• IMRT dose fractionation for head and neck cancer: variation in current approaches will make standardisation difficult.

      Ho, Kean F; Fowler, Jack F; Sykes, Andrew J; Yap, Beng K; Lee, Lip W; Slevin, Nicholas J; Academic Department of Radiation Oncology, University of Manchester, Christie Hospital, Wilmslow Road, Manchester, UK. (2009)
      INTRODUCTION: Altered fractionation has demonstrated clinical benefits compared to the conventional 2 Gy/day standard of 70 Gy. When using synchronous chemotherapy, there is uncertainty about optimum fractionation. IMRT with its potential for Simultaneous Integrated Boost (SIB) adds further to this uncertainty. This survey will examine international practice of IMRT fractionation and suggest possible reasons for diversity in approach. MATERIAL AND METHODS: Fourteen international cancer centres were surveyed for IMRT dose/fractionation practised in each centre. RESULTS: Twelve different types of dose fractionation were reported. Conventional 70-72 Gy (daily 2 Gy/fraction) was used in 3/14 centres with concurrent chemotherapy while 11/14 centres used altered fractionation. Two centres used >1 schedule. Reported schedules and number of centres included 6 fractions/week DAHANCA regime (3), modest hypofractionation (< or =2.2 Gy/fraction) (3), dose-escalated hypofractionation (> or =2.3 Gy/fraction) (4), hyperfractionation (1), continuous acceleration (1) and concomitant boost (1). Reasons for dose fractionation variability include (i) dose escalation; (ii) total irradiated volume; (iii) number of target volumes; (iv) synchronous systemic treatment; (v) shorter overall treatment time; (vi) resources availability; (vii) longer time on treatment couch; (viii) variable GTV margins; (ix) confidence in treatment setup; (x) late tissue toxicity and (xi) use of lower neck anterior fields. CONCLUSIONS: This variability in IMRT fractionation makes any meaningful comparison of treatment results difficult. Some standardization is needed particularly for design of multi-centre randomized clinical trials.
    • Inter-fraction motion and dosimetric consequences during breast intensity-modulated radiotherapy (IMRT).

      Jain, Pooja; Marchant, Thomas E; Green, Melanie M; Watkins, Gillian R; Davies, Julie; McCarthy, Claire; Loncaster, Juliette A; Stewart, Alan L; Magee, Brian; Moore, Christopher J; et al. (2009-01)
      BACKGROUND AND PURPOSE: Intensity-modulated radiotherapy (IMRT) can improve dose homogeneity within the breast planned target volume (PTV), but may be more susceptible to patient/organ motion than standard tangential radiotherapy (RT). We used daily cone-beam CT (CBCT) imaging to assess inter-fraction motion during breast IMRT and its subsequent impact on IMRT and standard RT dose homogeneity. MATERIALS AND METHODS: Ten breast cancer patients selected for IMRT were studied. CBCT images were acquired immediately after daily treatment. Automatic image co-registration was used to determine patient positioning variations. Daily PTV contours were used to calculate PTV variations and daily delivered IMRT and theoretically planned tangential RT dose. RESULTS: Group systematic (and random) setup errors detected by CBCT were 5.7 (3.9)mm laterally, 2.8 (3.5)mm vertically and 2.3 (3.2)mm longitudinally. Rotations >2 degrees in any axis occurred on 53/106 (50%) occasions. Daily PTV volume varied up to 23%. IMRT dose homogeneity was superior at planning and throughout the treatment compared with standard RT (1.8% vs. 15.8% PTV received >105% planned mean dose), despite increased motion sensitivity. CONCLUSIONS: CBCT revealed inadequacies of current patient positioning and verification procedures during breast RT and confirmed improved dose homogeneity using IMRT for the patients studied.
    • A novel imaging technique for fusion of high-quality immobilised MR images of the head and neck with CT scans for radiotherapy target delineation.

      Webster, Gareth J; Kilgallon, J E; Ho, Kean F; Rowbottom, Carl G; Slevin, Nicholas J; Mackay, Ranald I; North Western Medical Physics, Christie Hospital NHS Foundation Trust, Manchester, UK. gareth.webster@physics.cr.man.ac.uk (2009-06)
      Uncertainty and inconsistency are observed in target volume delineation in the head and neck for radiotherapy treatment planning based only on CT imaging. Alternative modalities such as MRI have previously been incorporated into the delineation process to provide additional anatomical information. This work aims to improve on previous studies by combining good image quality with precise patient immobilisation in order to maintain patient position between scans. MR images were acquired using quadrature coils placed over the head and neck while the patient was immobilised in the treatment position using a five-point thermoplastic shell. The MR image and CT images were automatically fused in the Pinnacle treatment planning system using Syntegra software. Image quality, distortion and accuracy of the image registration using patient anatomy were evaluated. Image quality was found to be superior to that acquired using the body coil, while distortion was < 1.0 mm to a radius of 8.7 cm from the scan centre. Image registration accuracy was found to be 2.2 mm (+/- 0.9 mm) and < 3.0 degrees (n = 6). A novel MRI technique that combines good image quality with patient immobilization has been developed and is now in clinical use. The scan duration of approximately 15 min has been well tolerated by all patients.
    • Radiotherapy for the treatment of longstanding head and neck hemangioma.

      Douglas, Catriona Mairi; Ho, Kean F; Homer, Jarrod J; Slevin, Nicholas J; Department of Otolaryngology-Head and Neck Surgery, Christie Hospital, Manchester, UK. Catriona.douglas@christie.nhs.uk (2009-08)
    • Rectal motion can reduce CTV coverage and increase rectal dose during prostate radiotherapy: A daily cone-beam CT study.

      Sripadam, Raj; Stratford, Julia; Henry, Ann M; Jackson, Andrew; Moore, Christopher J; Price, Patricia M; Clatterbridge Centre for Oncology, Bebington, Wirral, UK. (2009-03)
      BACKGROUND AND PURPOSE: Daily on-treatment verification cone-beam CT (CBCT) was used to study the effect of rectal motion on clinical target volume (CTV) coverage during prostate radiotherapy. MATERIAL AND METHODS: CBCT scans were acquired from 15 patients immediately after daily treatment. From these images, the rectum was contoured allowing the analysis of rectal volume cross-sectional area (CSA) and the determination of rectal dose. Rectal wall motion was quantified as a surrogate measure of prostate displacement and CTV coverage was subjectively assessed. RESULTS: Rectal volume decreased over the treatment course in 13 patients (P<0.001). Rectal wall regions corresponding to the prostate base displayed the greatest motion; larger displacements were seen in patients with larger rectal planning volumes. CTV coverage was inadequate, at the prostate base only, in 38% of the fractions delivered to 4/7 patients with a large rectum at planning (>100 cm(3)). In patients with small rectum at planning (<50 cm(3)) up to 25% more rectal volume than predicted was included in the high-dose region. CONCLUSIONS: Rectal motion during treatment in prostate cancer patients has implications for CTV coverage and rectal dose. Measures to ensure consistency in daily rectal volume or image-guided strategies should be considered.
    • Suboptimal use of intravenous contrast during radiotherapy planning in the UK.

      Kim, Su Woon; Russell, Wanda; Price, Patricia M; Saleem, Azeem; Department of Clinical Oncology, Christie Hospital, Manchester, UK. (2008-12)
      We aimed to evaluate the use of intravenous (IV) contrast during acquisition of radiotherapy planning (RTP) scans and to compare current usage with the Royal College of Radiologists' (RCR) recommendations. Questionnaires were circulated via the Academic Clinical Oncology and Radiobiology Research Network (ACORRN) website, email and post to 60 UK radiotherapy centre managers. Questions were asked regarding the (i) tumour sites where IV contrast was used, (ii) person administering the contrast, (iii) availability of dynamic pump, (iv) tumour sites that centres wished to use contrast, (v) reasons for not using contrast and (vi) awareness of RCR recommendations. 50 (83%) centres responded to the questionnaire, of which 27 responded via the ACCORN website and 18 by e-mail. Despite 38 out of 50 responding centres using IV contrast, and accessibility to dynamic pumps existing in 39 centres, IV contrast usage was suboptimal, with more than half of the centres (27/50; 54%) wishing to use it at more tumour sites. IV contrast was most often used during RTP of the brain, with suboptimal usage in lung tumours. None of the 50 centres administered IV contrast during RTP scan acquisition in all of the 8 RCR recommended tumour sites. Radiographers were mainly responsible for contrast administration, and a lack of staff was cited as the main reason for suboptimal contrast usage. Disappointingly, only 35 of the 50 radiotherapy managers (70%) were aware of the RCR recommendations. Redress of the underlying reasons for suboptimal IV contrast administration during RTP, including acquisition of the necessary skill mix by staff and implementation of RCR recommendations, would help standardize UK practice.