who may not be suitable candidates for surgery, stereotactic body radiation therapy (SBRT) is an alternative method of treatment. SBRT has proven to be an effective technique for treating NSCLC patients by focally administering high radiation dose to the tumour with acceptable risk of toxicity to surrounding healthy tissues. The goal of this comprehensive retrospective dosimetric study is to compare the dosimetric parameters between three-dimensional conformal radiation therapy (3DCRT) and volumetric-modulated arc therapy (VMAT) lung SBRT treatment plans for two prescription doses.

We retrospectively analysed and compared lung SBRT treatment plans of 263 patients treated with either a 3DCRT non-coplanar or with 2–3 VMAT arcs technique at 48 Gy in 4 fractions (48 Gy/4) or 50 Gy in 5 fractions (50 Gy/5) prescribed to the planning target volume (PTV), typically encompassing the 80% isodose volume. All patients were treated on either a Varian 21EX or TrueBeam linear accelerator using 6-MV or 10-MV photon beams.

The mean PTV V95% and V100% for treatment plans at 48 Gy/4 are 99·4 ± 0·6% and 96·0 ± 1·0%, respectively, for 3DCRT and 99·7 ± 0·4% and 96·4 ± 3·4%, respectively, for VMAT. The corresponding mean PTV V95% and V100% at 50 Gy/5 are 99·0 ± 1·4% and 95·5 ± 2·5% for 3DCRT and 99·5 ± 0·8% and 96·1 ± 1·6% for VMAT. The CIRI and HI5/95 for the PTV at 48 Gy/4 are 1·1 ± 0·1 and 1·2 ± 0·0 for 3DCRT and 1·0 ± 0·1 and 1·2 ± 0·0 for VMAT. The corresponding CIRI and HI5/95 at 50 Gy/5 are 1·1 ± 0·1 and 1·3 ± 0·1 for 3DCRT and 1·0 ± 0·1 and 1·2 ± 0·0 for VMAT. The mean R50% and D2cm at 48 Gy/4 are 5·0 ± 0·8 and 61·2 ± 7·0% for 3DCRT and 4·9 ± 0·8 and 57·8 ± 7·9% for VMAT. The corresponding R50% and D2cm at 50 Gy/5 are 4·7 ± 0·5 and 65·5 ± 9·4% for 3DCRT and 4·7 ± 0·7 and 60·0 ± 7·2% for VMAT.

The use of 3DCRT or VMAT technique for lung SBRT is an efficient and reliable method for achieving dose conformity, rapid dose fall-off and minimising doses to the organs at risk. The VMAT technique resulted in improved dose conformity, rapid dose fall-off from the PTV compared to 3DCRT, although the magnitude may not be clinically significant.

The present study reports myeloablative total body irradiation (TBI) on an isocentrically mounted linac by laying the patient on the floor and management of abutting radiation fields and partial shielding of lungs. Dosimetrical efficacy of this novel technique was evaluated.

In this retrospective study, dosimetrical parameters from TBI plans on whole-body CT scans of 46 patients were analysed. The prescribed dose to TBI was 12 Gy in six fractions delivered over a period of 3 days for myeloablative conditioning. TrueBeam STx platform Linac (Varian Medical Systems Inc., Palo Alto, CA, USA) was used to deliver opposing fields. Radiation fields were abutted to form a single large field using an arithmetic formula at source-to-skin-distance of 210 cm.

Discrepancies in dose calculated by treatment planning system were within 1·6% accuracy, and dose profile at the junction of abutting radiation fields was reproduced within 3·0% accuracy. The real treatment time for each patient was ~30 minutes/fraction. Monitor unit was weighted for multiple sub-fields to achieve dose homogeneity within 5·0% throughout the whole body, and the mean dose to lung was ≤10 Gy.

Our abutting radiation field technique for myeloablative TBI is feasible in any existing linac bunker. ‘Island-blocking’ is feasible in this technique using multi-leaf collimator. This technique is cost-effective as it does not require any costly equipment than the readily available equipment in any radiotherapy facility. In general, TBI requires laborious planning procedures and spacious linac bunkers; this novel technique has the potential to change previously held notions.

To explore student therapeutic radiographers’ understanding of obesity and cancer and to identify if student therapeutic radiographers believe that radiographers should have a role within weight management.

This study used a self-completed online questionnaire (google forms) to collect data from Radiotherapy and Oncology students, studying at one Higher Education Institution, to gain an understanding of their current knowledge of weight management. A retrospective margin of error calculation was carried out, showing a 9% margin of error with a 90% confidence level.

In total 57 responses were received, n = 50 BSc students and n = 7 pre-registration MSc students. Three key barriers to openly discussing weight loss management with service users emerged from the questionnaire data; these were a lack of time, lack of clear guidelines and lack of confidence. These barriers could potentially be addressed by improving education and training, making it easier for therapeutic radiographers to openly discuss weight management with service users.

Awareness of guidelines was suboptimal, with 82% (n = 47) of respondents unaware of any guidelines. In addition to this, the majority of students identified a lack of confidence as a barrier to them providing weight management advice. Despite this, 54·4% of respondents agreed that radiographers should have a role in providing weight management advice, with 22·2% of respondents being unsure. Findings suggest that behaviour change is required amounts both students and staff members, so that healthcare professionals are more inclined to have healthy weight management discussions. Perhaps more specialist roles need to be developed, so that healthy weight management discussions can become a norm.

Choroidal metastases are the most frequent intraocular secondary tumours, with a prevalence of 2–7% according to the literature. Our aim was to review a clinical case of choroidal metastasis.

We present a case of a 63-year-old male patient diagnosed in 2018 with lung adenocarcinoma cT4N0M1. The patient had three metastases in the brain, which were successfully treated with radiosurgery (RS). The patient was treated with chemotherapy with pemetrexed–cisplatin schedule. Five months after diagnosis, the patient presented with decreased vision in the right eye. After ophthalmologic evaluation, he was diagnosed with a right choroidal metastasis, which was treated with external beam radiotherapy with 20 Gy in five fractions, resulting in improved visual acuity and a complete clinical and radiological response.

The patient took part in a clinical trial that continued with systemic chemotherapy. Twenty-two months after radiotherapy to the eye, the patient has good visual acuity without any side effects.

Choroidal metastasis treated with radiotherapy achieves good local control, with limited side effects, allowing an improvement in visual acuity and consequently, an improvement in the patient´s quality of life.

Electron blocks are typically composed of a low melting point alloy (LMPA), which is poured into an insert frame containing a manually placed Styrofoam aperture negative used to define the desired field shape. Current implementations of the block fabrication process involve numerous steps which are subjective and prone to user error. Occasionally, bowing of the sides of the insert frame is observed, resulting in premature frame decommissioning. Recent works have investigated the feasibility of utilising 3D printing technology to replace the conventional electron block fabrication workflow; however, these approaches involved long print times, were not compatible with commonly used cadmium-free LMPAs, and did not address the problem of insert frame bowing. In this work, we sought to develop a new 3D printing technique that would remedy these issues.

Electron cutout negatives and alignment jigs were printed using Acrylonitrile Butadiene Styrene, which does not warp at the high temperatures associated with molten cadmium-free alloys. The accuracy of the field shape produced by electron blocks fabricated using the 3D printed negatives was assessed using Gafchromic film and beam profiler measurements. As a proof-of-concept, electron blocks with off-axis apertures, as well as complex multi-aperture blocks to be used for passive electron beam intensity modulation, were also created.

Film and profiler measurements of field size were in excellent agreement with the values calculated using the Eclipse treatment planning system, showing less than a 1% difference in line profile full-width at half-maximum. The multi-aperture electron blocks produced fields with intensity modulation ≤3.2% of the theoretically predicted value. Use of the 3D printed alignment jig – which has contours designed to match those of the insert frame – was found to reduce the amount of frame bowing by factors of 1.8 and 2.1 in the lateral and superior–inferior directions, respectively.

The 3D printed ABS negatives generated with our technique maintain their spatial accuracy even at the higher temperatures associated with cadmium-free LMPA. The negatives typically take between 1 and 2 hours to print and have a material cost of approximately $2 per patient.

To study the feasibility of constant dose rate volumetric modulated arc therapy (CDR-VMAT) in radiotherapy for gallbladder cancer by comparing dosimetric parameter suggested by International Commission on Radiation Units and Measurements-83 (ICRU-83) with step and shoot intensity-modulated radiation therapy (SS IMRT).

For this study, we selected 21 post-operative gallbladder cancer patients, which were treated with the IMRT technique from 2016 to 2019. For each patient, we generated SS IMRT plan and CDR-VMAT plan and were dosimetrically compared by parameters suggested by ICRU-83 for PTV. Homogeneity Index (HI) and Conformity Index (CI) were also calculated. For evaluation of Organ at Risk (OAR), we compared the mean doses, volume doses to the right kidney, left kidney, both kidneys combined, liver and max dose to the spinal cord. Monitor units (MUs) and treatment delivery time were also compared.

On comparing, we found that CDR-VMAT plans were highly conformed as CI and PCI (CI define by Paddick) were found more (0·98 ± 0·01 vs. 0·97 ± 0·03 and 0·86 ± 0·05 vs. 0·85 ± 0·05) than IMRT plans but not statistically significant. Better dose HI was found for IMRT plans with statistical significant difference (p < 0·001). The tumour coverage was found similar 98·24% and 97·83% for SS IMRT and CDR-VMAT, respectively. For D2%, the maximum dose to PTV was significantly lower in IMRT (p = 0·001). D50% and mean dose to PTV were also comparable to IMRT with no statistically significant difference. The OAR parameters were comparable in both the techniques. The mean doses and volume doses V10, V20 and V30 to the right kidney, left kidney and liver were also comparable with no significant difference (p > 0·05) was noted among them. However, the maximum dose to the spinal cord was significantly less in CDR-VMAT (21·1 Gy vs. 25·1Gy) than SS IMRT with p = 0·006. More MUs were associated with the CDR-VMAT technique, but shorter treatment delivery time than the IMRT technique.

On dosimetric comparison of two treatment techniques, we conclude that CDR-VMAT can be a valid option in radiotherapy as it achieved highly conformed dose distribution, comparable tumour coverage and OAR sparing as IMRT technique for gallbladder cancer.

Radiation exposure to the thyroid gland during breast irradiation can lead to hypothyroidism and this can impact on the quality of life. The aim of this study was to analyse if there is any difference in the radiation dose received by the thyroid gland during supraclavicular irradiation for breast cancer, with two different neck positions—straight or when the head is turned to the contralateral side to the breast being treated, when using a conformal technique.

All patients who received chest wall/breast and supraclavicular irradiation for breast cancer in 2019 in our department were divided into two groups based on the neck position as SN (neck positioned straight) and TN (neck tilted to contralateral side). The volume of thyroid gland, the radiation dose and volume parameters for Dmax, Dmean, and V5 to V40 of the thyroid were tabulated.

There were 72 patients included in the study with a mean age of 59 years, with 39 in the SN group and 33 in the TN group. There was no significant difference in thyroid volume between the two groups. Dmean, V15, V20, V25, V30 and V35 were significantly lower in tilted neck patients as compared to straight neck patients.

Neck positioned to the contralateral side of the breast primary may be recommended for conformal CT-based radiation planning.

To evaluate the efficacy of concurrent chemotherapy and high-dose (≥55 Gy) intensity-modulated radiotherapy (CCIMRT) in comparison with chemotherapy alone and intensity-modulated radiotherapy (IMRT) alone for unresectable locally advanced or metastatic pancreatic cancer.

Forty-six patients with pancreatic cancer undergoing CCIMRT (n = 17), chemotherapy alone (n = 16) or IMRT alone (n = 13) were analysed. Overall survival (OS), locoregional progression-free survival (LRPFS) and gastrointestinal toxicities were evaluated. The median radiation dose was 60 Gy (range, 55–60) delivered in a median of 25 fractions (range, 24–30). Gemcitabine (GEM) alone, GEM + S-1, S-1 alone, FOLFIRINOX and GEM + nab-paclitaxel were used in CCIMRT and chemo-monotherapy.

The 1-year OS rate was 69% in the CCIMRT group, 27% in the chemotherapy group and 38% in the IMRT group (p = 0·12). The 1-year LRPFS rate was 73, 0 and 40% in the 3 groups, respectively (p = 0·012). Acute Grade ≥ 2 gastrointestinal toxicity (nausea, diarrhea) was observed in 12% (2/17) in the CCIMRT group, 25% (4/16) in the chemotherapy group and 7·7% (1/13) in the IMRT group (p = 0·38). Late Grade 3 gastrointestinal bleeding was observed in 6·3% (1/16) in the chemotherapy group.

High-dose CCIMRT yielded acceptable toxicity and favorable OS and LRPFS.

Breast cancer is the most commonly diagnosed malignancy among women and accounts for about 25% of all new cancer cases and 13% of all cancer deaths in Canadian women. It is a highly heterogeneous disease, encompassing multiple tumour entities, each characterised by distinct morphology, behaviour and clinical implications. Moreover, different breast tumour subtypes have different risk factors, clinical presentation, histopathological features, outcome and response to systemic therapies. Therefore, any strategies capable of the stratification of breast cancer by clinically relevant subtypes are an important requirement for personalised and targeted treatment. Therefore, in the advancement towards the concept of precision medicine that takes individual patient variability into account, several investigators have focused on the identification of effective clinical breast cancer biomarkers that interrogate key aberrant pathways potentially targetable with molecular targeted or immunological therapies.

This paper reports on a review of 11 current clinical and emerging biomarkers used in screening for early detection and diagnosis, to stratify patients by disease subtype, to identify patients’ risk for metastatic disease and subsequent relapse, to monitor patient response to specific treatment and to provide clinicians the possibility of prospectively identifying groups of patients who will benefit from a particular treatment.

The future holds promising for the use of effective clinical breast cancer biomarkers for early detection and personalised patient-specific targeted treatment and increased patient survival. Breast cancer biomarkers can potentially assist in early-staged, non-invasive, sensitive and specific breast cancer detection and screening, provide clinically useful information for identification of patients with a greater likelihood of benefiting from the specific treatment, offer a better understanding of the metastatic process in cancer patients, predict disease and for patients with the established disease can assist define the nature of the disease, monitor the success of treatment and guide the clinical management of the disease.

The objective of this study has been to identify monitor unit (MU) and treatment time variations, volume coverage dissimilarity among 3D conformal radiation therapy (3D-CRT), intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) treatment plans for head and neck cancer (HNC) based on literature review.

A number of HNC cases were studied with the investigation of conformity and homogeneity index.

When high-dose modulation was required around small organs at risk (OARs), a clinically acceptable IMRT plan was achieved as VMAT usually required longer dose optimisation time. The greatest benefit of VMAT has been rapid treatment delivery allowing improved patient comfort, reduced intra-fraction motion and increased patient throughput. In some papers, 3D-CRT was shown not to meet well the requirements on parotid glands. One paper showed that cerebellum dose was lower for 3D-CRT than IMRT. However, it was found in other papers that OAR sparing with 3D-CRT was reasonable but in complex cases not enough.

IMRT usually consists of several treatment fields with different directions, hundreds of beam lets with modulated intensity, an advantage over 3D-CRT, whereas VMAT has advantage over IMRT due to rotating beam utilisation. VMAT has lower total MU and treatment times than IMRT and 3D-CRT, while maintaining similar dosimetric endpoints.

The Coronavirus disease 2019 (COVID-19) is spreading rapidly throughout the world. Lung is the primary organ which the COVID-19 virus affects and leads to pneumonia, an acute respiratory distress syndrome. COVID-19 infects the lower respiratory system, and the lung’s response to this infection is recruiting macrophages and monocytes leading to inflammation, this response causes widespread damage to the lung’s airways.

The purpose of this study is to review studies of using low-dose radiation as a treatment for the inflammation of the tissue and pneumonia resulting from COVID-19. These studies were compared with the risk of developing lung cancer during performed dose for the treatment of COVID-19 in radiation therapy.

Our study focused on in vitro, in vivo and clinical reports of using low-dose radiation for the treatment of inflammation, pneumonia and COVID-19. The risk of lung cancer resulting from suggested dose in these studies was also evaluated.

From the review of articles, we have found that low-dose radiation can lead to improvement in inflammation in different line cells and animals; in addition, it has been effective in treating inflammation and pneumonia caused by COVID-19 in human up to 80%. Since suggested doses do not remarkably increase the lung cancer risk, low-dose radiation can be an adjuvant treatment for COVID-19 patients.

Oesophageal carcinoma is one of the fatal cancers mainly because of its rapid spread and poor prognosis. Treatment modalities involves a multimodality approach, including surgery, radiation therapy and chemotherapy. Radiation therapy includes brachytherapy in the form of intraluminal radiation therapy. Brachytherapy permits delivery of high tumouricidal doses to superficial cancerous growth of the oesophagus while delivering much lower doses to the surrounding tissue. It is mostly given in combination with external beam radiation in patients with poor performance scores not likely to tolerate an aggressive chemoradiation regimen or as a boost to concurrent chemoradiotherapy. It is very effective in terms of local tumour control as well as in relieving symptoms in advanced/recurrent disease. Intraoperative brachytherapy and seed brachytherapy have also been tried to address the nodal disease.

We undertook a review of the available literature and techniques developed in the past three decades to emphasise the role of brachytherapy in curative or palliative settings in the treatment of oesophageal carcinoma.

Oesophageal brachytherapy will remain a tangible treatment of oesophageal cancer, although it is less commonly used due to high expertise requirement, lack of established evidence, risk of life-threatening complications and lack of interest in brachytherapy. It offers quick and useful palliation for a prolonged period, along with good quality of life and superior dosimetry. Use of novel applicators may allow dose escalation and lower toxicity. Seed brachytherapy is also emerging as a promising option in nodal recurrences.

Prostate cancer is the most commonly diagnosed cancer in men and it is responsible for about 10% of all cancer mortality in Canadian men. The current ‘gold standard’ for the diagnosis of prostate cancer is a prostate biopsy and the decision on when to biopsy a patient with non-suspicious Digital Rectal Examination (DRE) result and total prostate specific antigen (tPSA) of 4–10 ng/ml can be challenging. In order to shift the treatment paradigm of prostate cancer toward more personalised and targeted therapy, there is the need for a clear system that makes its detection binary so as to decrease the rate of inaccurate detections. Therefore in recent years, there have been several investigations into the development of various biomarkers with high sensitivity and specificity for screening, early detection and personalised patient-specific targeted medicine from diagnosis to treatment of the disease.

This paper reports on nine currently available clinical biomarkers used in screening for early detection and diagnosis, to reduce the number of unnecessary biopsies, in risk assessment of aggressive disease and in monitoring treatment response of prostate cancer.

Current clinical prostate cancer biomarkers have the potential for a personalised risk assessment of aggressive disease and the risk of developing distant metastatic disease and have been proven to be useful tools to guide clinicians in personalised patient-specific targeted treatment and in the shared decision making between patients and their physicians regarding prostate biopsy and treatment. Using biomarkers to select patients with a significant probability of aggressive prostate cancer would potentially avoid premature death from the disease, while at the same time would safely preclude patients who do not require unnecessary invasive intervention.

Merkel cell carcinoma (MCC) is a rare and highly aggressive neuroendocrine malignancy typically involving the skin. The majority of MCC involves the head/neck region and the extremities. Despite the aggressive nature of the disease, there have been several case studies that report spontaneous regression. We report a unique case of spontaneous regression of an MCC in a peculiar region in the anterior mediastinum with no cutaneous involvement.

A 50-year-old man who presented with a mobile low anterior neck mass, proven by biopsy, to be MCC. Subsequent PET/CT confirmed an FDG (Flurodeoxyglucose)-avid upper mediastinal mass. The mass gradually regressed over the course of 1 month subsequent to biopsy and was no longer palpable on exam or visible on subsequent CT scans. The patient was treated with intensity modulated radiation therapy with a total dose of 6,160 cGy in 28 fractions to the site of previously visible primary disease. At-risk nodal basins were also treated. On subsequent follow-up, the patient continued to have no clinical or radiographic signs of disease.

Spontaneous regression of an MCC is rare but has been reported mostly in the head/neck region following biopsy. It is unknown why spontaneous regression occurs. There is a possibility that biopsy may stimulate T-lymphocytes resulting in spontaneous regression.

This is the first case to our knowledge of spontaneous regression of an MCC in the anterior mediastinum with no cutaneous involvement. Most MCC are seen clinically due to skin changes with a majority of cases occurring in the head/neck region.

Giant cell tumour of the tendon sheath (GCTTS) is the second most common tumour of the hand. Despite surgery, local recurrence after excision has been reported in up to 45% of cases. Post-operative radiotherapy (PORT) has been found to be promising in preventing these recurrences in high-risk group. One of the reservations of PORT is secondary effects of radiation which may cause a decreased range of motion of the affected joint, sensory changes and nail changes. Surface mould brachytherapy can provide a high dose to target volume with a rapid fall of dose to surrounding structures. Despite this, it is less used, the possible reason can be less technical proficiency.

We have technically illustrated surface mould brachytherapy in a case of GCTTS of the left index finger, and compared dosimetrically with more widely used conventional photon and electron external beam radiotherapy.

The 6-MV photon treatment plan with a bolus plan provided the least dose to skin (106%) and phalanges (103%). It has a Homogeneity index (1·06) closest to 1, whereas the Conformity index of all plans was similar. The dose coverage was adequate in all plans. The second-best plan dosimetrically was the surface mould brachytherapy.

The aim of this case report is to describe the clinical presentation and imaging features of a patient with optic nerve leukaemic infiltration as the first site of relapse after complete response to systemic treatment.

We report the case of a 23-year-old man with history of acute lymphoblastic leukaemia (ALL) in complete remission. Six months later, the ocular examination revealed decreased visual acuity. Fundus examination showed a pale optic disk with blurred margins and multiple flame-shaped and dot and blot retinal haemorrhages in his left eye. A diagnosis of leukaemic infiltration to the optic nerve was made by magnetic resonance imaging (MRI). Cytological analysis of the cerebrospinal fluid did not show any abnormal cells or blasts.

A course of oral corticosteroid therapy was prescribed and 20 Gy of radiation was administered to the whole brain including the left orbit. Vision was improved dramatically in the left eye. Isolated optic nerve relapse of leukaemic infiltration is of paramount importance to early diagnosis, as vision can be saved if treatment with orbital radiotherapy is initiated promptly.