Bashar Al-Qaisieh1, Josh Mason2, Peter Bownes1, Ann Henry1, Louise Dickinson3, Hashim U Ahmed4, Mark Emberton5, Stephen Langley6. 1. Leeds Cancer Centre, Leeds Teaching Hospitals NHS Trust, Leeds, United Kingdom. 2. Leeds Cancer Centre, Leeds Teaching Hospitals NHS Trust, Leeds, United Kingdom. Electronic address: joshua.mason@nhs.net. 3. Division of Surgery and Interventional Science, University College London, London, United Kingdom; Department of Radiology, Northwick Park Hospital, London North West NHS Trust, London, United Kingdom. 4. Division of Surgery and Interventional Science, University College London, London, United Kingdom; University College London Hospital, London, United Kingdom. 5. University College London Hospital, London, United Kingdom. 6. St Luke's Cancer Centre, Guildford, United Kingdom.
Abstract
PURPOSE: Focal brachytherapy targeted to an individual lesion(s) within the prostate may reduce side effects experienced with whole-gland brachytherapy. The outcomes of a consensus meeting on focal prostate brachytherapy were used to investigate optimal dosimetry of focal low-dose-rate (LDR) prostate brachytherapy targeted using multiparametric magnetic resonance imaging (mp-MRI) and transperineal template prostate mapping (TPM) biopsy, including the effects of random and systematic seed displacements and interseed attenuation (ISA). METHODS AND MATERIALS: Nine patients were selected according to clinical characteristics and concordance of TPM and mp-MRI. Retrospectively, 3 treatment plans were analyzed for each case: whole-gland (WG), hemi-gland (hemi), and ultra-focal (UF) plans, with 145-Gy prescription dose and identical dose constraints for each plan. Plan robustness to seed displacement and ISA were assessed using Monte Carlo simulations. RESULTS: WG plans used a mean 28 needles and 81 seeds, hemi plans used 17 needles and 56 seeds, and UF plans used 12 needles and 25 seeds. Mean D90 (minimum dose received by 90% of the target) and V100 (percentage of the target that receives 100% dose) values were 181.3 Gy and 99.8% for the prostate in WG plans, 195.7 Gy and 97.8% for the hemi-prostate in hemi plans, and 218.3 Gy and 99.8% for the focal target in UF plans. Mean urethra D10 was 205.9 Gy, 191.4 Gy, and 92.4 Gy in WG, hemi, and UF plans, respectively. Mean rectum D2 cm(3) was 107.5 Gy, 77.0 Gy, and 42.7 Gy in WG, hemi, and UF plans, respectively. Focal plans were more sensitive to seed displacement errors: random shifts with a standard deviation of 4 mm reduced mean target D90 by 14.0%, 20.5%, and 32.0% for WG, hemi, and UF plans, respectively. ISA has a similar impact on dose-volume histogram parameters for all plan types. CONCLUSIONS: Treatment planning for focal LDR brachytherapy is feasible. Dose constraints are easily met with a notable reduction to organs at risk. Treating smaller targets makes seed positioning more critical.
PURPOSE: Focal brachytherapy targeted to an individual lesion(s) within the prostate may reduce side effects experienced with whole-gland brachytherapy. The outcomes of a consensus meeting on focal prostate brachytherapy were used to investigate optimal dosimetry of focal low-dose-rate (LDR) prostate brachytherapy targeted using multiparametric magnetic resonance imaging (mp-MRI) and transperineal template prostate mapping (TPM) biopsy, including the effects of random and systematic seed displacements and interseed attenuation (ISA). METHODS AND MATERIALS: Nine patients were selected according to clinical characteristics and concordance of TPM and mp-MRI. Retrospectively, 3 treatment plans were analyzed for each case: whole-gland (WG), hemi-gland (hemi), and ultra-focal (UF) plans, with 145-Gy prescription dose and identical dose constraints for each plan. Plan robustness to seed displacement and ISA were assessed using Monte Carlo simulations. RESULTS: WG plans used a mean 28 needles and 81 seeds, hemi plans used 17 needles and 56 seeds, and UF plans used 12 needles and 25 seeds. Mean D90 (minimum dose received by 90% of the target) and V100 (percentage of the target that receives 100% dose) values were 181.3 Gy and 99.8% for the prostate in WG plans, 195.7 Gy and 97.8% for the hemi-prostate in hemi plans, and 218.3 Gy and 99.8% for the focal target in UF plans. Mean urethra D10 was 205.9 Gy, 191.4 Gy, and 92.4 Gy in WG, hemi, and UF plans, respectively. Mean rectum D2 cm(3) was 107.5 Gy, 77.0 Gy, and 42.7 Gy in WG, hemi, and UF plans, respectively. Focal plans were more sensitive to seed displacement errors: random shifts with a standard deviation of 4 mm reduced mean target D90 by 14.0%, 20.5%, and 32.0% for WG, hemi, and UF plans, respectively. ISA has a similar impact on dose-volume histogram parameters for all plan types. CONCLUSIONS: Treatment planning for focal LDR brachytherapy is feasible. Dose constraints are easily met with a notable reduction to organs at risk. Treating smaller targets makes seed positioning more critical.
Authors: Amar U Kishan; Sang J Park; Christopher R King; Kristofer Roberts; Patrick A Kupelian; Michael L Steinberg; Mitchell Kamrava Journal: Br J Radiol Date: 2015-10-14 Impact factor: 3.039
Authors: Adam Ferro; Hee Joon Bae; Gayane Yenokyan; Yi Le; Todd McNutt; Omar Mian; Carol Gergis; Chloe Haviland; Theodore L DeWeese; Daniel Y Song Journal: Brachytherapy Date: 2017-11-23 Impact factor: 2.362
Authors: Bradley J Stish; Brian J Davis; Lance A Mynderse; Robert H McLaren; Christopher L Deufel; Richard Choo Journal: Transl Androl Urol Date: 2018-06
Authors: S Sara Mahdavi; Ingrid T Spadinger; Septimiu E Salcudean; Piotr Kozlowski; Silvia D Chang; Tony Ng; Julio Lobo; Guy Nir; Hamid Moradi; Michael Peacock; W James Morris Journal: J Contemp Brachytherapy Date: 2017-06-13